Boost hoses query...

[UrS4boy]

And this is an allegedly well known audi sport performance garage !!???

Oh, right. I forgot. Then they definitely thought that they were smarter than the Audi engineers.

[Gazmitchell]

Oh, right. I forgot. Then they definitely thought that they were smarter than the Audi engineers.

Yup. Guess so .

I'll endeavour to sort it out , maybe it will be transformed and fly !! Like I've been driving around for the last 3 years with handbrake on !?? Bahahaha

[newsh]

Lol yep got the standard hose from wastegate banjo but instead go plugging into N75 it had a small dia metal pipe then attached the others end is the pipe that then goes to bottom of turbo. !!!! Why would this be done ?

Plumbed up this way you're just using the WG spring to control boost. If you look in the WG you'll probably find a stronger than stock spring. This setup makes the throttle really responsive as you can get full boost at part throttle. The 10v Ur quattros were like this. Only thing is that if something goes wrong then you still get full boost.

With the ECU controlling boost via the N75, if you get a split hose or an air leak somewhere then the boost gets turned down to protect the engine.

[Gazmitchell]

Ok so further to this thread, new boost hoses on and wastegate, turbo, new N75 and DV , all plumbed in correctly.

Cow noise gone on acceleration now so that's one thing sort but still got a missing , holding back on boosting, with the odd violent miss, can't be coil wiring harness or coils as they were all renewed, wonder if it's plugs? Any ideas ?

[andy10v]

What is the boost pressure with the N75 unplugged? (the wategate may have a stiffer spring if it was being used to control boost)

Any fault codes?

Have you done a boost leak test?

[Gazmitchell]

What is the boost pressure with the N75 unplugged? (the wategate may have a stiffer spring if it was being used to control boost)

Any fault codes?

Have you done a boost leak test?

Will check if any codes now,.... Not done boost test leak, what's easiest way to do ?

And best way to see boost pressure with n75 unplugged ? What while driving Andy ?

How can I know if spring is stiffer than OE also as I've nothing to compare?

[andy10v]

Remove airbox lid/maf
Fit a bung with a valve in the maf hose
Remove the breather pipe from the maf hose and plug the maf hose
Pressurize the intake to 15psi

Listen for leaks, large ones will be audible, spray down with soapy water to find small ones. Check around all jubilee clips, injector seats etc.

I would also check the DV is ok, as when you pressure test like that you pressurize both sides.

Yup, just unplug the n75 and see what the max boost is, then see what the max boost is with it plugged in.

[Gazmitchell]

DV is brand new ... As is N75 . Just checked codes



553 MAF sig too
513 G28 speed sensor no signal

[Rikki Kitto]

N75 Wastegate Frequency Valve (WGFV) location, function and PN info: http://forums.quattroworld.com/s4s6/msgs/20987.phtml

The Audi diagram for 3B, ABY and ADU engines:



AAN N75 Hose set up. Long leg of N75 into the MAF to turbo hose:



Photo from Rikki Kitto's link (not sure if it is correct or not):

Just looked at this pic again and it is not correct the long pipe opposite the wiring plug goes into the maf turbo hose not the one in the pic sorry if this caused any confusion

[UrS4boy]

Just looked at this pic again and it is not correct the long pipe opposite the wiring plug goes into the maf turbo hose not the one in the pic sorry if this caused any confusion

Yeh. I didn't think that was correct. Hope you get it sorted quickly.

[Rikki Kitto]

Yeh. I didn't think that was correct. Hope you get it sorted quickly.

This pic was from a few years back we had just put the car back together after been in bits all over the garage for ages and fitted the N75 wrong but all is good now

[Gazmitchell]

Just looked at this pic again and it is not correct the long pipe opposite the wiring plug goes into the maf turbo hose not the one in the pic sorry if this caused any confusion

No all good as followed exploded parts diagram cheers

[Gazmitchell]

So new boost hoses, new MAF new ISV and new N75 and DV and runs better now than it's ever done since I had it . Progressive acceleration and boost no missing on full beans and no thru the windscreen jolts ! Better than it was set up for the mechanical boost bypassing N75 I think anyway. Now if I can just sort the temperamental fuse and relay for windows and sunroof ??