S2 3B Boost/Power question

[nynex]

Hi all, I recently got my first Audi S2 3B and when driving it I was expecting it to be a bit quicker than it is.
I have now fitted a boost gauge and found that the boost seems to fly upto about 0.5 bar and then just won't go any further.
Is this a standard limit for turbo boost and if so is it just a case of remapping to increse this limit?
Thanks in advance.

[Knight Rider S4]

You probably have boost leak or N75 valve is faulty should be 1 bar for standard 3B

[nynex]

ok thanks, to check if the N75 is faulty I just disconnect it?
is there any usual suspects for leaks? I did already have a look around and couldn't see anything noticeable.

[vertigone]

To be precise, You need to reach 0.8bars @ 3000rpm on a stock 3B (and no overboost with stock chips)
Look for leak put your system under pressure

[S2central.net]

Sometimes air leaks are easily found by just looking but others only really show up with a pressure test. If the car has original turbo hoses they will likely be well tired by now.

The weakest ones on 3B are the two silly little short hoses between the output of intercooler and the pressure pipe where it runs up to the throttle body.

The best way to test them is with a bung kit and an air line.

If the N75 looks old then definitely renew it - I think I have an unused 3B one here if that helps. Its just a solenoid driven air valve and they either break electrically or seize up/slow down mechanically to the point where they cannot respond to what the ECU asks it do.

[nynex]

thats brilliant cheers. I've never had to find leaks before so I'm sure this is going to be fun lol.

[Rusty]

Best thing is to find a friendly local member to help you out. I'm up in Bristol and have a boost leak kit. Ideally you want someone with VAG Com so that you can check for error codes.

If you want a garage reasonably locally then All Audi in Bristol are good and have a lot of experience with 3Bs, you want to speak to Neil or Alex (if he's still working there). They've owned a few 3Bs between them.

[nynex]

nice one, bristol isnt too far so maybe a day trip will be in order. I have VAG com which I used on my laptop for the Audi A3 I had, I was going to look into where to connect it on the S2 and see if there was any error codes coming up. Is it under the dash somewhere?

[Rusty]

Fuse box, you need a 2x2 Y connector to plug into more modern VAG Com cables.

N75 and boost leak are most likely the issues.

0.5bar is spring boost, N75 takes it above that

Boost leak will show itself as a fluctuating needle a lot of the time, it'll also cause the 'overboost protection' to kick in, basically it's like hitting the brakes when the boost builds.

We've all been there with stuff like this, it takes a while, some £ and hard work but it's worth the effort and will mean the car flies when you add a chip (and you will )

[nynex]

If the N75 looks old then definitely renew it - I think I have an unused 3B one here if that helps. Its just a solenoid driven air valve and they either break electrically or seize up/slow down mechanically to the point where they cannot respond to what the ECU asks it do.

PM sent S2central.net

Rusty I do have that cable I think, it come with the cable I got. The car does actually drive quite smoothly for a 91 car but I can just feel it's lacking something. I wasn't intending to chip it but now I am already starting to get a bit tempted although as you say I will have to fix this issue first.
What price are chips for a 3B, do they go onto a daughter board or is it more complex with them?

[S2central.net]

I can do your ECU for ~280bhp when you get your air leaks / N75 sorted - needs a MAP sensor upgrade as well - all in for £250. I have a spare you can try if you wish.

Just popping out to the bat cave to try and find that fresh N75 for you... I'll test it first.

[nynex]

awesome, thanks.
got someone coming to look at my old motor tonight so I hope i'll have some cash when it sells, I knew it wouldn't stay in my pocket for long tho, never does

[nynex]

thanks guys for all your help, when I get it sorted I'll post the findings.

[nynex]

I can do your ECU for ~280bhp when you get your air leaks / N75 sorted - needs a MAP sensor upgrade as well - all in for £250. I have a spare you can try if you wish.

Just popping out to the bat cave to try and find that fresh N75 for you... I'll test it first.

N75 working? I tried sending a PM but not sure if its working!

[nynex]

Hi all, I had a pressure test done and it turns out that there is some oil breather pipes that need replacing first, I asked at Audi and they can't get hold of one of them atleast, any ideas where I can source one?
The part number is 034 103 221 BF. I attached the Pipe layout location, I need the area 1a all the way upto about 1b.