Speed run electronics setup for 1/10? 100+ MPH
 

So I am looking around and currently piecing together a 1/10 sedan that I plan on taking past 100mph. Does anyone have any idea what the super fast guys run for motors and esc? I want the car to be on 3s at least preferably 4s maybe even more :ha:... I can get a Castle Sidewinder 5700kv combo and run it on 3s but I'm not sure if that will be enough for my goal.

Thanks for any input!

I cannot answer your question directly, but you could probably find a horsepower calculator online and see how many Watts you'll need given the approximated drag coefficient, your speed, and the frontal area of the car. You can them downselect a motor that meets the power requirement. This is probably a crappy answer.

Touring car, 2S 4.5T, ~70mph with proper gearing and boost. Ran on 3 cell that'd get you close probably. Drag is your enemy at that speed.

Wasn't Naoto hitting 80mph at the worlds warmup. That was a 2s boosted. Probably not fully either.

I know they were in the 70s at least. I cannot recall seeing an 80, but maybe. Agreed that they weren't setup for speedruns, so they could have gone faster. Not sure how long the tires would hold.

that is cool

Simple:

1512 Poseidon Motor
Tekin rx8
Geared 1:1 or as close as possible
SMC 6s lipo.
Aero Dynamic shell.
and an open smooth space!

Just remember a couple things in trying to hit your speed goal.

1) Voltage x kv rating = unloaded RPM (ie: a 5700 kv motor on 3 cells I'll use 8v per cell = 136,800 RPM before the load.)

2) How many RPMs can your tires and other equipment handle?

3) How many "Tire" RPMs do you need to spin to go 100 mph?

a 2.4 inch diameter tire (NOTE: Most tires will grow at RPM) is 0.62832 ft.

100 mph = 528,000 ft. per hour

Your 2.4" tire will need to "average" 840,336.13 Rotations per hour (divided by 60 for Tire RPM = 14,005.6)

So now your 5700 kv motor on 3 cell (24 volts) turning 136,800 RPM before the load needs to turn the tires 14,005.6 RPMs - so factor in your Sedans internal gear ratio (let's say it's 2.5:1) that gets you down to 54720 RPMs - which would put you at about a 3.90 Pinion/Spur ratio. to start with...or around 81/21 (48 pitch gears)

This is just 'Ball Park' info - note that using a BOOSTED Esc adds a different calculation because of increased RPM and Amp Load - the type of Aero adds Drag and Amp Load - which are all things you fine tune after a few easy runs.

AERO Blow Overs - Tire Blow Offs - Over Gearing/Voltage Calculations - Too Much Steering End Point are all things to consider and plan for.

When you wanna go REALLY Fast - build one of these Like NIC did.

http://rossa.org.uk/

A correction
 

3s lipo is not 24v. A 3 cells setup is only 11v.
Your math is way off.
Also..most brushless motor max out at 60k ram. You will not achieve 100k + rpm...you'll fry the motor and escape.
Ideally you want to balance the kv rating with the cell voltage to achieve as close to 60k rpm without over heating the system.
If you plan to go 4s or 5s and maximize your voltage, you'll need a motor rating to suit.
IE...a 5s pack is at max 21v. You will need a motor rated at about 2700kv.
All manufacturers supply gear ratios for their systems that you can use as a guide.

I got 108 with this setup on Sakura XI Sport :tire:

3300mah 3s lipo, 9000kv motor, Mamba Max Pro Esc, With 31t pinion and 80spur.

100 mph with a 5700kv motor on 3s is very doable. I would use a Mamba monster esc or at least a mamba max instead of the sidewinder which overheats pretty easily. My TC4 has gone 119 mph with a 5700kv 4 pole/MM2 on 4s. Just make sure you're using an aerodynamic body and foam tires for anything above 80 mph in a 1/10 touring car. Put stiff springs on all 4 corners.

Yep, either a 5700 or a 7700 castle 4pole motor, a mamba monster 2 preferable. gearing would depend on the car chosen. foam tires(contact). a good body and cut rear out. maybe a little weight on the front. bam!! easy recipe for 100.

Hey SWT, I was thinking of keeping it simple. I was thinking of starting with a light but sturdy car. Getting a hot motor & ESC and just timing it in say 1/10 of a mile. Then increase motor kv and hopefully I buy a strong enough ESC the first time around. If or when I've increased motor & batts, then it's time to consider wind drag. I've got a long way to go but I have a chassis drawn on paper. Let's see what happens next.

I would listen to this guy ^^ he went 144mph and I bought my castle motor from him too.

I am currently building a 100mph Rustler project.

using castle motor (1515 2200kv) and mamba max pro esc-both will handle
6s lipo. right now I am using 4s on 36T spur and 24T mod 1 pinion. Getting 60+mph on partial throttle. I need more roadway to open her up.

stability and control are very important so good tires are needed and a lot of people prefer GRP belted tires which do not balloon. You will need 17mm hubs.

I like SP Racing belted tires-they are made in Italy and are slightly larger than GRP tires.

weigh down the front (on 2wd). right now I got a 20oz alum custom made alum piece that I am using.

gyro-some say no but I will be using it. make sure your rc will go straight with out it first. I will be using hpi d-box 2 but I also have futaba gyc430 if needed.

rear hub carriers -1 degree for a little toe in action to help track straight too.

Ill be using SPC racing lipo batteries but for 4s Im using a turnigy lipo.

x01 rear wheels and SP racing in front.

http://i628.photobucket.com/albums/u...psp2aatjlw.jpg

http://i628.photobucket.com/albums/u...psfty1vmak.jpg

im still in tuning phase.

looks good man. and the slash is up to 160 now. lol