LLSR or not?
Thread Starter
TECH Enthusiast
Joined: Dec 2017
Posts: 676
Likes: 72
LLSR or not? I'm building a turbocharged engine for my 2012 camaro. I'm limited to 21 psi boost so looking to improve base engine power so my boost limit isn't as much of a cap on performance as it could be. 21 psi on a cam only 5.3 isn't gonna make as much power as 21 psi on a built 388 lsx. So here is my plan. Stuck on cam choice.
388 LSX
4.125 bore x 3.625 stroke
12 to1 compression (I have run high compression before with boost)
dart pro 1 ls3 heads (cleaned up casting flash in ports)
holley high ram
90mm throttle body
t&d shaft 1.7 rocker arms
Engine has always been hydraulic roller like most ls set ups but im contemplating a LLSR. Two cams I'm choosing between is
Btr 388 turbo cam
243/251 at 50
117 +5 lobe seperation
Hydrau.638/.633
Hydraulic roller
Cam motion LLSR
247/252 at 50
118 +4 lobe seperation
.731/.731
Seems like with the dart pro 1s the extra lift on the LLSR gets me in the higher flow area of the head.
Im told the LLSR and the btr are similar when taking into account the lash setting but i don't know enough about it to know for sure. What say everyone and why. Any guesses on base engine power figures.
388 LSX
4.125 bore x 3.625 stroke
12 to1 compression (I have run high compression before with boost)
dart pro 1 ls3 heads (cleaned up casting flash in ports)
holley high ram
90mm throttle body
t&d shaft 1.7 rocker arms
Engine has always been hydraulic roller like most ls set ups but im contemplating a LLSR. Two cams I'm choosing between is
Btr 388 turbo cam
243/251 at 50
117 +5 lobe seperation
Hydrau.638/.633
Hydraulic roller
Cam motion LLSR
247/252 at 50
118 +4 lobe seperation
.731/.731
Seems like with the dart pro 1s the extra lift on the LLSR gets me in the higher flow area of the head.
Im told the LLSR and the btr are similar when taking into account the lash setting but i don't know enough about it to know for sure. What say everyone and why. Any guesses on base engine power figures.
Last edited by jordoza; Jan 13, 2023 at 01:36 PM.
Why are you limited to 21psi?
If all you're worried about is power and staying under 21psi, just stroke the engine and it will drop your psi, then turn up the boost.
In general, the hydraulic is easier to set up and less harsh on your components.
If all you're worried about is power and staying under 21psi, just stroke the engine and it will drop your psi, then turn up the boost.
In general, the hydraulic is easier to set up and less harsh on your components.
Thread Starter
TECH Enthusiast
Joined: Dec 2017
Posts: 676
Likes: 72
Limited to 21psi because the ecm only has a 2.5 bar os. I could holley it and would but I lose the dash and a bunch of bcm controller stuff. I can put a gateway module set up but at 6k plus the holley set up I'd be 8k to 9k just to get it running.
What's the intended purpose of the car?
Daily Driver? Weekend Cruiser? Drag? Road Race?
For DD or Weekend Cruiser, since you're already doing a built engine, I would switch to a 4.000" stroke crank. That'll turn your 4.125 bore into a 427. With the longer stroke, you can make more power at a given psi. Then I would do a custom cam from BTR (or CamMotion). I say BTR just because you mentioned one of their cams as one of your choices, and I've done the custom cam process through them before.
If this is going to be a strictly race car, and you need the higher rpm performance (the type you would not normally see/notice/use on a street driven car), then go for the LLSR. LLSR will have more stability on the top end.
When I talked to BTR and had them spec out a hydraulic cam for a Dart LSNext 4.125x4.000 turbo engine for 100% drag race vehicle, with the Johnson ST2126LSR lifters, expected RPM running through the traps is 8200-8400. Just for reference information
Daily Driver? Weekend Cruiser? Drag? Road Race?
For DD or Weekend Cruiser, since you're already doing a built engine, I would switch to a 4.000" stroke crank. That'll turn your 4.125 bore into a 427. With the longer stroke, you can make more power at a given psi. Then I would do a custom cam from BTR (or CamMotion). I say BTR just because you mentioned one of their cams as one of your choices, and I've done the custom cam process through them before.
If this is going to be a strictly race car, and you need the higher rpm performance (the type you would not normally see/notice/use on a street driven car), then go for the LLSR. LLSR will have more stability on the top end.
When I talked to BTR and had them spec out a hydraulic cam for a Dart LSNext 4.125x4.000 turbo engine for 100% drag race vehicle, with the Johnson ST2126LSR lifters, expected RPM running through the traps is 8200-8400. Just for reference information
Trending Topics
Thread Starter
TECH Enthusiast
Joined: Dec 2017
Posts: 676
Likes: 72
The purpose of the car is hard to nail down. I do drive the car once or twice a week to work and back but it's not my only vehicle. I drag it occasionally, roll race, even some airport top end stuff at times. So kind of all around badass car. I change shock settings and swap rim and tire packages between it all. No one trick pony here. I know I'll never be top dog in anything that way but it gives you alot more time to have fun with the car in my opinion. Anyway my tolerance of marginal street manners is pretty aggressive.
The car is a 2012 SS camaro. Previous build went like this.
LSX 376
S480 96mm turbine
4l80e Jake's Trans brake
Ptc 3800 stall triple disk
zl1 rear 3.23
Viking adjustable shocks everywhere
full aftermarket suspension set up
car was fast but I wanted more. Lady hitting it kicked off the build up.
I'm guessing I was damn close to 1000rwhp. Looking To hit 1400 this trip around. Moving to twin turbos. Air to water intercooler.
I had already decided on a plan but reading about the success n/a guys have with the LLSR I decided I'd ask.
The car is a 2012 SS camaro. Previous build went like this.
LSX 376
S480 96mm turbine
4l80e Jake's Trans brake
Ptc 3800 stall triple disk
zl1 rear 3.23
Viking adjustable shocks everywhere
full aftermarket suspension set up
car was fast but I wanted more. Lady hitting it kicked off the build up.
I'm guessing I was damn close to 1000rwhp. Looking To hit 1400 this trip around. Moving to twin turbos. Air to water intercooler.
I had already decided on a plan but reading about the success n/a guys have with the LLSR I decided I'd ask.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'
Brett Foote
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
