Post by dave632 on Mar 22, 2020 17:06:51 GMT -7
I was asked by one of the buyers I sell cars to for some information. I did these tests to see how rear wheel speed related to on track MPH.
Set up my RPM/AMP checker and put the input at 16 volts to duplicate your conditions. I noted that the input voltage on my tester dropped to 15.2 volts when I ran the car that hit 10,000 wheel rpm, all cars dropped the voltage some but I noted this one. This is probably due to the wiring and controls that the supply goes thru as the main supply which is a 10 amp unit did not drop at all on its indicator.
I also set my track at 16 volts to compare the actual MPH to what the cars ran on the RPM indicator.
Here are the results, all are pancake style cars:
Stock 15 ohm chassis #1 Hit 7,394 rpm, track trap speed was 8.8 mph, current draw was .48 amps.
Stock 15 ohm chassis #2 -- 7,058 rpm, track trap speed was 8.3 mph current draw was about the same.
Stock 15 ohm chassis #3 -- 10.069 rpm, track trap speed was 11.1 mph current draw was .54 amps.
Modified mean green 6 ohm and other mods, this is the car that hit 22.5 mph at 20 volts and is exceptional.
----14,085 rpm, track trap speed was 17.3 mph with a current draw of.79 amps.
I have to admit this was interesting surprised me as I had not used the rpm checker in awhile but it seemed
to show an approximate speed relationship from the track to the checker. I forgot I had improved
the checker with a simple rubber band to hold the car to the rollers and there was little or no
wheel slip/bounce on these runs.
What this will NOT tell you is Elapsed Time which is of course very important. Many cars on my track have won
the speed battle and lost with a slower ET. Still it gives you an idea of how much power your car is
making. Getting it to the track is another problem.
Hope this helps out and gives you an idea of how your cars are performing. Check out Nitro slots for a lot of
HO drag racing info.
Dave
Set up my RPM/AMP checker and put the input at 16 volts to duplicate your conditions. I noted that the input voltage on my tester dropped to 15.2 volts when I ran the car that hit 10,000 wheel rpm, all cars dropped the voltage some but I noted this one. This is probably due to the wiring and controls that the supply goes thru as the main supply which is a 10 amp unit did not drop at all on its indicator.
I also set my track at 16 volts to compare the actual MPH to what the cars ran on the RPM indicator.
Here are the results, all are pancake style cars:
Stock 15 ohm chassis #1 Hit 7,394 rpm, track trap speed was 8.8 mph, current draw was .48 amps.
Stock 15 ohm chassis #2 -- 7,058 rpm, track trap speed was 8.3 mph current draw was about the same.
Stock 15 ohm chassis #3 -- 10.069 rpm, track trap speed was 11.1 mph current draw was .54 amps.
Modified mean green 6 ohm and other mods, this is the car that hit 22.5 mph at 20 volts and is exceptional.
----14,085 rpm, track trap speed was 17.3 mph with a current draw of.79 amps.
I have to admit this was interesting surprised me as I had not used the rpm checker in awhile but it seemed
to show an approximate speed relationship from the track to the checker. I forgot I had improved
the checker with a simple rubber band to hold the car to the rollers and there was little or no
wheel slip/bounce on these runs.
What this will NOT tell you is Elapsed Time which is of course very important. Many cars on my track have won
the speed battle and lost with a slower ET. Still it gives you an idea of how much power your car is
making. Getting it to the track is another problem.
Hope this helps out and gives you an idea of how your cars are performing. Check out Nitro slots for a lot of
HO drag racing info.
Dave