I just got my turbo installed and I'm running an open downpipe. Now I've read that the wastegate needs some exhaust backpressure so that the exhaust gases will pass through it (being the path of lower resistance) rather than the downpipe. The article I read said that with an open downpipe or a 3" exhaust+testpipe, the wastegate won't really be effective. Is this correct?

PS: The reason I ask is because I've got 5 count 'em five check valves teed off my MAP vaccum line and I'm still getting a CEL.


[Modified by filetofit, 7:59 PM 6/7/2002]

 

if the wastegate is mounted in a location that effectively controls boost (IE; not of off 1 runner) then u will not have a problem

 

i had a problem with the check valve setup on my GS-R. The car would shut down when u hit the gas. The vaccuum in the line to the map could not move back and fore. thats y they have the missing link.
i hope this helps

 

ie: The drag manifold?

 

If you have an external wastegate, control won't be a problem. If you have an internal wastegate and a free flowing exhaust, you might have a problem like me. Basically, my internal WG is too small, and there's no backpressure so the exhaust flows like crazy and the WG can't keep up and can't vent off all the excess boost, therefore causing a drastic boost creep scenerio. If I go WOT on my car, I'll hit 21 pounds...I'm supposed to be at 16-17.

Thats basically why an external wastegate comes in handy, its basically a for sure way to control boost because you don't have to worry about it being too small.

 

The turbine whel creates enough back pressure to where the exhaust would much "rather" come out the wastegate opening, than go thru the turbine. Even with a completely open downpipe.