VXL Mods for 4 year old?

[kirkham1963]

Hi guys, just ordered a new Summit VXL for my son - haven't touched an RC car in 20 years. Will probably run it mostly in grass/driveway etc. Planning to run on NIMH. I want to make it as controllable as possible, curious as to your suggestions. Planned on a TBR bumper, fan heatsink, new servo. What about smaller
pinion? Center diff? Rather keep him from doing wheelies and backflips to start - and he's a maniac on his go kart.

Thanks!

[SlashDigger]

Welcome to the forum. My 6yr old has a 1/16 Digger that I have made 4wd and upgraded to a VXL so it is a very similar truck to the mini Summit. I have his truck geared at 14/55 (14t pinion/55t spur) and I think that as low as I can gear it... I might be able to get a 13t pinion on it but I havent tried yet. The 14/55 gearing runs around 20mph. The esc also has a training mode that will cut power by 50% wich is great for the little guys. My sons truck is a wheelie machine and we have installed a mini revo wheelie bar on it. A center diff would help to reduce wheelies and you can also loosen the slipper clutch a little and this will also help reduce the wheelies. One of the 1st upgrades you may want is a new rc for yourself so you guys can beat up your trucks together

[jpfarmer13]

if you are gonna run it in grass the esc is gonna get hot so a fans a good idea. DO NOT GET THE INTEGY fan heat sink combo for the motor....its junk. I just got one and its broke right outta the box and has a very poor design...no way for air to excape

[Maxximum Overdive]

Two words= TRAINING MODE!

[rustlervxl4life]

lol kid with a vxl! But it's possible.

[gdayskippy]

This is some good info. I was wondering the same thing but im sure training mode will help. I just converted a 1/16 slash into a Digger for my son and the body just came in so time to have some fun.

[kirkham1963]

Thanks everybody, very helpful. SD - in training mode with the 14/55 gearing does that mean a 10 mph top speed? any cogging issues? What battery setup are you running? JPFarmer, sorry to hear - I, too, was looking at the integy heatsinks and saw your thread on it.

[SlashDigger]

Thanks everybody, very helpful. SD - in training mode with the 14/55 gearing does that mean a 10 mph top speed? any cogging issues? What battery setup are you running? JPFarmer, sorry to hear - I, too, was looking at the integy heatsinks and saw your thread on it.

I have not hit it with my radar gun but my best guess it is running 10-12mph in training mode. No cogging issues either and we run 1200mah Traxxas nimh batteries in parallel. We also run a Traxxas 2200mah 2s lipo but I usually save that battery for race day. He runs the nimh for bashing around the yard. The temps are also very good with that gearing setup. I have not installed an esc fan or motor heatsink yet. I constantly check temps and the hottest I have seen the motor is 155*f and I got those temps last Saturday after a full 2s lipo pack while it was 106*f here in MD

[Mrmerv76]

I bought my seven yr old a vxl summit from the start. We used training mode and it was ok but seemed to make everything sluggish. He really want the speed. When I put it in reg mode he did a lot better. IMO learning throttle control is the biggest success to being a good rc driver. Teach that first don't gimp the ride.

[toyota2]

I bought my 5yr old daughter a vxl merv and started her out on training mode and nimh batteries and now she runs it in regular mode on 30c 2s lipo and has a blast. The learn quick and you get to upgrade the broken parts lol.

[kirkham1963]

Hi guys, well I added the traxxas motor heatsink, LED kit and today we gave it to him. I'm very impressed with the performance and he did great with it, however the esc ran hotter than I would like. I have a 14T pinion I haven't installed yet - would the 14 tooth pinion make a big difference with the stock spur? Also, would holes in the windshield make a difference? We did a mix of driveway and grass - unfortunately I didn't heat gun it but it was certainly hot (esc). I ran it in both training mode and sport mode and same result. Granted, it was a 90 degree day today

Anybody have any good fan mounting tips for the esc? Thanks all.

[Jimmie Neutron]

How hot did it get?

[kirkham1963]

Thanks Jimmie - we took it out a third time (he was so excited) it went into thermal shutdown after 5/6 minutes of running.
I don't have a heat gun, unfortunately. FYI this was on the NIMH 1200 factory pack.

[Jimmie Neutron]

What is your current pinion?
What where the running conditions??? (dirt, grass, pavement... if grass, how long)

Ventilation will help, but is not the cure.

[28andyblue]

I did a transmission flip.It 1/2 the speed . The motor and esc run cool in long grass .
I run the traxxas 1200 battery and get about 25min
For my 4year old

[kirkham1963]

Thank you fellas.

[kirkham1963]

Current running conditions mix of grass and pavement (mostly grass), current pinion stock 16 tooth probably averaged between 1/4 and 1/2 throttle with my son driving. Only mods are T-Bone bumpers, front/rear big summit LED kit running through receiver channel 5. 28andy - thought about the tranny flip but read
about the high pitched whine so I figured I'd start without it - but perhaps its the answer. I was looking at
these 25mm fans ( http://www.muchmoreusa.com/motor-accys/index.html) last night though that seems to be a bandaid fix vs a solution.

Thank you fellas.

[Jimmie Neutron]

It does sound like possibly lower gearing will help... even the trans flip. I have done this for my 2 year old... I did not think it was that loud. Between that and training mode, she was almost able to handle it... until something else caught her attention. lol

Once you get temps under control, a fan will help lower them even further and also help make the electronics last longer.

Just to let you know... running an electrical system and anything other than full throttle will create more heat for the ESC.

[kirkham1963]

Thanks Jimmy, right after I posted above I did the trans flip and put a 15T pinion in. Everything feels smooth though I haven't ru power through it yet. Charging the packs now - report back
on how she does. Hard to explain to a 4 year old we have to wait for some cooling fans on his brand new toy Thanks
again everybody.

[kirkham1963]

I ran 3 packs through it after the tranny flip and 15T pinion today - 50% grass, 50% pavement. Didn't go into thermal mode
and was markedly cooler than pre-tranny flip/15T pinion. Thanks guys. I'm going to get a heat gun, but I think for peace of mind I'm going to get a fan as well. ESC seems cooler than the motor, but they are substantially cooler than before. Thanks for everybody's help.