P992A330

Ok

So I'm pretty new to the hobby and have a Traxxas UDR on order that I plan to trick out totally from ground up (great times sink during this time of isolation)... that said, I'm going to be using a Futaba 7PXR and the stock motor... my question is simple, because based on all the YouTube videos I've seen, seems like this thing hails butt.. even on 4 cell batter setup... is there a way to set the top speed, or better yet the acceleration to a more "Scale" normal level so as not to totally wipe out every time you try to accelerate to a higher speed (say 20mph or so)? Can that all be set thru the radio? or is it pretty much a "all on" or "all off" power throttle response?

Billy Kelly

iTrader: (9)

Most Traxxas ESC have a 50 percent or training mode setting. Otherwise you can reduce the throttle off the controller

Mojappa

you're gonna buy one of the most expensive radios out, but even the cheapest of radios have a lot of points between zero throttle and 100% throttle. but yes, you can set the endpoint of the throttle channel in the radio, thereby lowering the overall top speed. or..... hear me out..... you could also utilize that portion of the throttle trigger between 0 and 100, to control the top speed. just a thought.

the rc guy

you can put a stopper behind trigger on radio seen that b4 ..

Billy Kelly

iTrader: (9)

I used to tape foam behind the trigger. Worked like a throttle stop.

the rc guy

I have used Styrofoam. cardboard. Peanut packing ..a rubber band or 3 work great same with plastic bowl wrap...(red,green.yellow) lol

TwoBelugas

Someone mentioned on the traxxas forums that the vxl-3s can drive brushed motors just fine. I wonder if one can run the summit 775 motor in the UDR for a scale experience, since the brushed motor would make low speed much smoother.

anyway, idle speculation aside, 4s on training mode should slow it down considerably.

IndyRC_Racer

iTrader: (9)

Here is a link to the Traxxas UDR manual...https://traxxas.com/sites/default/fi...-OM-EN-R01.pdf

On page 20 of the manual, there are instructions on how to adjust the 3 different modes of the Traxxas VXL-6S speed control. As has been stated already the modes are:
Profile #1 (Sport Mode): 100% Forward, 100% Brakes, 100% Reverse
Profile #2 (Race Mode): 100% Forward, 100% Brakes, No Reverse
Profile #3 (Training Mode): 50% Forward, 100% Brakes, 50% Reverse

Here is a link to the Futaba 7PXR manual...https://futabausa.com/wp-content/upl...19/12/7PXR.pdf
I would suggest familiarizing yourself throttle end point adjustments and possibly exponential settings and/or throttle curve settings.

When setting up your speed control/esc to your radio, you will typically use 100% forward and 100% brake end point settings in the radio. After you have set this up, you can then assign one of the dials or knobs on your radio to adjust the maximum forward endpoint at any time. Starting at page 70 of the manual, you can see the different ways you can use the buttons and switches. It may even be possible to program one of the push switches/buttons on that radio to switch between full throttle and reduced throttle, but I'm not familiar with that particular radio.

You can also use throttle curves or exponential to adjust how the radio talks to the speed control/esc. Either of these settings can be used to make the throttle trigger less response as you initially pull on the trigger. There are much better explanations online and here on RCTECH.net to describe how to use these functions.

Basically the speed control/esc will always be capable of going 100% forward, but you can use your radio to limit how much forward % your trigger is telling the speed control/esc to use.

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As others have suggested, the simplest way to limit how fast a vehicle goes is to use a simple bump stop behind the trigger (foam, tape, rubber bands,etc). These options limit how far you can pull the trigger. The advantage of this type of solution is that can be easily removed if you use your radio for multiple vehicles. You can also easily install it if you are letting a more novice racer drive your vehicle.

Dave_S

iTrader: (1)

I'm not sure on the gearing options, but if you have 7pxr budget i really think you would be better with lower kv or even a sensored system. (Depending on how small of a pinion you can fit)

If you really want to trick it out I'd run sensored combo of budget allows.

If you are set on stock system I'd probably just put ESC in training mode.

if you are using high c rate lipo batteries I'm not sure I'd feel comfortable with traxxas stock LVC unless they've changed things and made it adjustable.

P992A330

Here is a follow up question on switching to the Futaba RC system from the Traxxas.... will the Traxxas speed control unit work with it? Or do I need to swap that out as well? Does it calibrate the same with with the Futaba radio as it does with the Traxxas one?

waitwhat

iTrader: (4)

The Servo and ESC both use a PWM (pulse width modulation) signal from the receiver. This is true for any servo or esc, so yes they ALL work with each other. In fact you can plug the esc into the steering channel on the receiver and your throttle would then respond to steering inputs. All radios have the ability to reverse the outputs of the channel as often steering is backwards due to the orientation of the servo. Likewise, for some reason almost every esc I've hooked to a Futaba receiver requires the throttle channel to be reversed before the esc would take a calibration from the radio. Calibration is the same on every esc in the sense that you are telling the esc what the full throttle, full brake, and neutral signal look like coming from the receiver.