2.7 rebuild
 

Hi

I am planning to rebuild my 2.7 CIS. When I have the engine apart I was thinking I could try to get some more HP out of it. I was thinking of keeping the CIS, change the cams to 964 profile, change pistons to increase the CR to approx. 9.5:1 and backdate the exhaust (SSI).

Anyone have any experience with a setup like this or have any comments/suggestions? What can I expect of horsepower for such a setup?

Sigmund, I'll be watching this thread closely as this is an upgrade I'd like to do in the future. I believe there's some good info on this topic in the 911 technical article section. Good luck, Pete

Yes, I plan to use the CIS. As far as I know it should be possible to get some 90mm JE pistons that will increase the CR to 9,5...?

i used forged 8.5 RS pistons w/CIS and no problems.

what was the hp. formula 10 per pt of c/r bump??
From the archives of what I think I know..the CIS will not care what your pistons look like or their c/r The cis will not work with cams that have over lap ( flapper valve jumps with the reversion thing)

I did a 2.7 about 8 years ago with SC cams, Euro pistons and kept the CIS. I milled .030 off the heads to get 9.0:1 CR. If anyone is interested I have dyno results of the engine in Excel format. Send me your email address and I will share the data. I sold the car 3 years ago. It is still running track/AX events after 8 years and sounds great according to a friend who sees the car occasionally.

I'm just finishing up another 2.7 with 2.9 Mahle 9,2:1 pistons and 3.2 cams. Still with CIS. It feels stronger than the previous engine but no data yet.
Both have early sport mufflers (loud).

Hi,
I'm interested would you please send me the dyno results of the engine.
Thanks a lot.

Can't you post the dyno result, if you have it in excel just take a screen shoot.