Compression increase = how much HP?

[DownShift96GSR]

Does anybody know how much HP per .1 compression? For example GSRs are 10:1. Now if I were to raise the compression to say about a 10.6:1 about how much power will that add. A friend of mine said its 5HP per .1 compression. So if my compression ratio is raised to a 10.6 is that equivilant to adding 30HP? I'm just looking for someone with more info on this compression ratio stuff. Thanx.

 

[Baldy201]

There is no specific number that if you raise your compression that you wil lget this amount of HP. there are many of other factors that your have to look at when uping comprssion. Cam duration, cam lift, flow quality, flow velocity, stuff like that. There is a point that you can have too much compression and numbers will start to drop off.

 

[DownShift96GSR]

Ok that kinda helps. I read in a old issue of HONDA TUNING tha you could take the pistons out of a B16A and drop them into a GSR motor and the compression will go up almost a full point. My friend is selling me some pistons and rods, although I don't need the rods, for $75 so that's what I'm doing and I was just wondering.

 

[hyper98gsr]

that is true. i have p30 pistons(jdm b16a).

 

[Baldy201]

Sorry my post was not too much help. I really dont have a lot of experiance with compression and HP numbers yet, but i am learing. When i find out more info i will post.

 

[DownShift96GSR]

I think I've anwered half of my question. I believe I have figured the dome cc's out on the B16A pistons. If I did my "homework" correct the cc's on those pistons are +3.0125 which will send a GSR's C/R to like an 11.4:1 but I could be wrong. I used the C/R calculator on ROSSPISTONS.com to figure it out. I also went to ARIASPISTONS.com to find each of the engines block specs. So if anybody knows any different feel free to correct my screw up.

 

[hyper98gsr]

yea thats the c-speed one right? i figured it to 11.3:1 then i added the .4 from the head gasket.

i have been hearing alot of talk lately about how you should stay with flat top slugs. you hear anything like that?

 

[Eviloliv3]

http://www.c-speedracing.com/howto/compcalc/compcalc.php

i love that thing, i probably go there at least 3 times a week, just trying out different combinations.

its also a great way to figure out what is what. as in what the real compression would be with 11.5 CR pistons in your engine (usually less than advertised)

 

[DownShift96GSR]

I haven't heard anything about staying with flat top slugs. It makes sense to stay with them if your gonna turbo the car....but otherwise I haven't heard anything.

 

[DownShift96GSR]

The website is off the hook. I wish I would have known about that one sooner. But i'm still trying to figure about how much power/torque are those PR3 pistons supposed to add?

 

[Eviloliv3]

pistons dont set a specific amount of HP. you have to tune them, and sometimes they work better in one engine than they do in another. any number that is given to you would be an extreme guess, and would only be assuming that you had perfect tuning unless otherwise noted

 

[hyper98gsr]

exactly. without your motor tuned you cant really estimate the gained horses. also, your motor is tuned to YOUR modifications. so it would be of little help to someone else, sometimes even with the same mods.

 

[DownShift96GSR]

THAT PRETTY MUCH SEEMS REASONABLE. QUESTION ANSWERED. WELL THANKS FOR THE INPUT AND THANKS FOR LETTING ME KNOW THAT WWW.C-SPEED.COM SITE.