[scooby9]

The wastegate throttles how much exhaust gas passes across the turbo vanes. It is essentially a bypass controller. When the wastegate opens up, less boost pressure builds up because the turbo is exposed to less exhaust pressure. When the wastegate fails, you typically get boost surge where the turbo is spinning up way faster than it should because the bypass is not opening up enough. However, the opposite could also occur where the wastegate does not open up enough and boost PSI is reduced.

The ticking sound is pretty normal with most boost controllers so I'm not sure if that's a true sign of wastegate failure.

Originally Posted by XLR8MF

Can someone elaborate exactly what the wastegate does and why it is failing in our cars? Someone I thought mentioned a rattling noise or is it just a hiccup?

[HPIA4v2]

Originally Posted by XLR8MF

Can someone elaborate exactly what the wastegate does and why it is failing in our cars? Someone I thought mentioned a rattling noise or is it just a hiccup?

I am no expert but had a turbo wastegate failed on me once, and according to video file I've seen/listened the 335i wastegate problem is very similar.
Rattling noise from turbo/s during decelaration, just rev the engine to 3500RPM and listen when RPM drops for any "metalic" rattling.

The wastegate control how much air pass through the vanes, controlling how fast the turbine, and at the end how much boost it produces.

Dealer can check for this more accurately, I imagine they go to diagnostic S/W mode and set engine speed known RPM and check for boost stability for some period if if falls under acceptable margin then they kick in TSB and if if really bad they may have to replace the turbo/s.

Bear in mind turbo gets hot (MY Audi A4 gets glowing red under freeway cruising speed) and metal gets soft in this condition so proper cool down after spririted drive may help a whole lot. My KO3 on my Audi fails then swicthed to KO4 and with proper cool-down before shutting engine my KO4 still going strong (holding boost at 14-15PSI).

[scottp999]

Originally Posted by scooby9

The ticking sound is pretty normal with most boost controllers so I'm not sure if that's a true sign of wastegate failure.

Agreed. I can hear the ticking on deceleration ever since the second I put on an aftermarket exhaust. The car runs fine.

[judec]

well, I had all kinds of failures on my turboed cars since I drive them, but never a wastegate failure (yet, /sigh/). Just to ad my 2 cents - the wastegate opens and closes all the time during operation of the engine, so it works all the times. Also it works almost the same regardless of turbo pressure, maybe it stays closed a littlebit longer with higher target boost, but it needs to work the same way as before anyway and it's not affected by higher boost as it's on the turbine side, not after the compressor. So I dont see any reason for it to fail because of higher boost induced by a "chip", intake, intercooler, downpipe or exhaust and in case of failure dont let the dealer fool U. It is some kind of a fatigue of material, as wastegates fail on unmodified cars, too.

Anyway, I would not irritate the cobra in this case, so if possible remove your chip (at least) and possibly the DPs, can spare U a trouble.

[Chaotic604]

Would there be no Waring light that comes on? Kinda pointless if not IMO.

[2GPP]

Just got my car back after it was in the workshop for 2 weeks having the wastgates replaced. Quite a few recorded in the UK.

[cn555ic]

Hey what happened with this...Did you get your car back???

[Supramano]

im dropping my car at the dealer on tuesday with the ship remvoed...again my dealer knows it was chipped. They told me they will have to open a PUMA case and a rep will come and inspect the car. He told me they will not volunteer the info that it was chipped, but he told me the hfc dps and the AA exhaust, with the ur cai and forged dvs arent gonna help. Hopefully all goes well, but i have a feeling their gonna void. If thats the case im gonna see how much its gonna cost and then evaluate. let you guys know.

[AJayE92]

oh shit i wann know

[judec]

crossing fingers man