Do you figure your gearing by motor temp . Or by lap time , I mean can you have the right gearing and the motor only getting about 124 degrees , our do you keep putting the gear to it so you are hitting the 160 degree mark? Oh yeah this is done with a 17.5 motor on a 88 foot oval in 5 minutes

From my experience with the 17.5, which like everyones is limited, you will have trouble ever getting it to 160 on carpet. The highest I saw with mine was 135 and that was rolled at 3.84 on a ~150' or so carpet track.

In the end the goal is to get the fastest 5 minute time you can, so the gear that gives you the best time is the best gear.

if you did want to go by temp I think a better rule of thumb for carpet racing would be......

17.5 (sintered rotor) low 130s
13.5 (sintered rotor) low 140s
10.5 (sintered rotor) 150-160

I'm sure some will disagree, that is just what I have found. It's also important to remember that the temp guns don't all read the same.

Would that be the same for asphalt for the 17.5? I'm in the process of building a brushless/lipo car for a asphalt track with run line of about 355'. Or do you think I will be able to get closer to the 160 mark.

Asphalt the temp will be higher. It's difficult to pin down a range there because of changing weather, but it will be higher.

Temp has way too many variables in it to use that only. If you have a car that is undergeared and not free through the corners it may get hotter than a car 2 ro 3 teeth higher but is handling better. Lap times should always dictate gear ratio. Temp guns are a great tool but not as precise as the amb counter/stop watch. Iknow for us the 10.5 and 8.5's are around 150F to 160F for 4 minutes on carpet with tight paperclip running line of 120ft. I have used the Crazy motor cooler and dropped about 20-30 degree's at the end of a run.

Just remember, adding more gear to try to get more speed may get the motor hotter but doesn't nessesarly mean more speed.. just mean's that you have have put more load on the motor getting it hotter by running a larger gear. this may not always be the case but just my opinion. handling is the big key factor tho.

Jon

Hey Butters

What have you been gearing your brushless in Plattsburgh?

Also is there a way to convert stock rollouts to brushless? Like for example if at one track a 2.00 rollout is the way to go on a monster, what would work for a 17.5?

The bottom line is that you win if you finish first. Regardless of temperature the fastest times that you can do without exceeding the a safe temperature is the only way. Temperature isn't a linear indicator, as said above it varies with the ambient temperature of the room/weather etc. Just do like you always did and gear till the car is as fast as it will go. Just monitor the temp so as not to burn out your motor.
Rick<><

Also is there a way to convert stock rollouts to brushless? Like for example if at one track a 2.00 rollout is the way to go on a monster, what would work for a 17.5?

I just crunched some numbers and this is what I came up with. There is probobly a better way of doing this using track lenth but that is way beyond me. I'm sure the salvas's could figure that out with no problem.


Track Motor Rollout BL Motor Rollout

Maximus / Cobalt: 2.00 / 17.5: I think there running about 3.60=80% increase

Track Motor Rollout BL Motor Rollout

Plattsburgh / Cobalt: 1.65 / 17.5 x 80% = 2.97

After racing plattsburgh I would say 2.97 is dead on for 17.5 rollout.

So take the rollout of a Cobalt stock for a particular track multiplied by 80% (1.80) to get a ballpark rollout for a 17.5.

Sorry Tom,

Actually...going from 2.00 to 3.60 is an 80% increase...just so there is no confusion. Also, you multiply by 1.8

Or...you could mutiply 2.00 by .8 and then add the product to 2.00

I like Math!

uh thats exactly what I said! http://www.8thcivic.com/forums/images/smilies/spinning.gif http://www.8thcivic.com/forums/images/smilies/banana-wave[1].gif hehe

nice edit usage!

You guys are the "BOMB" when it comes to math.HEHE and pretty fast racers also.