HOW TO IMPROVE 8.1L POWER. STOCK MANIFOLDS VS HEADERS. ARE SMALLER HEADERS BETTER? THE OTHER GUYS
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- เผยแพร่เมื่อ 24 ก.ค. 2024
- 8.1L PERFORMANCE-THE OTHER GUYS BIG BLOCK CHEVY! HOW DO I MAKE MORE TORQUE? HOW TO IMPROVE 8.1L PERFORMANCE! HOW MUCH POWER DOES THE 8.1L GEN 7 BIG BLOCK REALLY MAKE? DO HEADERS ADD POWER OR TORQUE? CHECK OUT PART 1 OF THE SERIES ON THE OTHER GUYS 8.1L, GEN-7 BIG BLOCK CHEVY. IN PART 1, I COMPARED THE STOCK, CAST-IRON EXHAUST MANIFOLDS TO LONG TUEB HEADERS (TWO DIFFERENT SIZES). I ALSO TESTED COLLECTOR EXTNSIONS AND A CUSTOM, ALUMINUM AIR INTAKE! THESE 8.1L MOTORS MAKE IMPRESSIVE TORQUE!
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Damn! That big block would give a 5.9 diesel Cummins a run for its money 💪
Tip o' the hat to Amos Garcia and Darren Goodman for supporting my habit! So cool to see viewers step up to support the channel. We have 17 different kinds of 8.1 awesomeness!
It was so exciting when all this came together, racing home to catch the live streams, and now sitting here watching the polished vid just like all the other motors.. makes me feel happy for the Gen7 finally getting some shine. Shouts out to Richard, Amos & Darren… long time in the making. Hopefully the tinkerers come at this motor and unlock unseen potential 🙏🏾
Super excited to see a series on the 8.1! Looking to do gradual upgrades on my truck and really looking for good information to help with that
CAN'T GET ENOUGH of the weird oddball engines ! Thanks, Richard ! 😃👍
Love this video! Got an 8.1 silverado and I'm super excited to see some cam testing!
Confirms what I felt when we did headders, intake and tune to a buddies 8.1 that was the most a tune ever picked up a vehicle, but I think that was just hacking the torque management off it.
Did you completely disable it or just lessen it?
No idea, it was a programer through Diablo sport.. we just told them about the K&N intake, headders and exaust. Told them we want as much as you can give us and they sent it. Compared to other tunes on factory stuff I've done that might pick up 10hp. This thing was like awakening an animal. Id say they probably shut it off, but I have no way of knowing.
Same with mine I removed 75 percent of the torque management. Gapped plugged to .045 tried a throttle body spacer because it was on it when I got it…. 180 tstat…. I never added headers since mine was a plow/tow truck and headers don’t last long without leaks and add a lot of heat underhood .
8.1's are massively over-engineered for what the factory rates them.
Good timing, I just got a 2004 8.1L and Allison trans from a top kick medium duty truck, I’m running Tri y headers into an x pipe and straight through mufflers, trying for as much torque as possible for towing in my Motorhome
Love this! I have a 8.1 in a rcsb 2wd 1/2 ton. Absolutely love it
Thank you for doing this Testing very informative for us 8.1 truck guy and again thank you.
Can't wait to see dyno results before and after the intake and tb mods!
As always Rich love the stuff you do.
would like to see the marine 496 HO cam dyno. GM 12683320 or Volvo part number 3861266.. Its a much larger cam but designed to use the stock valvetrain...
Can’t wait to see some cam in this thing! What a torque monster
200k soon you deserve it with the great consistent content
Richard your a beast do you ever sleep? Love your enthusiasm.....
Really need to cut open the intake and get rid of the baffle inside, it’s a huge restriction. I bet you’ll see more response to your other mods after that. Awesome video!
That is so cool! I really wish that the LS and 351W firing order was available for everything. The FE is a great candidate it has a center thrust main. So smooth and easy on parts!
You can get custom ground cams made with those firing orders. The LS is a 4/7, 2/3 swap.....and that firing order is the same as a Flathead Ford.
Hi Richard. Watching you go through the collector extensions thing I remembered how the street racers did it when I was a kid and wondered if you had ever heard of it before. These guys would spend every penny they could beg borrow or steal into their engines making sure they were blueprinted and balanced, ported heads, indexed spark plugs, you name it, if they could think of it, their engines got it. Dual point distributors set up on a distributor machine. Those were the days. My best friend had an FE and he could pull the distributor out, put it on the machine, set the dwell on the points and have it back in the engine and it running in 15 minutes. Back then no one in my area ran more than 430 gears because they had no way to get it to hook up anyway on biased ply tires unless they were at the track. One thing the poor boys learned early was that if you ran slicks and they hooked up, you broke things like rear ends, axels, drive shafts and transmissions. When this happened they didn’t have a way to get to work. Only the rich kids had a dedicated race car and no one would run the rich kids because they had no heart. They had their work outsourced, they didn’t do it themselves. Most guys in my area street raced their daily driver. ANYWAY…I ramble. LOL To determine how long the collector extension should be they would bolt up a piece of pipe about 2 feet long to the collector and spray paint it white. Then they would take their car out and flog the crap out of it. When they got back there would be a burned area in the paint somewhere on the collector extension, normally around 18 inches from the collector. They would cut the pipe off at the end of the burned areas and that would be how they tuned for max power. I always thought that was as perfect a shade tree way to do it as any. LOL
two things happening here-1 is the loss in exhaust heat with distance traveled
I suspect that engine has limited valve overlap and that is why you don’t see the headers doing much.
That's right. At first after reading you comment I was like "well who didn't know that?" and then I remembered not everybody eat/sleeps/breathes engines.
So for anybody reading my comment - bcbloc02's comment is true. It would be for about standard production engines until you run into exotics and like Honda VTEC and Ford SHO. That type of stuff has like motorcycle cam timing/duration specs.
Part of the fun of this sport is taking large displacement "moose" engines (pickup, suv) and hijacking the designer's intentions. "See that automatic transmission - friendly drooping torque curve trailing off to the right? What would be easiest way to "fix" that? A procharger or cam/compression & manifolds ?"
My friend has an 8.1 in a big motor home and I know it keeps up to a diesel pusher, except in fuel consumption. But it has certainly a lot of grunt and performed for 90,000 miles. It appears a great engine
I used to have a friend.
I have one of these 8.1s in my Silverado that is still running strong some 310k miles later. I am so happy to see you starting a series on these often over-looked engines. Can't wait to follow along as I hope to someday freshen this engine and move it over to my square body.
What engine oil do you use? Trying to decide if I want to switch from 5w30 to 15w40 like some people are saying.
This is my blue eyed angel 02 chev 8.1 this is my 2nd truck with the 8.1 my first was totaled by a person running a stop sign and I will never get over her totally but my replacement is a nice girl as well!! I would walk the earth to find an 8.1 and I'm so disgusted that this engine is no longer in production and the other big huge bummer is that they no longer have the Allison unless you get the Duramax diesel and I'm not excited about those as I just can't afford the issues that will arise. I love this torque test it just confirms my solid love for this engine!!! Just wish they still made them...
To bad GM discontinued the 8.1 l think if they would have made improvements with it simular to what Ford did with the new gasoline powered 7.3 engine the LS 8.1 could have made good horsepower and big torque numbers for bigger cars trucks and SUVs with 496 cubic inches making 480-520 horsepower and 575+ foot pounds of torque naturally aspirated could be done very easily if GM would have given any kind of effort in making some improvements in research and development and technology with the engine
Hp should be well over 505 considering the 7.0 427cid LS7 made that. If they used an aluminum block.
@@rescueaviationfilms1019 I doubt it. The LS7 makes that because it revs high and has a light rotating Assy/valvetrain. Also the block material has nothing to do with it but aluminum heads and direct injection with extra compression would help A LOT
Ikr?
No doubt. This is a good engine. I still run mine in a 02’ 2500HD. It’s 10,000 lbs truck. And it will hang with my 08 GT mustang til on a 40 mph roll race til bout 90-110 when it runs out of gear. That old motor is a monster, it’s a hungry monster loves fuel, but so worth it. get you one if ya get a chance.✌🏻🤘🏻
If I remember right the new GM 6.6 gas engine makes the same power as the new 7.3 with less displacement
*CONGRATS RICHARD ON 200K SUBSCRIBERS!!!*
...in advance!
This beast doesn't seem to 'see' the headers and it is rather detuned so it makes me wonder what even a mild camshaft would do for it. Hope to find out! Everyone can get behind a big happy torque monster like this. Universal appeal.
Brand new big block goodness 😁👍🏻
This engine is awesome! The factory had this one figured out!
My late friend, header builder Jack Davis, told me back when a group of fellow racers were towing with Chevy dually's with 454's, he built headers for his with 1-1/2" primary tubes 42 inches long into a 2-1/2" collector! Said it would pass everybody climbing up the grapevine to Bakersfield, and pass them at the gas station as well.
seems like a tall tale
@@richardholdener1727 He may have exaggerated a bit, but I heard mention of it from other racers that it pulled pretty good compared to stock 454's.
I’d love to see an altered plenum with those setups and a tune done. I own a Chevy avalanche 2500 and I’m curious as to which route I should take.
Awesome Richard! Makes me want an 8.1!
I have an 8.1 and allison to put in my 01' Silverado 1500, can't wait to see how it tows. 😮😁
Richard I'm planning on putting one in 26ft motor home...hoping/planning 4 wheel drive..my done is a 06 2500..8.1 w/allison...so...65-70mph tops...but beach driving...need bottom end and running cool..
Good stuff! Thanks, Richard. I can never seem to find definitive information on the stock cam specs., so I can never tell how much "bigger" any other cam is, with nothing to compare to. Hopefully you'll figure out the true specs. in future installments, including the intake lobe centerline.
Stock cam is 201/208 at .05 lift is .47 and .47 lobe separation I don’t know but assume it between 114 and 116
How about doing a comparison test of the gen 6 vs gen 5 or older exhaust manifolds. They could be a cheap upgrade for older big blocks.
Finally got something with a 8.1
Would like to see the dyno results with the Dart intake and Holley Sniper setup.
I have an 04 8.1 with a raylar modified intake. Raylar said put headers on if I put a cam in it. It has a 80 mil bbk throttlebody, and a Gibson catback on it . 193,000 kms on it Im still happy with it .3500 silverado srw. lngbx.
Love to see a ported or larger tb on that thing.
So what we now need is a comparison to an older BB with doing a cam swap/firing order swap to see how much more efficient the new heads and intake are. Obviously try to keep it apples to apples as much as possible. Maybe hp/ci and lb-ft/ci comparison.
Great video and I can't wait to see what else is to come.
The firing order does minimal is anything for power.
@@amospgarcia9152 its not about power. if you run a gen 6 or older cam in it, they have a different firing order and the system needs to know this. if you watch the video, Richard actually brings this up. This is also the reason I brought it up.
I was just unsure how changing the firing order is going to tell me how much more efficient the new heads and intake are. Sorry for not understanding what your saying.
@@amospgarcia9152 np. Just to clarify, the idea would be to swap in a older cam and compare the 8.1 to previous BB engines using hp/ci and lb-ft/ci to see how efficient (or not) the newer hardware is. to use the old cams though, the firing order has to be changed. they did that with retro style cam for the ls1 to give it the old school sb sound. it's not about making the change to increase power, its just to make it run correctly.
Can’t wait to see a mid to mild cam in this thing. It’s begging for more cam if headers don’t improve on the powah!!!!
I'm using 1 3/4 headers on my 496 big block. She runs good too
8Ltr. Each cylinder is the same as my cars entire engine🙂🇬🇧
Can’t wait to see heads/cam on this.
Then heads, cam and boost!
Those stock numbers are very similar to the ‘70 Caddy Eldorado 500
Wish you would have ran the mercruiser HO cam. Would like to see hp with fully optimized air,fuel,spark…
Love this test!!! I watched the long form videos. Did you ever figure out why it stopped making power? I apologize if you already answered this question.
Disregard my question. Just found the video. Who would've guessed?🤔
I have that same 8.1 vortec in my eagle 230 eliminator (boat)…….80mph all day
Yes please!
Rich, can you do the Ecotec3 4.3L? Large displacement V6 with LS architecture
Those heads and cam are choking the life outta that thing. I haven't seen such an airflow restricted engine in a long time.
the heads will support another 100+ hp, it's just the cam right now
This video makes me want to do 8.1 swap now vs traditional LS !
You better think it over, because the 8.1 I have uses a LOT of gas. If you don't really NEED the horsepower and torque, don't do it.
Came here after watching LT Holman making his 8.1 almost run 10s!
Definitely de-tuned" had 1 in a 2000 2500 HD, 4:10"s 6sp Allison, lots of potential to unleash" especially with forced induction"
I would love to see him add a dart intake and a 850 cfm double pumper
I have those coming
With cam sensor can you run sequential with the 6.0 LS style harness? And does it work in the TRUCK?
The 8.1l has more in common with the medium duty L21 than it did with the pickups L29. Its hard to believe just how much torque it makes down low.
I would absolutely love to see you do a 3V Tritan V10 next! Maybe custom cams and 2 turbos?
I suspect that with the advances in computer modelling, that when these things leave the factory they are optimized for their configuration. So I suspect that changing the go-zintas and go-zoutas will have little effect. Because of the efficiency in design for it's purpose, to make it do other stuff changing the intake, heads, cam and exhaust in unison would be required. Boost should make it do all the same stuff but more of it.
The computer modelling of everything will only get better and when engines leave the factory, I believe, will be getting the max VE for what they are designed. To get anything other than the designed power curves, I suspect, you will have to change everything, in the air/fuel/exhaust path to accomplish a largely different result...or add boost.
But we already know that.
they are not optimized for power-only their design power goal, along with many other design goals
It's just not moving a lot of air. 1-3/4" should be plenty (if they fit the port), and you really want longer primaries to scavenge at that low rpm.
But the 2.25" headers were as good or superior at all RPM, correct?
Is there a way to make the cable driven throttle body work with the stock computer?
I miss my old 8.1l, it had tons of power and could pull anything it just got horrible fuel mileage. I have a 04 lb7 now and it's not as powerful as my 01 8.1
Scavenging doesn't work unless there's enough valve overlap. The intake and exhaust have to "see" each other for it to work.
Hi Richard,
I purchased a 8.1L and was excited until I saw how little parts are available for it. The more I watch your videos the more I learn about this motor, SUPER videos. The question I have is I bought the long block with complete intake but no coils, coil mounting plate, harness or computer. Should I swap to a regular intake and carb set up?
I have not tested the carb intake yet
Biggest problem with this motor is massive intake restrictions. Find a way to convert the Nelson racing engines X ram twin throttle body intake for an LS to fit this 8.1 and you will see massive power gains. Combined with a ported head and the BR 300 cam you seem to like to run and I'm guessing you would be near 700 HP. And 625 torque.
I'm building one now running a msd l.s box with new coils forged pistons , carb intake with a 1000 cfm carb big 650 lift cam , big headers im going for the 700hp mark.
This is perfect for my grocery getter.
Take the upper plenum off theres air divider in the intake that hurts power
Can we get some Subaru Ej dyno stuff?
It's Mr 199 k 😎
You need to narrow the lobe separation as stock cams can be as high as 128 degrees which prevents wave tuning with headers.
Im sure the next thing he is gonna do is cam, heads, intake, and test it all on each step.
128 degree lsa?
@@richardholdener1727 yes, it isn't common, 118 is, but on the 5.0 TiVCT Ford it can be that high.
128 is a only due to vvt though right?
@@MrPhukyew correct.
You need to jam all that exaust out through a shitload of smaller pipes, just like the Bellagio fountains in Vegas they can shoot that water straight through the air
Would be interesting to see an initial run on a stock tune
we didn't run a stock ECU
@@richardholdener1727 You think a factory tune would produce more power than the engine was rated at?
Love it
Whats the best year truck to get this motor from
Ive been looking at this generation 8.1(L18) for a build. Been thinking of using the Dart intake though
How about a ported stock exhaust manifold vs a header.
long tube headers are usually better-not from flow, but from scavenging
I think it’s going to prefer the larger exhaust headers and extension.
Right.
Tells me what I wanted to know....old school bbc and the 8.1 have the same exhaust flanges.
yes
Do you happen to know if stock 8.1 exhaust manifolds bolted on a vortec 7.4 make any power gains? Wondering for stock truck pulling class.
have not compared those two sets
intake, cam and a bump in compression and this thing would probably really wake up.
So….. dual plane carb test? Please tell me someone makes that manifold. And I’m really looking forward to the cam swap! Thanks to everyone who made this possible.
He has a dual plane for it to test.
Dart makes the intake-we already have it
By changing the exhaust configuration with minimal gains says the intake tract is the cork not the exhaust. Head flow, intake flow and or the throttle body flow isn't good enough to back up the exhaust.
Does anyone make aftermarket intakes and heads for this engine or would that have to be custom or billet only?
Raylar Engineering makes heads for this engine but your bank account will take a big hit. The heads cost almost $4000.
I have a question... will big block headers for like a 454 fit on my gen 7 496? Because they want alot more money for the 496 as opposed to the 454...
YES-WE USE BBC HEADERS ON THE 8.1L
headers for a 2002 gmc 2500hd allison
I have an 8.1 in a 2001 2500HD SB 4x4 CC and I tow an 11,000lb boat with it. So....the engine was bone stock and made 411hp/545tq? up from 350/500. Was the torque management disabled?
there is no torque management in a Holley HP system (what I used to tune it)
8.1s are begging for more intake air…intake manifolds usually make the biggest difference
What about carbing it
Following!
Need help. Gen 7 knock sensors are hitting long tube headers. Is there a salutation?
move sensors or dent headers
🔔😎
Go for it !!!! 👍👍👍
Our work horse for some reason isn’t always going full power when I gas it? Any suggestions
STOCK ECU HAS TORQUE LIMITING
Did you ever do one with the dart manifold carb and HEI?
coming
@@richardholdener1727 awesome 😎
Actually, the intake itself is a substantial restriction, and once the intake is modified, the throttle body becomes a restriction. There's a lot to be gained there before a cam change.
At that point, Comp has two good camshafts, and there are cams available for the Mercury Marine version of that engine.
Beware that while you can install 1.8:1 rocker arms on the stock cam, most aftermarket cans, or marine cams will have severe piston to valve clearance problems with 1.8:1 rockers.
I wanna swap wanna of these 8.1 in something
I love your content, but hour long videos are hard to fit into my schedule.
those are live feeds so people can come on to ask questions
MAAAAAANNN... thats one b a d d-a s s BBC...!! LOTS OF THESE coming up FOR SALE... wrapped inside Suburbans and Work Trucks...
It needs a super truckasaurus Norris cam!
What I learned is I want one
Can you explain how and why GM limited the torque on these engines ?
with timing and/or dbw throttle usually and to increase longevity of the drive train
@@richardholdener1727 Thank you sir, Love all of your video s
You will get the biggest change on a larger throttle body and tune.