My 3B to RS2 project

[newsh]

This is with N75 bypassed.

[Jonas_R]

I think it is leaking between lower and upper part, or atleast leaking from the lower part because:

The more boost you make the more pressure you will apply to the lower part of the wastegate and thereby pushing the piston upwards in the wastegate which will then make air go through the wastegate instead of the turbo. If you cant get it to hold mechanical boost, then you can't have an airtight lower part of the wastegate.

[newsh]

I think you may be right, only one way to check, so will be putting a new WG on.

[S2central.net]

Smells like WG valve is sticking open...

Assuming your diaphragm (and upper chamber) is airtight you can use a vac pump to suck the WG valve up and off its seat... Then when you quickly release the vacuum from the upper chamber you should hear the WG valve make an audible clunk when it is pushed back onto its seat.

[newsh]

Too much boost Paul, it would have to be sticking closed or not opening enough..

I've had the thing apart, the diaphragm is good but there's quite a bit of play in the valve guide. Could be enough that the lower chamber is leaking down into the exhaust.

[S2central.net]

Sorry - confusing myself here tonight with your recent posts about tests at lower pressures...

I remember attaching an airline onto the lower chamber of a perfectly good RS2 WG and was amazed at how much air it leaks into the escape chamber.

It was long ago and I remember speaking to Mihnea about it way back then - he assured me it was nothing to worry about as they all do this - the design is not supposed to be airtight - even though your gut tells you it should be.

Trouble is how much blowby is OK and how much is not ?

Only three things can keep your WG closed if the ECU is not involved...

1. The WG valve is sticking - sticking shut that is
2. There is insufficient air pressure getting to the lower chamber to open the valve (checked that line and/or WGFV for leaks ?)
3. The diaphragm is leaky and/or there is excessive blowby from lower chamber into the escape chamber

Does that make more sense ?

[S2central.net]

See this video...

http://uk.youtube.com/watch?v=FJ_W6g04xso

Tis in German but seems to show an S2 WG under test with a 1.9bar spring... Cracks open ~0.5bar BOOST and full open 0.9bar boost.

[newsh]

Cheers Paul
Yes, thats where I'm up to with it. Could be there's some buld up of carbon on the valve stem preventing it from opening fully and I didn't notice on the other turbo cos it didn't blow hard enough at the top end.

At the moment the car drives a bit like a sports bike, its as if it comes on cam at 4.5k starts boosting and just builds power to the redline as the boost gauge sweeps higher and higher, definitely wrong but quite exciting

Anyway, need to get the WG off and changed and see what its like then. It is the original one AFAIK with over 200,000 miles on it Theres quite a bit of play in the valve guide and this is in effect a boost leak although I guess its supposed to be a known one and so can be mapped for. If you had a leak like that elsewhere in the system it would be a problem I'm sure.

[newsh]

Just fixed the interior lights which hadn't worked for 4 1/2 years. Thread Here
This was as the result of investigating a problem with the central locking which turned out to be related to broken wiring loom under the carpet near the bonnet pull.

[jogi730]

Well done mate! Nice to know all problems get sorted eventually. 4 and 1/2 years though - hope they don't all take that long?
Cheers
CHris

[newsh]

A good result finally, I hate it when these little bits don't work, makes the car feel crap
Still a little bit of water leaking in, so hard to see where it comes from, will buy a new boot for the bonnet cable asap, silicon sealant may not have completely cured it.

[newsh]

Some parts arrived, 3" silencer, dB Killer and a Lamda boss and plug

[Rocco]

Some parts arrived, 3" silencer, dB Killer and a Lamda boss and plug

3" silencer...for what???

do you have problems with the police and the goverment car specifications???

[robo]

3" silencer...for what???

do you have problems with the police and the goverment car specifications???

Its good to have car with exhaust no louder then 98db's.

[newsh]

It is stupid loud inside the car, I cannot drive it, just get a headache in the first 5 minutes.