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-   -   GPM Ball Differential Problem (http://mini-zracer.com/forums/showthread.php?t=10758)

Civic_Zen 2003.11.19 09:22 AM

GPM Ball Differential Problem
 
I have been working on my Enzo and I did the GPM motor mount and the GPM diff. Now when I take my car out all it does if I just hit the gas is turn circles always in a clockwise motion. This is if I'm not holding to the left or the right, and my steering trim and everything is set fine. I'm thinking its the diff, but I've tried tuning the diff with absolutely no results. All my enzo does is turn circles.

Can someone please give me and and all tips on what I can do to correct this problem. The only way i can get the car to go strait is to give it about 1/8 throttle and gradually increase it, but in most occurances it just spins out.

Another question I have is that when I read up on the MR-02 I decided to go with it because it was supposed to handle better. Well right out of the box, my Enzo didn't handle near as well as my friends Modena on the MR-01 chassis, if i was going WOT and turned it would spin out, no matter what, and would usually do 180s on command where as he can go full speed and turn with no problems. Now my Enzo is just 10 times worse, and is unusuable even though it was never much good at doing anything besides spin out any way.

What is wrong with my Enzo???

Cian 2003.11.19 09:36 AM

When you pick it up , and hit the throttle, does the other wheel turn at all? Can you turn the wheels manually? Is there interference with the shell and the wheel? Are you using bushings or bearings? Take the rear apart and put it together again.Tighten the diff as hard as you can. try running with it like that. Gradually loosen the diff a 1/4 turn at the time, until you are happy with the behaviour. I don't think it's a hard problem to solve, a little trial and error should do it...

Civic_Zen 2003.11.19 02:20 PM

When I pick it up, it seems fine, both wheels seem to be getting equal power, and like I said I have tightened and loosened the diff some already and have been tuning it, it just hasn't helped any. I suppose I will just try some more, but in answer to your other questions I have the metal ball bearings and no there is not interference with the shell and the tires.

I will try to tune the diff more, but right out of the box I tried the diff and it did the same thing. It was tight out of the box also, and even when it was really loose in comparison, there was no difference, all it does is turn in circles.

I also just think my car is bad, when I first got it it did the same thing just not as bad. Whenever I turned it just did a circle. I don't know what crack heads wrote the articles in RCCA magazine and said that the MR-02 was so much better then the MR-01 especially in terms of handling, but I can assure you that in terms of my experience, EXACTLY the opposite is true. My friends MR-01 will take my Enzo in any aspect of handling, acceleration, anything except because of the Enzo's CG being low, it doesn't flip. WOW - so I have a terrible handling Enzo that does nothing but circles, but at least it won't flip over right? :rolleyes:

The worst part is that I bought the diff, bearings, alum engine mount and other parts to fix the problems it had in doing these circles right out of the box, and the problems are 5x worse now after spending as much as I did on the car originally.

minten 2003.11.19 03:19 PM

Hmm, strange but don't give up.

First, is all the chims in the right places? one on each side of the diff?

Secondly, if the car spunn before you put the diff in maybe it's something else. Do you tighten the wheelnuts to hard? Is it something with the steering? Make sure that there is nothing obstructing or tampering with the steeringmovement.

Is the car straight? Lift one front wheel at a time and check how far you can lift it before the other lifts also. Then repeat with the nest wheel. Can you lift them the same hight? If not you have to find the place where it's tweaking. Usually the H-bar in the back.

You say that the wheels ain't touching the body. Check it by running the car carcarefully without the body and see how it handles.

It's often the very very small details that makes the car handle really bad so pay attention to the small details. Is it a small twig from the molfing form that's in the way some where?

I hope that you find the fault and get your racer going.

Oh just remeberd. I'm running my MR-02 on painted particle board and I just can't get the car to handle well if I use anything hotter than the standard motor :-( I do think that you have to get it to grip more in the back ans slide in the front for that. When you run almost even deg tires on the MR-01 you have to use 40/10 deg tires front and back on the MR-02 Enzo because of the weight balance and characteristics of the car.

/Marcus

Civic_Zen 2003.11.19 05:01 PM

We will see I guess. Ive worked on it for like 8 hours now tinkering on it in the last week. I appreciate everyones replys, hopefully I will find what the problem is. Thanks again, and if anyone else has any ideas, keep them coming.:)

herman 2003.11.19 09:51 PM

try changing the tires to a softer compound...
try dialing out the steering throw on the dual rate...

what type of surface do you run on? more often than not, if you take a turn full throttle, you will do donuts... easy in, hard out is the general rule...

and don't give up...

Krazy 2003.11.20 04:47 AM

Did you also try to take the diff. apart clean it and put some new diff. grease on it?
When i received my ball diff. it wouldnt work either....did what i just described and my mr-02 runs great now.

About the handling isue, a friend of mine has a mr-01 and we did a little handling race (I must say his mr-01 is full with optional parts and mine was as good as stock) and the mr-02 won with ease. The mr-02 does handle way better if you ask us :P

Keep us posted as soon as you find a solution.....

worst_enzo 2003.12.10 10:07 AM

sudden thought
 
have u ever try using another remote control????

because u said that your car runs in circle since it's brand new out of box. you know the sucky ko-pro remote breaks easy.



that was just a sudden thought, but are u running on stock tires?
what kind of surface are u running on?

the STOCK MR02 is much better handling than the STOCK MR01 definitely. all u need is some new tires ( depends on what surface u run on)

i tried to run my enzo on a carpet racetrack when i first got it, my car runs in circle too, cuz the tires couldn't grip at all. once i got some new tires (front 20, back 10), it handles much better, now i am using foam tires for front and back, i could take SOME (just some,, haha, i suck) of the hopped up mr01.

just my $0.02, my first post, new to forum, new to miniZ. =)

Slicks 2003.12.13 08:39 PM

Sounds to me like Worst_Enzo may have answered your problem. As I was reading this thread it sounded to me like a radio/controller issue. We had trouble with the cheezy radio that came with my daughters Enzo at first too.

The trim knobs for the steering rate on that controller are confussing I think.

1) Make sure that you are not on the same frequency as others. DO NOT trust what the number on the crystal says - they are for in Europe and do NOT match to the US (they have 12 channels and we have 6). Check the frequency number stamped on both the receiver and transmitter crystals and make sure that they match. Then make sure that they do not clash with anyone else running cars at the same time.

2) Try a new radio - one that you know works.

If neither of these work - Kyosho used to have a warrenty on the Z's check that out too.

good luck

slicks

arch2b 2003.12.13 08:52 PM

if your problem is it spins out every time you throttle, i have the smae problem with my 01 gpm diff on my 015 conversion. i can not accelerate straight unless i start fro a crawl. i to have spent hours tuning it with no luck. it's not a tx or rx issue, it's a throttle/handling issue. how do you tune it to run straight on heavy throttle? btw, switching to 10's in the back helps alot. i even got grovved 10's which were great in my 01 cr5. it's just a tuning problem i have yet to solve

mailboxck 2003.12.14 08:25 PM

Insufficient grip at the back?

Try using harder front tires...or springs...or add spacers to the front springs to make them harder

Or try using softer rear tires...or springs...or add spacers to the motor mount to lower the rear end (to shift the cg to the back = more rear grip) or remove the center shock that is inc with the enzo.

Hope this helps


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