Race Technology AP22
03 February 2003, 08:30 PM
#1
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Hi all
Has anyone used one of these and if so how accurate are they, REALLY ?
I was looking at getting the Apexi one which is about £300, but as the company that sells these is just down the road and they are cheaper was thinking of trying one, also the fact that you can download the data to a PC is a very nice feature.
Cheers
Cheers
Has anyone used one of these and if so how accurate are they, REALLY ?
I was looking at getting the Apexi one which is about £300, but as the company that sells these is just down the road and they are cheaper was thinking of trying one, also the fact that you can download the data to a PC is a very nice feature.
Cheers
Cheers
03 February 2003, 09:33 PM
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I played with one of these a year or two back when I was into kitcars.
They work by using an accelerometer and measuring the accelerations directly. They then turn those into speed/power measurements.
Be aware that you have to calibrate them for best results. This involves coast down tests to measure the rolling resistance and the areodynamic drag. I found this quite a chore and quite hard to do unless you live somewhere with empty flat roads.
I tried the box on my 106GTi and my R1 powered kitcar. I achieved 7.6s for the Pug and 4.1s for the kit. Both of those are realistic scores. If you put the weight of the car in it calculates how much power you have to do that acceleration too. It was spot on for those calculations as well.
A good fun gizmo. Recommended.
Marc
http://www.impreza-p1.org.uk
They work by using an accelerometer and measuring the accelerations directly. They then turn those into speed/power measurements.
Be aware that you have to calibrate them for best results. This involves coast down tests to measure the rolling resistance and the areodynamic drag. I found this quite a chore and quite hard to do unless you live somewhere with empty flat roads.
I tried the box on my 106GTi and my R1 powered kitcar. I achieved 7.6s for the Pug and 4.1s for the kit. Both of those are realistic scores. If you put the weight of the car in it calculates how much power you have to do that acceleration too. It was spot on for those calculations as well.
A good fun gizmo. Recommended.
Marc
http://www.impreza-p1.org.uk
04 February 2003, 07:00 AM
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Very good - but yes, they have to be set-up correctly to get an accurate reading to compare with other vehicles. Doesn't matter so much if you just want to see whether a mod gives you more power or not though 
Richard
Richard
04 February 2003, 01:55 PM
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I've used one with some success. I've got a trace in an Excel spreadsheet that show's me making a right b*lls up of the launch.
If anyone would like a look let me know and I'll post a link to it as soon as I stick it on my webpage. I may regret that when you see how badly I did... :-(
The only problem/gripe I had with it was the fact that it only logs every 10mph which means you don't often get some of the more intersting stuff like "how bad was that gear change" etc.
The tilt setting seems to be the most important and the handbook gives a rough guide on how to set it. You can use this to factor out how much the suspension squats under accelleration which makes the readings more accurate. Out of the box though I'd say it was probably good enough to give you a very good idea of your performance.
The person I borrowed it off used it to great effect on his Lotus Exige and it really showed up just how good the 190bhp mod was!
Steve.
If anyone would like a look let me know and I'll post a link to it as soon as I stick it on my webpage. I may regret that when you see how badly I did... :-(
The only problem/gripe I had with it was the fact that it only logs every 10mph which means you don't often get some of the more intersting stuff like "how bad was that gear change" etc.
The tilt setting seems to be the most important and the handbook gives a rough guide on how to set it. You can use this to factor out how much the suspension squats under accelleration which makes the readings more accurate. Out of the box though I'd say it was probably good enough to give you a very good idea of your performance.
The person I borrowed it off used it to great effect on his Lotus Exige and it really showed up just how good the 190bhp mod was!
Steve.
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