View Full Version : Mini-X Motor Mod results

04-01-2003, 09:50 PM
Well I finally had the time to do some solid testing of all the mods i currently run on my Mini-X.

PN-racing carbon brushes (http://mini-zracer.com/shop/product.php?pid=440)
Squat Motor Can with Ball Bearings and Neo Magnets (http://mini-zracer.com/shop/product.php?pid=312)
Blue PETG Upper Chassis Support (custom made)
Foam Bumper
6 Cell battery pack (http://www.tinyrc.com/shop/product.php?pid=260)

Set up
Soft Springs all the way around
Stock tires with street type grooves
Stock diffs (35T i think...)
Stock Version 2.0 Electronics

These added items (mainly the can, can bearings, neo mags, and carbon brushes) make the motor hum along much smoother. Also i timed the heats...what normally took me 3 minutes, basically hold finger on motor for 3 seconds before super hot, not takes upward of 15 minutes. I think the only next step is to lighten the chassis for even more possible speed...i wish i had access to a speed gun. To be honest i think these improvements added about 15-25% more speed.

[I]Looking forward to a possible race/test with tinyrc at a tennis court someday...bring the Mini-Z's...this X is hungry...

Heres some pics for fun....

04-02-2003, 10:27 PM
you can use a tread mill if you want to test speed

and very nice car. You should also try that FET stacking thing. If your motor isnt running to hot already

04-03-2003, 06:32 PM
Hey Binaryterror,
How much would it take for you to build me a motor like yours?
I REALLY want one of those. or just tell me where to get the parts to mod my motor? :D

04-04-2003, 05:57 AM

Click on the links in my description of modified parts.

you just have to buy the brushes and squat can from miniz-racer.com. Thats all i have done. It makes the motor more smooth and the temperatures are definately MUCH cooler.

very nice so far...Tiny you should bring those parts options over here for use with the Mini-X!!!!!

04-07-2003, 05:26 PM

That's a positive result. I have built and tested my motor outside of the car. I still have to add capacitors and motor wires before I fit it.


Did you fit the bearings on both ends of the can? If so, what's the result on fitting it.

You may remember we discussed this briefly before, as I commented on how much slop there is on the standard motor.
I assumed this "slop" was there for a purpose. Perhaps it's just bad manufacturing or overkill tolerances..

Some feedback on this would be appreicated.

04-07-2003, 07:39 PM
Originally posted by Mondo
Did you fit the bearings on both ends of the can? If so, what's the result on fitting it.

You may remember we discussed this briefly before, as I commented on how much slop there is on the standard motor.
I assumed this "slop" was there for a purpose. Perhaps it's just bad manufacturing or overkill tolerances..

Some feedback on this would be appreicated.


Yes I did place both bearings in the motor. I understand what you are saying about the slop being used to manufacturing/accident tolerances, but i have a strong blue "upper deck" piece, i made and added that makes the chassis flex _MUCH_ less than stock.

The motor runs with out any noticable binding or loss
of RPM with the 2 bearings in the can and the one on the support shaft.

With the recent snow (i know April and SNOW?) i haven't run it in about 3 days, but i plan to put the motor through some more testing on the tennis courts. I'll keep you fellow X fans abreast of anything that happens.

3series takumi
04-10-2003, 12:00 AM
can you post pictures of just your upper deck i would love to see that. i think i need that cause my motor stalls if the chassis is flexed.

04-10-2003, 06:09 AM
Here you go...i plan to make myself a new one eventually, i might make a couple spares. I'll let you guys know if i do.

Here is a pic in car:

Here is the side of it...thickness is 1/8" with a small narrow where it connects to the front suspension (hard to see).

Here it is...it is made from 1/8" thick flouro blue PETG. PETG is very strong while still lighter than lexan and acrylics. You could make it from G-10 fiberglass (which i have some of...i might try that too...)

04-13-2003, 04:43 PM
I finally had a chance to REALLY run my MiniX and MiniZ's today at the local elementary school's parking lot!

I installed a bearing in my X's motor can only (not the front) and Neo magnets. I also lubed the diff's with Associated lube as per IRC's recommendations.

The top speed is just a hair less than my MiniZ with X-Speed, ball diff, alloy stuff, etc. Handling is far superior than ALL of my MiniZ's, but my X will spin out if I crank it all the way right, but not left (???).

While the heat factor is definately lower than before, the motor still gets plenty hot. The Neo magnets picked up a TON of metallic junk off the parking lot!

Now all I have to do is find some MiniX and MiniZ racers to race with in my area :)

3series takumi
04-13-2003, 04:49 PM
my X's spin out goin right too!! what causes it. does anyone know how to fix it.

04-13-2003, 05:16 PM
I think this maybe caused by the un-equal lengths of plastic on the steering thing. The servo probably pulls and thus bends the steering bar when it is CRANKED hard left, thus eliminating the spin out. When you turn right the servo doesnt have much bar to stress thus it having a better turn to the right.

This can be adjusted with the EPA on the better controllers.

3series takumi
04-13-2003, 05:20 PM
i have my own tie rod and it does same thing

04-14-2003, 06:34 AM
It might be the placement of the servo and the way the steering is set up to work.

Someone needs to play with the sterring for sure.

Right now i am working more on cleaning my X and also waiting for my newest RC member...the XTM X-Factor (http://www.teamx-factor.com) !!!

My next need/want for the Mini-X is a better controller (which i should soon have, might have to replace the stock Rx though. But i do have a hitec shredder which is and was the smallest car RC Rx.

Guys...let me see pics of what you guys have done...

PS. I found that the upper deck is best made from the G10. I need to make some changes to my CAD work and I'll cut a couple out. Email me if you guys are interested (Cheap$$). jscobie@REMOVETHISwideopenwest.com

Dont forget to remove the REMOVETHIS from my email.

04-16-2003, 04:35 PM
ah...................yeah. that makes sense or it could be just that the electronics aren't calibrated properly.

04-27-2003, 09:16 PM
so if someone was making their own chassis or heavily modding the existing one, you could place the motor width wise on the chassis, so that the "gyroscopic recession" wasn't runing to the right it would be running towards the front or back of the car,
although this would cause the same problem that plauges (spelling?) all motor mods = lose of 4WD...

unless you use a shaft drive system to both difs...

which is difficult...

oh yeah and the space factor...

07-29-2003, 01:53 PM
I finally finished repairing my X.
It has the green motor can.
I can't find the magnets so they weren't changed.
I have the 6 battery set but am using a 4 set right now.
It didn't need the motor caps. It might when I switch to the shreder rx from my Hyperfly.
It has the carbon brushes also.
It runs well.

If anybody knows of a lexan truck body I'd like the site. TIA.

07-30-2003, 12:23 AM
I ran with 6 cells, bearing can, stock end-bell but I took off the brass bushing and replaced with bearing (as Takumi advice..). After 10mnts the FET got a bit warm so the motor truns to be as 'finger burner'. But it ROCKS..!! Still trying to mod to a monster.

Tbird Man
08-28-2003, 09:55 PM
Originally posted by j0llyr0ger
Hello, everyone. This is my first post here.

My suspicion is that the tendency of the mini-x to spin to the right but not the left is mainly due to gyroscopic recession. That is, the tendency of a gyroscope to react to turning moments applied to it's axis perpendicularly to the applied force.

Since the car is so small and light, it may exhibit some behaviors larger cars don't due to the fact that such things as gyroscopic recession are proportionally so much smaller on larger cars.

Think about it- the motor spins clockwise and the car spins clockwise much more easily.

Adjusting the EPA may compensate somewhat for the tendency to spin, but I believe it would not actually fix the problem. If you do try to compensate with EPA you might want to think about giving the steering less travel to the right than the left. The car already likes to turn right more than left, so instead of reducing both, simply reduce the right side travel until the reaction in that direction is reduced to match the reaction to the left. You don't want to throw away any left side steering travel- you need all you can get.

This idea occured to me after visiting the Champlin Fighter Museum in Mesa, AZ today http://www.champlinfighter.com and hearing a docent talk about how the Sopwith Camel turned so very much better to the right than the left for the very same reason- gyroscopic recession of the radial engine.

Or I could be flat wrong.
It's very late and my brane is tired. ;)

yes, what your talking about is called "torque steer" and is a big issue with shaft drive RC cars. you may also notice it on take off, it will tend to pull one way.

3series takumi
08-29-2003, 04:53 PM
torque steer is normally a problem caused by uneven axle lengths or an off centered diff. more power tends to go to the wheel with the shortest distance between the wheel and diff. the minix has equal everything so that is not the problem and with mine takes off it doesnt pull at all. the problem is that fact that the motor spins one direction pushing the chassis in the other direction. so in one direction the chassis is gettin pushed with the turn and the other direction it is gettin pushed against the turn. to over come it you can do what TA did to the TC3 (shaft drive car) and add a touch of camber on the problem direction to tune out the spin or tune spin into the other side if drifting is your style of driving. oh yeah and torque steer is more commonly found on front engine front wheel drive cars with a transversal engine set up. ;p thats a mouth full.

Tbird Man
08-29-2003, 06:09 PM
well my tamiya tl01 has massive torque steer, and it has equal length axle shafts all 'round. the motor even sits transverse, it is the shaft drive that does it.