HOW TO: PICK THE RIGHT TURBO 4.8L LS CAM. WHICH CAM WORKS BEST UNDER BOOST? DIY, JUNKYARD TURBO CAMS
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- เผยแพร่เมื่อ 19 ต.ค. 2021
- DO I NEED A BIG CAM FOR MY TURBO 4.8L LS? CAN I MAKE BIG POWER WITH A SMALL TURBO CAM? WHAT CAM WORKS BEST UNDER BOOST? ALL OF THESE QUESTIONS ARE ANSWERED IN THIS VIDEO, AS THE KEY TO BOOSTED PERFORMANCE FOR YOUR TURBO 4.8L IS ACTUALLY THE POWER CURVE OF YOUR NATURALLY ASPIRATED 4.8L. ESPECIALLY FOR DAILY TURBO PERFORMANCE AND STREET/STRIP APPLICATIONS. CHECK OUT THE DYNO RESULTS ON BOTH NA AND TURBO 4.8L COMBINATIONS AND DISCOVER HOW THEY TRANSLATE TO BOOSTED PERFORMANCE.
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Right on
The BTR Cam looks deceptively like a late ls1 cam. They didnt have 111° lsa but the lift and duration is really close. Looks like it will work with stock truck springs as long as theyre in good shape.
On a related issue, there is a dude with a Pontiac Sunbird with a small block with twin M90 blowers using a carb drawthrough. He had a single Edelbrock/AFB carb and runs 10psi or so with what looks like stock pullies on the blowers. Lots of fab work but the blowers dont seem too unhappy with the gasoline runing through them.
My buddy and I just completed a 2012 4.8 Silverado single turbo build. 80mm turbo, "stage 2" .612 intake, .596 exhaust 215°@.050 on a 114lsa cam, 799 heads, dual Pac valve springs, VVT delete, .080 black oxide pushrods, Aeromotive fuel pump, and injector upgrade. Will be set to 14-16psi. We got it fired the other night with the charge pipe off, and it was rich as hell. No leaks and looks good. It's going off to the dyno to get tuned next week. Would like to see 500w.h.p.
Truck Norris cam in a 4.8 with boost is a certified slayer for a tow rig
I just put cam motion 216/224 108+3 on my 4.8.. wonder how it’d do. literally put it in a week before they came out w Truck Norris.
@@SnIt3yAsTr0 it's about the sa.e what's the lift on yours
@@james10739 his cam is closer to the BTR truck stage 3 V2 for duration and lsa. lift is going to be the difference.
@@james10739 1.7 rocker ratio 553 .553. With 4*overlap
@@SnIt3yAsTr0 that's what they use for the truck cams and that truck Norris one to so it's basically the same
Perfect! Thanks.
Lerning by doing !
I propose you and robdamn do port testing on rotarys as a collaboration. He wants data. We want data. I really would like to see how power is really made thru port shapes and port timing.
WOULD BE COOL
90% of the time on the street is under vacuum. That's why I'm starting with small (ish) cam only L92 for my crown vic. 650-700 is all I really want to make boosted most of the time anyway. Maybe the ability to turn up to 9 or 1000 for no good reason at all lol
LS-9 + 4.8 = Wrong Cam, new t shirt logo Lol, Thanks for the great info!
I love your videos!!
THNX
I have that summit 212/227 cam for a 4.8 I’m planning on building going with ported 706 heads and a junk yard find bbk aluminum intake manifold , hopefully gona make 750 to the ground @ 20 psi
7pm Commy time, I'm in the Mexico City timezone. TEXAS
TEXAS HAVING LOTS OF ISSUES RIGHT NOW
@@richardholdener1727 ooof, maybe according to CNN? Come on man
I'm always five hours behind you guys. But it's tomorrow here. Noo Zeeland Sixually Transmitted Thyme. The Turbo Telephone Box from another Dimension. Cannot wait Ya'll!
@@johnboticki9154 Indeed. Texas looks like perfection right now compared to Cali. And I live in Cali....
@@ChurchAutoTestTexas is great unless you want your kids to learn actual history, instead of being brainwashed by Jesus freaks
Woot! Booooooost!
4.8+ls9 cam+pos disp blower=fun in a lightweight car
I really need to learn more about LS engines
Dig in.... They're really very simple, easy to work on, cheap, and tough. You can't go wrong.
Hey rich what you think I want to put a B303 cam in my stock 302 fuel injection 1988 works ok?
How about the L77 CAM?
How about a bigger cam and a little squirt of NOS down low? How about using a squirt of NOS to help spin up a huge turbo?
yes
What A/R?
👍🏽👍🏽
Dr Holdener, for a sbf 306, 11R 170 heads, tmoss ported RPM 1 efi intake, single 70mm ON3 turbo, TKO600, 3.55, 3000 lb Fox street car looking to get 600-650whp, which cam do you like better? XE274HR or XE266HR or something else? Looking to make peak power below 6K rpm
if that turbo will support that power level, either of those cams will get you there
Have you tested the ls9 cam on a 383 or a 408 stroker? Would be curious to see what the loss looks like.
it does the same thing on every motor compared to these cams
Have you done any testing specifically to make torque/power on the lower end of the rpm range?
I'm planning on building my 4.8 for turbo application in my 61 Continental. Which is a very heavy car. Not for racing obviously, but reliable fun power for the street.
small turbo and stock cam (or bigger motor)
@richardholdener1727 can you provide the part number for the JE forged pistons you used?
Personally I blame squirrels
The only reason to go really big is to manage torque and not over torque the low end to hit your hp goals
Some class drag guys go huge with the cam. X275 racers usually have a bunch of ancillaries on their build to make all the power they can if they boost because the turbo is the limit. They run huge turbine housings and really high rpm equipment so they can use a shorter gear.
richard i had a question i debating with the btr can you showed in this video and the truck norris nsr cam I want something streetable
that i can turbo the lift on the truck norris cam is less then the btr cam you show in this video so i just wanted your opinion on which one should i go with, which one would be better for my 4.8 that i plan to do twin turbos i won’t run a lot of boost maybe 8-10 lbs of boost i’m building my truck to have fun
torque cam and boost for a street 4.8L
@@richardholdener1727 so ur saying i should go with the BTR cam you show in this video ?
Can you mitigate the slow response from a big cam big single by using the same cam and going to a smaller twin setup? Would that affect “driveability” for a street strip setup?
that switch to twins is not the answer (if they support the same power as the single)
What about for supercharged engines? Would the same principles apply? How is boost response affected if at all. Would response be the same for a Roots style blower as a centrifugal type?
I was wondering the same thing. Since a roots blower gives instant torque, wouldn't that allow you to use more aggressive cam & heads, and have the blower boost low end torque?
cam does the same thing regardless of how you provide boost
positive displacement superchargers generally repeat the power curve at a higher number, as Richard has shown.
that's not counting undersize, overspun, or some kind of restriction that kills power as I've seen from personal experience.
Building a 4.8 with a comp stage 2 thumper, ls1 intake and wondered how that combo would suffice for a low boost turbo setup lime the gt45.
it will work-not a great cam choice but it will work
@@richardholdener1727 I agree... The 107lsa on that cam isn't a great choice for F.I. and boost.
@@richardholdener1727 hey whats your theme song called
Tsp 228r 600 112lsa a good cam for a mildy built 5.3 LS? Only going to make 750-800hp on a safe tune
you don't need that big of a cam for 800 hp with a turbo-a smaller cam would drive better
I was wondering about overlap in the cam and a turbo application. If you run twin turbo at say 8 psi of boost and idea of twin turbo is to drop the back pressure to 3 to 5 psi. Would a cam with a little overlap help or hurt power. I was thinking that a little overlap under boost would help blow out the exhaust gasses versus relying on scavenge effects of the exhaust. What's the truth on this.
the idea of twin turbo is not to drop back pressure below boost pressure unless you plan to minimize response. Cam overlap is fine on a turbo motor
@@richardholdener1727 thank you
Richard, if a single turbo is rated at 700 hp but you are running twins, what is the general limit of the pair of turbos?
1400 hp or so
Richard I want to see what happens with a smaller turbo and the ls9 cam. Would it create too much back pressure up top? Where would peak power start and where would it fall off? There's so much info I want to see in that situation.
the LS9 cam does what it does with any turbo-less power down low
@@richardholdener1727 so having the boost peak sooner won't make more power sooner?
What would you say the 4.8 in it's stock(ish) config makes "net" ? Like in a car accessories and all?
just look at the rated power output
@@richardholdener1727 yeah but I mean in your config with the headers and no cats and shit. I guess I'm wondering what the difference is between that first Dyno graph and a wheel or hub Dyno?
@@jasonbirch1182 At least 20% less on a wheel dyno with the cats, full exhaust, and full accessory drive .... Probably more.
Which btr cam stage do you recommend me get for 4.8 twin turbo setup ?
how much power?
I mean I’m planning on getting cam and twin turbo so that’s why I’m asking what’s a good setup
Do a late 90s 5.7 sbc turbo budget build. Stock everything except intake, carb and turbo. If you can use the stock manifolds.
Why?
@@chipcurrey653 why not?
@@chevynova-ev6qp last I went to the local lkq those 5.7s were the same price as a 4.8, except are older, and do not have 6 bolt mains, reluctor ignition timing, coil on plug, plastic intake, etc. Why would anyone run one now starting from scratch? And why would anyone turbo an existing one given the cost to switch?
@@chipcurrey653 idk what you paid for your 4.8 but my 5.7 is free first of all. Also I have an older 700r4 in my s10 instead of a 4l60 so it's actually cheaper to do a budget 5.7. And trust me...nothing special about what a 4.8 has to offer over a 5.7 ignition wise....100% nothing wrong with an aluminum intake, carb and distributor.
@@chipcurrey653 what trans are you running? What did you put the 4.8 in? What did you have to buy to do the switch
I don't know how Richard hasn't put a cam in his own truck yet
4l60e
@@richardholdener1727 good answer
So what would happen if you ran a super long duration on a low lift cam
the duration hurts low speed, lift has very little effect
It would run the same as if it had a high lift, but way less power, and you'd be putting up with the headaches of a big duration can with not much return. If it's a low compression motor, that would make things even worse as the big duration cam will be bleeding off a bunch of the compression that you do have.
Do you have a test with a BTR stage 3 kit (cam, pushrods, springs etc) on a 4.8 engine that has had the heads removed and bigger valves & mild porting? What turbo do you recommend on it for drag racing? Thanks!
WHAT POWER LEVEL DO YOU WANT-YOU LIKELY DON'T NEED THAT MUCH CAM OR PORTED HEADS
@@richardholdener1727 the engine is already built. I'm just wondering which turbo would work best for it. I watched your turbo test. GT45 would be a great low cost alternative. 😁
@@WagsAutomotivepick how much power you want to make, that's how you choose your turbo
What timing was here NA vs. boosted?
29 na-21 boosted
@@richardholdener1727 Thank you!
X
Hey Richard
What about doing a test with the same 4.8 and cams instead of a turbo but with a supercharger like the mustang supercharger 👍🏼
same results-what they do na-they do with boost