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Join Date: Jul 2006
Location: Norway
Posts: 71
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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?
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Sigmund 964 -92 911 -76 912 -67 |
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07-04-2007, 12:51 PM
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Join Date: Dec 1999
Location: Woodinville
Posts: 86
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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
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Peter Sarmany 1974 914/4 1.8 / 1976 911S coupe / 1976 VW Transporter / 1987 VW Syncro GL / 2004 Audi Allroad 2.7T 6 speed |
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07-04-2007, 08:35 PM
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Join Date: Jul 2006
Location: Norway
Posts: 71
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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...?
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Sigmund 964 -92 911 -76 912 -67 |
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07-04-2007, 11:11 PM
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Join Date: May 2001
Location: Peoples Republic of Long Beach, NY
Posts: 21,140
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i used forged 8.5 RS pistons w/CIS and no problems.
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Ronin LB '77 911s 2.7 PMO E 8.5 SSI Monty MSD JPI w x6 |
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07-05-2007, 06:20 PM
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Air Medal or two
Join Date: Jul 2003
Location: cross roads
Posts: 14,089
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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)
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D troop 3/5 Air Cav,( Bastard CAV) and 162 Assult Helicopter Co- (Vultures) South of Saigon, U Minh Forest, Delta, and all parts in between |
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07-11-2007, 09:28 AM
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Join Date: Sep 2001
Location: Sebastopol, CA
Posts: 111
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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). |
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07-15-2007, 08:06 PM
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Join Date: Jul 2007
Posts: 1
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Hi,
I'm interested would you please send me the dyno results of the engine. Thanks a lot. |
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07-21-2007, 04:14 PM
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Can't you post the dyno result, if you have it in excel just take a screen shoot.
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Magnus 911 Silver Targa -77, 3.2 -84 with custom ITBs and EFI. 911T Coupe -69, 3.6, G50, "RSR", track day. 924 -79 Rat Rod EFI/Turbo 375whp@1.85bar. 931 -79 under total restoration. |
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07-22-2007, 06:42 AM
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1977 Porsche 911 Targa 2.7s
