Wastegate Valve diameter

[newsh]

I've just discovered there are different sizes of wastegate on the S2 and I wonder if there are different part nos for the 3B and ABY Wastegates ( I was aware that the springs may be set differently but not of any other mechanical differences..)

This was discovered when my GT3071r was fitted and I was getting boost creep at high RPMs. We thought there might be a fault with the WG but actually it turns out that not only was it not opening fully due to poor machining but the valve was smaller than in the replacement one. It was obviously seriously impeding wastegate flow.

Anyone fitting a larger turbo and 3" system needs to be aware of this to avoid having to do the job twice.

[S2central.net]

I have an RS2 one in the garage - can measure that if you like... I'm not aware of any different WG types / sizes on the 20VT engines... Could it be you have one from an old 10V machine ?

[4WheelDrifter]

3B and ABY wastegate do indeed have different part numbers.

Here's the wastegate valve from my '91 3B.





I measure 37mm for the valve and 34mm for the opening.

[S2central.net]

One I have here is ABY/ADU - 034 145 705 E - valve measures 34mm... Rather that's the max width of valve I can measure as it sits in its seat i.e the opening is 34mm - same as Stu

[S2central.net]

Here's a pic...

[newsh]

Thanks guys, so we've got a 3B one and an RS2 one both with an opening of 34mm.

Yes its possible mine is from a 10vt but not since I've had it. Quite strange, I'll take some measurements tomorrow.

[newsh]

30mm for the opening and the valve only has about 6mm of travel

Pics taken with the valve fully open.

[javispa]

30mm for the opening and the valve only has about 6mm of travel

Which is the part number for this wastegate? Which car does it come from, have you checked this? Interesting thing.
Cheers!!

[4WheelDrifter]

What a strange thing. No wonder you were getting boost creep. IIRC you had boost trouble with the RS2 setup too.

[newsh]

What a strange thing. No wonder you were getting boost creep. IIRC you had boost trouble with the RS2 setup too.

Yup

[newsh]

Which is the part number for this wastegate? Which car does it come from, have you checked this? Interesting thing.
Cheers!!

I think the part number on these is on a tag under one of the cap bolts and this tag is missing..

[DavidG60]

I am experiencing the same boost creep problem with my setup.
It's a four cylinder (KR) with a RS2 manifold and wastegate.
The turbocharger is a GT3071R A/R 0.63 with K24 flange.
With the 18 psi spring in the wastegate, i can boost to 18 psi, but when i reach 6k rpm, it' creeping to 24-25 psi. (limiter at 7,5K)

My wastegate tag is 034 145 705E.
Did you solve this issue?
I'm asking myself if this wastegate is big enough???