Installed a new n75j valve andover the past few days have been testing it. WOW what a difference. If anyone recalls, I was having trouble with the boost levels not being where they should be. I was only boosting about 11psi and frantically trying to track down a boost leak.After looking over all the pipes and connections,I had pretty much eliminated that as the issue.Well, I had heard that the J version of the n75 is supposed to help withsmoothness, but man I had no idea what it really did. So I get it installed the other night and instantly more power. Spiking as high as 20psi in 1st and 2nd gear and then settling to around 15psi. Now that i've had it in for about a week and given the time for the ecu to adapt things are much more smooth. I currently spike at about 18psi and then hold 14-15psi all the way up to almost 6000rpm. What's funny is that I had heard the J valve was supposed to make boost come on stronger at a slightly later rpm, but it's very noticeable. Fullboost does come on about 500rpm later, but the difference is that it doesn't let off until almost redline. I watched the boost gauge like a hawkto confirm this.

Installation was a little tricky. Getting thoseone-time clamps off of the TIP can be a pain. I replaced all the "reusable" andone-timeclamps with the screw type. The real problem is that the n75j's electrical connector is on the other side so the wiring harness hits the corkscrew looking rubber hose next to it. It will fit, but it's kinda hard to get in there comfortably.

I had the n75c before and I think this is why I had so may issues with my boost. I understand now whyAudi replaced it with the n75f version. So for future reference, if anyone has problems reaching their specified boost levels and have eliminated boost leaks as a problem take a look at your n75. It might be the problem!

Oh, and I know that a MBC would fix the problem as well, but i have heard that straight MBC's can cause jerkiness on part throttle driving which I wanted to avoid.

Ian

 

Only if you install a ball and spring mbc. A bleed gives the best response. Not to mention you can get a nice bleed for about $45 from turbonetics

 

nice. thanks for the heads up.

what are all the differences between the letter after the N75? I have a 2000 180Q and it has not been reaching the boost levels it should..i still have to find time to try and locate any leaks..

 

Haha, now you tell me. I havea voodoo ball and spring, but I never installed it for that reason. I don't think I would really need it at this point unless I was hitting limp right?

 

I have a Turbo XS HPBC I got it from boostcontroller.com I like it so far but my clutch went out so i didnt really get a chance to test it and all so...

 

You can fun it in over boost mode (on boost machine website). you can then adjust it and it will eliminate most of the jerkyness