The Sub-Genius MOSFET mod

[SuperFly]

Hue35 and I are going to order some more, so if you're interested, post it here or PM me. Definitely a non-profit organization here.

[lefftoe]

ive been using putty to hold the fets in place before soldering........glue would prolly work too..........ive burnt my fingers on the first try.......hope this helps

[hue35]

Some observations about mosfet-modded cars... mosfettin' and A-B testin' is all I've been doing for over a week (a little racin' with SuperFly too).

Here's what I've learned...
The top speed isn't really improved the same as a dual cell, but the torque is increased a ton. The best part about the torque increase is that you can easily run the tallest KIT racer gears, which is what gives you the improved top end speed... a dual cell actually makes the motor go faster in addition to some extra torque. For example, I noticed a HUGE difference in top-end speed when I mosfetted a Canonball, because that huge-ass pinion gear makes for long gearing overall, kinda like a KIT racer. When I mosfetted a stock MS, it was zippier, but no real speed gain when compared side-by-side to a stock MS (both cars were set up with stock orange gears and yellow motors). Then I popped teal gears into both cars and the mosfetted car was starting to look better. Then I put red KIT racer gears in both cars... the stock MS pcb could barely turn the wheels, while the mosfetted car was turning them like they were orange gears. It was haulin' ass! And the handling is great because you don't mess with the weight distribution at all.

Also, I rounded up the balls to start pokin' at a MS Pro pcb. I tried the fwd-only version of the original mod shown at the beginning of this thread and it didn't work. Shit, I busted my Pro, I thought. Then I tried the version Dave posted (shown below)... and the mofacki worked!!!! I put green KIT racer gears and a perfection 3.8 in it... jimminy-phuckin'-shizzlet! About as fast as my black Camaro (dual-celled Zip Zap with a MS Pro PCB and perfection 3.8 ), except it handles way better.




more when I learn it,

hue35

[ph2t]

Great stuff man. You're becoming a true FET playa! I can now add a rule to my inbox to divert all those FET questions to you, lol!



Have you guys done a FET steering mod yet? I'd be interested to know your comments.

ph2t.

[hue35]

Have you guys done a FET steering mod yet? I'd be interested to know your comments.

yeah, I did one... I'm not sure I noticed much. I put a second steering spring in there and there wasn't enough extra power to make it work. Maybe if I add rare earth magnets to the mix it will turn those big-ass alloy wheels. The extra spring really helped to keep the alloys from pulling, just gotsta get the quick response back.

[crazydave]

Yep I agree, mostly a gain in torque, and a slight gain in speed, but as you found out you can turn that torque into speed.

For me they still seem alot faster because I race in small spaces.

The Perfection 3.8 was fast in my car, but the 4.2 Pro has got me approaching dual cell speed.

Have you tried a dual cell with the mosfets yet?

I'm keeping my car sane, but I did the mosfet mod along with the dual cell for Havok, and his cars are insane. I swear the Zip Zap is faster than my tri-cell Franken-Zap was.

[ph2t]

The mosfet steering helps on fullsize and pullback wheel mods........


ph2t.

[hue35]

No dual-cell mosfet yet crazydave, I will probably try one soon. Sounds like it should be a Zip Zap. It also sounds like it should have a 4.2 pro!

[lefftoe]

i have a fet/dual cell zip that is just ridiculous

the speed is just too much for the weight of the car.....imo

and fets on the steering helps my cars with alloys on em, but i still think there is too much grip up front

[crazydave]

i have a fet/dual cell zip that is just ridiculous

the speed is just too much for the weight of the car.....imo

Yep, gotta agree with that too, but it's fun aint it?

[hue35]

One potentially cool thing about too much power for the weight of the car, is adding the right amount of weight exactly where it's needed. I wonder if you could find the magic spot (the jee spot) that would make handling perfect?

[ph2t]

One potentially cool thing about too much power for the weight of the car, is adding the right amount of weight exactly where it's needed. I wonder if you could find the magic spot (the jee spot) that would make handling perfect?

A thin layer of lead across the bottom of the chassis (mounted internaly) would help I beleive. This would help maintain a low centre of gravity.

With all this power and torque increase I need to get off my but and finish developing my propo emulator. I might just focus on the speed controll. I've noticed that pulsing the fwd button from a standing start helps keep the car straight and not lose it off the mark causing inifinte spin outs. Any acceleration that ain't instant would definately help handling.

ph2t.

[SuperFly]

With all this power and torque increase I need to get off my but and finish developing my propo emulator.

That is why my next mod is going to be the anti-boost controller mod and mosfetting a boost car.

[crazydave]

Any acceleration that ain't instant would definately help handling.

ph2t.

In 1/10 scale off road they use a slipper clutch, to keep traction off the line. It just as simple as a friction pad system. Maybe something as simple as a loosly mounted gear would help.

I think I figured out my issue with the Thunder Charger PCB. See THIS if anyone wants to test it and confirm it for me. I'll probably be testing it as soon as I get some more mosfets, the TC PCB is strong to begin with.

[hue35]

Thanks, Dave... I've got more mosfets coming this week (SuperFly left his stash of mosfets at my place and I smoked 'em all), so I'll definitely try it out. I'm pretty comfortable putting this stuff together from a picture or diagram, but I have no idea how to figure it out, so thanks again for the diagram.