Ok guys, this is long overdue. With technology as it is today, most of us should be able to measure the performance of our cars using an application such as race chrono and taking measurements from GPS and the on-board accelerometers of our cellphones. With all the different brake upgrades we've seen over the years there still hasn't been any performance comparisons, I say now is the time to start trying.

As for how to do it, I can only tell you how I did my test. Using race chrono (it's free btw) I went into settings => other => expert settings => record internal sensors (as I wanted the readings from the internal accelerometers). Then started a new session, placed my phone face up (to get a clean reading from one of the accelerometer channels) right up against the center panel (didn't want it to slide around in that direction) and as soon as I had contact with the GPS satellites I was off

I'll go right ahead and post my measured values from today.

Max deceleration (acc. to cellphone accelerometers): 1.0G
Max deceleration (acc. to GPS data): 1.2G
Front calipers: '85 corvette calipers (single-piston, diameter 54mm)
Front rotors: '88 corvette standard duty (12" x 0,81")
Rear calipers: '85 Fiero (single-piston, diameter 48mm)
Rear rotors: '85 fiero
Master cylinder: '85 fiero (1" diameter)
Bias adjustment: none (prop-valve disabled)
Wheels: 17x7 on all corners
Tires: Goodyear Eagle NCT 5, 215/50R17. Treadwear 240
Road: medium-rough asphalt pavement

Weather: sunny, warm

Notes: Fronts seem to lock up first. Accelerometer readings could be affected by nose-dive. Braking was from 72kph (speed limited by surroundings). GPS accuracy is not good enough, external bluetooth puck would be a useful addition.

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http://cadanalysist.blogspot.com
http://iguitarer.blogspot.com

So do the G s equate to the stopping power, no need to measure stopping distance?

quote Originally posted by 2.5: So do the G s equate to the stopping power, no need to measure stopping distance?

Yup. With G's, you can measure distance and the time it took to stop from any speed. 1G = 9.8 M/s^2 or 32 ft/sec^2.

I'll have to measure mine next time I am out with the appropriate equipment...

-Dave

[This message has been edited by IFLYR22 (edited 08-07-2013).]

Seems like all you need to get distance is time. Can your phone measure time from beginning deceleration to stopped? Seems like that should be possible.

yes, all you need to get a distance is time. But distance is slightly harder to measure as the GPS (at least that of a smartphone) will not be updating quickly enough to get a reliable result so you'd need to have a marker at which you start braking and then a tape measure to check the distance travelled.

hopefully more people will repeat the experiment and post their results.

Not meaning to steal the thread or to have it go off on a separate tangent but I have been thinking about performance numbers recently and how Fieros, both stock and modified, compare to current, OE equiped, cars. Is there a thread with these numbers being compared? What key words would I use to make that search?

Naturally any performance improvement is good but shouldn't we aspire to compete with cars that put out respectable, if not impressive, numbers? When I had my 2.8 Getrag notchie, I could not keep up with a friend's Dodge Neon. That was humbling. I would very much like to correct that situation.

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Jonathan

'68-69 GTO Nose - The Project has Begun!
My '85 L67 Build Thread

benchmarking is absolutely in line with this thread, I was planning on testing my fathers C6 Z51 (as a passenger, he won't let me drive it for some reason) and other comparisons will be useful as well.