Quote:
Originally posted by JET+Oct 26 2003, 06:06 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (JET @ Oct 26 2003, 06:06 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-Raptor@Oct 25 2003, 04:27 PM
The wastegate hole diameter becomes a bottle neck in many systems with increased exhaust flow. You can make the entry into the wastegate as free and easy a transition as can be, if the wastegate itself is too small it is still a restriction and will still cause boost creep.
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You have to remember that restriction in a tube is consistent with the length of the tube. A wastegate port is only a restriction for 1/2", so it is not that big of a restriction. The low pressure area created on the other side will help to suck the exhaust out of the wastegate hole. Just think of the stock TB on the high HP cars, they get away with it because it is not very long.
Anyway, after taking my turbo off and porting it 3 different times, I finally figured out how to eliminate the creep on my 16g. I had a full 3" from the turbo back, so that is a good boost creep test. [/b][/quote]
So by that theory then, it wouldn't hurt to run a smaller turbo gasket that protruded into the exhaust flow by a centimeter or so because it is only .030" thick or so and couldn't be much of a restriction. Or weld a washer in your exhaust pipe and not worry because it isn't very thick. Also, if diameter of the gate doesn't matter, maybe people are wasting money going larger internal or external. I agree to some extent with your comment about the restriction being somewhat length dependant as well, but only in certain applications within specific velocity ranges. The higher the velocity of flow, the less it will require to create a significant restriction. Would you agree with that?