Boxster Acceleration TestsI've used a G-Tech Pro unit a number of times to compare my Boxster's acceleration in various configurations and situations, as well as to measure whether the modifications I've made to it have improved its performance. I've done this sort of thing before to other cars I've owned, and to the cars of people I've raced with over the years, so I like to think that they are pretty accurate. But all you have to do is look at the wide range of results from the same car with the same driver on the same day etc. etc. to realize that this is never 100% representative of what the car's potential really is. Still, trends do start to appear. (Note that traditional drag-strip equipment shows a lower 1/4-mile trap speed than the G-Tech Pro does because drag-strips measure the average speed over the last 60 feet; not the actual speed at the finish line like the G-Tech Pro does.)
In all cases the car is 100% original and I turn the AC and Traction Control off (unless otherwise stated). In most tests I've run with the top and windows up. In some of the tests I had the top down but I didn't make a note of it and can't remember for sure. I think the top was down for the tests on 4/26/99, and maybe 4/18/99, but I'm really not certain. As of the 5/7/99 tests I'm being careful to make a note of that. Also, for the zero-to-60 tests I usually shift into 2nd at ~6100 rpms, then just keep it in 2nd to 60 mph at which point the rev-limiter kicks in. I think the limiter hits just after the 60 mph mark, but it's hard to tell. Definitely seems to be the faster technique. For the 1/4 mile tests I always shift at ~6100 rpms in every gear.
Boxster Acceleration Test Results (best results shown in red) Zero to 60 mph: 1/4 mile (e.t. and trap speed): Rear-wheel horsepower: Comments: 3/25/99 ~64°F, 9/16 tank gas (top up all tests) 6.52 7.1 Traction Control "on" 6.85 Traction Control "on" 6.43 6.75 4/8/99 ~65°F, 7/8 tank gas 6.49 6.93 Tried 3rd gear shift at ~57 mph instead of running into the rev-limiter 4/18/99 ~70°F, 1/16 tank gas 6.63 6.25 15.39 @ 66.9 mph Had to brake for traffic at the last second 15.34 @ 93.0 mph Poor launch 4/26/99 ~67°F, 1/16 tank gas 14.94 @ 95.1 mph 14.97 @ 95.3 mph Poor shift into 3rd 14.87 @ 94.1 mph 154 hp Assumes 2,930 lbs. (2,755 + 160 + 15) 5/7/99 ~72°F, 1/16 tank gas (with "Korda" muffler, top down) 157 hp Assumes 2,930 lbs. 6.49 6.30 6.14 14.95 @ 94.3 mph 14.81 @ 95.7 mph Top and windows up 5/25/99 ~70°F, 3/16 tank gas (with "Korda" muffler, K&N air filter, top up) 6.15 6.23 6.18 6.46 14.99 @ 95.0 Summary:
While it has been easy for me to better Porsche's official test results of zero-to-60 in 6.7 seconds and the 1/4 mile in 15.1 seconds, I have yet to even approach the zero-to-60 mph e.t. of 6.0 seconds, or the 1/4 mile e.t. of 14.5 seconds at 94.6 mph that Motor Trend achieved. This may be due to the fact that the drag-strips they use have a stickier pavement than what I test on (and usually have many years worth of sticky race-rubber deposits layed down at the start line), or maybe their equipment is more accurate than the G-Tech Pro, or it may be that Motor Trend has better test drivers... I hope not! In any case, that's OK because I'm only trying to measure the relative performance changes resulting from different modifications and driving techniques. That's why I always use the same stretch of pavement and try to equalize variables like temperature and weight as much as I can.
It seems that the Korda muffler has definitely helped. The average of the 5/7/99 zero-to-60 tests was down from the 6.51 average seconds for all the previous tests to 6.31 -- a 0.20 second improvement. Note that this doesn't include the tests with Traction Control "on" or the test where I shifted into 3rd. But some of those earlier tests were with more gas in the tank. Counting only those tests using 1/16 tank of gas, the average was 6.44. So still at least 0.13 second improvement on average, and 0.11 second faster than the previous fastest result.
While it's hard to say for sure, the K&N air filter seems to have helped very little. Though the 5/25/99 series of tests admittedly were done with an extra 1/8 tank of gas, and perhaps that skewed the results. But while no new records were set the average zero-to-60 mph time was lower than in the next fastest series of tests by 0.05 seconds (6.26 vs. 6.31).
For now I'm done with the testing. But it might also be interesting to try some tests with the spare wheel and tools removed, lower or higher tire pressures, stickier tires, different shift points, higher-octane gas etc. Someday!
Just for fun:
Other Acceleration Test Results (best results only) Zero to 60 mph: 1/4 mile (e.t. and trap speed): Rear-wheel horsepower: Comments: 1996 Nissan Maxima SE (100% stock, 5-speed, full tank of gas) 7.12 16.00 @ 93.2 mph 164 Not bad for a stock grocery hauler! 1996 Nissan Maxima SE (as above, AND Stillen Exhaust System and Hi-Flow Intake Filter System) 6.66 15.46 @ 97.0 mph 166 Quite an improvement for just a few simple mods! 1993 Mazda RX-7 Touring (100% stock, 5-speed, 1/2 tank of gas) 5.40 14.36 @ 101.4 mph 197 Fast car! 1999 BMW 540i (100% stock, 6-speed, DSC "off", 1/2 tank of gas) 5.88 14.58 @ 102.2 mph -- Fast sedan! Very difficult to launch due to the very high torque -- lots of tire spin! © Copyright 1999-2007. Dennis Schøler Pedersen.
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