Waste gate adjustment

[2002Gt2]

OK, I know this topic has been beaten to death, but I learned something today and I thought I would share my new found knowledge with my dear old forum members. Let's get the specifications out of the way, '02 Gt2, Stock K24's, Orton flash, DV's, and a Europipe II (quiet).

To make a long story short, after the flash and DV's (pre-exhaust), my mechanic used the mark the nut method and turned each nut (clockwise) evenly. I believe at that time he turned them 4 full revolutions. Before the flash and DV's I saw the occasional .9 spike (stock) and the best dyno numbers were 444 rwhp, 426 rwt (stock). After the flash, DV's and my mechanic's wastegate adjustment (4 revolutions each) the best dyno numbers were 482 rwhp and 454 rwt and she was hitting 1 bar with a 1.1 spike. Both these runs were done in very similar conditions (temp 60's, humidity, same dyno and operator).

Finally I installed my Europipe and felt that the wastegates could use further tweaking. I asked a member of one of the other forums to borrow his wastegate psi tool and when it arrived I went to TPC, put the car on the lift and we tried to set the wastegates to crack open at 12 psi. Well, I've got to tell you; it is very difficult to look at the psi gauge at the same instant that the wastegates crack open and then the gauge hitting the magic number. We thought that we had it set and put her on the dyno, she hit 1.2 bar and the best run was 507 rwhp and 496 rwt (90 degrees). Well, needless to say I was pretty happy until I got her on the street. She was over boosting in 4th and 5th (1.3, 1.4 bar) and I felt the fuel shutting down; bad feeling. I went back (twice) that night and we turned the nuts back 2 full turns and I took her back out. FYI, it was about 90 degrees outside that day. Well, she continued to over boost,

I went back to TPC a couple of days later and unscrewed the nuts until they were both exactly 11 millimeters from the tip of the rear nut, to the tip of the rod. I used an electronic caliper, so they were dead balls even. I then marked the nut using touch up paint (guards red, of course) and began the painstaking process of turning the nuts several turns and driving her, checking the boost, coming back, waiting for her to cool, measuring again to be sure and then repeating the process again. After several adjustments, the top of the nut, to the tip of the rod was now 14 millimeters. I was just getting 1 bar at the top of 3rd and 4th. Well, I took her home and this morning, I started the process all over again. I finally after three test drives and 5 and a 1/2 more full turns I am seeing a solid 1.1 bar in 3rd and 4th with a 1.2 spike at 5500 rpm in 4th, and a solid 1.2 bar in 5th (140 mph and beyond). The temp outside today was in the high 60's with no humidity, so I hope it will not over boost in colder temperatures.

Thanks for listening and I hope this helps someone in the future who is trying to adjust their wategates. I attached a copy of the three dyno runs overlapping each other for further information. Take care and drive safe.

Dyno_Comparison.pdf

Edited October 1, 2007 by 2002Gt2

[smistry007]

thanks for the write up. Are you using stock WG's or aftermarket?

[2002Gt2]

thanks for the write up. Are you using stock WG's or aftermarket?

Stock.