I have a Turbo XS HP MBC I want to install on my car. I know I want to set the wastegate ( stage 2 ) to regulate the boost lower, somewhere around 12-14 PSI in 3rd and 4th gear pulls. My question and please excuse me for such a dumb question is how do I adjust the wastegate down to the 12-14. I assume I want less preload on in it. Correct ?

If I loosen the locknut can I adjust the preload by just turning the adjustment barrel ? I don't want to have to take that PITA heat shield off if I don't have too.

After I adjust the preload I do some WOT runs and I'm looking for the boost to level off at 12-14 correct ? Even though it may spike higher ? Or is the 12-14 the spike I want to see from the WGA ?

Then I install the Turbo XS to spike around 16-17 max PSI in those same 3rd and 4th gear pulls ?

Hozay, PSI, LSP, any of you coming to Virginia anytime soon? I could use your help, then I could ask stupid questions privately,,,,,,,,,,,,lol.

 

You are absolutely correct in your methods.

With an S2 WGA it takes the PCM a bit of time to "learn" that you ONLY want it to boost at a certain level. So when you start to see it spike, and it spikes way too high, just hop off the gas. Many have reported that after a few times of doing this the PCM "learns" not to allow it to spike so high.

If its still spiking too high, you're going to need to readjust the WGA and "back it off" a bit. Your absolute BEST bet when doing this test is to leave the heat shield off for these runs, then put it back on once the WGA is set where you want it.

 

O.K , I just went out and found a lonely little country road that's great for playing with the car on. Here's what the turbo was doing,

1st gear pulled 4 PSI and 1st was gone
2nd gear pulled 15 PSI and 2nd was gone
3rd gear pulled 17 PSI and leveled off at 15PSI
4th gear pulled 18 PSI and leveled off at 15 PSI
5th gear pulled 17 psi and I was going too fast so I had to stop this test,,,,,,,,,,,,,,,

The ECU has only been in the car about 150 miles I guess. Is that long enough for it to have adjusted itself ? It felt real damn strong throughout these runs.

Is an MBC going to help, should I even bother ?

The way the car is running right now I'd hate to mess it up. I don't have any problem whatsoever with PTB with the setup I have now either, you can drive normally and never see any boost, but it's sure there when you want it.

 

You don't have to use an MBC if you don't want to. Think of it as two things to adjust rather than just one. Some people find problems with that and don't like doing it so they end up with just the WGA. You could always put it on there so you have more control of your boost (i.e. want to turn it down a bit and don't feel like messing with the WGA, etc.)