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View Full Version : Compressionratio with high boost?



suutari
01-14-2005, 12:19 PM
What compression rates are you using and what boost?

How about say 8.8:1 + 14lbs boost...

What is teh TOP compression ratio without detonation problems with programmable ecu that someone has came up say around 14+ lbs boost figures?

XR7 Dave
01-14-2005, 12:25 PM
Stock is 8.4:1. I'm not sure I undersand your question completely. You can run 10:1 with 14psi if you have the correct tuning and fuel. It also depends on altitude. With the stock programming anything more than about 9.0:1 is generally going to result in issues because the stock timing (on most SC's) is pretty aggressive already. Not all SC's are the same, it depends on processor code.

Hock
01-14-2005, 02:41 PM
How bout at sea level?

suutari
01-26-2005, 01:37 PM
Hmm.. well I have programmable ecu so I guess 8.8 is okay. Just want to check things before putting the motor together. I'm planning to install new cam too in ball park figures around 272 intake 280 exhaust 112-114 lobe angle and about 11mm lift at the valves..

XR7 Dave
01-27-2005, 09:41 AM
Hmm.. well I have programmable ecu so I guess 8.8 is okay. Just want to check things before putting the motor together. I'm planning to install new cam too in ball park figures around 272 intake 280 exhaust 112-114 lobe angle and about 11mm lift at the valves..

11mm is about stock lift. You should be looking for at least 13mm.

suutari
02-03-2005, 10:27 AM
In BMW 325i ;)....