hp per point of compression?
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TECH Fanatic
Joined: Mar 2003
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From: Jersey boy
hp per point of compression? i know its been said before but i went through about 6 pages of 200 posts each with the search function and couldnt find it.
anyway. does anyone know how much horsepower is gained from adding 1 point of compression? im looking for prefferably a precentage number but anything that comes to mind would be a help
. just wondering if it would be worth it bump compression on a stock mototr 
anyway. does anyone know how much horsepower is gained from adding 1 point of compression? im looking for prefferably a precentage number but anything that comes to mind would be a help
. just wondering if it would be worth it bump compression on a stock mototr 
TECH Senior Member
Joined: Nov 2001
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From: Troy, AL
Re: hp per point of compression? It's less and less the higher you go. I.E. the gain in going from 10:1 to 11:1 will be alot more than when going from 13:1 to 14:1. My guess? Going from 10:1 to 11:1 will yeild roughly %.03.
Re: hp per point of compression? There was a test in Car Craft awhile back that indicated 3%-4% per full point of compression, and IIRC, they went from 8:1 to 11:1 on the same motor by using different thickness head gaskets and/or stacking multiple head gaskets. Not my preferred method for lowering compression (especially on a quench-head motor), but the results were pretty consistent.
I'll see if I can dig up the magazine later tonight.
I'll see if I can dig up the magazine later tonight.
Re: hp per point of compression? I just went through that today. I found a research paper from the 20s and Vizard's book. According to those resources, it looks like around 1.5% per point. However, it also looks like you can run 10 degrees more duration on the cam per point of compression, which might make more power.
