I have been around R/C for a very long time, but I have never really completely understood drive frequency when it comes to speed controls. Honesty I have never worried about it in the past but since I've been running brushless I'm thinking maybe I should do my homework. Anybody have an easy, plain explanation? What drive frequency should we be using for 13.5, 10.5 or even 3.5? Can drive frequency be an effect tuning tool especially in the world of brushless?

A speed control is just an electonic controld switch. the frequency is how many times the switch is turned on and off per second. A higher frequency makes for a smother throtle responce. The drive frequency can not be changed on a brushless speed control. only the minimum drive frequency, whitch is how much power is given to the motor when you first tuch the triger.

So when I pull the trigger to start the main and my car doesn't move right off and takes a sec to get going that could be minimum drive frequency? Does anyone know the steps to change it on a 4 cell spectrum GTB?

Thanks
Joel White

Nope. It's not min drive frequency, there is no such thing. It is min drive %. All this basically is the minimum amount of throttle you can give the car. I think the stock setting is either 2 or 3%. It wouldn't have anything to do with a delay when you pull the trigger. A delay when you pull the trigger is not normal.

That is what I was thinking too Pat. We have 2 GTB's, and they both do the same thing. I guess I will have to break out the manual for the radio, and the speedo and start testing.

Make sure your radio is set to your speed control. It has to be set properly first before you can do anything else. If the deadband is too high this may cause a delay or if one of the FETs is burned out it may start from a dead stop. Make sure the rotor isn't locked or the mesh isn't too tight. I know on some of the Lipo models the lipo mode will cause the car not to move from a dead stop if you are using 4 cell batteries. The under voltage protection kicks in a prevents the motor form turning.

Make sure it's not your dif slipping also.

I have been around R/C for a very long time, but I have never really completely understood drive frequency when it comes to speed controls. Honesty I have never worried about it in the past but since I've been running brushless I'm thinking maybe I should do my homework. Anybody have an easy, plain explanation? What drive frequency should we be using for 13.5, 10.5 or even 3.5? Can drive frequency be an effect tuning tool especially in the world of brushless?

Like Al mentioned, a higher drive frequency will make the throttle "smoother" by taking away some punch. Most of the brushed speedos that had adjustable drive frequency used a kHz number, where higher number is less punch, lower number is more punch. Drive frequency should have no effect on top end, and should make no difference if you race a class/track where you never lift. Brushless speedos and some brushed don't truly have a drive frequency adjustment, but most will have a form of "punch control" which is effectively the same thing.

IMO, for all brushless classes on carpet(except maybe open mod), you should use the most aggressive throttle setting(drive freq/punch control). If you race on dirt, cap tires, or asphalt surfaces, this is something that can be a great tuning option for your driving style. I think it's more important in B/L that it was in brushed because the B/L motors have so much more initial torque than brushed motors. If you car feels like it really "squares up" the back end when you pick the throttle back up, trying reducing your punch. If your car feels like it drives straighter off the corner, chances are you were spinning tires before. Hope this info helps!

Drive frequency doesn't applyto brushless motors, only brushed.

Thank you all for the input. :) Over all it seems as though this is not a make or break issue. And here I was hoping to find some special frequency to pick up another tenth or two. Like I tell everybody else looking for the secret button to push "Keep working on the chassis". lol...

So when I pull the trigger to start the main and my car doesn't move right off and takes a sec to get going that could be minimum drive frequency?



Make sure it's not your dif slipping also.
I have seen diff slip be a problem in the main for some people, especially if you run ifmar qualifiers. Every heat, your gingerly getting on the throttle, and even in practice your not jumping on it hard from a dead stop, so you never notice the slip until the horn blows in the main.

Not the diff guys.

Changed from profile 1 to profile 3 on the GTB, and good to go.

Min drive is the only difference between 1 & 3. That difference shouldn't show up on oval setup. Min drive is how far the trigger can be pulled before the car moves. 2% vs 3% isn't that big of a difference. Maybe somebody changed the setting. Stock setting in profile#1 is 2%, Profile #3 is 3% maximum is 12%. It sounds to me that the radio wasn't setup for that speedo initially and by changing the profile you may have matched your radio with the speedo.

Well I also modified a few of the settings. I will have to look at them and see what ones.