9Eleven

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 on this forum 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 ***** 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 know 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.

NAO

Cool write up Mario..........I've been testing one this week that runs to 1.5bar and redlines @ 8K.You should try getting that to full boost in 3 & 4th...............The jail cell has been beckening all week........

9Eleven

Jeez Neil, 1.5 bar @ 8k? That's insane. Yea, it's funny, my friend at TPC said, "You need to run her wide open throttle in 6th to make sure she doesn't over boost." Yea sure, where the hell am I going to do that? I got her to a steady 1.2 bar in 5th and got her up to 145 mph. I didn't look at my rpm's, I would guess it's right at 5500 rpms give or take. She tops out right at 132 mph in 4th. BTW, thanks for all of your continued guidance, it is nice to know I can always reach out and pick your brain. When is this beast of yours going public?

Kevin

1.2 bars is the max suggested sustained boost for the small K24 compressor wheel (sounds like you are there).. Just like suggesting that 1.0 should be the max sustained boost for the even smaller K24 wheel that is in the stock K16..

The fuel cut was your throttle-body shutting down on overboost.

Typically the left or drivers side wastegate is turned .5 to 1 turn (positive gain) vs the difference between each turbocharger due to the leverage of the offset rod on the right side turbo.

9Eleven

Does that mean that if both rod ends are equal lengths that the wastegates are still not adjusted equally?

Kevin

Yes...

What did you note the measurement prior to doing the adjustment??

TXGold

Is there any elementary reading on wastegate adjustement that someone can point me towards?

9Eleven

Yes, but during the attempt with the pressure tool we didn't keep track of the turns, but the nuts were marked. Do you know what the rod lengths are for each rod stock? I do remember them being the same length prior to any adjustment.

Kevin

Every turn is a mm of adjustment. Both rods have different geometry.

When you lose your baseline you need to sync both turbochargers. This is done with a dial indicator and regulated pressure. The actuator arm is measured when you apply .5bar of boost. You were using a hand held caliper. A dial indicator is set up in a stationary position, set up to measure the fine movement of the lever/wastegate.

9Eleven

Are you talking about using a vacuum/pressure tester? BTW, she over boosted again this morning in the colder temperatures (58). So I dialed each wastegate back a full turn. Now she hits 1.1 at the top of 3rd (5000 plus rpm) and holds 1.1 in 4th and 5th. I guess I would rather be slightly under the recommended max boost than slightly over it. Kevin, can you post something related to the air pressure test method and what would be the best tool to get an accurate reading. I tried that method and it was far from accurate, at least for me anyway.

Kevin

Google "dial indicator"

You never want to use a vacuum tester. You need a regulated precise air pressure. Adjusted in 10th of a bar increases.. And then you use the dial indicator to measure the travel of the wastegate lever.. NOT the actuator rod, because the rod will be moving and changing when you start adjusting the tension.

It sounds like you went on a wild goose chase.. Typically if you were at 1bar with 1.1 peaks I would have told you to turn the nut 1 turn on both sides. That would have given you 1.2

9Eleven

You can say that again. I think I may have finally dialed them in this morning, but it was a major pain in the rear. You'll have to excuse my ignorance on the subject, but how would you get to the wastegate to move when you test it. I would assume that the dial indicator will give you bar pressure, but what gives that reading? You may have to post a DYI on this one Kevin. We with limited knowledge will screw it up if you don't explain it at a 3rd grade level. BTW, do you still offer a wastegate upgrade?

KPG

There you go bragging about your education again. That hurts , especially to us guys who flunked Kindergarten I will have a package for you soon. That is another beer you owe me...and that makes 2. Glad to see the car is running well. Be good buddy, Kevin

Oak

no need for twist and test.

9Eleven

Oak, unfortunately the homemade pressure tester didn't work very well. Consequently, I had to "twist and test" until they were dialed in. I am open to any and all other suggestions because the "twist and test" method is tedious and time consuming.