Boost Issues
 

I have had my car for a little over 2.5 years now and recently discovered a crack in my flexpipe and have had it fixed. When i first chipped my car i boosted around 18psi and once my exhaust was fixed it seemed to go down to 15psi max. It has gone down slowly overtime and now i am lucky to boost at 10. My mechanic said it was my DV but i am not sure. Is this a bad DV or N75 or what?

best bet is to just do a boost leak test, could be a combination of a few things.

Are you still running a stock dv?? If so that is probably contributing to the problem. Your stock dv has a diaphram inside of it that is really weak and fragile, it cant handle the added boost pressure your dv is more than likely wore out and is leaking your boost right back into your intake. I had a similar problem, replaced it and walla!! Holding boost.

well the big problem is that i have a month old (new) APR R1

did you install the R1 as per instructions?
Alot of ppl have had issues regarding the R1, I have not but will be replacing mine with a forge 007 soon.
the R1 has a life time warrenty, you could always go to an apr dealer and have them check out the valve. if it has an issue, they could repair it on site. i know this as mine has been repaired twice. just remove the valve so you don't get stuck with labour charges.

another issue could be the electrical valve.
it goes dv, stupid valve, then manifold. just bypass the electrical valve (n249 I believe its called) and connect the dv directly to the manifold. just make sure you loop the n249 electrical valve.
Mine was faulty, I didnt see the point of replacing it when I could just bypass it.

you guys are kick ass. i love this forum. i'll check it out and get back to you. thanks a lot

so i know for sure it is not the diverter valve, and as far as bypassing that electrical valve wouldn't that make my car lag a little bit? we checked for boost and vacuum leaks but did not find anything, my mechanic thinks i need to replace my n75 but i am still a bit skepktical. is there anything else that could be causing my lack of boost? when i shift into a new gear and let the clutch out a little bit too fast the engine gives no power and i have to let off the throttle completely for it to build boost again, much more so than just a normal bog, if that helps. thanks guys.

so the lack of boost is not a leak, the dv, the n75, or the MAF. i guess bypassing the n249 might be next if there are no more suggestions?

As much as I hate to say it, but is it possible that the turbo itself is going bad?