right no i have a 92 z28 with a 305 5spd. it has the ram air setup, airfoil, cat back exhuast, forged pistons at a 10:1 compression ratio, and a mild cam. this summer i am probably going to spend between 2 to 3 grand on my car and i'm either going to get slp headers, big mouth manifold, siamesed runners, and a 150 shot of nos. with this setup i figure i will be in the low 13's or high 12's. OR do you think instead of buying all that get a turbo. i think the turbo will probably be around the same price as the other mods combined, so which one should i do? thanks

 

Considering your budget, i'd go with a set of mods like a good set of aluminum heads, headers, and do the appropriate intake/fuel system mods. Considering what you have already done, those mods should definatley give you some measurable gains. Now a turbo would be even better. It'll cost about the same.........times 3.

 

ziiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiing *PSSSSSSSSHT*




turbo baby

 

ATI super charger

I rest my case..

 

That wasn't an option.

 

Well a super charger and a turbo are the same thing just a supercharger runs off a belt so nah

Plus that is a damn good power adder.

 

Turbo is more efficient than super chargers.


(yet more expensive)

 

super chargers may drain a little power but the gains you get from it are worth it, especially the ATI, but thats my opinion.

 

You are running too high of compression to run much boost, but your motor sounds like it would handle the nitrous just fine I would recommend going with a good set of heads though. I have some spare vortecs...

 

If compression is an issue why are you pushing him back to cast iron heads.

Get him into some aluminums, then he could run *some* boost.

 

How can he run more boost with aluminum heads? A 64cc combustion chamber is the same wether cast, or aluminum. The aluminum head isn't going to run at a cooler enough temp to let him run more boost. If he wanted to go with bigger combustion chambers, then I could see that, but a cast head will handle boost just as good as aluminum. Aluminum will just cost more.

 

Since you got 3 posts I'll figure you haven't read up much.


Aluminum is far less prone to detonation due to its different thermal Inefficiencies. Heat escapes the combustion chamber, thus moving you further away from preignition (detonation)

64cc for 64cc, aluminum will tollerate a whole point more of compression than cast.

 

I have read up a lot more than you think I know. I have a tpi truck running 12 psi and and I get 12.47@ 112. I have done all the work myself, and I know what I am doing around boost. Using my fjo wideband o2 system I have determined that stock polished cast iron heads are no more prone to detonate than aluminum heads. I have had both. He can't run much boost with either heads with 10.0:1 compression. It is as simple as that. His motor is better for No2

 

*humbly bows to his royal highness*

 

Sorry to get defensive. I just really think that his car would get a lot more with No2.

 

Although...


I am however currious how your 02 sensor told you that you weren't detonationg sooner with cast vs aluminum heads

Is it a dual purpose 02/knock sensor

 

It also has data logging

 

cough cough *ATI super charger* cough cough

 

Well....not to stir the pot or anything, but GMI Fast claims to have run 10.5:1 compression with quite a bit of boost. Check out the power adders board.

 

not stiring anything up

Plenty of high compression people are making some decent boost

just takes brains and effort

 

Exactly. With a well thought out combination of parts and a lot of tuning it can be done. However, for what 92TPIZ28 wants I'd recommend the nitrous, simply for the sheer amount of work a turbo setup takes. You've gotta be crazy to attempt a turbo setup. Just like me

 

tpi_roc You are right, you can still boost with high compression. And, his car would be badass with a turbo, but not nearly as badass as with a 150 shot.