Wastegate wear?

[dkw_dude]

Hi fellow S2 fans!
I have a -91 S2 3B, it has rolled ~220 tkms. I think the wastegate is somewhat tired, but don't know if it affects performance, don't want to exchange it unless I have to.

The membrane is in good shape I think, but when I pressurize the intake there's a significant leak in the WG when going past ~0,5Bar (guess this is the actuator opening, and air leaking past the stem?). When squeezing the WG hose the pressure stays up nicely.

Removed the WG cap and measured play in the WG "valve", was ~1 mm.

Is this normal or should i change the wastegate?

Regards,

[Lee]

I can't help you on your problem but I love your signature: "Expensive fun, but you only live once.. ". My kind of thinking!

Welcome to the board. I'm sure you'll find help here from one of the resident experts.

Lee

[S2central.net]

I have noticed this on several S2's - with less miles than yours. I'm told it is a normal thing, but it must reduce performance if the WG actuator is leaking that much air. My car is the same recently and I have seen this weirdness. I don't want to mess with my own wastegate, so I have bought a spare one (from Marcos cavern of S2/RS2 parts) to do some investigation and see what is really going on.

My current WG won't even hold 0.5bar on the actuator input hose... and recently I've seen max boost drop from 1.4bar to 1.2-1.3bar - so unless I have a little air leak - possible - I am suspicious of this WG behaviour.


Paul

[Doug_RS2]

Are you putting positive pressure in via the banjo connection of the wastegate?

I'm sure mine has a bit of play as well.

[S2central.net]

Yep - positive pressure into the actuator input - am sure mine is leaking more than it should. It can't be the actual WG 'cracking' below 0.5bar on my car - I'm assuming there must be some sort of seal around the actuator shaft that is shagged out after 120k miles. Mihnea says he's seen it often... and reckons its 'normal' but I don't like it as it must surely detract performance as pressure is surely being lost.

I will be testing the spare WG when it arrives home from the Italian Job.

Lets hope we can find a source of a suitably wondrous after-market seal or engineering firm that can restore these leaky WGs to full health. Gotta wonder if AET or any of the other well known turbo reco firms can do this kind of work. Anybody BTDT ?


Cheers,

Paul

[Doug_RS2]

Paul - I'm getting the 3B wastegate from Marco (just becasue my shaft is bent ) Do you want to have a look at that as well - as another comparison? I'm in no hurry for it.

We can try a few cars this weekend, with a mityvac, if you want some more data?

[S2central.net]

Yeah Doug - please do that if you can...

I've got Jim, Martyn and Sal here over the weekend for various chip, Samco and diagnostic treatment so I'll also stick the trusty MityVac onto their WG's as well.

We should then have about ten results to compare...

Cheers,

Paul

[newsh]

Paul, I've got a virtually new WG on mine for comparison if you'd like to test it.

[dkw_dude]

Thanks for the warm welcome Lee , nice to see the interest in this topic. I'm trying to get hold of a used one in good shape, would be interesting too see if it makes any difference. I believe some power is lost because of the worn wastegate, but don't know how much.