Motor power question for vintage runner

[paul]

Hi Guys,
I have 3 motors to choose from to put in a "frankenstein" vintage runner:

1. tamiya rs-540sh (screw holes line up, pinion meshes, don't see why it wouldn't work)
2. Trinity "monster horsepower", red end on it, also says "1985 world champions" on it
3. stock blue/silver edinger motor

The only info I could find was for the rs-540sh, and I saw conflicting speed ratings/numbers (anywhere from 13,500 to 20,000rmp). Could someone please let me know any info as far as the power of those 3? I'm using a tamiya teu-101bk. Thanks for any info!

[SteveK]

What kind of car? The mounting pattern should be standard on all motors, though most open-endbell motors have two holes on each side.

There are a bunch of motors with better performance that use the same silver can as the Mabuchi RS540. Axial has a 27 turn, Duratrax, HPI and Traxxas all sell a 20 turn motor (probably the same one), and HPI has a 15 turn motor as well. Tamiya has a hotter version of the RS540 with a black can. They won't be all that great, but they should be reasonably powerful, certainly better than the RS540 (which is a 36 turn with zero degrees of timing).

The Tamiya ESC is technically rated down to 23 turns, but the 20 turn motors will work fine, the 15 turn HPI should be OK too. I have a couple of them from Tamiya kits, I am looking at this Associated heatsink to stick on the top:
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJSU9&P=7

One of RC Car Action's columnists did a dyno test of the Mabuchi, and has done them on other motors. I have them all in PDF on my iMac, I'll search for them in a little while and see if I can find the stats he got.

[SteveK]

OK, found them. The dyno readings for the brand new Mabuchi motors were putting out 11,300 RPM at 20 amps (and 285 'something' power numbers, he doesn't say what). When the motors were broken in by running them in water, cleaned, lubed, and comm drops applied, the readings went up to 312/12,400.

By comparison, a couple competition stock motors (from 1997) put out 15,500 and 18,000 RPM at 20 amps. The first motor had up to 1/3 more torque, but lower RPM, so one was for tighter tracks while the other was for higher-speed tracks.

Some other low-turn modified motors, 11 to 13 turns, were dyno tested in issues around the same time, and they all 25-50% less torque than the stock motors, but almost double the RPM at the same amp draw.

I see test numbers of 5V, 6V, etc, so I don't know that the dyno numbers can be used to compare exactly how it will run on a 7.2V car pack, which will be degrading the whole run. It's a good comparison between the two motors on the same test though.

I would say the RPM ratings you saw were accurate, depending on the quality of the battery you are using.

[paul]

OK, found them. The dyno readings for the brand new Mabuchi motors were putting out 11,300 RPM at 20 amps (and 285 'something' power numbers, he doesn't say what). When the motors were broken in by running them in water, cleaned, lubed, and comm drops applied, the readings went up to 312/12,400.

By comparison, a couple competition stock motors (from 1997) put out 15,500 and 18,000 RPM at 20 amps. The first motor had up to 1/3 more torque, but lower RPM, so one was for tighter tracks while the other was for higher-speed tracks.

Some other low-turn modified motors, 11 to 13 turns, were dyno tested in issues around the same time, and they all 25-50% less torque than the stock motors, but almost double the RPM at the same amp draw.

I see test numbers of 5V, 6V, etc, so I don't know that the dyno numbers can be used to compare exactly how it will run on a 7.2V car pack, which will be degrading the whole run. It's a good comparison between the two motors on the same test though.

I would say the RPM ratings you saw were accurate, depending on the quality of the battery you are using.

Thanks for this great reply! I'll have to read more thoroughly and check everything out later (on my way out the door now), but basically the car (gold pan, everything stock) will be a backyard basher. I don't have a track or anything local as far as racing goes so I'm left to the backyard of the place where I rent (large tree covered area about 1 acre...many obstacles...perfect off road setting ) I have the trinity motor in it now, I don't really see the blue/silver going back in it. Another option I have is a tamiya bz(?) dirt tuned motor that has never even been used -bought it for my boomerang, but decided to shelf it after all the work rather than run it. Thanks again!

[Erich Reichert]

the esc should be able the handle all three honestly. I ran a sport tuned 540 in my Thundershot reissue for years and it was fine. I would turn my choice to which is still available and not. Don't want to burn up a perfectly good vintage motor just fooling around with the car. You can buy the tamiya motors still while the other two... good luck finding another

[paul]

the esc should be able the handle all three honestly. I ran a sport tuned 540 in my Thundershot reissue for years and it was fine. I would turn my choice to which is still available and not. Don't want to burn up a perfectly good vintage motor just fooling around with the car. You can buy the tamiya motors still while the other two... good luck finding another

Thanks for the advice! That's actually what I decided to do... I'm using the tamiya BZ motor but man has it given me problems. I had to add a heatsink to the ESC (wouldn't stop overheating over the weekend [90 degrees out]), chewed up 1 idler gear on sunday, and then one actually "exploded" today. The clip popped off of it, and wound up embedded in the opposite idler gear, and the original idler that the clip came from broke apart on one side.

I guess maybe the bz motor is too much for the original 6 gear? I'm not really sure. I know that the first catastrophe was due to the PO not gluing the screws onto the idler gear because 1 worked it's way out and fell between the gears and that's what caused the first situation. I have pieced it all back together with 1 slightly chewed idler (about 4 teeth). I'm going to put the regular 540 in it now and order some new idler gears.

[Erich Reichert]

Ya I'm not sure about the BZ, I've never run one before. The SH should be more than enough to have some fun with. Just keep in mind that while that TEC esc is a decent basic speed control, its just that... basic.

[SteveK]

http://www.tamiyausa.com/product/item.php?product-id=53930
The turn limit for the ESC is 23 turns, so that motors is within the limits but it's probably right at the limit of a motor that you'd want to use. It would be considerably hotter than any of the closed-endbell motors I listed above. I like those motors because they are durable and cheap.

What heatsink did you use? I've popped a couple of them apart to rewire them, and that black metal thing is meant to work as the heatsink. Tamiya has replaced the 101BK with this one: http://www.tamiyausa.com/product/item.php?product-id=45041
You can get a lot of the ESCs found in RTR kits really cheap on eBay. I found the one Associated included in the SC10 for $20.

[paul]

http://www.tamiyausa.com/product/item.php?product-id=53930
The turn limit for the ESC is 23 turns, so that motors is within the limits but it's probably right at the limit of a motor that you'd want to use. It would be considerably hotter than any of the closed-endbell motors I listed above. I like those motors because they are durable and cheap.

What heatsink did you use? I've popped a couple of them apart to rewire them, and that black metal thing is meant to work as the heatsink. Tamiya has replaced the 101BK with this one: http://www.tamiyausa.com/product/item.php?product-id=45041
You can get a lot of the ESCs found in RTR kits really cheap on eBay. I found the one Associated included in the SC10 for $20.

Thanks! Yeah, I was thinking that the motor was getting near the limit. I'm pretty sure the motor is a 23 turn (too lazy to look it up right now). Anyway, I made a custom heatsink from an old video card heatsink. I cut it out, then sanded both surfaces starting with 400 and went up to 1500 then used jb weld to attach it (at recommendations found on some other sites for working with cpu heatsink combinations). Works really well and only overheated once with that motor since I added it to the original esc. Pics below. The only reason I'm using this esc is that I had it from a tamiya kit so it was basically "free" I'm going to look into the link you posted though about the replacement for sure though.