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  • RCSC

My CAT TXT Race Truck

hawnmt

Rock Crawler
Joined
Apr 27, 2007
Messages
709
Location
Hawaii
Some folks might remember this truck(there's a thread about it somewhere in here I think) because I raced it at end of our last RCMTC-HI season. While it was wicked fast it had a few problems like cogging, stiff suspension, and link setup. So when the season ended I worked with JoeWorks on making some design changes for a new chassis.

DSCI0068-1.jpg


The result is the new JoeWorks V4.0. The new chassis straightens up the link geometry so I don't have to use bent links. The battery mount is also slightly different and that allowed me to mount the E-Revo transmission, level. By levelling the trans I can now run smaller pinions. I was limited to 14t pinions on the V3.0 chassis because the motor would contact the driveshaft. And last, the chassis is about 1.25" taller. 1" is for the longer 120mm shocks I am now using and the extra .25" was so I could get rid of the bent links used on V3.0. I made the change from the 5700kv motor with 14t pinion on V3.0 to a 4600kv motor with 12t pinion on this truck. Joe actually finished the chassis a few months back but I had other things going on so it went on the backburner. I finally got it back together and running for the last race before the Mid-Season Championship.

Chassis: JoeWorks V4.0
Axles: Tamiya TXT
Transmssion: Traxxas E-Revo (single motor, single speed)
Driveshafts: Traxxas Revo Center Shafts
Shocks: Hot Racing 120mm Air Shocks
Tire/Wheel: Imex Pullers on Tamiya TXT rims
Esc/Motor: Castle Creations Mamba Max Pro/4600kv combo

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BTA steering system I made. It's tight but the drag link does clear the bottom links and the top links do not touch the servo even when the shocks are fully compressed.
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4600kv motor
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The entire drivetrain sits below the level of the top links. In fact the entire battery, motor, and most of the transmission sits near the centerline of the wheels.
HPIM3152.jpg


Yes, I kept the stock rod ends. On a lightweight truck like this the stock rod ends will only pop under very severe crashes. In fact I just freestyled my truck at Mids and the front top link only popped after I tried a backflip and it landed crooked on the front axle very hard.
HPIM3153.jpg


The trucks sits with about 1/3 of the suspension travel of the 120mm shocks in droop.
HPIM3154.jpg


Performance:
I like the handling much better than the old setup. I might have lost a little speed going to the slower motor and smaller pinion but it's not really noticable. The benefit is that I now have better slow speed control and absolutely no cogging. Still working on the adjustments on the esc and I definitely need more wheel time. This truck drives so much different than any other truck I run. It accelerates like a bat outta hell and jumps require total different throttle inputs than I'm used to. But she's proven she has the the stuff to run in Outlaw Class, now I just gotta drive it.

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have you thought about switching to a sensored motor, the MMpro switches from sensor to sensorless at mid throttle"thumbsup" no cogging and wicked top end:mrgreen:
 
Do you have overheating issues with the 4600?

Kinda, but since we run Monster Jam style courses I'm only running around 40 seconds per race at a time and 1.5 minutes on freestyle. It's when I'm doing test and tune sessions that I'm really running it for long periods that the motors heats up.

have you thought about switching to a sensored motor, the MMpro switches from sensor to sensorless at mid throttle"thumbsup" no cogging and wicked top end:mrgreen:

I've thought about running a Novak HV motor like the SC guys do but I'm not sure I need all the torque of the big can. I've thought about Novak's new 550 cans but I'm hearing mixed reviews on them.

With the setup now I don't have any cogging but I do wish I had the butter smooth throttle on the low end like sensored motors.

What motor would you recommend?
 
Kinda, but since we run Monster Jam style courses I'm only running around 40 seconds per race at a time and 1.5 minutes on freestyle. It's when I'm doing test and tune sessions that I'm really running it for long periods that the motors heats up.



I've thought about running a Novak HV motor like the SC guys do but I'm not sure I need all the torque of the big can. I've thought about Novak's new 550 cans but I'm hearing mixed reviews on them.

With the setup now I don't have any cogging but I do wish I had the butter smooth throttle on the low end like sensored motors.

What motor would you recommend?
they're not out yet, but I've heard good things through the grape vine about the new tekin SC 550 motors"thumbsup" mix that with the tekin or MMP sensor/sensorless ESCs and youd be golden
 
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