High Compression and Blower?

If its 11:1,you be find on race gas with a bit of boost.

Oh,and I support the nitrous idea, you can run pump gas and keep the timing were its at for around town.Also,its probably better,especialy if your 02 sensors are new,or your injectors are small.As the lead in race fuel can gum thous items up after awhile.

JS94cobra said:

Is anything done to those GT40 heads? Any port or valve work? If you are putting 270 with stock gt40 heads I would bet you'd get over 300 with some different heads. Of course you'd want to stay with a 64 or 65cc head because any smaller your CR is going to go up even more. As far as the blower is concerned, if it was me I would not run a blower with a 11:1 CR. Although 6lbs boost may be ok with the right tune. With a 11:1 CR and 6 lbs boost your new CR will be around 15.5:1. At 8lbs boost it will be around 17:1. If you want a blower and some more boost get some head with a BIG combustion chamber...70cc 72cc...to try to get that CR down some. Or you could get some flat top or dished pistons. I know the piston part is a pain but you'd be happy with the end result and some 400+rwhp.

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Tell me what my converted CR was running 10 psi and a static CR of 9:1.

Also, I gather that with 8.5:1 CR 13 psi is very safe, and up to 15 psi on 93 octane pump gas is doable. What are their effective compression ratios and how do they compare with 11:1 at say 6 psi? I'm going to gamble that they're both higher than 11:1 @ 6 psi. You're cramming more than twice the air into a combustion chamber that is only about 30% larger...

If I'm right, 11:1@6psi should be ok on pump gas with efficient heads, a sufficient intercooler, and timing set right.

Thanks,

Chris

QUIKSVT said:

WELL I WAS THINKING THAT THE GUY AIGHT GOING TO RUN RACE GAS.. AS MOST OF US JUST RUN PUMP GAS.. BUT YES EVERYTHING IS POSSIBLE.. BUT I WOULDN'T DO IT.. I WOULD OF RAN 9:1 THEN THE BLOWER.. 11:1CR ON RACE GAS AND 6-9 POUNDS STILL AIGHT SMART.. BUT OH WAIT.. I'M SURE YOU GUYS GOT A "FRIEND" OR "READ" ABOUT A GUY DOING IT..

TELL ME THIS THEN.. IF 11:1CR AND A BLOWER WORKS SO WELL.. THEN WHY IN THE WORLD DOES EVERYONE THAT BUILDS A BLOWER MOTOR RUN LOW COMPRESSION?

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You already know all this stuff as you have a '95 Cobra that's faster than the Pro50 cars with about 1/3 the hp! Rock on... I'll explain it for us lesser beings:

You're not limited by your blower/turbo on pump gas. You're limited by detonation. Lowering the compression ratio will allow you to move more air into the cylinder by increasing the boost before detonation than the other way around. It won't burn as efficiently as a higher CR with lower boost, but you'll have more than enough air to make up for that.

However, you don't have the same restriction on race gas that you do with pump gas. More than likely, your restriction will be in the turbo/blower that you're running, and in that case, higher boost AND higher compression will result in more power than higher boost AND lower compression.

You don't have to start arguing physics to me, I know that more air always equals more potential power, but if you're blower/turbo limited to its max air volume, as you will be on race gas, you up the compression as much as possible before detonation to make the most amount of power possible.

Did this make sense to anyone? I don't know if I am any good at explaining things.

Chris

STANGateURlilSS said:

wow what a smart guy.. thats probably why he makes 977whp @8000+ rpm on a stock short block lmao

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Stock long block.

Ah, I see. It was just a joke...

FastDriver said:

Ah, I see. It was just a joke...

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ding, ding, ding... we have a winner...