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Discussion Starter #1
Hello everybody,

Has anybody here tried this armature? I'm thinking of buying one and putting it a slightly modifiedTomy sg+ chassis (poly traction mags, silicone tires). I race with several friends on tomy tracks with the stock power transformers. I have a hot 3 ohm arm that I tried, it runs like a scared bunny rabbit untill it gets further away from the power source and then it slows down. Will I have the same problem with the BSRT gold hot stock arm? Will I need to upgrade motor magnets as well?

Thanks,

Dave G.
 

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Dave, Lower ohm arms would need stronger motor mags. More important,
your problem of the car slowing away from power source will need track power taps & higher amp power supply. :)
 

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Agreed on the power supply comment Dom...

I run the gold hot stock arms in my G3R setups for HOPAC racing and they run great with the standard ceramic magnets. Mind you these are 6 ohm arms and not the 3 ohm you're talking about.
 

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Discussion Starter #4
Marty,

So this armature would run great on a standard Tomy track/power supply? Is the arm better/faster than the sg+ arm? I have an opponent that I can out handle on the twisties, but he always manages to get at least a 1/2 car length on me on the straights.

I want to beat his a--! And excuse my ignorance, but what's HOPAC?

Thanks, Dave G.
 

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Discussion Starter #5
Dyno Dom,

Yeah, I found out after the fact that the 3 ohm arm would need more track power. I've since yanked it, and went back to the standard sg+ arm. If one of the guys ever decides to get a high power track amp, I'll try it again.
 

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Marty,

So this armature would run great on a standard Tomy track/power supply? Is the arm better/faster than the sg+ arm? I have an opponent that I can out handle on the twisties, but he always manages to get at least a 1/2 car length on me on the straights.

I want to beat his a--! And excuse my ignorance, but what's HOPAC?

Thanks, Dave G.
It will run much better on a quality power supply than on the Tomy stuff, it's why your hot 3 ohm arm sputters away from the powersupply as well.

That being said, the arm should still outperform a standard SG+ arm, unless said arm is one of the 1 in 100 perfectly balanced and freaky fast arms.....

HOPAC is just our local racing group up here in the Northwest, the founder is the owner of Scale Auto/BSRT and makes the arms you're running. :)
 

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Sure thing Dave, I would recommend the 148 arm, it's tied off so you don't have to worry as much about potentially throwing a wire....
 

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A BSRT 149 Gold Power Hot Stock armature because of it's light weight.
Put a .005 steel spacer on the front of the arm to run on the bushing in the endbell,
with a .005 to .010 insulator between the spacer and the commutator.
Then check the axial play in the arm is not too tight.
And if you want to ream the arm bushings with a hand reamer .060 to .062.
With a BSRT 417 Delrin 7 tooth pinion and a 422 Delrin 22 tooth crown,
and it will be perfect.

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You really should learn how to setup your SG+ with a stock arm before laying out extra cash for a specialty arm intended for SS racing. The stock Tomy arms have plenty of speed in them.

Have you:

1) Reamed your bushings? Cost = $0.00
2) Tweaked your endbell? Cost = $0.00
3) Broken in your brushes? Cost = $0.00
4) Tweaked the shoe hangers? Cost = $0.00
5) Switched to a better gear setup, say 7/22 or 7/21? Cost = $3.00
6) Switched to an 0.059" rear axle? Cost = $2.00
7) Tried different shoe springs, maybe one thousandth up, or stretched stock springs? Cost = $1.00
8) Statically balance you stock arm? Cost = $0.00
9) Switched to a better shoe? Cost = $1.50

If you knew every other part of your setup was up to par, then yes, a fresh new tweaked arm is highly likely to equate to improved speed. Buying a worked up hot stock arm may or may not help your cause if you are losing performance in other areas. You need to remove any uncertainty.
 

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AFXToo, On your tip #7, how do the stock springs compare/differ from after
market springs? (thousandths) Tip #8, can you explain static arm
balancing?
Superfist, In ohming arms, does the vibration cause "spooling-up"?
Good info, thanks! :)
 

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An armature that ohms even on all 3 legs of the windings is a good one.

What I meant by spooling up is when you test a car in your hand with a power supply or on the track, you'll feel the vibration from a out of balance arm or a bent axle that you might not see.
That will really kill the performance.

Increasing the pick up shoe tension dose improve the electrical contact.
You can tell when that's right when the shoes stay clean because there is no arcing.

* But I do like the balanced arms and good gears,
they make the cars sound good on the track.

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DAve G one thing you may have overlooked is if all things being equal including gearing, a possible reason you may handle better and he has more top end in the straights is that he has bigger diameter tires and you have slightly smaller. If you go to larger tires you may lose some handling.
 

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Cant tune a rocket...if ya cant tune a turd.

The trick is not necessarily knowing what to do ...but rather that once you have done something; recoginizing how it affects the other components of your chassis/car.
 

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Discussion Starter #16
AfxToo,

Answering your questions:

1 - No
2 - Yes
3 - Yes
4 - No
5 - Yes, 7/22
6 - No
7 - Yes, stretched springs
8 - No...How do you do this?
9 - Yes, BSRT shoes

Thanks for all the tips. I thought some of you might be interested in knowing that I popped in a different stock arm in my favorite chassis. I don't know what happened, but the thing just ran from everybody. At first there was not much improvement, but after about 10 min. of practice laps, it just opened up. The opponent that I mentioned earlier? I killed him....I would have lapped him too if hadn't of deslotted. Still won the race.

Still haven't purchased that BSRT arm I mentioned, but I am seriously considering it.
 

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Discussion Starter #18
Superfist,

It was a stock SG+ arm, they both are. Whatever the ohms are on that. This is what I thought was odd. The arm I popped in was from an older black plastic SG+ chassis that had cracked. It was a good running car. Not as fast as my current favorite chassis. Not even sure why I switched arms. But when I put that older arm in, like I said it just flat out ran everybody. I later raced one of the guys who had a rtr BSRT, and he was the only one who could keep up. But I even out ran him on some the twistie bits.

I still can't get over it. Everyone kept asking me "what did you do to that car?" All I did was put in that old sg+ arm.
 

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hi dave

when you replaced the arm, which end bell did you use? the one from the broken chassis or the one from the race chassis? some end bells (like ones with nicely broken in brushes) can make a big difference.

since you dont ream your bushings (which i do but think is a pain) you might consider buying pre-tweaked end bells (scale auto) or pretweaked bushings (scale auto or scale engineering) some guys like the blue poly bushings, i like the brass ones.

if your rules allow it, use a titanium rear axle. you can buy 0.059 titanium rod by the foot from small parts . com, or you can buy titanium axles individually from scale auto. they make a BIG difference. if you likem PM me your address and i will send you a rear end to try. let me know what tire hieghts work well on your track.
 
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