Fun with the GTech Pro RR

[scalbert]

Let me preface this with stating these times may not be an absolute. However, relative times for comparison are pretty reliable. I purchased the original GTech Pro (actually a 2nd generation but is now considered the original) about ten years ago and found it to be quite useful. At the time I was tuning my Typhoon and my wife's Eclipse GS-T and found that provided the same stretch of road was used and leveled in the garage, the comparative runs were accurate in determining acceleration changes after changing parts or tuning. Overall times may have been off a little and was not a benchmark although my comparisons at Atlanta Dragway often showed very good accuracy. But that was at a flat and level track which is more conducive to providing accurate results for such a meter.

That said, this new unit is much better and shows promise of real accuracy on the road. Regardless, it is certainly a great improvement when just comparing the supplied PC interface and analysis tools. But it does appear the new unit is more forgiving to vehicle differences and pitch when compared to the older unit.

Anyway, I received the newer GTech Pro RR for Father's Day this year and immediately went out and tried it. Below are some runs from last summer in my '01.5 S4, our '00 M Roadster and our '04 Toyota Sienna XLE Limited (yes, a minivan). All runs were done at the same location with the ones last summer done in about the same conditions for all vehicles; about 75 - 80 degrees and clear. Following the first plot is the second taken this morning with the difference being that the temperature was about 35 - 40 degrees. The reason for just being 0 - 60 is that there is no where around which is flat and straight enough to get anything more. It is hilly and no roads are straight. All vehicles are in the same configuration as they were in all runs

All in all it was about what I expected. I picked up about the same amount in all vehicles with the outside air temperature being about 40 degrees cooler. The minivan picked up the most but was obviously the slowest. However, even though it was slow compared to the others, when thinking about vehicles I had many years ago it isn't bad. It was certainly quicker than the '83 Cavalier (about 12 seconds) and my '88 Prelude Si 4WS (about 9 seconds).

What I have been surprised about is the overall accuracy. Now this cannot be taken as an absolute, it can certainly be looked at more seriously. All times are not that far from where they should be. The Sienna and the M Roadster are stock with the S4 having the GIAC X chip and Borla exhaust. The only car I have run at the track is the S4 and what was shocking was the short times comparison. When I bogged a launch at the track I ended with a 2.0 - 2.1 60 foot time. This was the same as what I had with the GTech Pro RR. The shown run earlier today was a freak in that I nailed the launch perfectly. All other runs with a 1.9 - 2.0 short time were in the 4.4 - 4.6 range. When I ran a 13.1@106.6 at Atlanta Dragway last spring (prior to the exhaust) I had a 1.97 short time.

Summer Runs:


Winter Runs:

[rktskicar]

If you look at my picture poster, you will see that I have been using my Gtech Pro Comp (same as RR) for some time (lots of graphs). I think it is a another good tool besides VAG for checking tuning..

Bruce

[scalbert]

But what do you mean by config?

S4 GTP Files

[rktskicar]

don't know.

Bruce

[scalbert]

I had mentioned in the original post about having GIAC X and Borla exhaust. But in further analysis more may be needed.

I have the previous version, about a year old, of the X chip; not the current release. To help remove the TC I did install an MBC after the runs last summer which I failed to mention earlier. You may be able to see this in the curves.

[Rolf]

[rktskicar]

Do you have anything else plugged into 12V power? Some pretty wicked launches (0.9 g's or so). Good stuff! My current clutch RS4 is new, so I havn't launched it yet (still in break-in period).

Bruce

[scalbert]

Yea, I noticed that about the RPM pick up. Perhaps I need to recalibrate it with everything off.

The launch for the 4.2 run was just about perfect and I doubt I could repeat it easily. I was either bogging or slipping the clutch. An upgraded clutch would certainly make it easier to repeat good launches.

I am trying to decide if I upgrade the clutch now or just wait until I go to K04's. I never launch the car so it seems like it may be a waste of time at this point. However, a few more tests like that and the decision may be made for me. ;-)

[rktskicar]

I waited until K04's for new clutch. I have only about 250 miles on it so far.

Bruce