20/21 cams and CIS

[rdane]

In an earlier thread and some cut and paste,

Noah said, "964 camshafts are compatible with CIS injection, but produce about 10 more horsepower and a more peaky power curve.... Where stock CIS engines are out of breath by 5,000 RPMs, with 964 cams they pull strongly straight up to redline.

All the U.S.-market 911SC’s ran 8.5:1 compression until 1980, when they were permanently upgraded to 9.3:1 compression, and the Carrera 3.0’s had 8.5:1 compression. You can get a respectable power increase (especially in torque) by bumping compression up to 9.5:1, or even 9.8:1.........roughly speaking, you get about a 10 percent power increase per compression point increase.

That should be 20 hp for the SSI and muffler, 10 on the cam and another 20 for the compression increase from 8.5 to 9.5. That makes an additional 50hp on a 180 @ the crank start should give you 230 at the crank or 200/ 205 at the wheels. Noah's came in at 203 IIRC.

Just dynoed my '79 today. Here are my engine specs:

Turbo camshaft oil line restrictors
B&B stainless front spoiler oil cooler
Webcam, performance grind, 20/21 camshaft
new OEM rockers
SSIs and a dual outlet Danke stainless
Pre 1974 oil lines
light Flywheel

182hp at the wheels and 168 torque

HP drops at 6500rpm
Torque drops at 5500

Torque starts @ 3800/4000
High Performance Aluminum Flywheel

Not bad for a engine that started new from the factory with 180 hp at the flywheel and now has approx. 215 hp and 190K miles. No problem running the engine up to 7K just no need as the dyno graph shows.

Looks like the Noah's original numbers and speculation was pretty close. Easy to see what I will be doing next

[turbo6bar]

So if I am reading you correctly, you believe a stock engine with 8.5:1 CR will yield about 155 HP to the wheels. That would be 180HP minus ~15%. The cams and exhaust added about 25-30HP.

Hmmm, I have an 83 engine (higher CR), small port heads and the early EURO SC injection. Match port heads, add SSIs, and later do the cams. Sounds like fun...

I thought you were going to buy a 3.6?

Jürgen

[rdane]

Sorry Jurgen I double posted this.

Hre is the other thread:
http://forums.pelicanparts.com/showthread.php?postid=960199#post960199

Still looking at another engine but while that one is in the works I ma adding to what I have

Can some one lock this thread or delete it? We cna continue the conversation on the duplicate post. TIA