How are the Rx8 & T8's holding up?

[brushlessboy16]

Alright maybe its just me. but Gearing up and down DOES NOT change motor rpm. I dont get why people keep trying to say that A different pinion will "slow down" your motor. Rpm is based on 2 factors. KV and the ability of your battery to hold voltage under load. Pinions have nothing to do with it- if your packs are not up to par however, a gearing change will equal a slightly lower rpm but moving up a tooth or two will not magically make your motor slow down..


Can any one tell me what rpm range in which the t8 motors are most efficient. I have heard around 28k rpm... can anyone confirm or deny this?

[Marvin]

I don't think anyone was saying that, but if you are geared higher, higher gearing = higher top speed and slower acceleration. I think TekinTeamMgr was suggesting using a larger pinion to help tame the low end a bit, as the acceleration would be reduced.

[SpEEdyBL]

Originally Posted by brushlessboy16

Alright maybe its just me. but Gearing up and down DOES NOT change motor rpm. I dont get why people keep trying to say that A different pinion will "slow down" your motor. Rpm is based on 2 factors. KV and the ability of your battery to hold voltage under load. Pinions have nothing to do with it- if your packs are not up to par however, a gearing change will equal a slightly lower rpm but moving up a tooth or two will not magically make your motor slow down..


Can any one tell me what rpm range in which the t8 motors are most efficient. I have heard around 28k rpm... can anyone confirm or deny this?

Just an FYI, here is how you find loss in rpm. Take voltage/resistance to get your absolute max theoretical current. Then take the no load rpm (kv x voltage) and divide that by abs. max theoretical current and you get rpm loss per amp. (You subtract this from the total no load rpm, not the kv) You will draw more amps when geared higher, therefore you will lose some rpm. You are right that is usually small, but not always. I've tried a 20 tooth with my 1900 and it did not seem nearly as fast as the calculated 49 mph and took forever to get up to speed. At the end of the run, pack was only 110F and motor 140F. 6s with a 14 tooth was just in comparison in terms of speed and power. Although motor temps are usually between 145 and 155 with this setup, its not like its less efficienct. It is making WAY more power with only a small increase in temps. So I would say efficiency is better described on a basis of how your geared and where you are running rather than what the rpm of the motor is. If I tried to go around the track with my 6s and use low throttle, im sure that would heat up more than if ran 4s with higher gearing.