Diverter valve only works sometimes

[dedecv3]

HI,

I have an 02 1.8t w/ the following mods
GIAC chip
Full 3 inch exhaust
neuspeed intake

I recently purchased a Fast Road Closed Loop Diverter Valve (piston) from Forge. I currently have it hooked up as a blowoff valve w/ the air being dumped into the atmosphere instead of the AI. I was told by a vw tuner shop in my area that this would not cause any problems, however, my car sometimes is producing almost no boost....When i start my car up and run it hard....it works great and i get the loud whoooosh sound, nice and smooth.....however, when i cruise down the highway for a bit and then try to run it hard....its almost like there is no boost.....and the whoooosh sound when i let off is not very loud and seems kind of drawn out....anyone else had any similar problems when hooking it up as a blowoff instead of a DV. i dont want to take it back to the vw shop if it is not the DV that is the problem.....i can tell you though that the stock DV valve that was on it worked well and didnt ever lose any boost and it was on w/ the other mods for about 8000 miles. Any ideas

[dedecv3]

I changed the DV so that it is blowing into the AI now instead of atmospheric....however, i don't think i am getting quite as much power as i was when it was atmospheric, and working properly. Anyone else had similar situations when working w/ a BOV verses a DV. Also, could someone explain what exactly happens in the ECU that causes the BOV to seemingly dump the boost prematurely???
Is it possible that my "N75" is bad?? I was reading other posts and thought the "surging" problem that i was having when it was a BOV sounded similar to issues someone else was having w/ an "N75".

[rh3017]

the computer does not tell the DV or the BOV when to release the pressure. it just happens when the pressure gets down to a certian level.

this sounds like something that happend to a friend of mine with a 03 GTI. he brought it into the dealer and it ended up being a lose hose off the turbo. it took them a while to fix it and it kept falling off but they ended up replacing the hose clamp. it was all comverd under warinty.

he only had a CAI and i see you have much more. if you can find a dealarship that is mod freindly which im sure you can. just go in and ask one of the sales men if there are any mechanics who "mod there car" and ask if you can talk with them. they shold be cool about your mods and not void your warinty.

[veedubmechanic]

The release of boost is caused by the engive vacuum being applied to the dv through the small vacuum line at the top of the valve. VW boost program in regulates the a/f mixture according to the released bood being put back into the intake stream rather than atmosphere. The maf sensor is calibrated to read backpressure from boost and if the airflow isnt read properly the ecm will get confused and run limp mode untill the correct pressure is found. VW routes boost back into the intake to keep boost pressures high so turbo lag is almost eliminated. Routing excess boost into atmosphere on low boost "stock" is pointless and causes the turbo to have to overboost to keep the boost at the correct level.
Try running the boost back into the intake like its supposed to.
Also the n75 valve is just a "vw" boost controler-has nothing to do w/ dv

Also at higher speeds and higher gears there isnt as much boost. 1st and 2nd gears have the 14psi I believe and 3-4-5 have less 8psi. Less boost = less noise.