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Old 10-04-2020, 02:52 AM   #128 (permalink)
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Originally Posted by M_a_t_t View Post
For those who have done this and watched the reading for TPS what kind of repeatability did you get? I was testing my hand throttle while reading the resistance of the TPS on the car and got a ≤50 ohm variance between tests. This equates to ~2.3% (3.44k ohm with no input and 1.26k ohms at full throttle). When I use it though I do get pretty consistent results as far as speed to the tenth of a mph.

2.3 percent throttle variation? Seems a little high.

I didn't bother using the throttle stop after the first few tests because I could manually hold the throttle to 1 per cent (watching the live TPS percentage readout on my Motec dash) eg 20-21, 20, 20, 19, 20, 20, 20, 21 (etc).

One thing that I have learned though is that you must enter the test straight at dead-on the same speed and then move to your throttle stop position. In my case I enter at exactly 100 km/h (there's a tree I sight against) and then go to throttle-stop position, which might then raise or lower that speed by the end of the straight, depending on the aero changes.

But best test is windows open / windows closed - then at least you know you're measuring real stuff.
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