BlueTexan24

I'm not 100% sure I put this in the right place so feel free to move it.

But I've talked to quite a few tuners the last few years about how you cant run x amount of compression with x octane fuel because it limits timing, BUT there has been a few tuners who don't agree with that completely. To my understanding some guys "lock in" a certain degree throughout the entire rpm range and to me that doesn't make much sense because different cylinder pressures would require different amounts of timing, and from what I have personally seen timing is usually what ends up killing these motors, not boost or nitrous. I get that more timing = more power up to a certain point, but for say why couldn't you run a 12.5 compression motor on 93 or even 87 if the timing is set low enough? with a good quench area of course. Less timing=less cylinder pressure that you could make up with compression, not to mention fuel mileage is increased as more compression and less timing needed to reach the same power level vs less compression and more timing to overcome the lack of compression to get the power back up. I read somewhere that Foose wasn't a big fan of adding timing (liked adding boost) on his truck and i feel like that is the reason his 4.8 lasted like it did.

I may be way off on some of this, so feel free to tell me I'm wrong cause that's what I'm on here for is to learn something new.

I figured some of you long time tuners on here have thought of this same thing and possibly have tried it.

George C....

Timing makes power period this is why ppl run methonal for race fuel with big compression
Same goes for ethanol

On 93 youre limited to what you do

1 build i did was 11.0cr 16 psi and 13* on 93 made 806 rwhp on mustang dyno...plugs say this is safe and car proved this

Few builds ago i ran 9.0cr and on 12.5 psi i was able to get away with 26* on 93/meth

Latest build i have going on is 10.8cr and will be 10psi and probably keep timing 12* on 93


So you have various ways to go about it but in end you have to work with what you have

But anytime you can run timing youll make more power and torque

BlueTexan24

Thanks George, you've built some badass trucks btw

How did the 11.0 cr 16 psi motor run compared to the 9.0 12.5 psi motor with double the timing?

George C....

One was a ls3 6.2 vs 5.3

So hard to compare but ill say the camaro drove like stock and power everywhere then boost hit and was crazy

Years ago i had a 8.6cr or 8.8cr 4.8 cant recall been so long ago...that was a turd everywhere except in boost

Compression makes for a better driver

Just have to becareful you dont run not enough timing and as EGTs will go thru roof

BlueTexan24

Gotcha, I Appreciate the insight.