Form what I understand the ETA has a 9:1 compression, correct?
I boosted a 9.1:1 GM V6 last winter and is running 12's in an auto FWD car. My Firebird has 11.5:1 and am twin charging it. I will see the same effective compression at 6psi as a stock 9.6:1 V6 with 10psi (which is common place in my community).
What people don't realize is that when you apply more air to an engine (boost), you are raising the effective compression (compression the engine sees while running).
So, if we have a 9:1SCR and add, let's say, 6psi over atmosphere, it translates to about 12.7:1 effective compression. You are still pounding the same ammount of air in that cylinder as a 8.5:1 motor at 7.5psi - although I am simplifying this, you get the point; cam, porting, chamber shape can all have effet on the outcome.
Let's discuss,
-John
I boosted a 9.1:1 GM V6 last winter and is running 12's in an auto FWD car. My Firebird has 11.5:1 and am twin charging it. I will see the same effective compression at 6psi as a stock 9.6:1 V6 with 10psi (which is common place in my community).
What people don't realize is that when you apply more air to an engine (boost), you are raising the effective compression (compression the engine sees while running).
So, if we have a 9:1SCR and add, let's say, 6psi over atmosphere, it translates to about 12.7:1 effective compression. You are still pounding the same ammount of air in that cylinder as a 8.5:1 motor at 7.5psi - although I am simplifying this, you get the point; cam, porting, chamber shape can all have effet on the outcome.
Let's discuss,
-John
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