1.8T BOOST PROBLEM

[imported_ceefna]

Hi, have running problem on my A3. Has TD04 turbo fitted and various other mods eg front intrecooler, n75j, 4 bar pressure regulator a forge dump valve and custom re-map.
Engine comes onto boost at 2700 rpm then spikes to 17psi as the revs climb boost drops off to 10 psi by 5000 revs seems engine really holding back, but then boosts again to 17psi and back to 10psi keeps doing this till engine revs out like you are going on and off the throttle. Rubbish for overtaking as it goes like chuff then holds back then goes then holds back. Hope this makes sence to somebody?
thanks for your time
CFN /ubbthreads/images/graemlins/noidea.gif

 

[Rob W8]

try replacing the N75 valve for an F version. See my thread, I had a similar problem.

Hope it helps mate.

get it from vagparts.com for £42, easy to fit.

part no. 058906283F

Rob

 

[imported_ceefna]

Thanks for your reply Rob, I still have my standard valve, do you think it is worth trying that?
cfn

 

[imported_ceefna]

Have just fitted std N75 valve back on and now drives like standard car, showing 8psi boost. Wonder if std valve is bust?
Any ideas?
CFN

 

[Rob W8]

sorry mate, am no expert. Only know that mine is now ok after the change. Maybe because yours is mapped with a J valve it is different?
Is it still surging with an F valve? Might be worth replacing the J valve?

Rob