Porsche Enthusiasts Club Forum

Hi all,

I have a few wastegate questions which I haven't been able to find answers to on any forums
1/ When testing the wastegate - to check the spring / diaphram and exhaust valve seal - I was going to apply pressure to the top, and inspect when the exhaust valve opens. (This is also to test a donor part I have) What bar pressure should I start to see the exhaust valve open? This probably applied to those shimming a wastegate to test the pressure which the wastegate needs to open the valve.

2/ Whats the best way to remove the wastegate? It looks like taking out the whole exhaust system - undoing the connection to the turbo, and the inlet pipe to the wastegate body. I need to replace the exhaust gaskets there are a few blows. The clarks garage guide seems impossible for my car, because the wastegate has studs for the inlet pipe, as opposed to bolts on the donor part I have?

3/ I see there are 2 part numbers for the 944 wastegate - one I believe is for the 250bhp model, mine is 951 123 015 04. Are they interchangeable? I.e. for a 220bhp model with part number ending 04, can the 250bhp wastegate be fitted?

4/ When should you shim a wastegate? I want the car to remain stock. In my mind, if I want to stay stock, only if the spring resistance is too weak should you shim the wastegate (unless you're trying to change the boost). This kind of circles back to #1, what bar should I be looking at for the WG to open?

Thanks in advance!

Hello,

1/ A new OEM wastegate uses a spring rated to open at a pressure of 0.4 bar.

2/ I can only comment on the later style cross pipe, but the easiest way I have found is to remove the front elbow at the wastegate inlet, then loosen the two rear bolts on the flanges of the outlet pipe of the wastegate going back into the main exhaust then sliding it out frontwards together with the wastegate. If the wastegate was never removed there is a 100% possibility that the studs will break off from having turned into very rusty bits over several decades, and the holes will have to be cleaned and retapped to be used with new bolts. You do want to use stainless steel bolts instead of studs & nuts when putting it back together. In fact, PET mentions 4 replacement bolts for connecting the outlet pipe to the wastegate.

3/ The early style wastegate as found on most of the 220hp cars feature larger cooling fins than the wastegate as found on the later 250hp cars. Makes no functional difference and both style can be swapped.

4/ See 1/

Hi TMM,

Thanks for your reply. I'll post my test results here in case they are useful for anyone to show what a used wastegate is like.

I presume for #1, that a worn wastegate will open at less bar pressure? I think mine opened at more, so I was concerned the diaphram was damaged or its a bit seized.

Thanks
Austin