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spuggy spuggy is offline
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Join Date: Jul 2003
Location: Glorious Pac NW
Posts: 2,831
Originally Posted by Alan L View Post
I understand it is for dumping excess pressure?
Yeh, separate wastegate dump pipe. If it has a little stubby muffler as well, it's the factory Euro-style separate wastegate - some cars fed the wastegate into the muffler, the back pressure from which can make it harder for the motor to dump excess boost, so separate is better.

I run the stock factory muffler with an open wastegate pipe. Nice and stealthy pottering about until it starts regulating boost - at which point you basically go to an open exhaust from which a very hot flame issues...

Any suggestions on how to check the operation of the over boost valve would be useful.
Multimeter across the terminals, pressurize. Factory manual says it should open (break circuit) at 1.1 - 1.4 bar, IIRC. And therein lies a clue - if you leave it disconnected, the fuel pump circuit won't complete and the car won't start...
'77 S with '78 930 power and a few other things.
Old 09-14-2007, 07:58 AM
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