Got an interesting project going at the shop right now for a customer. Got a lowered chevy 1500, with a 337 CI motor (327 bored .06 over). Currently its turbocharged, with a holley dominator, running 22lbs of boost with water injection, but the guy wants to run TPI (and already purchased the manifold,). Unfortunately he also wants to turn 7k rpm. How do you think siamesing the intake like madmax did will work? He gained a lot more rev capability on his, just wondering how you all think it will work with a turbo. If your not familiar with the siamesed intake manifold thing check it out at
https://www.thirdgen.org/techbb2/sho...iamesed+intake

I tried to him into a stealthram or lt1 intake conversion but ... he wants what he wants, so I'm trying to make it work as well as possible to keep him happy. Any input would be appreciated

 

Tell him he is on crack and that a TPI will NEVER EVER support 7000 rpms.

Besides, there have been some problems with people siamessing too far down and going lean on #5 or #7 due to poor air distribution between them from the siamessing.

I wouldnt do it personally.

Get a carb style intake and convert it to EFI. Or try harder to get him to purchase a stealth ram or LT1 intake.

Good luck.

 

Is he using the TPI becasue it was free or what? This doesn't make sense. A guy running a turbo water injected motor had to have laid down some cash somewhere along the line and it sounds like he's cheaping out now. Tell the tight a$$ to open up his wallet a little more either that or start saving his pennies for some other efi unit. That TPI dream just isn't going to make it into reality. He could also look into a holley tbi that would work well with the setup he already has and it's not terribly expensive.

 

Heh, that's what I thought too, I think I'll tell him that the labor cost of siamesing the intake will be more than the cost of the stealth ram or LT1 intake. Damn I hate stupid customers, except for the ones that don't mind spending money of course.

 

Hes probably one of the people who want it because it "looks" cool. Granted, it is the best looking induction system, but looks arent everything.

Guido, I havent heard about the lean condition due to siamizing... could you explain more please?

 

I'm not Guido, but if you look at the firing order the #7 cylinder fires right after the #5 cylinder. If you siamese the base you pretty much join the area they are drawing air from, and if #5 pulls too much air then #7 's not going to be able to get enough air, and run leans. Least thats my understanding of it.

 

If 7 doesn't have enough air, it'll run rich. There have been some odd failures that got explained away by airflow distribution issues. The thought process might be that with the batch fire injection, 5 might be stealing some of the fuel <shrug>.

With forced induction, you don't need the super long runner lengths since the torque is huge to start with. Even though the siamesed base helps one cylinder draw from another, the runner diameters will still be a significant restriction. Give him an absurd price for siamesing such that he wants to go HSR or single plane. For looks, he could always do an LT1 intake with some custom engraved MBA fuel rail covers too!

A.