I am building a 21.5 class 2WD buggy and cannot decide which way I want to go with the R/C system. I understand that this will be a situation in which latency and response is pretty important. I have a lot of Traxxas cars/trucks, and I use a single TQi transmitter for all of them. Ideally I'd like to do as I've done in the past and just buy an additional TQi receiver for the 21.5 buggy, but I am wondering if this is the best option in terms of latency/response. I also have a Spektrum DX5 Pro and a Spektrum SR315 receiver laying around, but I just don't care for how bulky the DX5 Pro is. I'd like something simpler in all honesty. I'll add here, price really isn't a determining factor in my choice. Obviously I don't want to buy a completely new high end system - but I don't mind spending $100 or so for one of the Futaba/Sanwa systems. I've never owned a Sanwa system, but I know a LOT of racers use them due to the response. I'm just wondering if the MX6 & RX391W will offer an advantage to a simpler system like the Futaba or Traxxas TQi. Obviously, out of the four options, the Spektrum SX5 Pro with it's 5.5ms frame rate will give me the best bang for my buck return, but honestly, I just don't like the feel of the radio.

My considerations are as follows:

- Traxxas TQi system, FHSS protocol? (unknown speed/latency/response)
Total cost, appx $50 for an additional receiver

- Spektrum DX5 Pro & SR315 receiver, DSMR protocol (5.5ms frame rate)
Total cost, free. I already own it.

- Futaba 3PRKA & R203GF receiver, S-FHSS protocol (supposed 13.6ms frame rate, unknown?)
Total cost, $100-$110

- Sanwa MX6 & RX391W receiver, FH-E protocol (unknown speed/latency/response)
Total cost, $100-$110

Thoughts and opinions?

Thanks!

I know it's their big selling point but given that human reaction time is 120ms+, a difference of 8ms isn't going to make much difference. I say sell the radio you don't like or use it on a car to share with friends, and either get a new one or stick to the TQi.

Not sure I'd recommend the Sanwa fh-e models though, since they don't work with any other Sanwa gear. I'd rather get something compatible with the off brand Fh3/fh4 rxes

Futaba protocols:

Reaction time to unexpected stimuli can be that long or longer, but in RC you're pre empting the inputs and a latency of 100ms is definitely tangible.

Don't buy a 3PRKA. Especially not at that price. Far too basic for racing. If you want Futaba (which is what I user personally), get the 3PV as a minimum.

I'm sure the Sanwa experts will chime in on the merits of the MX6.

Almost every racer is using Futaba or Sanwa. Even Spektrum's top driver is running Sanwa at the current world championships. Having said that, your Spektrum radio is probably the highest spec option available to you from your list.

The Traxxas radio is for bashers only.

MX6 is trash, everyone I've seen buy one locally had radio glitches and ended up replacing it pretty quick. The rest of the Sanwa range is reliable but that model is a dud.

Even as a Sanwa fan, I would not recommend the MX-6. Way too many negative reports and no upwards compatibility. Every other current radio (and many older) would be a good choice though.

Noble 4?

Not in that price range.

a good thing the radios are only 8-10ms different, not 100ms

Flysky NB4 and never look back. I have all the Top end Transmitters. and I always grab the NB4 first. I have the NB4 in all my crawlers and Bashers. my Race gear has Futaba 7PX but recent upgraded to the 10PX. But seriously considering selling it and getting the Noble Pro for racing and having only the Flysky Protocol. For the price of the NB4 its unbeatable.

All the radios you've just mentioned are well out of their $100 budget.

Basically the DX5 is indeed the cheapest option with decent specs. Raise the budget a bit and you can go for a 3PV or a MT-4(4)

Well I agree with you that OP probably won't notice the difference.

​​​​​​However, it is cumulative and it does make a difference regardless of your physical reaction times. 8ms is quite a lot, 4% change for the average. That's huge, really huge.

Used to see this all the time in arguments about frames per second, input lag, etc. You can't react that fast so it doesn't matter, but it does because it's all cumulative.

And now nobody thinks 30 fps is good enough any more.

​​​​

Keep your DX5. There's nothing wrong with it. As for reaction time, you're running it in the 21.5 class, so frame rate time is not going to make a difference. Just make sure you have fast servo. Once you get into modified class, frame rate might be a consideration. One of the greatest things about the DX5 is the cost of receivers. They are only like $25. That's a lot cheaper than a $75+ for a Futaba or Sanwa. So, if you have multiple cars, it won't cost you a fortune in receivers.