Richard holdner......i don't know what I'd do without you.....you make the time I spend in the bathroom on my toilet so much more entertaining and informative. ....
What makes the gt45 so good is the 1.05a/r is not so large as to make smallish displacement v8s(the most common) laggy while still flowing enough to make power at relatively low boost. It hits the sweet spot for the majority of hobbyists.
Based on your testing/data, I grabbed a 5.3 with gen4 rods/lifters, installed a mild stage2 cam and ported 706 heads with a GT45. It's a pretty cheap combination that makes alot of power in a street car.
@@evanwelch3235 yea I've changed a few things but that's a solid setup. The eBay gt45 is hard to beat for the price but the 7875 is a better option for 4.8/5.3. You can safely and reliably run 5-13 psi on either turbo with a good tune. Some guys take engine apart gap the rings and reseal, some just run them. A cammed 4.8/5.3 with either turbo at 5-10psi can make 450-550hp and capable of well over 600 depending on combination.
Thanks for all of your testing. Im building a drag week project with my dad and my sons and your videos have converted my dad from "it needs a big block" to "turbo LS is the way to go"!
Richard you are directly responsible for me taking my just 5 year restored 78 TA, from 180 hp to 800 hp. Started watching in March 2020 and promptly turboed my Pontiac. By May it was done correctly and with plenty of runs on it, pretty solid. Using the factory y pipe and a 78mm turbo. Ring gap and e85 👍 Why dont everyone do this?
@@richardholdener1727 Richard, can you do a video or a short showing us how to route the waste-gate and blow-off vacuum lines on an efi and also a carbureted setup?
A tip is to measure the compressor outlet temp, if you compare them at the same boost you will get a good number on the compressor efficiency differences.
@@richardholdener1727 I do what I can. A like here and there and a watch every chance i get. Thanks for putting up with me on FB messenger! Keep the content coming. I appreciate the data
Richard has always said the gt45 was a decent turbo to 700-800 hp max builds. I believe this test more than confirms this. That VS 7875 seems to be the logical next step up over 800 hp turbo with its low back pressure At 700 ish hp in this test. Great work.
cool test richard, these are the tests that I enjoy the most. I know its hard and doesn't seem to work that great doing a air to air intercooler test on the dyno because of the lack of airflow, but I was wondering if you could do a test sometime of a higher horsepower combo of like 1000 horse and test out different air to air intercoolers if you put a really strong fan infront of them. Like a smaller dimension 3 inch core to a big 4 inch core or even something bigger and test pressure drop and temperature drop across it. thanks for everything you do
On the first run on the gt45 for every 2psi of boost you added you pretty much got 15hp, just thought that was pretty cool how accurate it was for every time you added boost at least for the gt45
Been boosting daily since 1985 (Buick T Type) and owned just about every turbo performance model since. 87 GN, 89 944 Turbo, 91 Syclone, 93 Mitsu GSX, 94 RX7, 97 SupraTT, 04 Evo 8 RS, 05 C6 Vette rear mounted 80mm GTS. and the most important lesson I learned was always use a tighter stall convertor than everyone else and keep tranny temps low, have a small wet single nozzle nitrous setup on a hobbs switch. i usually ran a 50 to 90 hp jet and set the hobbs to cut off nitrous at 5-7 psi. i always kept the system on in case someone wanted to try me i was always a wide open throttle away from full boost. and in case i needed more i also had a scramble button on my shifter that would give me max boost and disengage the hobbs switch for as long as i held that button for. always having the next size up turbo, a tight convertor, and my spool up kit use to smoke everyone and kept repair costs down. those big loose stall convertors tear up transmissions and driveline parts and buildup too much heat., holding the brakes and gas to build boost off the line is suicide.
Compressor efficiency and back pressure made the difference. I guess something could be said for journal bearings and turbine clearances to housings as well
A pair of gt45s on a 6 liter should be fun, that is what we're going to do thank you for the great work. I'm looking for back pressure to boost pressure for a pair on a 6 liter so I can have Ashley cut a cam
This is a GREAT vid for many reasons. It shows a "small" compressor can still be fine for an LS and how a large turbine can massively affect response. I think the best part is running all at 11psi & measuring drive pressure. That effectively shows doubling backpressure on a turbo engine shows a loss of 15%. Knowing there's a fairly linear power increase til the compressor is done, that means the tiny 65mm turbine would make the same HP as the 88mm with an extra 4-6psi of boost. In other words, there's no need for an oversized turbo unless you can't increase boost pressure (tune-OS limit, MAP sensor, etc)...or blow out exhaust gaskets from backpressure. For future reference I'm adding the turbo sizes vs HP at 11psi: 76-65 605 HP 62-69 636 HP 69-77 658 HP 78-75 679 HP 75-82 672 HP 75-88 706 HP
At the higher back pressure, the T76 requires ~35 HP more than the Summit turbo to pump the exhaust gasses. The higher back pressure also reduces scavenging by ~35% reducing mass air flow by ~8%. That's my best guess. I wish we could get mass air flow readings, it would help explain a lot sometimes.
High back pressure is choking the motor. The psi might be the same but the cfm of air flow is different. Boost pressure is a measure of air flow restriction. A turbo is a closed loop system that is controlled by pressure. When back pressure drops there is less restriction on the intake side, without pressure control we would actually see boost pressure drop. With a supercharger you actually see the pressure drop when anything is done to make the engine breath better, because the supercharger has nothing to increase airflow to maintain a pressure setpoint.
This confirms my stance. I always tell people to go bigger on turbo. Smaller turbos make less power and more heat at the same boost levels. So when people say every turbo will make the same power at the same boost given the hp parameters of each turbo is wrong. Always go as big as you can afford in my book. But that’s just me.
The turbo that comes into power sooner will be better on the street. That big turbo is perfect for drag racing where your leaving on a trans-break or 2step and your not worried about spool time.
@@madmod yeah maybe. I’m used to big turbo small displacement stuff. So turbo lag on street I don’t find to be an issue. If I had the luxury of a 4.8 v8 that made 300ftlbs at 3k rpm I’d be going to the big boy. Partial throttle driving who cares about spool time...
@@Turbokrankenwagon i feel you haha. I have a 4.6 2v and its getting a roots blower lol. Turbo is looking to be awfully affordable these days though. I figure id see even less back-pressure than a 4.8/5.3 truck motor so i could probably have better luck with one of the smaller exhaust sides and not compromise in power or boost response on the street.
@@madmod the casual observer doesn't notice that he doesn't start these pulls until 3,000 RPM. For most street motors that's 50% of the RPM range if not more. Smaller really makes a difference from 1500-3000. You get off the line in first gear, shift to second and go WOT. That's the street side of the performance equation he rarely ever looks at because of dyno limitations.
I think it would be interesting to use identical as possible turbine housings as possible. Back pressure is so important. Ive run a little t3/t4 50 trim .63 hot side, compressor flow was about 43 lb/min. Car trapped 122mph. Swapped to a holset pro40 about 71 lb/min with .55 hot side. Car trapped 117ish. Backpressure was 2.5:1 and settled to 2.2:1 at 25psi intake pressure. When you cant get the combustion gasses out, you mix it with incomming air resulting in garbage combustion. There is a lot of power on the hot side.
I’d love to see a test where the same turbos but with different upgraded features are tested. For example, journal vs ball bearing or maybe different compressor wheel designs/upgrades.
Still not bad for the gt45 $140 "or so" 69mm ...really good budget turbo ..wonder how many made there start in the ls world with this turbo...long gone but still a soft spot for it..
The GT45 price point would be interesting to factor in here too; gains per $ of turbocharger I suspect it gains quite a lot of points vs the other units ($160 vs $450-600?), it also appears to have really good power delivery for daily use rather than just for peak performance, a number of the units had stronger curves than the T45, and the T6 would be fine for race/exhibition purposes but annoying every day.
You should purchase one of these and try it out Aftermarket GT42 GTX42 Turbo Charger Billet Wheel T4 Inlet 6 Bolt Outlet it would be awesome to see the dino numbers I run the same turbo on a 2015 custom built Tahoe and it runs awesome I would love to see the numbers versus these other turbos
Another great video Richard thank you, a brilliant head to head comparison. A clarification on sizing when you say 62 mm Comp and 69 mm Turbine, I presume that 62 mm Comp means that the inducer size (inlet dia of the compressor wheel) is 62 mm and 69 mm Turbine means 69 mm dia of the turbine exducer (the smaller dia of the turbine wheel where the exhaust gases leave the wheel). Yes?
I have a set of DNA tubular unequal length headers and they work great. Put some ebay titanium heat wrap on them and an ebay turbo blanket. It drastically cut my spool time and I have had no issues with them.
I don't know why the power being down on the higher back pressure would be surprising to you, Richard. If there is more exhaust back pressure at a given PSI boost, it takes more energy to push the exhaust out of the system, which means you'll have less power output at the crank. Compare headers to a stock exhaust in the same way. We put the headers on an engine to free up back pressure, which allows us to produce more power/torque. This is the same thing. When there's less back pressure, the engine doesn't have to work as hard to push the exhaust out of the system, which means there's more power to do work at the crankshaft. Less exhaust back pressure = more crankshaft power.
@@richardholdener1727 - I wasn't trying to compare the action, but rather the consequence of putting headers on an engine ... although, what is scavenging? It's the process of moving exhaust more efficiently out of the system. This means the engine has less mass to move, which means it frees up power. With a turbo, if the hot side is more efficient and does not create as much of a blockage for the exhaust to get out, the engine doesn't have to work as hard to push against the back pressure. Less back pressure = less work = moar powa.
Paulster2 Richard knows what he's talking about. But scavenging is where enough exhaust gases are able to exit through the exhaust, that a low pressure zone is created (or a vacuum), that vacuum in turn draws more air in through the intake valve as it's opening (more air and fuel = more power). Excessive back pressure will disrupt this effect, therefore not allowing the same amount of AF charge to enter the combustion chamber at 1 given time. Obviously this will have a negative impact on power production, hence why the increase in back pressure hurt power the power output. But that has nothing to do with the engine having to "work harder", or use "more energy", it's just able to breath better with less back pressure. I'm sure Richard already knows this, as he is much more seasoned than I am, I'm just really getting my feet wet with all of this stuff. He's been doing test like this since before I was born I'm sure lol.
Pumping action of the backpressure is not the only consideration. If there's more backpressure than boost, you still have that much extra exhaust gas remaining in the cylinder preventing fresh (burnable) air from getting in. Some of it will actually flow back into the intake manifold during valve overlap.
Hi richard - my experience with china turbos is good but the compressor house is not shim'd is if you tighten the comp house up it will pinch the wheel - you can see it if you start the motor then slowly tighten the wheel it will stop spinning - also the turbos are only supported by one of the bushes this it how they are ment to be allows for the rotating mass to move against gravity the turbo does move around spin a bike wheel between your hands and turn around while holding it
In the future, I'd like to see a non-preheated test for each turbo. That tells us if it's going to be a laggy turd on the street. Just at one common boost level to show the weakness between all of them. It'd also show if the cheap turbos are using heavy or poorly designed wheels or bad bearings that prevent it from spooling. Thanks again for all of your awesome work.
@@richardholdener1727 Ohhh, OK. Thanks Richard. I was under the impression that you'd have to do a brake stand, rev to 4k for 10 seconds to get everything red hot to achieve the same results. So I'm guessing that it's just another side effect of the dyno cell wind tunnel. In a typical engine bay, things would be nice and warm. Thanks again for the replay and for all that you do!
New subscriber here! I run this same exact CX racing turbo at 11psi on an 8.2:1 Pontiac 400 with bowl blended 4X heads. I’ve wondered how effective it would be to do some deeper testing, as I’m sure hot side back pressure is off the charts. Home garage built and tuned, the thing rips for the price!! I do not know how much power it actually makes though.
Need to put up the final bests of each turbo with full curve. I'm not a peek HP guy. I like to know where the power is on a graph. Then based on application I could figure out what is best for that application.
The power difference at the same intake manifold pressure (but higher exhaust manifold pressure) is from the higher in-cylinder PdV pumping work caused by the turbine housing being too small, restricting flow and increasing pressure. If you had a cylinder pressure sensor it would be very clear that the negative PdV work during the EVO period is much bigger when you have higher back pressure. When the exhaust valve is open, the higher back pressure acts against the piston, creating more negative work that is robbed from the crankshaft, producing less shaft horse power. With turbine sizing you need to find the sweet spot between too much lag and too much BP.
Sounds good on paper, but you have completely ignored the inert residual exhaust in the chamber because of backpressure. You have also ignored the heat buildup in the chamber and valves, when the pressure differential does not allow cooling from fresh air and fuel on valve overlap.
Yes, the exh residual does go up slightly with more back pressure, but its on the order of a few %. This will raise the temperature at the start of the cycle,and reduce the VE thereby reducing power slightly. Similarly, the higher engine dP will reduce scavenging, reducing power too. However, I think these losses are small compared to the higher PMEP caused by the high back pressure. With proper instrumentation this can all be measured and proven. If the airflow rate (which it should be if the boost is the same ), spark timing, etc are the same then you should have the same IMEP. If you had a cyl pressure sensor, you could measure the IMEP and PMEP. Assuming the the same IMEP between the different turbos, then the only other loss is the PMEP. Which is caused by the high back pressure. The moral of the story is that cylinder pressure senors tell you everything. I dont really know how these guys do engine testing with out them.
I imagine there's a multitude of reasons for less power at same boost. But it boils down to efficiency whether that's in the turbine design, bearings, general tolerances, etc.
please apologize for my english im a frenchy... bigger the turbo his, bigger the power will be. for sure the exhaust pressure will play alot on that. people think that there is an easy calculation about 1 bar (14.7 psi) and oem hp. add 1 bar to make double hp. Yes it does that most of the time when using middle turbo size. We reach on a honda motor that makes 178 whp fully built motor at 0 psi. (waste gate open). with a 72 mm at 5 pounds we did 374 whp (on race fuel for sure). I done runs a diesel turbo on a street setup, it was a gt3576klvn (variable turbo). The hybdrid thing that you should try its to find a 120mm with a vnt systeme. you would see big hp at low psi and an amazing low back presure because of vnt systeme at any rpm. With that kind of big turbo you ll find out missing fuel fast from small injectors. i loe your video and your tip by the way im not bashing here. just telling if you canget a real big turbo you ll freak out on hp gain on low psi. by the way if you get a vnt and you cant run the electric vnt motor, there is some mechanical actuator that can work or just finding the right spot for spooling and not having too mutch back pressure at full rpm. vnt turbo can be really big and it doesent matter the engine size because of the vnt. Please try that and show to the entire world
so why we reach 374 whp at 5 psi? you said you would like a magic hybrid match between gt45 and another turbo. get an variable real big turbo you ll see my friends (over 120mm). no offense richard
Emusa shows a gt45 with billet wheel and a 1.15ar exhaust. I would love to see that compared. Interesting to see what those small changes actually do in performance. In the diesel world all the "batmo" wheels and the like are sold as world changing, I'm interested to see the difference on the dyno. That newer version of the gt45 might be a better match for 5.3 and 6.0.
Batmowheel is good but they are really heavy for billet wheels and ungodly expensive. There are some Chinese billet wheels that weigh 80% of what a batmo does and will flow 95% or more what they do. They were great when they came out but compared to the gtx Garrett or sxe warner they are kinda meh.
19:13 you're really going to confuse guys with this one. We need to be talking in terms of mass air flow not boost. From an instructional standpoint explaining the A to B airflow difference is substantially more useful than looking at horsepower at a given boost level because there are so many factors going into pumping efficiency.
Do you know what exhaust housing is on your dna gt45? I see several, would a larger housing, like a 105 or 115, that are shown now, drop back pressure if this one is the std 70ish sized ones that have been around for years?
Simple answer, which you already know, Richard! More power on same boost pressure means the turbo is more efficient, producing less backpressure to produce the same boost. I wonder if the exhaust temperatures were higher on turbos with the same boost levels that produced less output power. That is pretty universal, yes?
Its all about the turbine and compressor geometry. The gt45 is outdated tech and likely creates more heat per lb of boost. Also cheaper turbos tend to run more wheel to wall clearance which reduces efficiency.
I've got problems with my 2016 f150 3.5L ecoboost tubors. I see replacement turbos on ebay. Just wondering if there worth getting? I not looking for adding power just to be able to use my truck in normal operations.
I could see wanting a baby turbo w a stock converter. But you'll just blow it up at 600-700hp. The rpm drop on the shift with a stock converter is insane. You really need 3-3500 stall on a turbo LS at these power levels. My 4.8 spools an s480 1.32 t6 just fine. 1.2 0-60... and 8.7 @ 158 1/4. I literally have to pull a ton of power and ramp it back in based on speed to get it to hook on the street. Low end response is the last thing any "street" turbo v8 needs in my opinion.
Remember, less backpressure at peak boost = lower temperatures and the flexibility to advance the ignition timing at peak boost levels at a minimal risk engine damage from fuel air detonation on throttle body and common rail port fuel injected systems, Direct Gasoline or Indirect Gasoline Injected (Diggi's and Iggi's) the dynamics are pre engineered to operate under higher cylinder pressures and engine temperatures without the complications of pre ignition, DIG GDI DGI, which ever order, Indirect injection uses a separate chamber to initiate the ignition, acting like a magnum primer in a large caliber firearm, to optimize the application and transformation of the dynamic properties in the contained explosion into a more efficient, effective, and complete concentration of the released energy into a concentrated point of applied physical force, very high boost can be transformed into higher engine efficiency power and force output.
Richard, do you think that this as a single, the S475 on my 390 at 13 lbs would be between 800-900 and be happy? I have the thick truck block and crossbolt mains on 2 and 4 and I plan on a block fill up to the core plugs. Do you think that would be better for the FE with that boost curve? I am kind of thinking of a T4 hot side at 13. Or would I be better off with a pair of GT45s and 13? NA power will be at 500 hp/ 500 ft lbs with twin45s intercoolers and E85, and a Roller cam from Bullet 245@.050 and.600 lift on a 110. 3800-4000 lb car.
Believe the CX racing 76 is a p-trim 65mm wheel. Which is why it did poorly. The t4 S475 is a 75mm exh wheel (same size as vs 78/75) T6 s475 is an 87mm. You measure the exducer (small side) when sizing exh. wheels on turbos. Borg lists the big side of the wheel. Not accurate to compare major exh. wheel size on some turbos and the minor exh. Wheel size on others. Thanks for the test! My moneys always on the T6!
@@richardholdener1727 the exhaust wheel? Cx doesnt make a 76mm compressor with a 76mm exh wheel im aware of? They have a q or p trim exh. wheel 68mm or 65mm. Unit on the vid didnt look like a q to me and even the bigger .96 t76 cx units we used as twins had a 65mm exh wheel. Even tho it was labeled as a "q-trim"If u have a 76 exh wheel, u have a unicorn. Show me where to buy those! Both listed as .65 wheels. www.cxracing.com/turbocharger/turbocharger-t4-turbo/TRB-T76-Q96-R www.cxracing.com/TRB-T76-P68-N
Awesome, great vid again. I was just about to email you and mention I was thinking about the vs7875, do you think any other inexpensive turbo was better for my 11 to 1 383ci (280/212cfm & 235/242 112lsa) w/ 1000+hp goals. I was hoping Summit would do a s480, but maybe i should look at it too. What are the VS and Summit max hp again? I cant remember where you mentioned that info..
Great test! What I struggle with is a decent waste gate can cost just as much as a turbo. The generic GT45 cost less than a good waste gate. If you can't control the turbo properly what is the point?
Building a 6 liter twin 56mm turbo (Kinugawa TF06-18KX) for drifting I run into this reasoning all the time. I want back pressure (at top, from turbo sizing, signs of high gas velocity). Back pressure (turbo sizing for spool up) is what will help me get my 800 horses instantly when I need them after I had to correct for the driver error of the leading driver. I also want those 800 hp straight away after I have been braking into a corner and need to rip the tire loose again, once loose the power needed will be reduced by 20-30%, so a 1000hp engine with a 500hp building boost up to 1000 is not as fast as a 800hp engine that has 800hp when I throttle on, it will have 500hp when I need 800, and 1000hp when I need 600.
You never want back pressure. You want high exhaust energy, which usually mean high exhaust velocity (since exhaust mass is relatively constant for a given power level/fuel combo). Back pressure hurts boost response, but a smaller housing/wheel will give you better exhaust velocity at lower rpm in exchange for increased back pressure at high rpm. The trick is finding ways to increase exhaust energy before boost onset (as well as reducing turbo rotating mass/friction) without increasing back pressure. That's where all the newer aerodynamic solutions on the latest turbos really help.
@@ChurchAutoTest True, but I think Mr. Olof meant that he is willing to trade ultimate HP for good throttle response for his track car. Entirely reasonable IMO.
@@ChurchAutoTest I have put a couple of brackets in there, you are correct in what you are saying and it is a language barrier. If we were choosing between two turbos of the same tech level (like a g25-660 and a g30-770) the one that shows more back pressure on top will probably be faster in my application if it can make the power I need. Ball bearing also makes a significant difference in mid corner even though they do not show any large gains in a dyno As an example, this year we had one car at the track making 550hp with very little back pressure and one car making 460 with 1:1.05 ratio. The car with 550hp did not have full boost before first corner which was in 3rd gear, the 460hp car had full boost in first gear. The leap was enormous down the starting straight. Note that this is cars not built for dragracing and not having tires that would stick in a drag racing start, the cars dont have sequentials with ignition cut either which would help in this case
I’ve watched the video a dozen times but I can’t find a graph of all of the turbos horsepower and torque compared to each other- am I missing it? Was hoping to see a graph like you showed for backpressure, but for power output. Maybe in a different video? Hard to compare them and make a selection when we can’t see how they all do at 7, 9, 11psi etc overlayed with each other to have a comparative view of spool time and power.
I’m messing with a turbo 500 Cadillac. So what I’ve learned yes Cadillac will need rods, pistons, and probably a girdle. Ls rods gen 4 will just work up to 1000 with gapped rings. I imagine the 500 max limit should be 500 with cast parts on low boost. If you follow you’ll be able to find out as I do…
It would have been a better comparising if you would roll the engine in, now it just looks like larger is better I bet that if you ran all of these on the street in the small gears one of the mid sized turbos would feel (and go) the fastest I have changed to smaller turbines and smaller compressors because of this in my own cars, the large ones werent as fast for my application
You almost can't do that on an engine dyno. It has a brake and can hold the engine at an rpm. If these were done on an inertial chassis dyno it would be easier to duplicate the on road experience. You could put the car in drive (1:1) and start the test at different rpm to see the response. Inertial dynos aren't great at simulating driving because they aren't meant to do that they are to compare measured horsepower. You can get some interesting data though.
@james avery yeah that is what Im saying, just think that most guys that will look at these graphs wont understand what Richard is saying when he says that the smaller turbos have better response (which in the terms Im used to use does not mean the same thing, as a non responsive turbo in my meaning still can spool up at lower rpm but not be as snappy as a modern turbo like a g25). Looking at the graphs, which to me is accurate, a bigger turbo looks like it is allways better cause there are very few people that care about the benefits of a ball bearing (which has better, in the words meaning for me, response). I just get the feel that its so easy to missunderstand this test and whats quick on the street
Richie you need to do a compound triple turbo style test with the GT45 . Have two GT45s feeding into one on a 4.8 . That way you get good response and over 1200 hp capable.
Out of curiosity, how reliable are these cheaper turbos? I mean I always figured they'd make decent power of course but how many pulls are you getting out of these ebay/cx racing etc turbos before they start wiping out bearings? Or are they all using the same internals as the bigger names, just less efficient wheels and housings 🤔.
It's a couple things. There is a change in airflow because the pumping efficiency goes down with higher back pressure and there is power required to pump the exhaust out. If you think about a really bad exhaust that is stock on a truck or sedan, there might be as much as 10psi residual pressure at peak power. You would think that swapping some delta baffle mufflers with cat bypass pipes would increase power and it does. The same thing happens here, when you have the pistons having to pump the exhaust out against pressure it takes power, the lower the back pressure in the exhaust pipe the more power you will make.
@@timothybayliss6680 that's why I said kinda in it's own way lol. Maybe VE isn't the best term. Lol. I've always figured that is more "N/A" terms but thanks for helping me understand.
Ok.. maybe I’ll get lucky and someone can assist a newbie setup - deciding , best fit for purpose .96 or 1.25 A/R 7875 Gen 2.5 7875 … if anyone can provide some real life experience that would be fantastic ! And very much appreciated 1972 gmc 1500 SWB 6.0 LQ9 swap Street Roddin’ use only (no track) Stage 2 turbo pro LS cam , springs , lifters etc… Run pump gas Goal: 600fwhp / Boost pressure : 7-13 psi Key is - never going to hit the track but some dumb street use to be accounted for 😆🤷🏻 Seems like every 7875 testing I come across is with the 1.25 A/R was all Merry Christmas 🎄 to those who celebrate it!
I always wonder how many folks fall for the cheap turbos? I've never seen one last a long time. After using Borg Warner turbos from Jose at Forced Inductions and putting over 300,000 miles on a S475/83 with a LQ4 I try and talk all my buddys out of the cheap turbos. I've seen quite a few have bearing failures and trash a engine.
Isnt most of the cost of these in the bearings? Cheap turbos have a sort of standard set of bearings vs higher dollar use the higher performance bearing material.
whats the best turbo for 5.3? I don't need to make 1000 peak hp at 7500rpm. id like 700+ hp. I have a tbss intake, 90mm throttle body, pro ls stage 4 cam, spring and trunion upgrade, ported 799 heads. I want low rpm power/fast spool. 700+ hp is enough
Probably gt45 there good for about 800hp on a 5.3. I have the same gt45 on my 5.3 i wouldnt waste money on a expensive brand unless your want more then 800hp
Richard holdner......i don't know what I'd do without you.....you make the time I spend in the bathroom on my toilet so much more entertaining and informative. ....
All the best plans were made on the Porcelain Throne
My wife always laugh cuz all she hears is engines roaring lol
What makes the gt45 so good is the 1.05a/r is not so large as to make smallish displacement v8s(the most common) laggy while still flowing enough to make power at relatively low boost. It hits the sweet spot for the majority of hobbyists.
THANKS FOR ALL YOUR TESTING!!!!
Based on your testing/data, I grabbed a 5.3 with gen4 rods/lifters, installed a mild stage2 cam and ported 706 heads with a GT45. It's a pretty cheap combination that makes alot of power in a street car.
hey there i hope you see this. how's that combo working out for you? is it reliable? how much boost are you running? thanks
@@evanwelch3235 yea I've changed a few things but that's a solid setup. The eBay gt45 is hard to beat for the price but the 7875 is a better option for 4.8/5.3.
You can safely and reliably run 5-13 psi on either turbo with a good tune. Some guys take engine apart gap the rings and reseal, some just run them. A cammed 4.8/5.3 with either turbo at 5-10psi can make 450-550hp and capable of well over 600 depending on combination.
This is almost my exact set up, still need to snag the lifters but I can’t wait to see what she can do!
@@tylershimek6167 make sure to get a good set of lifters from BTR, Johnsons, Morels or Summit. Delphi/oem LS7
@@BDauto86 I had to gap my rings since the cylinders had rust in them. New rings with a ss2 and springs. I’m hoping to break 600
Thanks for all of your testing. Im building a drag week project with my dad and my sons and your videos have converted my dad from "it needs a big block" to "turbo LS is the way to go"!
turbo big blocks also work well
@@richardholdener1727I’m working on one of these myself 500 Cadillac 92/103mm turbo
Richard you are directly responsible for me taking my just 5 year restored 78 TA, from 180 hp to 800 hp. Started watching in March 2020 and promptly turboed my Pontiac. By May it was done correctly and with plenty of runs on it, pretty solid. Using the factory y pipe and a 78mm turbo. Ring gap and e85 👍 Why dont everyone do this?
send pics
Pictures or it didn't happen. 😅
@@richardholdener1727 Richard, can you do a video or a short showing us how to route the waste-gate and blow-off vacuum lines on an efi and also a carbureted setup?
A tip is to measure the compressor outlet temp, if you compare them at the same boost you will get a good number on the compressor efficiency differences.
or the turbine inlet temperature.
Richard is a legend, he knows his shit!
is it bad practice to get notified Richard uploaded a new video, and hit like before you hit play? You know it's gonna be good
THAT IS PERFECT
@@richardholdener1727 I do what I can. A like here and there and a watch every chance i get. Thanks for putting up with me on FB messenger! Keep the content coming. I appreciate the data
Lots of people can't be wrong. Well at least two of us 😂
I'm guilty
Richard has always said the gt45 was a decent turbo to 700-800 hp max builds. I believe this test more than confirms this. That VS 7875 seems to be the logical next step up over 800 hp turbo with its low back pressure At 700 ish hp in this test. Great work.
cool test richard, these are the tests that I enjoy the most. I know its hard and doesn't seem to work that great doing a air to air intercooler test on the dyno because of the lack of airflow, but I was wondering if you could do a test sometime of a higher horsepower combo of like 1000 horse and test out different air to air intercoolers if you put a really strong fan infront of them. Like a smaller dimension 3 inch core to a big 4 inch core or even something bigger and test pressure drop and temperature drop across it. thanks for everything you do
I agree, perhaps a eBay core vs Garrett vs Spearco and Griffin etc..
Bar vs Tube and Fin
On the first run on the gt45 for every 2psi of boost you added you pretty much got 15hp, just thought that was pretty cool how accurate it was for every time you added boost at least for the gt45
Been boosting daily since 1985 (Buick T Type) and owned just about every turbo performance model since. 87 GN, 89 944 Turbo, 91 Syclone, 93 Mitsu GSX, 94 RX7, 97 SupraTT, 04 Evo 8 RS, 05 C6 Vette rear mounted 80mm GTS. and the most important lesson I learned was always use a tighter stall convertor than everyone else and keep tranny temps low, have a small wet single nozzle nitrous setup on a hobbs switch. i usually ran a 50 to 90 hp jet and set the hobbs to cut off nitrous at 5-7 psi. i always kept the system on in case someone wanted to try me i was always a wide open throttle away from full boost. and in case i needed more i also had a scramble button on my shifter that would give me max boost and disengage the hobbs switch for as long as i held that button for.
always having the next size up turbo, a tight convertor, and my spool up kit use to smoke everyone and kept repair costs down. those big loose stall convertors tear up transmissions and driveline parts and buildup too much heat., holding the brakes and gas to build boost off the line is suicide.
Got dang Rich, you've owned some "bucket list" cars.
None of those vehicles came with everyone's best indestructible friend the 4l80E
Careful exhaust system design will be needed to keep back pressure to a minimum. So often overlooked.
I was just thinking this .
Love the low buck videos.
Compressor efficiency and back pressure made the difference. I guess something could be said for journal bearings and turbine clearances to housings as well
A pair of gt45s on a 6 liter should be fun, that is what we're going to do thank you for the great work. I'm looking for back pressure to boost pressure for a pair on a 6 liter so I can have Ashley cut a cam
I feel pretty good about getting a Gt45 now, lol and I needed this motivation to get to work finishing it....
I just love the value for the money that these cxracing turbos offer.
@@madmod yea so much better than the eBay GT45 lol
@@JohnnyAnderson1 they have a good quality gt45 that is probably comparable to the dna turbo.
This is a GREAT vid for many reasons. It shows a "small" compressor can still be fine for an LS and how a large turbine can massively affect response.
I think the best part is running all at 11psi & measuring drive pressure. That effectively shows doubling backpressure on a turbo engine shows a loss of 15%. Knowing there's a fairly linear power increase til the compressor is done, that means the tiny 65mm turbine would make the same HP as the 88mm with an extra 4-6psi of boost.
In other words, there's no need for an oversized turbo unless you can't increase boost pressure (tune-OS limit, MAP sensor, etc)...or blow out exhaust gaskets from backpressure. For future reference I'm adding the turbo sizes vs HP at 11psi:
76-65 605 HP
62-69 636 HP
69-77 658 HP
78-75 679 HP
75-82 672 HP
75-88 706 HP
I doubt you see 100 hp at the same boost level if the turbo will support that power level to begin with
At the higher back pressure, the T76 requires ~35 HP more than the Summit turbo to pump the exhaust gasses. The higher back pressure also reduces scavenging by ~35% reducing mass air flow by ~8%. That's my best guess. I wish we could get mass air flow readings, it would help explain a lot sometimes.
You can probably roughly gauge MAF based on power output.
He isn't using a MAF
In the next video would You please overlay just the top power runs from each turbo? Thank You for all of the testing and great info!
Great video. I'm learning more every video I watch!
This man doing the most for us. Cheers!
That 75/82 on a 6.0 is a ton of fun on the street.
Turbine A/R housing size is a big part of back psi. Efficiency of compressor wheel is a big part of boost power
High back pressure is choking the motor. The psi might be the same but the cfm of air flow is different. Boost pressure is a measure of air flow restriction. A turbo is a closed loop system that is controlled by pressure. When back pressure drops there is less restriction on the intake side, without pressure control we would actually see boost pressure drop. With a supercharger you actually see the pressure drop when anything is done to make the engine breath better, because the supercharger has nothing to increase airflow to maintain a pressure setpoint.
Thank you. It looks to be the gt45 and T76 would be idea for street. The other "bigger" turbos more for race.
This confirms my stance. I always tell people to go bigger on turbo. Smaller turbos make less power and more heat at the same boost levels. So when people say every turbo will make the same power at the same boost given the hp parameters of each turbo is wrong. Always go as big as you can afford in my book. But that’s just me.
The turbo that comes into power sooner will be better on the street. That big turbo is perfect for drag racing where your leaving on a trans-break or 2step and your not worried about spool time.
@@madmod yeah maybe. I’m used to big turbo small displacement stuff. So turbo lag on street I don’t find to be an issue. If I had the luxury of a 4.8 v8 that made 300ftlbs at 3k rpm I’d be going to the big boy. Partial throttle driving who cares about spool time...
@@Turbokrankenwagon i feel you haha. I have a 4.6 2v and its getting a roots blower lol. Turbo is looking to be awfully affordable these days though. I figure id see even less back-pressure than a 4.8/5.3 truck motor so i could probably have better luck with one of the smaller exhaust sides and not compromise in power or boost response on the street.
@@madmod cool man, let’er eat!
@@madmod the casual observer doesn't notice that he doesn't start these pulls until 3,000 RPM. For most street motors that's 50% of the RPM range if not more. Smaller really makes a difference from 1500-3000. You get off the line in first gear, shift to second and go WOT. That's the street side of the performance equation he rarely ever looks at because of dyno limitations.
I think it would be interesting to use identical as possible turbine housings as possible. Back pressure is so important. Ive run a little t3/t4 50 trim .63 hot side, compressor flow was about 43 lb/min. Car trapped 122mph. Swapped to a holset pro40 about 71 lb/min with .55 hot side. Car trapped 117ish. Backpressure was 2.5:1 and settled to 2.2:1 at 25psi intake pressure.
When you cant get the combustion gasses out, you mix it with incomming air resulting in garbage combustion. There is a lot of power on the hot side.
I’d love to see a test where the same turbos but with different upgraded features are tested. For example, journal vs ball bearing or maybe different compressor wheel designs/upgrades.
Still not bad for the gt45 $140 "or so" 69mm ...really good budget turbo ..wonder how many made there start in the ls world with this turbo...long gone but still a soft spot for it..
I would like to see this same/similar tests on 5.3 and 6.0
The fast 5! ROFL! Classic! ❤️
The GT45 price point would be interesting to factor in here too; gains per $ of turbocharger I suspect it gains quite a lot of points vs the other units ($160 vs $450-600?), it also appears to have really good power delivery for daily use rather than just for peak performance, a number of the units had stronger curves than the T45, and the T6 would be fine for race/exhibition purposes but annoying every day.
Do you have a link to THIS specific GT45 Turbo? there are like 10k different versions on Ebay
get wither dna or maxpeedingrodsp
You should purchase one of these and try it out Aftermarket GT42 GTX42 Turbo Charger Billet Wheel T4 Inlet 6 Bolt Outlet it would be awesome to see the dino numbers I run the same turbo on a 2015 custom built Tahoe and it runs awesome I would love to see the numbers versus these other turbos
Another great video Richard thank you, a brilliant head to head comparison.
A clarification on sizing when you say 62 mm Comp and 69 mm Turbine, I presume that 62 mm Comp means that the inducer size (inlet dia of the compressor wheel) is 62 mm and 69 mm Turbine means 69 mm dia of the turbine exducer (the smaller dia of the turbine wheel where the exhaust gases leave the wheel). Yes?
I have a set of DNA tubular unequal length headers and they work great. Put some ebay titanium heat wrap on them and an ebay turbo blanket. It drastically cut my spool time and I have had no issues with them.
I don't know why the power being down on the higher back pressure would be surprising to you, Richard. If there is more exhaust back pressure at a given PSI boost, it takes more energy to push the exhaust out of the system, which means you'll have less power output at the crank. Compare headers to a stock exhaust in the same way. We put the headers on an engine to free up back pressure, which allows us to produce more power/torque. This is the same thing. When there's less back pressure, the engine doesn't have to work as hard to push the exhaust out of the system, which means there's more power to do work at the crankshaft. Less exhaust back pressure = more crankshaft power.
HEADERS DO NOT MAKE POWER BY FREEING UP BACK PRESSURE-SCAVENGING IS VERY DIFFERENT
@@richardholdener1727 - I wasn't trying to compare the action, but rather the consequence of putting headers on an engine ... although, what is scavenging? It's the process of moving exhaust more efficiently out of the system. This means the engine has less mass to move, which means it frees up power. With a turbo, if the hot side is more efficient and does not create as much of a blockage for the exhaust to get out, the engine doesn't have to work as hard to push against the back pressure. Less back pressure = less work = moar powa.
Paulster2 Richard knows what he's talking about. But scavenging is where enough exhaust gases are able to exit through the exhaust, that a low pressure zone is created (or a vacuum), that vacuum in turn draws more air in through the intake valve as it's opening (more air and fuel = more power). Excessive back pressure will disrupt this effect, therefore not allowing the same amount of AF charge to enter the combustion chamber at 1 given time. Obviously this will have a negative impact on power production, hence why the increase in back pressure hurt power the power output. But that has nothing to do with the engine having to "work harder", or use "more energy", it's just able to breath better with less back pressure. I'm sure Richard already knows this, as he is much more seasoned than I am, I'm just really getting my feet wet with all of this stuff. He's been doing test like this since before I was born I'm sure lol.
Pumping action of the backpressure is not the only consideration. If there's more backpressure than boost, you still have that much extra exhaust gas remaining in the cylinder preventing fresh (burnable) air from getting in. Some of it will actually flow back into the intake manifold during valve overlap.
@@kerryb2689 thank you for reiterating what I just said. Nothing wrong with redundancy!
Bro your the best no competition seriously!
Appreciate that
Rich thanks for the videos!
Hi richard - my experience with china turbos is good but the compressor house is not shim'd is if you tighten the comp house up it will pinch the wheel - you can see it if you start the motor then slowly tighten the wheel it will stop spinning - also the turbos are only supported by one of the bushes this it how they are ment to be allows for the rotating mass to move against gravity the turbo does move around spin a bike wheel between your hands and turn around while holding it
I don't have that problem with any of the turbos-the wheels all spin
Nice video! Thanks Richard.
In the future, I'd like to see a non-preheated test for each turbo. That tells us if it's going to be a laggy turd on the street. Just at one common boost level to show the weakness between all of them. It'd also show if the cheap turbos are using heavy or poorly designed wheels or bad bearings that prevent it from spooling. Thanks again for all of your awesome work.
your turbo is pre heated when you drive
@@richardholdener1727 Ohhh, OK. Thanks Richard. I was under the impression that you'd have to do a brake stand, rev to 4k for 10 seconds to get everything red hot to achieve the same results. So I'm guessing that it's just another side effect of the dyno cell wind tunnel. In a typical engine bay, things would be nice and warm. Thanks again for the replay and for all that you do!
Awesome video man very informative keep it up
Great video on on differences between all outputs from each turbo. I'm going try one of gt-45 on 350 chevy vortec.
Well you talked me into getting the gt45 I'll be buying them tonight!!!!
Nice work Richard!!
Great video Richard, keep em coming!
Boost pressure is one thing, volume/air density is the determining factor.
What are the measurements of a GT45 inlet and outlet in mm?
New subscriber here! I run this same exact CX racing turbo at 11psi on an 8.2:1 Pontiac 400 with bowl blended 4X heads. I’ve wondered how effective it would be to do some deeper testing, as I’m sure hot side back pressure is off the charts. Home garage built and tuned, the thing rips for the price!! I do not know how much power it actually makes though.
Maybe you could do tests on waste gates. I'm new to your show so mabe you have.
I’m actually on the market for a turbo. Good to know these results
Need to put up the final bests of each turbo with full curve. I'm not a peek HP guy. I like to know where the power is on a graph. Then based on application I could figure out what is best for that application.
The power difference at the same intake manifold pressure (but higher exhaust manifold pressure) is from the higher in-cylinder PdV pumping work caused by the turbine housing being too small, restricting flow and increasing pressure. If you had a cylinder pressure sensor it would be very clear that the negative PdV work during the EVO period is much bigger when you have higher back pressure. When the exhaust valve is open, the higher back pressure acts against the piston, creating more negative work that is robbed from the crankshaft, producing less shaft horse power. With turbine sizing you need to find the sweet spot between too much lag and too much BP.
Sounds good on paper, but you have completely ignored the inert residual exhaust in the chamber because of backpressure. You have also ignored the heat buildup in the chamber and valves, when the pressure differential does not allow cooling from fresh air and fuel on valve overlap.
Yes, the exh residual does go up slightly with more back pressure, but its on the order of a few %. This will raise the temperature at the start of the cycle,and reduce the VE thereby reducing power slightly. Similarly, the higher engine dP will reduce scavenging, reducing power too. However, I think these losses are small compared to the higher PMEP caused by the high back pressure.
With proper instrumentation this can all be measured and proven. If the airflow rate (which it should be if the boost is the same ), spark timing, etc are the same then you should have the same IMEP. If you had a cyl pressure sensor, you could measure the IMEP and PMEP. Assuming the the same IMEP between the different turbos, then the only other loss is the PMEP. Which is caused by the high back pressure.
The moral of the story is that cylinder pressure senors tell you everything. I dont really know how these guys do engine testing with out them.
I imagine there's a multitude of reasons for less power at same boost. But it boils down to efficiency whether that's in the turbine design, bearings, general tolerances, etc.
Personally I blame squirrels
I told you this Richard last year , that different turbos made different powers at the same psi . You argued with me how I was wrong.
If both turbos can support the same power level at the same boost with the same back pressure-same power
What we need guy's is a electronic back flow regulator valve, once the turbo is spun up why need more pressure
Can we get a similar test on a 6.0L?
please apologize for my english im a frenchy... bigger the turbo his, bigger the power will be. for sure the exhaust pressure will play alot on that. people think that there is an easy calculation about 1 bar (14.7 psi) and oem hp. add 1 bar to make double hp. Yes it does that most of the time when using middle turbo size. We reach on a honda motor that makes 178 whp fully built motor at 0 psi. (waste gate open). with a 72 mm at 5 pounds we did 374 whp (on race fuel for sure). I done runs a diesel turbo on a street setup, it was a gt3576klvn (variable turbo). The hybdrid thing that you should try its to find a 120mm with a vnt systeme. you would see big hp at low psi and an amazing low back presure because of vnt systeme at any rpm. With that kind of big turbo you ll find out missing fuel fast from small injectors. i loe your video and your tip by the way im not bashing here. just telling if you canget a real big turbo you ll freak out on hp gain on low psi. by the way if you get a vnt and you cant run the electric vnt motor, there is some mechanical actuator that can work or just finding the right spot for spooling and not having too mutch back pressure at full rpm. vnt turbo can be really big and it doesent matter the engine size because of the vnt. Please try that and show to the entire world
the size of the turbo does not change the calculation unless it is too small
so why we reach 374 whp at 5 psi? you said you would like a magic hybrid match between gt45 and another turbo. get an variable real big turbo you ll see my friends (over 120mm). no offense richard
Emusa shows a gt45 with billet wheel and a 1.15ar exhaust. I would love to see that compared. Interesting to see what those small changes actually do in performance. In the diesel world all the "batmo" wheels and the like are sold as world changing, I'm interested to see the difference on the dyno. That newer version of the gt45 might be a better match for 5.3 and 6.0.
Batmowheel is good but they are really heavy for billet wheels and ungodly expensive. There are some Chinese billet wheels that weigh 80% of what a batmo does and will flow 95% or more what they do. They were great when they came out but compared to the gtx Garrett or sxe warner they are kinda meh.
19:13 you're really going to confuse guys with this one. We need to be talking in terms of mass air flow not boost. From an instructional standpoint explaining the A to B airflow difference is substantially more useful than looking at horsepower at a given boost level because there are so many factors going into pumping efficiency.
99% of people talk boost-not mass flow
Right on
Do you know what exhaust housing is on your dna gt45? I see several, would a larger housing, like a 105 or 115, that are shown now, drop back pressure if this one is the std 70ish sized ones that have been around for years?
Simple answer, which you already know, Richard!
More power on same boost pressure means the turbo is more efficient, producing less backpressure to produce the same boost.
I wonder if the exhaust temperatures were higher on turbos with the same boost levels that produced less output power.
That is pretty universal, yes?
Its all about the turbine and compressor geometry. The gt45 is outdated tech and likely creates more heat per lb of boost. Also cheaper turbos tend to run more wheel to wall clearance which reduces efficiency.
Would it be possible for you to start adding in average hp/tq.
So the ebay turbo is the one that has no name brand on it ?
I've got problems with my 2016 f150 3.5L ecoboost tubors. I see replacement turbos on ebay. Just wondering if there worth getting? I not looking for adding power just to be able to use my truck in normal operations.
This is gold.
This was an awesome comparison
Clearly there is no free lunch. You sacrifice responce for power however good response makes a car great. Turbo lag is just sad for daily drivers.
Is lag sad for a dd though? I just considered it foreplay. 🤷
@@tomcelica I prefer to be at the party rather than waiting in line to get in.
@dazaspc hahaha good point!
I could see wanting a baby turbo w a stock converter. But you'll just blow it up at 600-700hp. The rpm drop on the shift with a stock converter is insane. You really need 3-3500 stall on a turbo LS at these power levels. My 4.8 spools an s480 1.32 t6 just fine. 1.2 0-60... and 8.7 @ 158 1/4. I literally have to pull a ton of power and ramp it back in based on speed to get it to hook on the street. Low end response is the last thing any "street" turbo v8 needs in my opinion.
Remember, less backpressure at peak boost = lower temperatures and the flexibility to advance the ignition timing at peak boost levels at a minimal risk engine damage from fuel air detonation on throttle body and common rail port fuel injected systems, Direct Gasoline or Indirect Gasoline Injected (Diggi's and Iggi's) the dynamics are pre engineered to operate under higher cylinder pressures and engine temperatures without the complications of pre ignition, DIG GDI DGI, which ever order, Indirect injection uses a separate chamber to initiate the ignition, acting like a magnum primer in a large caliber firearm, to optimize the application and transformation of the dynamic properties in the contained explosion into a more efficient, effective, and complete concentration of the released energy into a concentrated point of applied physical force, very high boost can be transformed into higher engine efficiency power and force output.
Richard, do you think that this as a single, the S475 on my 390 at 13 lbs would be between 800-900 and be happy? I have the thick truck block and crossbolt mains on 2 and 4 and I plan on a block fill up to the core plugs. Do you think that would be better for the FE with that boost curve? I am kind of thinking of a T4 hot side at 13. Or would I be better off with a pair of GT45s and 13? NA power will be at 500 hp/ 500 ft lbs with twin45s intercoolers and E85, and a Roller cam from Bullet 245@.050 and.600 lift on a 110. 3800-4000 lb car.
I think I would get the inexpensive s475 T6 from Summit on a 390 at 900 hp
Believe the CX racing 76 is a p-trim 65mm wheel. Which is why it did poorly. The t4 S475 is a 75mm exh wheel (same size as vs 78/75) T6 s475 is an 87mm. You measure the exducer (small side) when sizing exh. wheels on turbos. Borg lists the big side of the wheel. Not accurate to compare major exh. wheel size on some turbos and the minor exh. Wheel size on others. Thanks for the test! My moneys always on the T6!
T76 MEASURED 3 INCHES
@@richardholdener1727 the exhaust wheel? Cx doesnt make a 76mm compressor with a 76mm exh wheel im aware of? They have a q or p trim exh. wheel 68mm or 65mm. Unit on the vid didnt look like a q to me and even the bigger .96 t76 cx units we used as twins had a 65mm exh wheel. Even tho it was labeled as a "q-trim"If u have a 76 exh wheel, u have a unicorn. Show me where to buy those! Both listed as .65 wheels.
www.cxracing.com/turbocharger/turbocharger-t4-turbo/TRB-T76-Q96-R
www.cxracing.com/TRB-T76-P68-N
Awesome, great vid again. I was just about to email you and mention I was thinking about the vs7875, do you think any other inexpensive turbo was better for my 11 to 1 383ci (280/212cfm & 235/242 112lsa) w/ 1000+hp goals. I was hoping Summit would do a s480, but maybe i should look at it too. What are the VS and Summit max hp again? I cant remember where you mentioned that info..
Ur the goat
Great test! What I struggle with is a decent waste gate can cost just as much as a turbo. The generic GT45 cost less than a good waste gate. If you can't control the turbo properly what is the point?
Vsracing 44mm v2 is what i used with my gt45 no issues here. Got it for around $99 on summit.
I want to see what you can do with a Ford 3.7 cyclone v6 with a turbo.
Building a 6 liter twin 56mm turbo (Kinugawa TF06-18KX) for drifting I run into this reasoning all the time. I want back pressure (at top, from turbo sizing, signs of high gas velocity). Back pressure (turbo sizing for spool up) is what will help me get my 800 horses instantly when I need them after I had to correct for the driver error of the leading driver. I also want those 800 hp straight away after I have been braking into a corner and need to rip the tire loose again, once loose the power needed will be reduced by 20-30%, so a 1000hp engine with a 500hp building boost up to 1000 is not as fast as a 800hp engine that has 800hp when I throttle on, it will have 500hp when I need 800, and 1000hp when I need 600.
You never want back pressure. You want high exhaust energy, which usually mean high exhaust velocity (since exhaust mass is relatively constant for a given power level/fuel combo). Back pressure hurts boost response, but a smaller housing/wheel will give you better exhaust velocity at lower rpm in exchange for increased back pressure at high rpm. The trick is finding ways to increase exhaust energy before boost onset (as well as reducing turbo rotating mass/friction) without increasing back pressure. That's where all the newer aerodynamic solutions on the latest turbos really help.
@@ChurchAutoTest True, but I think Mr. Olof meant that he is willing to trade ultimate HP for good throttle response for his track car. Entirely reasonable IMO.
@@TwoLotus2 yes could be a language issue
@@ChurchAutoTest I have put a couple of brackets in there, you are correct in what you are saying and it is a language barrier. If we were choosing between two turbos of the same tech level (like a g25-660 and a g30-770) the one that shows more back pressure on top will probably be faster in my application if it can make the power I need. Ball bearing also makes a significant difference in mid corner even though they do not show any large gains in a dyno
As an example, this year we had one car at the track making 550hp with very little back pressure and one car making 460 with 1:1.05 ratio. The car with 550hp did not have full boost before first corner which was in 3rd gear, the 460hp car had full boost in first gear. The leap was enormous down the starting straight. Note that this is cars not built for dragracing and not having tires that would stick in a drag racing start, the cars dont have sequentials with ignition cut either which would help in this case
I’ve watched the video a dozen times but I can’t find a graph of all of the turbos horsepower and torque compared to each other- am I missing it? Was hoping to see a graph like you showed for backpressure, but for power output. Maybe in a different video? Hard to compare them and make a selection when we can’t see how they all do at 7, 9, 11psi etc overlayed with each other to have a comparative view of spool time and power.
😕
Awesome as usual, but can you please also test a Holset HX 55 turbo. Nobody ever do an comperison with a Holset turbo. Thanks again for a great video.
Also a pair of holset hy35w using the internal wastegates 👍👍👍
On a cadillac 472,500 and or an l s engine. You need to replace most of the junk internal parts to make a badass very high hp engine.
I’m messing with a turbo 500 Cadillac. So what I’ve learned yes Cadillac will need rods, pistons, and probably a girdle. Ls rods gen 4 will just work up to 1000 with gapped rings. I imagine the 500 max limit should be 500 with cast parts on low boost. If you follow you’ll be able to find out as I do…
It would have been a better comparising if you would roll the engine in, now it just looks like larger is better
I bet that if you ran all of these on the street in the small gears one of the mid sized turbos would feel (and go) the fastest
I have changed to smaller turbines and smaller compressors because of this in my own cars, the large ones werent as fast for my application
ROLL THE ENGINE IN?
You almost can't do that on an engine dyno. It has a brake and can hold the engine at an rpm. If these were done on an inertial chassis dyno it would be easier to duplicate the on road experience.
You could put the car in drive (1:1) and start the test at different rpm to see the response. Inertial dynos aren't great at simulating driving because they aren't meant to do that they are to compare measured horsepower. You can get some interesting data though.
@james avery Yes, but what he means by that is not very obvious. Now most of you guys run automatics where this might be less of an issue but still
@@richardholdener1727 You said that you "rolled it in" when you got that power loss due to the large size on the T6, thats what I ment
@james avery yeah that is what Im saying, just think that most guys that will look at these graphs wont understand what Richard is saying when he says that the smaller turbos have better response (which in the terms Im used to use does not mean the same thing, as a non responsive turbo in my meaning still can spool up at lower rpm but not be as snappy as a modern turbo like a g25). Looking at the graphs, which to me is accurate, a bigger turbo looks like it is allways better cause there are very few people that care about the benefits of a ball bearing (which has better, in the words meaning for me, response).
I just get the feel that its so easy to missunderstand this test and whats quick on the street
Richie you need to do a compound triple turbo style test with the GT45 . Have two GT45s feeding into one on a 4.8 . That way you get good response and over 1200 hp capable.
Two gt45s will do 1200. No need to complicate things! ❤️
@@tomcelica Yes of course they will , are you also aware that they'll make full boost around 5500-6000rpm on a 4.8 ?
And yes there are better ways to make 1200hp on a 4.8 , a single S476r will make that power and spool up nicely , but where's the fun in that .
@@dilsher12 No I wasn’t. I do not own a 4.8, only a gt45.
@@dilsher12 1200 Hp on a 4.8 sounds fun to me.
Out of curiosity, how reliable are these cheaper turbos? I mean I always figured they'd make decent power of course but how many pulls are you getting out of these ebay/cx racing etc turbos before they start wiping out bearings? Or are they all using the same internals as the bigger names, just less efficient wheels and housings 🤔.
I have run these for 10 years
Wouldn't the reason for the different outputs be the volume of airflow they produce? Or with more back pressure change volumetric efficiency
It's a couple things. There is a change in airflow because the pumping efficiency goes down with higher back pressure and there is power required to pump the exhaust out. If you think about a really bad exhaust that is stock on a truck or sedan, there might be as much as 10psi residual pressure at peak power. You would think that swapping some delta baffle mufflers with cat bypass pipes would increase power and it does. The same thing happens here, when you have the pistons having to pump the exhaust out against pressure it takes power, the lower the back pressure in the exhaust pipe the more power you will make.
@@timothybayliss6680 wouldn't that kinda (in it's own way) be volumetric efficiency
@@joshmajors5963 the term is cylinder fill percentage. Volumetric efficiency is hard to do because you get numbers close to 200% even at 13psi boost.
@@timothybayliss6680 that's why I said kinda in it's own way lol. Maybe VE isn't the best term. Lol. I've always figured that is more "N/A" terms but thanks for helping me understand.
Does anyone know the specs on the 62mm? Is it a T3? 6266? I have one with a t4 housing in thinking about running on a 5.3 for autocross. Thanks
Ok.. maybe I’ll get lucky and someone can assist a newbie setup - deciding , best fit for purpose .96 or 1.25 A/R 7875 Gen 2.5 7875 … if anyone can provide some real life experience that would be fantastic ! And very much appreciated
1972 gmc 1500 SWB
6.0 LQ9 swap
Street Roddin’ use only (no track)
Stage 2 turbo pro LS cam , springs , lifters etc…
Run pump gas
Goal: 600fwhp /
Boost pressure : 7-13 psi
Key is - never going to hit the track but some dumb street use to be accounted for 😆🤷🏻
Seems like every 7875 testing I come across is with the 1.25 A/R was all
Merry Christmas 🎄 to those who celebrate it!
use the 1.25
@@richardholdener1727 Thank you!
For the $$, give me twin GT45's and be done with it, IMHO.
I always wonder how many folks fall for the cheap turbos? I've never seen one last a long time.
After using Borg Warner turbos from Jose at Forced Inductions and putting over 300,000 miles on a S475/83 with a LQ4 I try and talk all my buddys out of the cheap turbos. I've seen quite a few have bearing failures and trash a engine.
Ran a GT45 E Bay turbo over 77,000 miles on a 302 in a Fox Mustang with no issues. Made 540 whp at 12psi. & it was beat on religiously
@@jedwards100able you sir, I would consider lucky haha. All of the ones I've seen failed with less than a few thousand miles.
I would love to see what my turbo would do on a ls, it's a bw S500 94/110 and it likes to move some air lol
Isnt most of the cost of these in the bearings? Cheap turbos have a sort of standard set of bearings vs higher dollar use the higher performance bearing material.
over simplification
Do a big bang test on a built 4.8,5.3,6.0,and 6.2.😁 Stock block limit.
thank you for the prompt reply what size injector for about 700 hp ? this is going in a 2007 Solstice Gxp with 6L80 trans.
80 POUNDS
Everybody needs a bosom for a pillow
Everybody needs a bosom
Mine's on the 45
whats the best turbo for 5.3? I don't need to make 1000 peak hp at 7500rpm. id like 700+ hp. I have a tbss intake, 90mm throttle body, pro ls stage 4 cam, spring and trunion upgrade, ported 799 heads. I want low rpm power/fast spool. 700+ hp is enough
Probably gt45 there good for about 800hp on a 5.3. I have the same gt45 on my 5.3 i wouldnt waste money on a expensive brand unless your want more then 800hp
do you gap the rings on all these stock bottom end test motors?