M06 Handling

In the interest of seeing how the forthcoming rear motored M06 might handle I fitted my M04 with a Lipo and used the 170 gram weight saving to add a load of weight behind the rear axle. Right now I have 200 grams of lead sitting on the rear bumper.

So how does it handle ? Well its a massive improvement on throttle. I can floor the car out of a corner and it just goes, its noticably quicker than an M03 and there are no more spin outs under acceleration. Unfortunatley its still a dog under braking. Got a few more ideas to try, otherwise I will just have to marvel at the straight line speed and avoid corners.

Duane.

Hmm, I'm interested in the result of your research.
What tires are you using for front and rear? Which inserts?

i wonder how it will be in the corners, since thats where all of the mini DNA usually is, i hope that it comes out well in the handling department as it is a short wheelbase so im thinking it will spin out quickly because of that......i really hope not

Great as my M04RR is in a straight line, its a disaster under braking. I am going to try disconnecting the servo in case there is some interference from the motor causing the servo to tweak under braking. I dont think this is the problem but its a quick one to test.

Tyres are s-grip rear and standard fronts, suspension is very soft on the rear an almost solid on the front.

Duane.

Wauw, that will be an understeered car then.
Without the weight, if you're too early on the throttle when coming out of the corners, then the car will spin out.

I have the M04M. On carpet (high grip track) it's wonderful.

Duane,.....try softening up the front some....maybe if some of the weight can shift forward onto the springs it wont be so quick to lift the rear tires off the ground under braking...? If there is no droop at the rear, it will also lift off.....might be worth trying, I dunno...

Alternatively, try a set of the rides all round.....they certainly help traction on the FWD's..

With the weight the car understeers on throttle which is fine for now, but the braking is driving me mad. I tried the car with the servo disconnected and the car was more stable, I am certain there is something wrong with my electronics - they are a mix match of Ace, Hitec and Futaba and as they were the last I had in my box, some of them have probably been rejected from one of my other cars.

I cant get the car to run straight for more than a minute.

I will swap in some better electronic before I drive myself nuts.

Once the electronics are sorted I will check the axles, tyres, shock lengths and then I am stuck.

I tried rides a while back and they really didnt work. I will try them again though just to be sure.

Duane.

Shocks and tires are the areas I would chack first, once you are sure the elecs are OK...

Grahams mini was all over the shop....on the stock pogo shocks....a set of 3racing TRF clones and it is a COMPLETELY different animal....

Hi,
The m04 is still keeping me busy. There is an as yet unidentifed mechanical problem which causes the car to track to whichever side it was last turned. I have changed the electronics even the transmitter to no effect.

The car has two degree rear toe which is not standard so I will refit the original rear upgrights. I have adjustable camber links on the rear and will swap these back to the original parts and build a new set of shocks based on the manual and see where we go from there.

I have been walking up and down the street behind the car and even at walking pace, something mechanical is causing the car to 'jiggle' at the back.

Getting there.

Duane.

Mine used to do the butt wiggle too. Also it used to have mind of it's own under full throttle and veer left or right for no apparent reason.

But I think it stopped now.

I really think it was something to do with the tires. Make sure they are glued properly cos I think this was my problem. It stopped when I changed tires and has not come back.

I always look for unstuck tyres when a car goes one way under acceleration or at high speed, but I have been walking up and down the street with the car running a foot infornt of me and it still holds whatever direction it was last turned even at a walking pace. This makes me think its not shock related or tyre related. It has to be either m-chassis slop or the two servos I have tried are not returning to center.

Anyway in desperation while trying to figure out which end of the car was generating the problem I moved my 200grams of lead from behind the car to right over the servo at the front. Wow, I expected an unusable car, but it actually drives well.

Its counter intuitive, but having all the weight at the front makes the car really stable under braking. If you think about it for 2 seconds its obvious, you have the rear tyres trying to slow the car down, while all the inertia is at the front pulling forward so there is very little chance that the back is going to break away and over take the front. in effect the weight of the front is dragging the car forward and stopping it from spinning out. Obviously I cant floor the car out of corners any more, but with a bit of weight at each end I might be onto something.

Hi Duane!

are you using a tamiya high speed/torque servo saver? if not, then thats whats causing your problem. the tamiya ones will make your steering go back from where you left it even if you're using a cheap servo

try putting a servo horn on (no servo saver) just to see if this fixes it. but don't run into anything

Your servo is not centering....

Split the weight front/rear in difering amounts until you find the sweet spot fo weight transfer..and alter the shok=ck springs at the same time....at some point the car will be more controllable..

wait for the M06...lol

jebjeb wrote:

Hi Duane!

are you using a tamiya high speed/torque servo saver? if not, then thats whats causing your problem. the tamiya ones will make your steering go back from where you left it even if you're using a cheap servo

Daune

Ian is right here, I had exactly the same problem with my m05, I switched the stock servo saver for the high torque one, and problem solved!

Hi,
I fitted a Tamiya 'high torque' servo saver while building this car. It reduces some slop but gives terrible ackermann, and there is still plenty of slop in the rest of the steering so in the long run I will fit the stock part to get a sensible geometry.

Right now it does look as if my problem is that both servos that I have tried are not returning to center. I have tried two receivers and have a regulator so the rest of my electronics should be fine.

I will try a few servos on the bench before fitting the most reliable one.

My only other idea is that the amount of slop in m-chassis axles is allowing the car to stay cocked to whatever side it last turned.

Duane.

Mystery solved.

Its taken three evenings and countless set up changes to work it out, but now I have a car that brakes in a straight line and can be nicely balanced through the corners with the throttle.

It all came down to a single screw. To cut a very long and frustrating story short, the servo saver screw appears to have been causing the tiniest amount of binding around the servo center and of course, every time I tested a servo I did out of the car with any old servo horn so never saw the problem.

I will leave the car alone for a few days, I am a bit sick of looking at it, but the weight saving you get from a Lipo makes the M04 hugely tunable just by moving stick on lead around.

Duane.

Well since there is no dedicated thread to the M04, I thought I would post this here because this thread deals with RWD handling.

Ed, this question is for you. Are u running toe in or out on your M04?

Front knuckle, stock. Toe is between 0 - 1 degree toe out.
Rear upright, stock.
Camberlinks front and rear, stock.

I ve been introduced to Tamiya TRF and therefore, becoming handy in shimming :-)
As a therapy, I shimmed where ever possible on the suspension and steering.
Also limit the up and down travel of the shocks. 3 mm inside and outside the shocks (TRF)
Having said that, with rear 2wd, tires are the most important setup!

Tried several times foam tires on asphalt and got frustrated with it. => Use your time for something else!
However, on carpet, wonderful!

What works till now for me at Wonderland, type A slicks at the rear and M or S grip at the front.
As legacy, I still have those since 2005. Not much profile anymore on the M and S grip tires.
Just ordered 60 size Shimizu slicks to try, as an alternative for the Tamiya tires.

Cheers Ed, I have not taken to shimming anything yet, apart from the driveshafts, there is a lot of side play in theaxles. I have a few sets of unis I will try at some stage.
Will dial in sme toe out. I have the shimizu's but was testing on the dusty Tarmac outside, expectation was low, but it handled like crap. Might add a little weight at the rear too. Everything else is stock. How loose is your diff?

I have TA03 ball diff from the old days. Not too tight and make sure you put loctite to secure the diff nut.
For the side play in the axles, shim it on the hex side. Just before the pin to secure the hex for the wheel.
Which compound of Shimizu are you using? Standard inserts?
Shock oil used is 30 rear and 40 front i believe, can t remember. Haven t touch it since ages. The beauty of m chassis :-)
Strangely, blue springs at the back and yellow front instead of softer at the rear.

Also to remove the slop on the hinge pins at the rear:
Spray the pin with wd40, then put ca glue at the holes where the pin suppose to go.
When the glue is dry, you can remove the hinge pin. No more slop and you ll have a consistent rear toe ;-)

Ed, not got that into it yet, don't really want to spend to much time with this one, I may persevere though. I have simple oil shocks at the moment but have limited the droop and ride height. Think the shimizu'are the soft ones

Hi,
I finished building the Yaw Control system for my M04 last night. It actively controls throttle input and initiates counter steer based on a gyro and the transmitter input.

It have adjustable gain for the throttle and steering channels so you can control how much counter steer or throttle intervention you get. I have also added ajustable 'damping', the idea here is that to prevent the car from fighting itself as intervention takes effect, the system will become less responsive the longer that intervention is active. I added this based on my experience with previous gyros which would oscilate, the damping effect should prevent oscilation.

While the hardware is finished, I expect to have a lot more work to do as I feild test the software.

Initial project introduction here -

http://rcarduino.blogspot.com/2011/12/anti-yaw-control-part-1.html

Duane

Duane,

Sounds wonderful.
Please bring it to the track, so we can compare it with my throttle and steering control.
I programmed mine between my ears on to my hands
May be a combination of both works well.


Andy,

Perseverance is required!
I'm busy with getting it right since 2005

Put a harder compound tire at the front!!!
Also you can try to increase the trackwidth at the front.
Put 1mm spacers at the hex. This will decrease the grip at the front

Duane, talk is cheap, get to the track lol!

Ed, initial testing reveals that there is a lot of understeer, which is a good sign. A bit of tire sauce on the rear should aid traction there. Not going to do too much tweaking until at the track, it needs to run properly there rather than the dusty street.
Ideally I want to get an mo6, but like the idea of the hearing advantage on the 04