I am looking to understand what CC means and what are good and bad numbers.

Just wrapping up a build for my '10 SG. HD 103 kit, SE255's w/ compression releases. Jugs shaved to achieve .001 deck height and squish set at .040.

Had the heads cleaned up a bit, nothing extensive and the mechanic says they are 87 CC. I understand deck height and squish but do not know about the CC's???? According to him my compression should be 9.9-1, which I'm told the 255's will like.

Can anyone comment on any of the above numbers, good OR bad?

 

All you motorheads & no comments or explanations! LOL

 

cc's as far as heads go is what the actual volume of the heads are. The bigger the volume the less compression you will have. If you do a google search for twin cam compression calculator you will find a site that lets you plug your numbers in and find out what your actual compression ratio should be or close to it. Bigboyzheads has a great calculator.

 

http://www.bigboyzheadporting.com/TwinCamComp.htm

 

http://www.bigboyzheadporting.com/TwinCamComp.htm

You'll LOVE the build! I was a little uncertain initially about my cam selection, but this thing wicks and pulls like a freight train straight off the line.

 

Thanks for the link guys.

I am not sure of some of the numbers, but maybe I can get those from the wrench.

He is saying 9.9-1 but with the numbers I put in it was closer to 9.4-1. I am hoping he is right!

 

Measure your deck height, get as close to .030" quench as possible with the appropriate Cometic head gasket. If 87cc is where you end up with your heads in conjunction with the aforementioned, get a good tune and hold on!!! That would make for an approx. CCP of 202 @ sea level. Granted you have access to good fuel and/or good tuner. The 255 cams will move that bagger down the road in a hurry and you'll run out of throttle before they run out of OOoomph! You'll be over 100ft/lbs TQ right out of 1800rpms. Gone Pecawn!

There is no replacement for displacement REGARDLESS of some of these "dynotune" sheets flying around in here.

 

I get 9.71 (corrected) compression with the 25 intake close using my calculator, .040 gasket, 87 cc chamber, zero deck and flat tops. 204 ccp.
You do have flat top pistons, right?


Do you have compression releases?

That bike should rock.


Edit: The calculator did show your Static (uncorrected for cam) compression to be 10:1 so your guy did tell you right.

 

keep us posted after the build, sure sounds like a great recipie.

 

Thanks guys! Heading to pick it up in an hour or so. Can't wait to get a few miles on it and have it Dyno tuned. Going with a TTS Mastertune and having Doug Lofgren tune it.

Yes, manual compression releases & flat tops.

Should easily be 100 ft pounds, maybe more I hope!