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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,273
When you remove the big origonal blow off valve housing or intermediate manifold there will be 2 unused 8mm threaded bolt holes in the intake manifold that were used to hold the oem housing onto the intake manifold.

Then you will have to weld on an aluminum support bracket to the back of your short neck intercooler if you're using that.
The bracket goes down to the bolt hole or threaded boss that is closest to the CIS air flow meter housing.
It fits and works perfectly and it's alot easier to remove and reinstall than the origonal setup with it's harder to get at hoses and hose clamps.

Here's a pic of the back of the used long neck half bay garretson intercooler I have on my car before I cleaned it up, polished it a little and installed it.
You can see the support bracket on the back.

Left to right the fittings are:
cold start aux air valve, throttle body, deceleration valve, oem boost gauge sending unit, the rear mounting bracket, 2 small fittings are for the wastegate hose fitting (a 90 degree fuel line fitting will screw in there for the hose) and the overboost sending unit, and the larger one is for the hose going to the C2 blow off valve you'll be using in the big rubber hose origonally for a 964 turbo off the CIS unit with a long neck intercooler.

The other hose connection for the decel valve will be visable on the intake manifold after you remove the origonal blow off manifold, it will be right below where the decel valve fitting on this intercooler is when it's installed.
Using it as a throttle body bypass valve/vacuum limiter valve like it is origonally installed is optional and up to the user.

I plugged the intake manifold fitting and currently have the decel valve venting to atmosphere because I like the little fooosh sound it makes if you have .3bar or more turbo boost when you let off on the gas between upshifts and it richens the mixture to around 10:1 on deceleration which is not a problem.
If it is hooked up to vent back to the intake manifold like it origonally does it slows down engine deceleration between upshifts as if the flywheel gained another 30 pounds and I really don't like that..
It may actually improve throttle responce a little when you get back on the gas during upshifts because it helps keep the turbo spooled up along with the blow off valve with a closed throttle between shifts andventing metered air to atmosphere between shifts makes the fuel mixture just a little richer the instant you get back on the gas kind of like an acceleration pump would do in a carburator.

Here's a pic of the bottom of my intercooler while installed showing the decel valve vented to atmosphere with a small downward angled hose to keep water from getting in if caught in rain or a carwash.
Old 11-23-2009, 10:21 AM
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