XMSRacing

iTrader: (11)

I really have to ask something here... how in the world are you guys gearing these things to 6.5? I've got mine at 7.3 and it comes off the track pretty warm. Even the thought of jumping to 6.5 makes me smell burning motor without doing it! Are you guys running on outdoor, very flowing tracks? My track flows, but it still has a few turns that you need some grunt to get out of. I'd think 6.5 would just smoke a motor on my track.

XMSRacing

iTrader: (11)

BTW... I thought Trinity brushes sucked in this motor. 767's still seem best to me. My only thought is possibly the motor wants more gear with other brushes... but I dont think brushes are going to make a 3-4 tooth difference in my motor. (basing that off of you guys running at a 6.5)

Marcos.J

iTrader: (239)

I ran a a 6.17 last week at B&B hobbies and its a nice flowing track and the motor came off the track at 132 degrees not bad at all

Desolas

iTrader: (2)

I race on a somewhat tight carpet track, and gear at 6.8-7.13 depending on the layout, if it's more flowing or tighter mid field.

The motor comes off hot, but not excessive. You have to carry a lot of speed through the turns though or it will tend to bog, but if your speed is right the motor helps you keep it much better.

Try it and see if the car is quicker, and just run it and check it every minute or two. If it gets too hot, or your car is slower, go back to where you were.

bukil

iTrader: (39)

May I ask. What batteries do you use? How long does it last?

The reason I ask is because I'm trying to gear my FT TC4 to 7.0. I'm afraid that my batteries (3300 matched) won't last throughout the race. Sorry for the newbie question.

Thanks in advance,
Mark

maxepower

iTrader: (1)

Just make sure you take the temp through the window of the can to get an inside the motor temp. It could be 40-50 degrees hotter on the inside!
Just my 2$

maxepower

iTrader: (1)

One of the selling points of this motor was they were designed specifically for the higher MAH batteries. New 3300's will work but I would use at least 3600's and that way you wont have to worry about not lasting the full 5 minutes for a race!

NOZ69

I ran my CO27 Pro on the weekend in my FT TC4 at 6.0 (72/30) using matched IB3800`s & it came of cooler than my Monster at 6.9. Haven`t got a temp gun but I could hold my fingers on the can for about 30 secs. I tried to run at the lower gearing 6.4 to 6.9 & it just didn`t like it.

Had me second guessing for a while, wondering if i`ve over geared it but it`s fine & seems to be getting stronger.

Maybe it`s because we live "Down Under" but ALL the stock racers in our club seem to be in the low 6`s & even the high 5`s. The track changes meet to meet, over 2 netball courts one meet tight (Electric) next more open (Nitro`s)...go figer

Cheers

bukil

iTrader: (39)

I ran my CO27 Pro tweaked with a heatsink this past weekend in my FT TC4 geared at 7.2 (69/24) using matched 3300s. The motor came off hot!. I could only hold it for three secs! Was my motor undergeared or overgeared? Do I need 3800s?

I tq'ed the stock class. I was not able to run the A main because my motor won't spin unless I move one of the wheels then pull the trigger. Is my motor dead or does it only need to be rebuilt?

Our track here is located at Freedom Park in Camarillo, CA. It's not a fast flowing track. There is only one fair straightway then lots of turns. I hope this gives you (motor gurus) an idea on how I'm suppose to gear my car.

Thanks in advance,
Mark

BlackKat

2 comments.....

1) I find (unmatched, 2 year old) 3300's suitable for use with the Cobalt.

2) You TQ'ed stock class yet you don't know what a hung brush means? All your motor needs is a re-build and it should be as good as new

v0rtex

iTrader: (9)

The rule is simple, no need to be a 'motor guru' to suggest a ratio. Gear the motor so its hitting peak RPM at the end of the longest straight. You may adjust it slightly from there based on temperature if you feel it needs it.

John Tag

iTrader: (42)

We run the CO27 outdoors touring from 6.0 to 6.20 peak about 3/4 main straight away to still have great infeild power...

bukil

iTrader: (39)

Yes. I TQ'ed stock class. I was using brushless system before so I didn't care what those brushes mean and some other technicalities associated with it.

The track here does not have a brushless class so I had no choice but to go brushed mode. When I was racing, the car felt really slow. This is probably because I'm used to my brushless (5800 and 5.5R)so it was easy for me to drive.

Anyway, back to the gearing issue. Should I gear it to 7.0?

Thanks in advance,
Mark

bukil

iTrader: (39)

Sorry for this noob question but how would I know if I hit the peak of my rpm?
I have only been racing for 6 mos.

Thanks,
Mark

Ike

iTrader: (8)

Just have to go by feel, you should be able to tell if the car is topping out or still accelerating at the end of the straight.