Will need to be a solid roller cam for sure, and a pretty agressive one at that. I think you might be shooting high with those HP numbers though. Might be worth trying to fit a set of 18 degree SBC heads or a SB2 head for that matter if you are heart set on the LT1.

Although just scrapping the LT1 and dropping in an SBC never hurt either.

 

Which pipes in the PTK kit do you consider to be too small?

 

well we will be using a solid roller that will be custom ground once I can get ahlod of comp and talk with the guys over there. and the pipe sizing I'm worried about with the PTK kit is the Primaries. Since this motor would make near 550-600 N/A I want something that will make sure this thing can breath. That's my biggest hurdle right now is deciding do I custom make something or do I go with this kit and hope I can get 1 5/8 or 1 7/8 primaries since they are a shorter run. Oh the joys of building a turbo motor... Then again thats why I put this post up, looking for imput and opinions plus the added knowledge.

Chris

 

Yah, after a guy from comp told me there was hardly enough piston/valve clearence for a hotcam, I wont take anything they recommend me to heart. And when I asked about a custom cam he just looked in the book for one they already made
I would look elsewhere for a cam especially if your going for that much power. Im not sure if Joe O does turbo cams but it doesnt hurt to find out.
-Mark

 

My thoughts may vary from others, but- I say: If you're going to run a big single turbo, don't worry yourself with the cubic inches AT ALL. Build a short block that will handle the power (ie: 355). run a fairly short rod (5.85) and a good stock stroke crank.. A good sized turbo won't care what your cubes are (generally), the turbo will make the power. Get some really good heads to help the turbo, and you'll need a good tranny and rearend to handle the 1200HP the 88MM turbo will put out.

been there, done that
...Brady

 

Exactly.

 

I agree w/ Brady on cubes. The heads and the turbo sizing is far more important than how much the motor displaces.

For a turbo cam...Ed Curtis @ Flowtech. He knows a little about turbo motors...just a little though.

 

i agree on the cubes too...ive been trying to tell my friend this for years, they just wont listen.

now if your just wanting a little boost sure a stroker motor would feel alot better, but some people just dont understand that no matter how much power the motor makes, the turbo can only make so much power. hell, too small a turbo on a good sized motor would actually be a restriction. some peolpe need to read alittle on CFM's!!!

 

ok here's a little revised set-up for you guys.

383ci.
scat 7000 superlight crank
oliver billet rods 5.7"
J/E forged pistons for 9.5:1 with 76cc heads
Cometic 4.040 bore head gaskets
AFR 227 heads
PTK turbo kit with a liquid to air intercooler
Garrett PT-96 with a 1.5 a/r turbine
and then comes the selection for the cam.
running through a Heavily ported LT4 intake or a sheetmetal version and an Oval blade t/b.

hows this sound?
chris

 

Not bad. Pretty close to what I have in the car now. How much street time will the car see? I'd keep the port sizes down a little if it's more of a street car. Maybe a 210 w/ a 64 or 72cc chamber instead of a 227 w/ a 76cc chamber. You can still run a 1.6 exh. valve which would be perfect for an 1-3/4" primary.

I like the Cometic gasket. Not sure if it'll hold the power you're looking at (I'd o-ring the block if it were me and be done with it).

The two things I'd change would be the crank (Callies or Lunati) and the compression. With a -31cc piston & a 64cc chamber, you should be right @ 9.00:1, if not smaller.

 

You do realize that the PTK kit uses 1 3/4" primaries, right? The biggest restriction, AFIK, is the downpipe is too small for really big HP applications, but that's an easy fix.

 

Actually I didn't know that the PTK kit uses 1 3/4" Primaries....that should suffice. The car is not going to see the street very often. It's primarliy a race car with a possible weekend trip 3 towns over that takes maybe a 15 min. drive. So from what your saying is I need to fab a Downpipe.....I think I can manage that. With a 76cc head and the cometic gasket, if the piston is .1" down in the hole I only need a 5cc dish. I could always mill the block down and 0 deck it but then I need a 26cc dish. I think I might just have it zero decked. I was also considering having the block o-ringed but I do want to check the cost of it. I know that's coming from the guy who's going to spend $3K for a rotating assembly and almost another $3K for a set of heads. But that would be added to the machining costs to a block that I don't even know if it'll handle the power. Look at me now I'm doubting things I should be... It's definately something to think about.

Chris

 

If you're really just looking for a number, it might be more feasable to use an aftermarket SBC such as a Motown or Dart block and build a large displacement small block. By the time you machine the stock LT1 block as well as fill the bottom of it, plus add the splayed mains and any other tricks, you've basically payed for a motown block that needs a hone. I know everyone says you don't need displacement to make power, and they are right, but it's alot easier to make big power with a bigger bullet if you get my meaning. The only reason to limit the displacement, IMO, is for class rules. If you're not racing in any particular class, you can run the biggest bore/stroke combo the block will handle and top it with a set of 15 degree heads. That plus the turbo would easily make the power you're looking for. Just something else to chew on.

 

The hole reason we started with the LT1 idea is the kid that owns the car gets a lot of heat from guys we know about owning a "Dog"...They all have the LS1's and they think that no LT1 can keep up. Then the ones that do they're too scared of because they sound like race cars. So the Idea is run a Turbo car that doesn't make too much noise on the street but is still incredibly fast for what it is. And I have a little bet going on with one of the guys at Speed Inc. as to this car vs. his New N20 Motor he's building for his car (it's already gone 9.80's). So it's a combo of friendly bets and rubbing it into peoples faces with an LT1. The car we're doing this to has already run a best of 12.17 @ 115ish. All it really has is bolt-ons and a 150 shot. He made his first bottled pass and he wanted to go faster. We're also "toying" with the idea of spraying until the turbo spools....depends on how the car launches though. As it is now, the thing still has a completely stock suspension...including the front sway bar.

Chris

mongse1--what would be the easiest way to get ahold of ED to talk cams with him?? thanks chris

 

Call me a rookie, but why on earth would you '0' deck a block for a turbo motor? Also, how do you get a piston .100 in the hole?