turbo cam and lower compression

greggy2belly
02-09-2006, 11:00 AM
i was wondering if u guys could help me out. i have a 94' Impala SS and i am looking to put a turbo kit on it. the question that i have is what is needed to bump compression down to around 9:1 and what kind of cam should i look for that is still completely streetable and can pass emissions in Illinois. i am going to b going with stock heads minues new valve springs and crane 1.6 gold race rockers. i am building up the bottom end, and having it bored .030 over, but i am going to keep my crank in there and have it b a 355. i am going with a 4-Bolt main conversion and looking to get forged pistons and rods. now my question to u guys would b how would i lower the compression down to around 9:1 and what size cam should i get. i have the hot cam in it right now, but i would rather get a cam more made for a turbo. anyother information that u have would b greatly appreciated.

thankss alot guys,
greg

engineermike
02-09-2006, 05:29 PM
Really and truly, the Hot cam will be fine.

5.0THIS
02-09-2006, 07:02 PM
The hotcam IS NOT ideal. He's going to have it apart anyway. I see no reason why you would leave the Hotcam in it :irk:

SiDeWaYZz28
02-09-2006, 07:38 PM
go with a set of 31-cc pistons and check out combination motorsports they have alot of turbo cams to choose from

engineermike
02-09-2006, 09:01 PM
The hotcam IS NOT ideal. He's going to have it apart anyway. I see no reason why you would leave the Hotcam in it :irk:

Seeing as how no one REALLY KNOWS what an ideal turbo cam is, the Hot cam will be fine. Check out Jose's most recent creation. A 370 LS1 making over 1100 rwhp and the cam is 236/242 - 112. Is THAT an ideal turbo cam???

Mike

INTMD8
02-09-2006, 09:19 PM
Unless I'm thinking of another car, I thought the 1100+rwhp, (6-speed?) car that Jose did the turbo for used a 224/226 113lsa cam.


We did use a 236/242 112lsa cam in our shop car. (994rwhp t400).


As to the original question, you would lower the compression ratio by using a dished piston, or using cylinder heads with a larger combustion chamber.

You didn't mention a power goal, and I do agree that the hotcam would work fine, but -alot- of power can be made with even a much smaller cam.

What are your power goals? What turbo are you using?

engineermike
02-09-2006, 10:21 PM
Unless I'm thinking of another car, I thought the 1100+rwhp, (6-speed?) car that Jose did the turbo for used a 224/226 113lsa cam.

We did use a 236/242 112lsa cam in our shop car. (994rwhp t400).

I stand corrected, Brady. My point still stands, though.

INTMD8
02-09-2006, 10:28 PM
Brady?

engineermike
02-09-2006, 10:32 PM
Dammit, I stand corrected again. . . I'm having a bad day there, Jim.

INTMD8
02-09-2006, 10:44 PM
Lol :)

greggy2belly
02-10-2006, 12:25 AM
don;t have any goals right now. the turbo is only a T04B i believe. people run around mid 12's at around 10psi. i am going to b upgrading it eventually, just not right now. i plan on having Speed Inc. do the tuning for it. i just wanted an idea of what piston to run for around 9:1 compression. the heads r gonna stay stock right now. i;m probably just going to bring them in for a valve guide, 3-angle job, and re-surfacing it. the heads just have bigger springs, and 1.6 rockers. i am going to everntually go bigger, but i don;t have the money for it right now.

thankss alot,
greg

5.0THIS
02-10-2006, 05:49 AM
Seeing as how no one REALLY KNOWS what an ideal turbo cam is, the Hot cam will be fine. Check out Jose's most recent creation. A 370 LS1 making over 1100 rwhp and the cam is 236/242 - 112. Is THAT an ideal turbo cam???

Mike


Who's to say that motor wouldnt make more power with a better cam. By the way, there are plenty of smart folks out there that know what an ideal turbo cam is. They REALLY KNOW. Like most folks, I dont see a reason to be different just because different CAN and MAY work.

engineermike
02-10-2006, 07:12 AM
I've been reading about turbo cams for years now and I can't seem to figure out what's best. But you're saying that "greggy" should be able to figure it out in the next few weeks??? Jim has tested some turbo cams and I'd say less than 5 people in the country have done enough testing to really know what works, and they aren't talkin'. The Speed Inc. cam looks sort of like some popular turbo GN cams, but totally opposite of the ever-popular Cam Motion cams. Other turbo GN cams look like the Cam Motion cams. The only thing anyone can really agree on is that the LSA should be 112 - 114. Some people even say that 112 is no good, but the stock turbo GN cam is on a 106.

Maybe, 5.0This, YOU can recommend a good turbo cam for him?!?

5.0THIS
02-10-2006, 09:58 PM
I've been reading about turbo cams for years now and I can't seem to figure out what's best. But you're saying that "greggy" should be able to figure it out in the next few weeks??? Jim has tested some turbo cams and I'd say less than 5 people in the country have done enough testing to really know what works, and they aren't talkin'. The Speed Inc. cam looks sort of like some popular turbo GN cams, but totally opposite of the ever-popular Cam Motion cams. Other turbo GN cams look like the Cam Motion cams. The only thing anyone can really agree on is that the LSA should be 112 - 114. Some people even say that 112 is no good, but the stock turbo GN cam is on a 106.

Maybe, 5.0This, YOU can recommend a good turbo cam for him?!?


An "ideal" turbo cam may not be the same thing from motor to motor. Certainly the design of a given motor, particularly it's cylinder head design, may influence what might work the best. I never said I was an expert, only that there are people out there that are. I do know enough to know what I have seen work better in some LTx motors, and the Hotcam isnt it ;)

Mike I think you were just having a bad day yesterday :p :D