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Old 11-11-2016, 12:28 PM   #1
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Default hpi sport3 question...

just a quick question as im new to the hobby, i recentley bought a brushed hpi sport 3 (bmw e30) which i have now converted to brushless with the absima 1/10 bl eco brushless esc combo i have also changed the spur gear from a 75 to a 66t and purchased a 32t pinion my question is would the jump from a 27t to a 32t pinion 5 teeth increase be too much?? any advice would be greatly appreciated thanx
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Old 11-11-2016, 01:29 PM   #2
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Here is a thread specifically for the Sport 3 here on RCTECH.net



I'm not familiar with the brushed motor that comes with that car. Best basic advice when swapping motors is....
- Make sure you have good cooling on the new motor (may need to add a cooling fan or heat sink or both)
- Run the car for a minute and then check the temperature of the motor. If it is above 150 degrees Fahrenheit you may need to reduce gearing and/or reduce timing if possible. (Here is a cheap example at Harbor Freight - http://www.harborfreight.com/infrare...ter-93984.html)
- Check with the manufacturer of the motor for recommended gearing for your application

Here is a support link on Absima's website including an email address

I'm currently racing VTA. Check here for rules/info: http://www.usvintagetransam.com/
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Old 11-11-2016, 03:43 PM   #3
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This question isn't reliant on what type of car you have, unless you're worried about maybe breaking other drivetrain components because of a huge increase in power/stress to them.

You will need to look at the recommended gearing options and specs for your specific motor and take into account your desires for performance and any limitations you may have if you run in sanctioned events. Certain gear ratios are acceptable for some motors while other motors they may not be. Do you run the car in sanctioned events? What do their rules say about motor size and gearing? What do you want from the car, acceleration, top speed or a good middle ground?
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