Boost hoses query...

[Gazmitchell]

In the process of changing boost hoses for new roose ones and my turbo to MAF one has had the very smallest take off blanked off ? Any ideas as to why ? And the little sensor think it's the N71j ? With the two vac nipples on has no pipes connected ,just the plug . It obviously was like this when I bought it , and seemed to run fine like this, part from the cow noise on boost... Which I'm hoping to sort . Thanks all.

[Rikki Kitto]

Any pictures, sounds like the N75 has been deleted for some reason

[Rikki Kitto]

Cow noise might be the diverter valve

[andy10v]

Sounds like the N75 has been removed from boost control, but left plugged in?

N75 should have 3 ports, one to maf hose, one to the turbo compressor housing and one to the wastegate.

Your car could be set up using the wastegate spring to control boost, any signs of an adjustable nut or bolt on the top of the wastegate?

What does the car boost to?

[Gazmitchell]

Ok cheers for replys.. So not sure what it boosts to tbh, I do have a gauge off here connected but it's in the glove box!

I've had a cow noise when giving full beans on acceleration for quite a while but cause it's not a daily driver and I only get out in it now and again I've just put up with it as I don't give it loads when out . I've had all hoses off and as I say changing for roose black - used to have em on my escos and look nice. While hoses off the stock DV has damage inside on the seal so that's knackered new 710 sorted from TPS, and that's when I found the little sensor tied up with no pipes attached etc. car is also having a new idle actuator too as it has idle issues on start up then unplug it and it's fine... Just working through its niggles and give it some love ! I could do with a pic of wher these vac pipes all go if poss so I can suss it. Can't see any manual boost valves etc either..

[Rikki Kitto]

http://www.s2forum.com/forum/showthread.php?t=58396&highlight=S2+dead&page=4

Make sure the long pipe on the N75 goes onto the large hose, I think

[andy10v]

http://forums.quattroworld.com/s4s6/msgs/20987.phtml

Boost can be controlled without a manual boost controller, the preload on the wastegate can be increased or a stiffer spring fitted. Not normally recommended as the ECU cannot control boost, it is how Superchips S2s were done, also people sometimes bodge cars to get them to boost.

Automark used to use manual boost control via the wastegate.

[UrS4boy]

N75 Wastegate Frequency Valve (WGFV) location, function and PN info

I could do with a pic of where these vac pipes all go if poss so I can suss it. Can't see any manual boost valves etc either..

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):

[newsh]

The N75 is a T shape.

The central leg of the T goes to nipple on the face of the turbo cold side.
The shorter of the 2 "arms" goes to the Wastegate.
The longer of the 2 arms goes to the MAF hose. (Usually plugs straight in)

[Gazmitchell]

Thanks for the posts and pics guys , that's a great help...should be able to sort from these.

I bought the car from a customer of dialynx - who they sold it for ,3 yrs ago, and they did all the work on the car.? Thought they'd have know what they were on with these cars ? Tho I've heard good and bad about them...

[Gazmitchell]

Ok so on further investigation with this, the banjo bolt hose from turbo has been bypassed from the N75 and goes straight back into the lower cold side on the turbo directly under where the hose attaches, and d checking with the number on it which ends in J which apparently is the 3b solenoid. Now don't know exactly why this has been done ? , maybe faulty, but ordered new from TPS with K prefix, so hopefully moving forward.

[UrS4boy]

Ok so on further investigation with this, the banjo bolt hose from turbo has been bypassed from the N75 and goes straight back into the lower cold side on the turbo directly under where the hose attaches.

Where is the shakes head emoticon when you need it. Like this

or maybe better, this:

So nothing like this?:

[Gazmitchell]

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 ?

[UrS4boy]

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 ?

Because a) they had no clue and/or b) they thought they were smarted than the Audi engineers?

[Gazmitchell]

Because a) they had no clue and/or b) they thought they were smarted than the Audi engineers?

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