FDR for SP v3 6.5T motor?

[Cardnim]

HI all,

My motor is getting quite hot (80 degrees normally) and I wonder if my FINAL DRIVE RATIO (FDR) is wrong.

Here's what Im running:
Schumacher Cat SX2
S.Passion v3 6.5t motor
S.Passion GT.2 (lpf) ESC
22t pinion
83t spur
33/23 internal steel idler gears

I cant find any info about the FDR for these motors either in the manual that came with it, or on Speed Passion's website.

Can anyone help?
Thanks guys.

Andrew.

[Big G]

what size track are you running on? indoors/outdoors?

Punch and Timing settings on the speedo?

I usually find mine running around 71oC for my 7.5 v3 on a small indoor track low grip.

[Cardnim]

Hey Gareth, cheers for the assist mate.
I just dont know enough to work out if Im doing something wrong or not.

OK, answers to your questions:
- indoor, astro track; quite tight I would say, motors dont really get a chance to open up much;
- turned off all punch/timing on the ESC, and timing on motor = 0 degrees (I think!)

Thanks mate

[Big G]

try gearing it down a bit to see if it effects the temps. We regularly end up having longer finals than heats so I gear down slightly to keep temps down.

[Cardnim]

The only thing Ive changed on it, is gone down to an 18t pinion, but temps stay the same?!
Thats why Im confused.

A friend said about checking out the final drive ratio on the makers specifications to see what the motor should be run at. He reckons Im gearing too low and that I should be looking for a 23t pinion to give an FDR or about 9.3.

This is a bit greek to me to be honest, but maybe it makes sense?

[Big G]

I can't remember what I can ran in the SX2 as it was a while ago, but I ran a 24/81 setup with a 10.5

hopefully someone else can shed some light on the cat setup

[Cardnim]

Cheers Gareth, thats good to know mate.
Can you remember what make of motor that was?

[tyreman]

I ran mine on 25/80 in my SX2 and never changed the gearing, i wouldn't worry about the temp too much unless it goes over 100deg, mine run around 85-95 deg after a run.

[Cardnim]

Thanks Tyreman - thats good to know!
I'll not worry so much about it and stick with the gearing as is.

Thinking about your gearing, wasnt that ridiculously fast though? I guess it depends on the motor, but 25/80 on mine I would think would be mental!

[tyreman]

It was a speed passion 6.5 with a 12mm rotor so less torque and more rpm, but seriously though you need to gear these motors a little higher than say an LRP X12 6.5, otherwise you won't get the top end out of it.

[Cardnim]

Ahhh, ok I see.
At a race on Saturday, some of the other racers were saying that my car seemed under powered. Maybe thats where I was going wrong then.
My fear is that by increasing the pinion size, i will heat up the motor even more, increasing my problem. Is this a relevant concern?

Thanks for the help guys- this is really useful for me