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spuggy spuggy is offline
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Join Date: Jul 2003
Location: Glorious Pac NW
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Quote:
Originally Posted by les_garten View Post
I think there may also be an interaction between the high overlap and the metering plate in the CIS fuel head that does not respond well to back pulsations into the manifold. Don't quote me on this though.
Heh. Sorry Les, I quoted you. No trouble mate..

The above is perfectly true for N/A cars, I've read. And the main reason the old 'S' cams are a lot hotter than SC cams.

But it doesn't apply to a turbo I'm told - as there's so much distance between the intake valves and the plate that it's not a factor in the same way.

I think the issue here is that they're high-overlap cams, and don't work well out of the powerband - an effect that you can offset somewhat with EFI.

So it comes down to whether you want top-end performance at the expense of lower/off-boost (964 or hotter), or good low-down, off-boost response - and still improved on-boost power over factory (SC).

My tuner told me "your car would make more power with 964 cams". I told him I thought the car was very streetable, and that I didn't feel like I was exactly hurting for top-end...

It seems to me like the original poster doesn't like the characteristics of the 964 cams in everyday driving and would like to trade some top-end for better low- to mid-range. Especially given camgrinder's comments that the 964 cams move the boost point up the rev range as well as giving less low end response than SC.

TURBORS930, can you comment on that? What turbo are you running and what other mods do you have?

Also, I see that camgrinder gives 1.26mm for 964 cams, and you're asking about using 1.46mm as though that would be retarding them, whereas that would appear to be advancing them 0.2mm?

Whose cams are these, and what did they recommend they be timed at? How do they compare to camgrinder's profile?
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'77 S with '78 930 power and a few other things.
Old 12-18-2007, 12:03 PM
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