JHM tune is in. They had it ready unexpectedly ahead of schedule already on Friday. That’s a first in the tuning world. Great job. Can only say thanks. Writing to 3 tuners they were the only ones to reply at all (and quite promptly) so they got the business. Simples.
So I got it flashed today. With a 4G LTE stick and a second battery hooked in parallel. In Russia you’ve got to improvise sometimes…
As expected it’s not easy to feel differences with the butt dyno here. Not like tuning a turbo car. The car doesn’t particularly feel faster but it does feel slightly different, if anything probably smoother at low revs. Another impression is that the throttle openings are larger at smaller pedal positions. But again not a difference I would notice if I hadn’t been driving 30 mins before, I certainly won’t notice a difference anymore tomorrow.
To get an idea of potential gains here I did a VCDS logged 3-8K run right before flashing. Literally. I think it was about an hour until I was logging a similar run with the JHM tune on the same stretch of road. It had gotten 1 degree colder in that time, negligible difference. Virtually no wind and average barometric pressure of 1015 hPa.
The obvious problem after the first baseline run on the old Dmitry map was that the car has slowed down. A lot. Yes it’s 12 or 13 degrees C warmer now, but I wasn’t expecting it to be 0.7 seconds slower than the last time I tried it a couple of weeks ago. I didn’t log most runs, but from video footage I had one 7.75s when it was 3 degrees C out. At 16-17 degrees C today I got an 8.41. In fact, I did a videotaped 8.0 weeks ago when it was actually 20 degrees C, considerably warmer than today.
The only actual change to the car has been summer tires (Michelin Pilot Super Sport) instead of Dunlop Winter sport 3D. Same size. I can imagine rolling resistance being higher, but not this much higher. Tires would be melting if that much energy went into them…otherwise there are no codes, ignition timing is strong and MAF readings aren’t abnormal either. Down to 155 g/s from 160 g/s when it was 2 degrees out isn’t much of a drop.
So I have no clue where the performance has gone. It doesn’t “feel” any slower but the stopwatch doesn’t lie.
All this was BEFORE actually tuning - but good thing I got a quick log in or I’d be bitching about the tune right about now. When I did flash the car and went straight back for another run it improved by 0.12 seconds. From 8.77s VCDS to 8.65s. Video and tach made it 8.41 and 8.27 respectively.
So the fact that the JHM tune made the car at least slightly faster was reassuring in the way that it is reacting in a predictable manner, even if the difference is small. It would have been bigger had the JHM run not weirdly been slower from 7 to 8K. Breakdown of times from VCDS:
[b]Dmitry 0097[/b] [b]JHM[/b] performance Δ
3-4000 1.63s 1.62s -0.01s ±—
4-5000 1.70s 1.66s -0.04s +2.5%
5-6000 1.67s 1.60s -0.07s +4.4%
6-7000 1.79s 1.74s -0.05s +2.9%
7-8000 1.98s 2.03s +0.05s -2.5%
8.77s total 8.65s total
6-7000 in 4th 3.31s 3.18s -0.13s +4%
All this is taken from ONE run only. So accuracy isn’t as brilliant as it could be but the general trend is there.
I only logged group 003 in VCDS so RPM, MAF and requested ignition timing. JHM requested spark advance is slightly greater but not a lot. For example the baseline run was seeing a min/max of 30.0-34.5 between 7000 and 8000 mostly 33-34.5. With JHM the min/max was 33.8-36 averaging closer to 35. Between 5 and 6 it was about identical. Bit odd that the only place where I saw more ignition timing was the spot where it was losing time perhaps, but I’m not convinced it would repeat itself in subsequent runs. Though the fastest logged run I have on record (at 3C ambient) was only doing 28-30 degrees at the top. Bit weird that.
Either way it’s hard to troubleshoot for missing performance when from all logs the car looks like it’s running great. Quite annoying.
With the piggies and a JHM tune I think the car should be below 8s on the tach for the Arthur test when it’s only 16-17 degrees C out. It’s still cool weather by all means. If anyone has any ideas I’m all ears.