funny boost

[malcolm30029085]

having trouble with my boost, if my s3 is driven fast (foot flat to the floor through the gears ) the boost spikes right up 2 bout 14 psi and holds bout 10 ish. but if driven normaly ie on the motorway, and then i go to accelerate the boost struggles to build up and barely reaches 8-9psi.also as the boost gauge is climbing it seams to be fluxtuating up and down, could this be the dv not holding the pressure??
its not had a re-map,also got new n75(j), and checked for leaks!!

 

[Sandip]

What is the gauge been tapped into? Its sounds like you may have a leak somewhere

 

[sportstractor]

hmmm, i heard that N75 J's dont work for everybody??

boost or vaccum leak possibly

 

[malcolm30029085]

the boost gauge to pluged into the top of the dv, maybe i should try the standard n75, how can i test the dv??

 

[feville]

My friend had boost flux problems with his j valve, he adjusted the screw on the valve which sorted it (after some trial and error).

He was boosting about 22psi/holding 20psi tho on mapped software.

 

[malcolm30029085]

which screw is that??

 

[feville]

On top of the valve there is a hole machined out to access a flat screw (T fitting on the bottom) this adjusts the valves internal spring tension. Pretty sure there are some threads out there on it, i haven't had any experiance myself but it could be worth a shot?

 

[Lemon S3]

Also try changing where you plumbed your gauge into, don't think its 100% when using the dv vacuum pipe.
T piece from the fuel regulator, I've never had a problem with it.