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Discussion Starter · #21 ·
Thanks, MM. Love the Porsche. But I鈥檇 like to see the 2 ohm new car go! That must be one of those current eaters RichD was talking about 馃榿. Merry Christmas everyone!
 

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I noticed that my new Auto World 4-gear cars have wobbly wheels and are gutless. So I'd like to fix them up.
Oh my. That's a can of worms I happen to be going through right now. 4-gears have all sorts of mechanical issues.

1) The cluster shafts are loose
2) The armatures are often missaligned in the chassis because the top and bottom parts of the chassis don't line up well
3) Wobbly wheels/tires
4) The idler gears are sloppy

That's just the quick notes. There are other issues.

But like Model Murdering says. If you take the time to work through each section. You can resolve most of the issues.

Merry Christmas to all!
 

Rich Dumas
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Here is an article on tuning Aurora T-Jets: T-Jet Tuning Article by RHD Rev 11.pdf
Here is one on tuning non-magnet 1/32nd cars: Tuning for Non-Magnet Racing Rev 5.pdf
The axles in Mega G+ cars are very soft and sometimes get bent when the wheels are installed at the factory. With the rear axles you can remove the tire, slip a length of brass tubing over the wheel and apply a slight twist. That would at least make things a little better. You could buy a replacement rear axle assembly and hope that the axle is straight. Finally, you could use a proper hardened axle, you might have to use aftermarket wheels as well.
 

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Rich: "Finally, you could use a proper hardened axle, you might have to use aftermarket wheels as well."

Fiddling with, or using inferior parts is how the manufacturer's got ya here in the first place. This is why H0 and 1/32 have a big aftermarket representation. If and when the bug hits ya, you'll want quality parts.

I'm probably a coupla updates behind, myself. Rich's takes the time to keep his tutorials updated, something that isnt really found anywhere else. Set aside a block of time. Bring pencil and paper, extra food and drink, and maybe your light camping gear.

The underlying message is that indescrimnantly mashing wheels onto inferior axles is bad practice. duh. The factory included.
 

Rich Dumas
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Since there are minor differences between the original Aurora Thunderjet cars and the later ones from Johnny Lightning/Auto World and Dash I elected to do separate but similar articles for each of those. The second generation Dash cars and the new Wizzard cars could be included in the original Aurora T-Jet article. Model Motoring did a T-Jet clone called the Thunder Plus as well, I have never seen one of those.
Here is (hopefully) a link to my Google Drive page, it has all of my articles that are still available: My Drive - Google Drive
That link may only work for me, let me know if it does not work for you. With Google Drive I have made my documents all public, but the entire page may not be. I think I will compile a list of the latest versions of my articles and put that on Google Drive as a public document.
I suppose that it is time to update many of my articles, so much to do, so little time.
 

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Discussion Starter · #31 ·
Boy, that was fun! I have a used short wheelbase MG+ car that came with a body I wanted and it鈥檚 my experimenting car. Finally got around to installing front axle and o-ring tire set and rear axle, gear, hubs and silicone tire set I bought a month or so ago. Put softer front springs in the pickups and left stock magnets in. It鈥檚 like a whole new car. I turned the AFX tri-power pack to the Expert setting and the car was plenty drivable on a 30鈥 track whereas stock car is not. Fast but very controllable, I could slide it on the insides and use guardrails on outsides. Can鈥檛 go WOT on my track but still a lot of fun. Might try the stronger magnets but pretty happy with it as is. Ran it for my wife a little while ago, pretty sure I鈥檓 about to do one of her long wheelbase cars next ha! Pretty sure most of those mods are available for the Autoworld cars cbwho, might be worth trying.

Is there a hub puller/press for front wheels or is it not needed? I have one to pull rear hubs and press hubs and gears but haven鈥檛 seem one for the front. And is there any way to clean these motors? I was going to use motor spray but theres no place to get it in. Tried sparing through endbell, no bueno.
 

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Discussion Starter · #32 ·
What voltage do y'all generally use with the MG cars? Finally got to drive one last night and it was a blast. I ran at 18.5 V last night and the car felt good. The modded MG+ also felt good at that voltage which makes me think I could run them against each other. Just want to be sure 18.5 isn't too much for the MG motor. Thanks.
 

Rich Dumas
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My club runs Mega G+ cars at 18.5 volts. They don't get much faster in a straight line if you increase the voltage, they just become more difficult to drive. We found that with Mega G+ cars with some chassis the traction magnets can be lower in the chassis. Even if the magnets were the same strength not every car would have the same amount of magnetic downforce. For that reason we have a spec for the distance between the bottom of the magnets and the bottom of the chassis.
 

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Discussion Starter · #34 ·
We found that with Mega G+ cars with some chassis the traction magnets can be lower in the chassis. Even if the magnets were the same strength not every car would have the same amount of magnetic downforce. For that reason we have a spec for the distance between the bottom of the magnets and the bottom of the chassis.
I was just sitting here wondering about that very thing. When I lowered my MG+ it stuck to the track great, but we ran my wife's tonight and it wasn't even close. I could feel the difference when I lifted them off the track. I ended up putting stronger magnets in hers and it now has a little more downforce than mine with stock magnets, but not a lot. I'll measure and see if there's a difference. Thanks for the tip.
 

Rich Dumas
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In some cases you will be able to push the magnets lower in the chassis to get more downforce. The magnet pockets in different chassis are not all the same, so even if the magnets are all the same strength there will be differences between the cars. It is easier to push up the magnets in a more stuck down car to equalize your cars. Because the amount of magnetic downforce is proportional to the square of the distance between the magnets and the rails even a tiny adjustment can make a big difference. I have a home made downforce tester that is useful for that sort of thing and there is now a device called a Digi-Tune tester by Peter Doane available from Lucky Bob's.





Those seeking stronger traction magnets for Mega G+ cars can find them at Viper Scale Racing.
 

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Discussion Starter · #38 · (Edited)
I pushed her magnets far as they would go before we ran her car. Could be just weak magnets, but I'm wondering about the distance because even with level 42 magnets her downforce is just a hair greater than mine with stock. Both are SWB chassis with the same body. Going to try to take a look at it this evening. That's a great piece of kit with the scale. Have seen the commercial downforce testers. The one track in our area has magnet limits so waiting to get out there and see what they use to measure.

Edit: RichD, do you have any tips for measuring from bottom of magnets to bottom of chassis? I don't have small enough calipers or ruler or anything to fit in there. Best thing I can think of is to take a small piece of cardboard or a toothpick and mark where it sits flush with chassis.
 

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I believe that similar stories have been fairly routine regarding disparate speeds between mg+ cars since their introduction.

Usually it ends with "I called Racemasters (AFX), and they provided a new car, no problem".

Maybe worth a shot to give them a call.
 

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Discussion Starter · #40 ·
Her MG+ car is very fast. The stronger magnets gave her just a little more downforce than I have in mine which makes for some VERY competitive racing! She's happy, I'm happy. Just looking into the reasons for the downforce disparity between 2 cars with the same setup to add to my own personal knowledge base.
 
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