Raptor with 8:1 gears?

[cwayaustx]

Anyone run the GE d398 Raptor with 8:1 gears? For a street cart with rear seat, wondering how much torque loss the gears would cause for neighborhood mild hills and take offs. Have an alltrax 400 amp but will probably get put my spm 72650 in it.

[JohnnieB]

Going from 12.44:1 gears to 8:1 gears will decrease the torque where rubber meets road by 36%.

If it has taller than stock height (18") tires, that is also a torque loss.
If it has a rear seat, that is increased workload.

Going from a 400A controller to a 650A controller will increase low end torque by 37.5% if the battery pack can produce them and the amp delivery system can deliver them. That means you'll have about the same as stock torque less the torque loss from tire height, if they are taller than 18".

So the question becomes, can the motor survive the heat that is going to be generated?

[cwayaustx]

2/0 welding cables, sw202 reversing contactor and 6 new 8v US batteries. The amp restriction would be the battery capacity. I know the GE motor is built like a tank, I won't be pulling any crazy hills of anything, just cruising the hood. I have a 72v cart on 26's for the trails. I just don't want to lose a ton of torque on take off or the small hills in the neighborhood. Ill monitor motor temps either way just trying to decide if I want to go with gears or more voltage and have to worry about RPM's..

[cgtech]

I have heard from a friend who worked in the development of that motor that it is designed to withstand a lot of rpm (he said up to 10k to be specific). I asked him that specific question about that specific motor. I have never had need to use it on voltages higher than 48 myself, and as always, motor heat is the limiting factor. I have run that motor on 8:1 gears and 48v 650a, street size tire in a strictly flat street scenario (he used it as a car alternative in central part of town), it is very fast, 40+ mph. He could beat most across the intersection, and keep up with traffic no problem.

[cwayaustx]

Originally Posted by cgtech

I have heard from a friend who worked in the development of that motor that it is designed to withstand a lot of rpm (he said up to 10k to be specific). I asked him that specific question about that specific motor. I have never had need to use it on voltages higher than 48 myself, and as always, motor heat is the limiting factor. I have run that motor on 8:1 gears and 48v 650a, street size tire in a strictly flat street scenario (he used it as a car alternative in central part of town), it is very fast, 40+ mph. He could beat most across the intersection, and keep up with traffic no problem.

Thanks, that's exactly what I wanted to know. I knew the raptor is built near bulletproof, that's why I waited until I could find a GE raptor, didn't go with the and "replacement". Given the same speed with 12:0 vs 8:0 the motor would be spinning less RPM's with the 8:0's. I won't be doing hill climbs or repeated launches so I think I can keep the heat under control. I might consider going with 8-6 volts in place of the 8 volts.