View Full Version : Two stack or not to stack, that is the question..

2013.06.14, 12:21 AM
I recently blew the std 3010 fets on my 2008 drift Scooby Impreza wrx (AM board) by using an overgeared 50T pn :-(, so whilst I was down at Insidelineracing in Santa Clara i was able to pick up some newer 8858 FETS.

Thanks Guys, super super friendly shop - totally recommended :-) even loaned me multiple sets of batteries so i could spend time on their track after my own ones ran out.

one FET job later (done tonight) i pulled off the busted 3010's and put a single stack of 8858's on the am board, now in terms of a comparison to the older 3010's if I look at power handling, the new fets are equivalent to a double stack of 3010's.( excellent news)

i'm going to run various motors in the Scooby impreza but i don't think i'll go less than 50 turns in the drift car, is it excessive to add another stack on top for safety ?

I emailed Phil NG at PN ( super fast response Thanks Phil) and asked him for the recommended AWD gear ratios for the PN 50T, he sent me a great pic of the AWD gear chart and he says an 18 x 30 combo should be good on stock 3010's.

So, does it need to be completely belts and braces? even with the newer and 8858's are people still stacking them ?

I think the question is who runs mod class with an awd and stacked fets?, what fets, motors and gear combos are you running and seeing no overheating issues with?

if i ever go less than 50T i'm pretty sure i'll need to double stack, atomic says as much for their chilli, but their stock r evolutions looks good on a single stack of 3010's and it's a 44 turn ( must run cool).

Last question, since I burned out my 3010's and i replaced them with better ones since you cant get 3010's readily, does this mean I'm forever banned from stock class racing with a 70T ?

All useful advice appreciated, thanks !

2013.06.14, 05:27 AM
I'd add a second layer just for safety. Most stock class rules limit the motor, not the board, so you should be fine with upgraded FETs. Only exception I can think of would be a "box stock" class. Good luck!

2013.06.14, 12:38 PM
he sent me a great pic of the AWD gear chart and he says an 18 x 30 combo should be good on stock 3010's.
What AWD gear chart is that? AFAIK AWD pinions come in 15/17/19 and spurs come in 27/29/31.

I'm running an untouched ASF board in my AWD with the stock Kyosho motor, I will eventually change this to a PN 70T. It runs fine with 15x31 which is the gentlest ratio you can get. Not terribly quick but it works fine for a tight track. Surprisingly I have not overheated with this setup, but I had heat problems in the past using a 3Racing motor with a taller gearing. It wasn't a problem with the FETs, just the motor got too hot and shut down.

2013.06.14, 01:06 PM
The safe gear ratio is 5.7-6.0, I recommend you run 18 pinion and 30 Spur


2013.06.14, 01:07 PM
That info and chart was provided directly by Phil ( PN )

2013.06.14, 04:33 PM
Yea, never mind me, I'm a dink. I now see that PN makes additional pinions, spurs, and motor plates that Kyosho doesn't have.

2013.08.21, 01:54 AM
Fets upgrade are allowed on stock class. Go 10 stack if you can:D