Couple tech questions specific to my build.
Thread Starter
Teching In
Joined: Jan 2018
Posts: 2
Likes: 0
Couple tech questions specific to my build. Mega truck build. 2003 5.3 powerplant. LS6 cam and springs. Typical mods to handle boost. Stock heads. On3 76mm front mount with .96ar and 2.25” crossover piping. 4000 rpm summit nitrous converter, full manual TH400
Target: 15 psi / 750 hp at the crank. Using an a2w intercooler 100 octane unleaded through 80# injectors
My my biggest concern is turbo lag, what size intercooler piping would you recommend? And with my set up, what rpm do you think I’ll cross the 10# of boost mark? The truck will be ready to run next month, but I wanted to talk to the forum on this one to make sure I don’t do anything to hurt my situation when it comes to the cold side.
This is my first post, but I’ve been researching on here for quite some time, thanks in advance for any input.
TECH Enthusiast
Joined: Dec 2017
Posts: 676
Likes: 72
I would run 2.5 to the intercooler and then 3.5 from intercooler to the throttlebody. That being said here is some advice you didnt ask for. 750hp at 15 pounds is not going to happen with a 5.3 and an ls6 cam. 5.3 even if you got the badass l33 was 310 hp at the crank then the ls6 cam will add 35 hp at the crank. Making a possible 345 hp and that will become a 295 at the wheels with 15% drivetrain loses. Your truck will have far more then 15% loses in my opinion. Even in a perfect would 14 pounds would double the hp of an engine making it 590 at the wheels. So at 15 say 610. It will be less then that for sure cause this isnt a perfect world.
im not trying to crap on your combo just saying be realistic. Second is the converter. If you bought a 4000 stall built for nitrous it is probably going to suck for turbo. Plus the extra load a truck like yours is going to put on the converter is going to make it stall way different then the advertised rpm rating. Honestly i cant even guess what that converter is going to do. Your combo is different then most around here and most off the shelf stuff isnt going to work like it is advertised. Having a custom converter speced will make a huge difference in how well your combo works.
im not trying to crap on your combo just saying be realistic. Second is the converter. If you bought a 4000 stall built for nitrous it is probably going to suck for turbo. Plus the extra load a truck like yours is going to put on the converter is going to make it stall way different then the advertised rpm rating. Honestly i cant even guess what that converter is going to do. Your combo is different then most around here and most off the shelf stuff isnt going to work like it is advertised. Having a custom converter speced will make a huge difference in how well your combo works.
Thread Starter
Teching In
Joined: Jan 2018
Posts: 2
Likes: 0
I appreciate the input on the piping size thank you. The converter is tricky, yes it’s a big 5500# truck, but the load on my trans and converter is not what you would think. I have 6:72 axle gear ratios, and a 3:1 transfer case. It’s really just going to be a lot of test and tune / part swapping once the weather warms up here in Michigan.
