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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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Originally Posted by cole930 View Post
Simply slowly apply air to the lower wastegate port and read how much it takes for the wastegate to open, .7 bar spring should require .7 Bar air pressure to open.

Let me just add one little piece to this. Provided your WG is in good condition with minimal blow-by through the valve guide and/or seat, Coles advice will hold true. You may find that when bench testing, air pressure in excess of the stated spring will be needed to open the valve due to air leakage past the guide (in the neighborhood of .8 or .9 bar of pressure to open it). But when in the car the exhaust pressure has an additive affect to the boost air pressure and it will open just fine at .7.

I found that to be the case years ago when testing my Tial before installing. My old stock WG took almost 15 psi to open with a .8 bar spring on the bench (and I could hear the air blowing by), but it worked just fine in the car.
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 06-17-2010, 10:19 AM
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