My current turbo (wastegate linkage/actuator) doesn't seem to be liking the Accessport Stage 3 tune.

Anytime I hit 50%+ throttle in 5th or 6th at low RPM it goes into limp mode. Believe to be the ECU isn't seeing as much boost produced as it's calling for.

Skeptical of it's longevity (even tho it's only a problem on Stage 2-3) I decided to search for a JCW turbo.

Found an Alta 42MM turbo instead. Does anyone have experience running this size turbo or similar on the canned AP tunes?

I spoke to JMTC and he advised the stage 3 tune would have the car seeing 26 PSI with that turbo. So I'd say that's out. But their site does say that size turbo works fine on stock tune. Perhaps Stage 1 would work? I don't have a readable wideband to confirm.

My rush is that I have a track day in just over a week and won't have time to custom tune it, I haven't even gotten the turbo on yet. Advice?

 

http://blog.perrinperformance.com/al...turbo-upgrade/

So the tune I want exists

 

I hope you checked with Jeff Perrin to ensure the tune you want is available. The post in your link is dated may 2011, back when the AP was still fully supported, and Perrin was still doing custom tunes.

My own experience with AP custom tunes was also going into limp mode (P2885 or P2884) at 50% throttle, 5th or 6th gear, and low RPM's. I learned to downshift into boost RPM range before hitting the throttle. Before I went with Manic tunes, Perrin wouldn't do mine again --- he told me that my previous 282WHP was the max he'd tune for, even tho I already had aftermarket rods and pistons. So, even if he will do a custom tune, it might not be the max your car is capable of.

Then there's JMTC --- I have no experience with his tunes. However, the two people I know that have them, both have the "MAF - less" tune, and both have indicated that these appear to be "trial-and-error" tunes --- it takes several iterations to get it right, IF it ever gets right. And, is the JMTC stage 3 the same as an AP stage 3? As you add more mods, the stage ID becomes less and less meaningful, and a custom tune more and more necessary.

Another thought --- our N14 PCV system won't tolerate much over 24 - 25PSI. Exceeding this range will blow out a diaphragm, disabling the whole system. So choose your turbo system carefully.

My advice --- work with a Manic tuner to select a turbo, then get the appropriate set of tunes. Manic eliminated my P2885 - P2884 limp mode, smoothed out normal driving, found another 15% WHP, and I can still use the AP for everything except map storage.

 

To save the valve cover, just install an additional good check valve. I used a Boomba Racing one with my set-up. Installed in the timing chain side PCV line. Wish I knew that before killing 2 valve covers.