Pretty muchwhat the title says...What kind of Power difference is there between a high compression and a low compression N/A engine given the same displacement and H/C/I etc...
I've been wondering about it since I started driving my low compression turbo motor around...tomorrow IRS retting Dyno tuned but I'm still curious as to how big of a loss you take with compression issues. I'm guessing the difference between 8.8:1 and 11:1 is about 100hp.


Speaking if which, any guesses on tomorrow's results? Forged 370ci motor with high flow WCCH heads, 218/218 114LSA CAM and free flowing exhaust behind a 4l80e.

 

~380-400rwhp because of compression, cam, and 80e.

 

There's a formula but I forget, something like each .1 CR+ = X hp.

you are dyno tuning tomorrow?

394rwhp

 

I think it all depends on the cam and head combo...a high compression engine with a cam with a lot of overlap can run more timing than say a high compression with a small cam, as the engine with the smaller cam will be more prone to detonation. I believe that in most cases though, with all things being equal, and a camshaft of decent duration (somewhere in the middle of what's optimal for both high and low compression), high compression wins. I'm not an engine guru, this is just how I see it from what I've learned through the years.

 

not much help, but post your results. I may end up running mine NA for a while. Only thing is im stock heads, boost cam, 10.4 CR

 

I always thought of it a little differently but i may be way off...

A high CR engine with a High DCR would have timing limitations but make more power with less timing.... Because of the build up of heat caused by the CR and DCR it would be prone to detonation this is where higher octane comes into play. A low CR engine is more forgiving on the timing meaning it could run more because it would produce less heat thus less prone to detonation but it would make less power...

 

Well some of you guys sure optimistic!!
I'm guessing 320rwhp and that's being conservative so maybe it's more. In all fairness I've yet to actually do a full pull on the truck for various little things I've got to finish on it. Right now I'm headed down to put the Wilwood's back on and drill out the PCV so it will stop popping off...hope that drilling that valve will not create so much backpressure.
I will post up when I find out...

 

If you dyno 320 rwhp, you need to burn that thing to the ground...

 

1 pt is about 4%. so your down about 8-10% in power.

 

im sayin youll do at least 350 RWHP liked stated above if yoiu dont make at least that then something is wrong IMO