60-130 MPH: New performance measurement!
05-04-2005, 06:28 AM
#257
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Originally Posted by rmrmd1956
shouldn't the gt2 (assume it is 996 gt2) with upsolute chip and
cargraphic exhaust run in the eights?? just curious about such an awesome car...
I don't know. I may be a poor driver?
The AX22 is very accurate, so I would suspect the other claims.
Speedo video is a 'poor man's version' of the AX22 and full of error.
The AP22 predecessor was good, but the wrong tilt factor could change your results significantly. The 911 has a lot of "squat" under acceleration and the correction for it with "sports car suspension" under corrects so that some of the "squat" is calculated as linear acceleration, making the times "too good"
That was my assessment after much back to back testing
cargraphic exhaust run in the eights?? just curious about such an awesome car...
I don't know. I may be a poor driver?
The AX22 is very accurate, so I would suspect the other claims.
Speedo video is a 'poor man's version' of the AX22 and full of error.
The AP22 predecessor was good, but the wrong tilt factor could change your results significantly. The 911 has a lot of "squat" under acceleration and the correction for it with "sports car suspension" under corrects so that some of the "squat" is calculated as linear acceleration, making the times "too good"
That was my assessment after much back to back testing
Can you explain why the AX22 is more accurate than the AP22 ? How does it correct for the various suspension set ups ?
Thanks
05-04-2005, 11:06 AM
#258
Drifting
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9.5 is very fast and you are obviously using accurate measurement--thanks,
My only tests have been using stop watch and passenger and speedometer.
I will purchase a device and try again.
thanks for the input.
m.k.
My only tests have been using stop watch and passenger and speedometer.
I will purchase a device and try again.
thanks for the input.
m.k.
05-04-2005, 11:49 AM
#260
Burning Brakes
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It would appear that the ax22 and ap22 both use an accelerometer as their technology. Perhaps someone can explain why their accelerometer is more accurate than say a passport G tech. Yes I know it has GPS, but it appears that the data for the 60-130 is coming from the accelerometer not the GPS. Any explaination would be appreciated. Also simple english, as I'm a not an engineer.
05-05-2005, 12:13 AM
#261
The AX22 uses both GPS and accelerometer data to do its calculations. In the software, you can force it to use only one or the other, but its greatest accuracy is when both are used. The AP22 is good, don't get me wrong, and it is a lot cheaper too. All accelerometers are prone to slight error and as measurement time lengthens, this error grows. The GPS data allows auto correction by calculating accelerometer based position and comparing it to the GPS position. This allows 'self correction' over long time periods. Of course GPS position also has error, so nothing is perfect!
05-06-2005, 01:12 AM
#263
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rmrmd1956
Thanks for the explaination. the C&D article is very informative. While some dis the perfomance meters, they appear to be very accuracte. BTW, I ran my Passport G-timer against the clocks at the old Carlsbad raceway when I ran my E55 amg. It was off by less than 1/10 on every run. The mph was faster by 2-3 mph. I figure that is a result of the dragstrip measuring speed for only the last 60'.
Problem with using the Passport, for this test is you must be able to run the 1/4 mile with speeds up to 130 or it won't give the the desired 60-130. I'll rerun next week with some VP 103. I'm sure I can better a CGT.
Thanks for the explaination. the C&D article is very informative. While some dis the perfomance meters, they appear to be very accuracte. BTW, I ran my Passport G-timer against the clocks at the old Carlsbad raceway when I ran my E55 amg. It was off by less than 1/10 on every run. The mph was faster by 2-3 mph. I figure that is a result of the dragstrip measuring speed for only the last 60'.
Problem with using the Passport, for this test is you must be able to run the 1/4 mile with speeds up to 130 or it won't give the the desired 60-130. I'll rerun next week with some VP 103. I'm sure I can better a CGT.
06-10-2005, 02:40 PM
#264
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Went today for a drive in the desert with a friend and my video camera.
Some background...VERY hot ambient temps, temperature 41 Degrees Celsius in the city, so more in the desert
car had been running fast for 109 kms before timing, 2 people on board, 91 octane gas, running at 1.1Bar. Rear wing at max downforce.
Timed by passenger at 5.6 seconds, however on the video the 5.6 is not very clear, yet clearly below 6 seconds. Accelerated on third gear and nailed 130 mph right before cut-off on fourth gear, therefore one gear change.
Some background...VERY hot ambient temps, temperature 41 Degrees Celsius in the city, so more in the desert
car had been running fast for 109 kms before timing, 2 people on board, 91 octane gas, running at 1.1Bar. Rear wing at max downforce.Timed by passenger at 5.6 seconds, however on the video the 5.6 is not very clear, yet clearly below 6 seconds. Accelerated on third gear and nailed 130 mph right before cut-off on fourth gear, therefore one gear change.
06-10-2005, 04:27 PM
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Rassel
I don't think it is fair to compare
I forgot to mention that I have one 3 disk cc insert to reduce exhaust sound in one of the exhaust pipes, the other flew out
I don't think it is fair to compare
I forgot to mention that I have one 3 disk cc insert to reduce exhaust sound in one of the exhaust pipes, the other flew out
06-10-2005, 07:33 PM
#269
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Jean
Astounding accelration. For a frame of reference, that would put your car somewhere in the 10 second range for the 1/4 mile ON PUMP GAS! What is the weight of your car? I'd like to see what the power to weight ratio is.
Astounding accelration. For a frame of reference, that would put your car somewhere in the 10 second range for the 1/4 mile ON PUMP GAS! What is the weight of your car? I'd like to see what the power to weight ratio is.
06-11-2005, 01:39 AM
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Marty, the temperature was around 106 F in the city.
JJayB I have to weigh the car again but when I had almost finished it, it weighed around 1350Kgs, or 3000lbs. But we were two on board yesterday during the run.
I would not expect hp to be beyond 650 hp at all under these conditions.
JJayB I have to weigh the car again but when I had almost finished it, it weighed around 1350Kgs, or 3000lbs. But we were two on board yesterday during the run.
I would not expect hp to be beyond 650 hp at all under these conditions.