(Acceleration:
In total, Jim made five acceleration runs and one power run separated by a short break to let the Mustang cool down (and to disperse the cloyingly strong burned rubber smell!) Three runs included his son and I in the car, where the last two had just the two of us. Also, since this new test site has a slight slope to it, I decided to only quote averaged runs.
){kind=link}
The averaged (uncorrected) runs with his son aboard were 14.4 seconds @ 98 mph, and with just the two of us the times dropped to 14.3 seconds @ 100 mph. The 0-60 times varied between 6.2 and 6.3 seconds, mainly because Jim had trouble hooking up. He had so much trouble, in fact, that he set a new record for the longest burnout. The Burnout King is dead; long live the Burnout King!
){kind=link}
Power:
As you may remember, I have made a few modifications to the corrections spreadsheet, and I don't think I'm 100% there yet. With that in mind, the best uncorrected averaged output from today's runs was 216bhp @ 5900rpm, and 218lb-ft of torque @ 4800rpm. After corrections that comes out to about 275bhp and 280 lb-ft of torque. The 2005 Mustang GT has a published output of 300bhp @ 5750rpm and 320lb-ft torque @ 4500rpm. Whether the difference is due to a green motor (there's only about 3000 miles on the engine) or my spreadsheet I'm not certain yet. Regardless, the output is in the right neighborhood and the car certainly is fast!
You can see the power curve from the single power run we performed. I did not use its figures to calculate max power and torque since the run was one-way on the slightly-sloped road. Instead the figures above came from a pair of averaged acceleration runs.
){kind=link}
Technique:
If you've already viewed the video clip you have already seen a couple of the runs Jim did. We experimented a bit with softer launches, harder launches, and different shift points. For example, we found that Jim had to make sure to wind the motor past 6000rpm in third, or he'd end up shifting right before the end of the quarter mile.
){kind=link}
When you look at the launch comparison, you can see a wide variety of launches. The best ones were around 2500rpm with heavy throttle, followed by a bit of feathering to keep the tires at least loosely connected. In theory the best launch would be a bit more power right from the stop, but fast throttle feathering to keep the RPM level near the torque peak (without too much wheelspin.) It seemed like Jim's P235/55ZR17 Pirellis struggled to cope with the power output more than Brian's P245/45WR17s. Both Jim and Brian had very close 0-60' times, but Brian had very little wheelspin where Jim had quite a bit. Then again, Brian's tires are 50-75% more expensive, too...
){kind=link}
After looking at the shift points Jim used and comparing it to the power curve, I'd suggest that Jim shift closer to 6000rpm since the engine's power is starting to fall off there, and the shift would drop it right on top of the torque peak. That should improve the quarter mile ET by a tenth. This may prove to be a double-edged sword though, since shifting earlier in first and second means that he'll probably have to wind the engine into the redline in third to avoid shifting at the end of the quarter mile. Decisions, decisions!
){kind=link}
One change to shifting technique that doesn't have a downside is speeding up each gearshift. You can see by the Mustang's acceleration graph that each shift is dropping the acceleration to zero or nearly so. If Jim can speed up the shifts he should benefit by a nicely reduced ET. You can see this more clearly by a shift comparison between Brian and Jim's Mustangs.
){kind=link}
){kind=link}
Corrections and Other Factors:
Well, I had a bit of extra work with these runs due to a couple factors: (1) "Test Site South" is slightly sloped, so I averaged one run from each direction, and (2) after three runs we ejected Jim's son from the Mustang and tried again. That meant I had to use two different weight readings as well as two averages. So, there are two correction spreadsheets this time: runs with three people, and runs with two people.
| Recorded Data | Corrected Data | |
|---|---|---|
| Two People | 0-1/4 mile in 14.3 secs @ 100mph | 0-1/4 mile in 13.9 secs @ 103mph |
| Three People | 0-1/4 mile in 14.4 secs @ 98mph | 0-1/4 mile in 13.8 secs @ 103mph |