Opened My Dart 225's to 65cc
 

Together with my 4cc Mahle forged pistons and 4" crank can anyone tell me what comp ratio i am at? We run 95 ron fuel here at worst but mostly i use 98ron. Did some cleaning up while there too! I dont want to get into detonation situ's, what kinda cc's are you guys running. 4.070 Bore by the way.
http://i118.photobucket.com/albums/o...na/pipette.jpg
http://i118.photobucket.com/albums/o...xportdarts.jpg

With GM MLS gaskets and 005 out of the hole I get 11.769633146784093:1 cr.

Here's the link I always use:
http://www.csgnetwork.com/compcalc.html

I am using standard LS7 head gasket, i'm not sure your calculation is accurate enough..:)

What leads you to believe that?

4.07 bore
4.00 stroke
4.15 bore diameter
.053 compressed thickness
65cc combustion chambers
-4 cc valve reliefs
.005 out of the hole assuming you decked the block some.

= 11.702361206703528:1 CR

Zero deck = 11.561075648797588:1

.005 in the hole = 11.423471805965205:1

If you give me the pistons you are using and your deck height I can get it down exact.

use this http://www.c5frc.com/calculators/Com...Calculator.htm

Sorry i was being ironic! Thanks for the help...really! Standard deck height. I am waiting on the rods to land so i can see whether i am poking out or not! I've also got to slot the piston on the exhaust side as the centre on the L92 pistons is not in the same place, which will drop the comp a smidge, so i should be good to go as far as to not having detonation problems. Cheers.

Assuming you are using the following Mahle L92 pistons:
http://www.andersonperformance.net/mahlel92.jpg

and the block deck is stock at 9.240" with 6.125" rods as specified puts the pistons in the hole .010"

With all these assumptions, the compression ratio is:
http://www.andersonperformance.net/lstvr-cr.jpg

Yep, thats the ones. Thanks for the info.

Cheers Paul.