I need to know what the N/A compression limit is for 93 pump gas.

I was just wondering if anyone could help me out because most of the answers i got for my question have been around 11-11.5:1 and i think that is b/s, especially since a stock tibby is running 10.3:1 while being built for 87 piss water.

i am thinking 12.5-13, but i think 13 will give me some troubles with the chance of a bad fuel load. So could i manage 12.7:1 possibly?

How about with full time methanol or water injection (13-13.5possible?)? (this is what I really want to do)

 

What kind of management do you have?
What kind of cams do you have?
What is the rest of the setup?
How are you going to achieve this compression ratio? (shaved head? pistons?)

 

look at the title man. wink1.gif

 

Some people do a combination of both

 

Don't get confused about the Tib coming with 10,3:1 comp ratio and be able to use 87 gas; it also depends (Like Larry is suggesting with his questions) on how much the ECU is retarding spark to avoid detonation with the 87 gas. Put it this way, if the ECU is retarding spark all it can be retarded to allow 87 gas, there is no more room to play in the ECU side, so you would count only on the gasoline self antidetonation properties on static compression...

I am not sure how high you can go on 93 gas, but I don't think you could come close to 13:1 on stock ECU, as other folks suggested you, I think around 11,5:1 could be it. Also, don't miss that just a tad more compression (like rising it from 10,3:1 to 11:1) would give you very noticeable results; you don't have to rise it a full two static points to benefit.

Hope that helps