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911nut 911nut is offline
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Join Date: May 2001
Location: Michigan
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Originally Posted by WERK-I View Post
Personally, I would go the SSI route for the following reasons;
1.) Like you said the primaries on the 993 HE's are bigger, so you will see a increase in spool-up time due to the loss in exhaust gas velocity. Not really an issue for a track car, but for the street...noticeable.
2.) I don't know how long the 993 HE's will remain "cheap".......
3.) The SSI's are known to produce good power and are very reliable. A friend of mine runs that setup on his track car and hasn't had any problems over three years.
4.) The 993 HE's operating under high turbo temps is an unknown factor. What's their longevity?

On the other side of the coin.....I do think a nice polished set of 993 HE's look better than the SSI's.
There may be some tradoffs with this system:
* shorter exhaust gas path, therefore more energy available to spool up the turbo due to less thermal and friction lossess.
* Reduced backpressure vs stock system due to shorter path and bigger primaries
* Larger primaries reducing gas velocity, increasing turbo spool time

Some experts indicate that large primaries are desireable on turbo applications as heat energy is responsible for 80% of the energy driving the turbo.

The only way to know how it will all work is to build a set.

The 993 H/Es should hold well as they are made from a far more robust material (409 SS) than aftermarket headers. For me, that is one of the attractions of this system.
As for 993 H/E cost, I don't foresee a big demand for them unless all the SC/Carrera owners decide to put 3.6 engines in their cars
Paul B.
'91 964 Turbo
Port matched, SC cams, K27/K29 turbo, Roush Performance custom headers w/Tial MV-S dual wastegates, Rarlyl8 muffler, LWFW, GT2 clutch & PP, BL wur, factory RS shifter, RS mounts, FVD timing mod, Big Reds, - 210 lb

Last edited by 911nut; 12-13-2008 at 07:27 AM..
Old 12-13-2008, 07:24 AM
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