Compression Ratio

[burntire]

What is the consensus for compression ratios on a supercharged motor.

For example if you had a 02 GT with a Centrifugal blower making 12-15 PSI. What would those with buiding experience spec out the CR at?

[yeahloh95]

i would keep it to around 9.0-1 is there an intercooler involved ?

[Killercanary]

i would keep it to around 9.0-1 is there an intercooler involved ?

Troy, from the little I know about mod motors, I'm pretty sure they can tollerate higher compression ratios than pushrod engines typically can due to a more efficient combustion chamber. Since I have never built nor owned one I will not offer a recommendation.



Burntire, what octane is available to you out there? It may help those that have actually built mod motors help with a recommendation.

[burntire]

We have 91 octane with sand in it. LOL

Yes the application would be intercooled. Procharger P1-SC

[SonofaBish]

I would say between 9.0:1 and 9.5:1 ...

I think its a worthwhile tradeoff to feel safe from detonation, and just add a little extra boost... plus some sort of intercooling or water/meth cooling helps bring ease to the mind...

[no1sirbutler]

whats the main purpose of the car? street, strip or both...this will help

[biminiLX]

Troy, from the little I know about mod motors, I'm pretty sure they can tollerate higher compression ratios than pushrod engines typically can due to a more efficient combustion chamber. Since I have never built nor owned one I will not offer a recommendation.



Burntire, what octane is available to you out there? It may help those that have actually built mod motors help with a recommendation.

Paul, there's an 1100hp 10:1 5.4 4V/3.6 KB build in the new 5.0 mag, Milhovetz (who knows how to build a mod motor) said the 4V combustion chamber can tolerate the higher compression, no mention of the 2V.
If this is a pump gas street motor you plan to put miles on, I'd think you'd be safer staying around 9-9.5:1. No reason to push it IMO.
-J

[burntire]

whats the main purpose of the car? street, strip or both...this will help

Primarily street.

[somethingclever]

Higher elevation can tolerate higher C/R.

[Ares]

From what I am finding most say keep it above 9.0:1 for street use.

[no1sirbutler]

me personally, i wouldnt go past 9:1...w/ that level of boost your cylinder pressure will be really high and im not sure if 91 octane will support it.