Boost Compression Ratio
Thread Starter
Melting Slicks
Joined: Feb 2006
Posts: 2,163
Likes: 5
From: Houston
Boost Compression Ratio
When you run lots of boost keeping the heads planted on the deck seems to be a big concern. Some people I've talked to seem surprised that I do not push any water with stock heads, gaskets, and bolts at 17psi. I am getting ready to up it to 20psi which some people would think is just nuts.
I have some doubts about which factors are most key in keeping the heads down. I'm thinking that 20psi is not that much ASSUMING a cool combustion temp with no detonation.
Either way I wanted a way to roughly measure how much actual pressure was in the cylinder. After calculating it manually I found this online calculator.
http://www.rbracing-rsr.com/compression.htm
It looks like I'll be going from an effective comp ration of 22.64:1 to 24.79:1.
Has anyone has an lsx setup with a higher effective comp ratio? What was the setup, and what types of issues did you run into?
I have some doubts about which factors are most key in keeping the heads down. I'm thinking that 20psi is not that much ASSUMING a cool combustion temp with no detonation.
Either way I wanted a way to roughly measure how much actual pressure was in the cylinder. After calculating it manually I found this online calculator.
http://www.rbracing-rsr.com/compression.htm
It looks like I'll be going from an effective comp ration of 22.64:1 to 24.79:1.
Has anyone has an lsx setup with a higher effective comp ratio? What was the setup, and what types of issues did you run into?
Le Mans Master
Joined: Oct 2006
Posts: 6,080
Likes: 0
From: Houston TX
I got this:
Boost and Altitude Correction to Compression
You are running 20 PSI of boost at an altitude of 100 feet. Your motor's static compression is 9.5 :1. At this boost level and altitude your effective compression ratio is 22.41 :1, and without altitude correction your compression ratio would be 22.43 :1.
Boost and Altitude Correction to Compression
You are running 20 PSI of boost at an altitude of 100 feet. Your motor's static compression is 9.5 :1. At this boost level and altitude your effective compression ratio is 22.41 :1, and without altitude correction your compression ratio would be 22.43 :1.
