Top speed race class
 

Hey guys here locally they are doing a top speed challenge in mid Feb. and they have different classes. The new class they added for this year was a monster truck class, and minimum weight limit is 10lbs. Also they put a battery limit to 3S lipo or 10cell NiMH....no MAH limit and also no amount of motor limit, so 1, 2, or 3...etc if you can fit it. Tires and body have to be off road tread and stock body. Should be fun....now million dollar question is...what to run? I have my 3905 truck with dual VXL's which I will enter it, but my 3906 is still stock . What ESC's and motors should I be going with on it for just top speed runs?? I'm am thinking 65-75mph is what will be needed. I have some extra springs that I will cut to lower the truck down LOW, and then try to lower the body mounts low as well. The speed freaks let me know.....


Just remember the battery limit is 3S lipo or 10cell NiMH....no MAH limit

Good luck getting any 10lb vehicle to 60+ mph on 3s. Basically, you're going to have to get a higher kv motor than is typically used in a monster truck. Along with that, expect a large current draw and lots of heat. I'd start by looking into a high current ESC and a Neu 1515 or Feigao 540 XL motor somewhere in the 3000kv range.

I do have to say that 3s really is a pretty dumb voltage limit on a 10lb vehicle.

4s would be much more interesting and open up alot more options

Now remember guys, jthe 3S limit is PER motor. If you run 2 or 3 motors...or more, each one can get 3S or 10cell power to it.

In that case, maybe something like dual MM 5700's on 3S each?

Your still going to have to run a high KV motor and they are both going to want a lot of current to reach those speeds.

Maybe 2 Feigao 9l as well.

You didn't say that in the original post...that changes a lot of things.

I'd go with something like twin Feigao 540 7L's on 3s each.

Actually, MM7700 will tolerate 3S for short bursts.

It is going to be REALLY hard to reach 65mph on 3S with a truck, extremely difficult. I would say 50mph would be doable. Anymore would require alot of R&D and multiple ESCs on multiple motors [translated into EXPENSIVE!!!]

Matt

Well my 3905 has dual VXL3's and dual Velineon's in it. I am going to upgrade my 3906 as well with whatever combo you guys think will work best. Twin mamba ESC and twin 7700's or 5700's sound good? Of course on 3S lipo's max....

do you have unlimited room to do it? you could drop the chassis as low as possible and run a set of jumbo kong tires ;)

With a 3S limit, I would run a pair of KB45's with the appropriate KV. Just make sure your ESC and packs will handle the current they will draw.

I'll also throw in a suggestion that you look into using the new Pro-Line premounted LPR tires/wheels. You'll get far less ballooning than regular MT tires and they're much lighter as well. You'll just need to have 17mm hexes on whatever you're planning to run though.

http://prolineracing.com/products/html/LPRpremount.html

According to Brian's speed calculator, 65+ mph should be possible with 2 MM5700's. Also, tire ballooning will increase his top speed, so I don't think you should try to minimize it.

Gearing up is a much better option for hitting top speed than to desire tire ballooning IMO. Trying to keep a truck tracking straight with pizza cutter tires is no easy task for the driver or their steering servo having to fight such a large inertia.