Audi S3 boost problems

[goodbuzzman1]

When i picked up my s3 a few weeks ago i knew it would need a bit of work. ive sorted most of the problems but one remains.

The boost seems to be a bit intermittent.

so far i have checked for boost leaks. i found that there were leaks in a few breather pipes and also a small leak in the turbo intake pipe.

I replaced all the offending pipes with nice new silicone ones at the weekend but there till seems to be random hesitance when i put the foot down. sometimes it pulls like a train and other times it stutters and then boosts.

When i was replacing the TIP, i did notice a slight bit of play in the turbo left to right.

Ive also been doing a bit of reading about the N75 valve so this evening i unplugged it and went for a spin.

I have to say, the car felt like it had only 120hp but it was absolutely smooth all through every gear.

does this mean the valve is good or bad

ANy help on what to do next would be much appreciated

cheers

 

[Vex182]

Have you also checked the DV is working as it should? A good idea to check for any fault codes too

 

[russwuss]

If you unplug the N75 you'll be boosting to around 6psi.. Hence why it feels about 120bhp - I'd try swapping the N75 and see if it makes a difference. Was the first thing I had to replace on my S3.

 

[russwuss]

http://bit.ly/1ivqPVG

^ that's the one you want, they are more expensive from Audi if
I remember correctly..

 

[goodbuzzman1]

Have you also checked the DV is working as it should? A good idea to check for any fault codes too

how exactly would i go about testing it

 

[goodbuzzman1]

http://bit.ly/1ivqPVG

^ that's the one you want, they are more expensive from Audi if
I remember correctly..

do you think its worth replacing? i might just get one anyway and try it.

 

[<tuffty/>]

Have you scanned for fault codes yet?

<tuffty/>

 

[goodbuzzman1]

I will be giving it a scan this evening. I just wanted to repair the obvious boost leaks before i did

 

[goodbuzzman1]

Ok. So i scanned the car this evening and it didnt give me any fault codes (apart from one for the radio antenna)

I tested the diverter valve and that seems to be ok.

What i did notice was that the pipe that goes from the diverter pipe over to the turbo pipe is suffering from the same heat related collapsing as all the other ones i have just replaced. One of the bends is especially bad and i cant imagine much can flow through it. but how much affect could it have? enough to affect performance?