can the dynamic CR be calculated?

i am planning on pr3 pistons in my b18b1 and bumping the static CR up to 10.8-11:1, and i have mild regrind cams installed already. i say mild, cause i gained approx 10whp/wtq from them.

problem is, i don't know what the lift/duration specs are for the cams, and i don't want my dynamic CR to be too high once i install the pistons

thoughts?

here's fuel/ignition setup:
MSD ignition w/external coil
255lph walbro pump
91 octane
OEM 240cc injectors w/fuel pressure at 48-50psi at WOT

i will have adjustable cam gears and full p&p head/im/tb installed prior to dyno run for tuning w/wb o2




[Modified by DOHCDX, 6:03 PM 1/24/2003]

 

"dynamic" as in on boost compression ratios? yes, they can be calculated.

11:1 Compression 6 lbs boost ~15.5 c/r

11:1 Compression 7 lbs boost ~ 16.3 c/r

11:1 Comrpession 8 lbs boost ~ 17.0 c/r

Etc etc...

 

i cant see anything thats he said about boost....
..well anyways.. here ya go...but your gonna need those cams specs...
http://www.rbracing-rsr.com/comprAdvHD.htm

 

I know it can be calculated but I'm not sure how. If you get the specs on the cams and talk to a really good head porter, they can probably help you out. The cam manufacturer can probably held you pick a CR too.

 

no, definitely NOT under boost

thanks for the link.

 

:wink:
heres more:
http://www.team-integra.net/sections...?ArticleID=472

http://www.team-integra.net/forum/di...1&ThreadPage=1

 

well, i don't know how accurate this is...

here's the results, i estimated 40deg for intake ABDC cause that yielded ~211psi for cranking pressure, which sounds about right. thing is, it said the dynamic CR would be 10:1 at my elevation

 

yes, excellent info!!!!!