Another Update - Now Stage 2
So, some changes since my last update. The owner of GIAC read through the string of posts and reached out to Eurotune to offer a stronger tune, though limited to 93 octane and above. (The original tune would run on 91.) I took them up on it and had the updated tune installed several weeks ago, intending to get back to the strip as soon as possible to test it. Between the weather and track availability I didn't make it back until Friday night. I only made two passes:
1/4 mile:
12.504 secs @109.97 mph
12.457 secs @110.69 mph
The 1/8 mile splits for those two runs:
8.037 secs @ 87.83 mph
8.010 secs @ 87.99 mph
60 foot times were 1.888 and 1.863 seconds
So, to analyze: The ETs are faster than the previous GIAC tune, and less than a tenth from the APR tune, especially the second run. The trap speeds are also better, at 110 or slightly above, which matches the APR tune. The numbers tell me that both tunes are making very similar peak HP (based on very similar trap speeds), but the APR tune is slightly stronger off the line. Overall, I'm satisfied with the outcome, and when I consider the GIAC transmission tune (which I like much better than the APR version) GIAC has the superior package.
About two months ago the folks at APR reached out to me, making me an offer I couldn't refuse. If I loaned them my (physically stock) Golf R for a week or so for dyno testing, etc., they would make me a ridiculous deal on a downpipe, intake and intercooler. Didn't take much thought really, so I dropped the car off on a Monday and they delivered it back to me (actually drove it to my home) 10 days later. The new hardware was installed along with the Stage 2 ECU Tune (93 Octane High Torque) and the APR TCU tune. The front wheels were caked with brake dust, so I know all the 'testing' didn't happen on a dyno, but that was the deal, and I'm happy with the results. The new pieces look great (especially the intake which is 'front and center' in the engine bay.) The downpipe is easy to see, but I had to use a flashlight to see the intercooler. All have prominent APR logos, but as I said, they look great on the car.
I finally got the chance to head back to the dragstrip last night, doing three quick runs before having to leave for another appointment. Two time slips are attached: A run from earlier this year with the 93 Octane GIAC tune (ECU and TCU): 12.655@108.53 and the best run from last night with APR Stage 2: 12.161@113.34. So, the change is noticeable from the seat of the pants and at the drag strip. That said, I was disappointed by the drag results, as I'd hoped to go less than 12 seconds. I have a Vbox and have done a couple of 1/8 mile and 1/4 mile runs. All the quarter miles were under 12 seconds on the Vbox, and the quickest was 11.8. So, I'm hoping there's more speed to be had at the dragstrip, and I think there are two causes for the slower than expected times: 1) It was hot, almost 90 degrees, and a little humid, and 2) severe rear wheel hop off the line each time I launched. I tried to attach an in-car video of one of the runs so you can hear and see the effect of the rear axles hopping, but don't know how to do it. (I'll take guidance from anyone who has some.) I'm hoping that if I lower the rear tire pressures I can get better grip. (The best launch was with the suspension in Comfort mode. Sport mode was much worse.)
Lastly some thoughts on the tunes and APR work. You notice the turbo lag more now, though I realize that's perception not reality, as the larger downpipe should allow it to spin up faster than before. I think it 'feels' more laggy because the boost is so much stronger when it comes on. The change is much more striking than before, and the car pulls hard all the way to redline. Another thing I notice with Stage 2 that I didn't with APR Stage 1 is the amount of torque that gets dialed back at each gearshift. I never noticed it with the APR Stage 1, but I did notice it with GIAC Stage 1, and it's even a little more pronounced with APR Stage 2. I know they back off the torque for a moment during each shift, though I'm not sure if it's to protect the trans or for some other reason. In any case there is a momentary pause after each shift before the torque rushes back. You don't notice it when using launch control, but you do at 3/4 throttle.
The sound is sportier with the new downpipe. I left the original exhaust system in place, because I don't actually love the noise from a boosted four cylinder, and I don't want it to drone on the highway. It doesn't drone, but it does sound deeper and throatier at part throttle and is louder at just about any given throttle and RPM combination, then settles down when cruising on the highway.
Lastly, I still don't love the TCU tune from APR, though I can live with it. It's annoying behaviors are still present, though some of them are less noticeable with the added torque. For example, it still races from 1st through 3rd gears, but the added torque means you can still accelerate briskly even when it's short shifting at under 3,000 RPM. The downshift from 4-3 is still abrupt and jerks your head forward, but the trans doesn't exhibit the most frustrating glitch from before, when it would switch back and forth between two adjacent gears, especially 2-3 and 4-5. That particular behavior is what led me to try the GIAC tune last year. Also, I do like Sport mode from APR better than GIAC. The GIAC version is more 'Sport Plus' and would hold the gears longer than I wanted, sometime a lot longer. The GIAC tune also tended to over-rev some of the gears, especially 1st and 2nd. I saw 7300 rpm once on a 1-2 shift and I worried that I had broken something, though the engine seemed fine afterward.
That's it for now. I plan to head back to the strip when I can and see if it's possible to dial back the wheel hop and lower the E.T. Thanks for reading.
