Shimmed wastegate, how to chose opening pressure.
01-14-2002, 03:50 PM
#1
Track Day
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Join Date: Jul 2001
Location: Sunderland, England
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Shimmed wastegate, how to chose opening pressure.
Hi,
My '86 turbo has been reprogrammed to run 13.5psi. During acceleration it overboosts slightly to 14psi. To get the benefits of the new programmes I had the wastegate checked to see if the spring had gone weak.
With the wasteagate removed from the car compressed air was hooked up to the diaphragm.
The valve opened with 5.9psi applied.
I am told a new standard wastegate will open with 8.1psi applied in the same way.
So I shimmed my wastegate to open at 8.8psi.
Can anyone confirm what pressure a new standard wastegate opens at when tested as above?
More importantyly, what would be the best pressure setting for my wastegate knowing I want to run 13.5psi. I am more concerned with getting the turbo to spool up than top end power.
Regards
Paul R
My '86 turbo has been reprogrammed to run 13.5psi. During acceleration it overboosts slightly to 14psi. To get the benefits of the new programmes I had the wastegate checked to see if the spring had gone weak.
With the wasteagate removed from the car compressed air was hooked up to the diaphragm.
The valve opened with 5.9psi applied.
I am told a new standard wastegate will open with 8.1psi applied in the same way.
So I shimmed my wastegate to open at 8.8psi.
Can anyone confirm what pressure a new standard wastegate opens at when tested as above?
More importantyly, what would be the best pressure setting for my wastegate knowing I want to run 13.5psi. I am more concerned with getting the turbo to spool up than top end power.
Regards
Paul R
01-14-2002, 05:42 PM
#2
Race Director
The pressure that opens the wastegate should only be indicative of the strength of the spring tension. Which should be strong enough to resist exhaust pressure, but not so strong that you can't open it by applying pressure to the diaphram.
As to the "how to apply pressure to the diaphram", and "how to get the turbo to spool up quickly", that's a boost-controller issue. Only an electronic controller will have the intelligence and programmability to do what you really want.
As to the "how to apply pressure to the diaphram", and "how to get the turbo to spool up quickly", that's a boost-controller issue. Only an electronic controller will have the intelligence and programmability to do what you really want.