my least favorite subject, power

1y ago

5.2K

This is probably my least favorite subject when it comes to cars. Power. Straight line performance. I think there's lots of technical goodies going on when it comes to performance tuning. In fact, I love the science behind tuning. But I think a lot of tuning companies would agree with me when I say that most car enthusiasts chase big numbers. For me, it was just about adding some and keeping the reliability. Upping the top-end power and the response. So I chose Unitronic as my first tune.

Unitronic was posed to me by a friend as the "best" tune for a Mk7. Not because it was the fastest, but because the power delivery was linear, it was responsive, and most importantly - CONSERVATIVE! Yes, a 63HP gain is considered conservative on this platform. After tuning the car, I was ecstatic. It felt like what the GTI should have been from the start. Monster mid range. Nice pull to 6000. Holy crap, the car ripped! And it showed, too, literally.

Turbo glow after a hard canyon thrashing.

I was loving this tune for a solid... 300 miles. Then, problems. I was running a 91 octane OTS flash tune with 92 Octane Oregon gas. But, that didn't stop my car from going into limp mode. And no, not just when the turbo was glowing. In fact, the night I got the tune, I went out for a test drive with my roommate to show him the performance. On the very first pull, midway through 4th gear, the car flat lines. I thought my turbo popped. I'm freaking out.

Come to find out I had encountered the notorious limp mode. Okay, a fluke, it happens. No, it happened a lot. In fact, in 1,000 miles it happened a total of 3 times. I couldn't do it. I couldn't drive my car wondering if I'd loose all power every time I got in it. Thankfully, I was able to return the tune, and went back to stock life for a while.

Fast forward a few months and I tried a new tune, Eurodyne. This tune ripped. Harder than Unitronic I'd argue, and only barely lacked the finesse. Either way, I loved it. I beat up on JB4 + downpipe guys and had a great time with it...until I moved back to Salt Lake. See, Utah sucks for two reasons: high altitude and bad gas. My car felt sluggish and data logs showed I wasn't crazy-- I wasn't hitting boost targets! Even after finally taking the plunge to Stage 2 (adding a downpipe) the car still lacked the performance it had back in Oregon.

I set out one night to finally figure out what was happening. I ventured out with a friend to diagnose the issue once and for all. We started the data logs. Tried one tune. Underboost. Tried another file. Underboost. What was happening? AFR's? Fine. Timing Pull? Minimal. Wastegate... maxed. Wait, maxed? Really? Hmm... POP. Yup, you guessed it, that little IS20 turbo didn't like flowing 100% of exhaust gasses through it's tiny 54mm turbine wheel at 6500rpm. And it broke. Broke the turbo shaft right in half. There I was, 37,000 miles on the clock with a non-running vehicle. Shit.

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