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Old 02-01-2011, 12:19 PM   #1
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Default brushed equivilant to 17.5T brushless

Hey guys, sorry about the noob-ish question but I can't find the info I'm looking for via search...

I've been bashing nitro's forever, and decided to get into some indoor onroad electric racing for the winter to keep my friday nights busy. The group I'm running with seems to run 17.5 brushless motors, and brushed motors. I'm just not sure what type of brushed motor they run that competes with a 17.5T brushless. Can anyone elaborate on this for me?

I have a brushed setup kicking around, (stock motors, ESC, NiMh's) and that's why I figure I'll use it. Just cheaper (for now) so I don't have to make the swap to brushless. Maybe do that next year...

If you can suggest a good motor to run that would compete with these guys. We're running 1/10th 4WD TC's on carpet. Winding course, not an oval. I'll be running a Cyclone TC.

Thanks everyone!
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Old 02-01-2011, 12:24 PM   #2
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The closest to a 17.5 would be a 27 turn stock brushed motor. If you can find one, the co27 "cobalt" motor was about the best before the switch.
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Old 02-01-2011, 12:40 PM   #3
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That's what I thought, but one of the club exec's told me a 27T stocker (which is what I planned running) would be slow compared to the 17.5 Brushless guys.

I guess I'll just show up with my 27T stocker, and see how things go... Maybe run an extra high-mAh battery? Like a 5000 mAh?
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Old 02-01-2011, 12:43 PM   #4
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i ran a cyclone s in the hpi challenge...& i use a epic x pro motor..( black can red sticker) i came in.. 4th in the A main
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Old 02-01-2011, 12:56 PM   #5
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I have never run brushed, but I would think that with todays ramping ESC's, a 27t can't keep up with a 17.5T boosted.
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Old 02-01-2011, 12:58 PM   #6
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Originally Posted by chensleyrc1 View Post
The closest to a 17.5 would be a 27 turn stock brushed motor. If you can find one, the co27 "cobalt" motor was about the best before the switch.
Spot on!

With a 5000mah Lipo and a low on resistance speed control, you'll be able to hang with the slower half of a 17.5 no boost field, usuallly. They'll get you long term on gear ratios, though, as brushless are more tolerant of temps than the brushed motors.
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Old 02-01-2011, 03:54 PM   #7
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You won't be able to hang with a esc timed 17.5. But in spec mode the brushed will be competitive, at least for the first half of the race. The brushless motors dont drop off as much as the brushed did.
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Old 02-01-2011, 05:10 PM   #8
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Mounting a fan on the brushed motor will help with the heat fade.
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Old 02-01-2011, 05:26 PM   #9
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At least a 19t if not lower.
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Old 02-01-2011, 05:29 PM   #10
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At least a 19t if not lower.
Maybe if your running against 17.5s with dynamic timing programed in. If not then 27 turn brushed is the equivalent.
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Old 02-01-2011, 05:49 PM   #11
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At least a 19t if not lower.
+1
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Old 02-01-2011, 05:53 PM   #12
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Depends on the class, I'd say a 30turn or something would be close.

2S 17.5 non-boosted seems a little faster than brushed stock used to be. however 1S 17.5 non-boosted is way slower than I remember brushed stock being...
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Old 02-01-2011, 06:31 PM   #13
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2S 17.5 non-boosted seems a little faster than brushed stock used to be. however 1S 17.5 non-boosted is way slower than I remember brushed stock being...
That's all because of battery voltage and current delivery....NO WAY can round cells get anywhere near the performance level of today's average 2S lipo. The voltage/current delivery curve of even the best matched cell pack only compares in the first minute or so with a lipo, after that, the round cells begin dropping off quickly...and the lipo will still be going strong at a higher voltage level. So in essence, yes, lipo powered brushed motors seem faster because they get a higher voltage and greater current delivered to them for a longer period of time compared to nimh round cells.

My track allows 27T brushed/2S with the 17.5 non-boosted if that's all you have, and we run 27T/2S with our Muscle Car class (basically VTA). Geared in similar manner, the brushed motor can hang with the slower half of the field....but like I said earlier, you have more room in temps to overgear with a brushless than you do with a brushed motor wether you put a heatsink/fan on it or no, so in the long run if the brushed motor tries to overgear and hang with the brushless.....it's going to let the magic smoke out! You'll do OK in the colder weather, but if you're running outside in the heat, the 17.5 will take the win easily.

Wanna beat a 17.5 with a 27T? Drive better lines! But it's got you in the long run. Sooner or later, heat, brush wear, and simple magnet aging will make maintaining a 27T in the long run a false economy. There are TONS of gently used or nearly new ones for sale everywhere, usually cheap, but I'd only run one if I had to. For the cost of the proper support equipment ALONE for a brushed motor, you could get a Tekin RS/17.5 combo! Oh, and while replaacement brushes are a dime a dozen.......it's getting harder and harder to find decent replacement 27T armatures that are worth owning. Heck, dollar for dollar, if you simply have to run a 27T and had no other equipment, I'd replace the brushes until the arm smoked, throw the whole thing in the trash, and replace it with a like item.

Of course, it's easier to smoke check a brushed ESC, too, so figure if you're dedicated to a season of NON-silver can brushed racing, have a replacement motor or two, lots of extra brushes, and a spare esc on hand for quick swap out! If you already have motors, brushes, and all the support equipment, maybe it'll be economical for you, at least until your consumables (replacement brushes, and more importantly, armatures) runs out.

Figure the OP is wanting to put a 27T/nimh combo in a modern chassis and run in the 17.5 TC class......and unless you have mad motor tuning/tweaking skills, are relatively masochistic, and are an ace at the wheel....you're gonna be outclassed in weight and motor performance. I have a box FULL of 27T motors of darn near every flavor, and the only ones that consistently perform well enough to put with the brushless 17.5s are the CO27s. You can find 'em on ebay usually for at or under the $25 mark in new to gently used condition.

Or just bite the bullet and go brushless as soon as your budget/interest allows.....you'll be much happier!

ETA: Integy has some (4 or 5 different offerings) 27T arms for sale mega cheap...for a reason. EVERY can I've ever tried one in they dyno like crap.
As a bench mark, my Robitronics measures, in Watts, most good stockers in the high 80s to low 90s. GREAT stockers in the mid 90s to low 100s. With a handfull of rare exceptions (I number all my motors, and keep full records of every one, from new through every brush replacement and rebuild), I've NEVER gotten an Integy replacement arm in ANY can, with ANY brushes, with EVERY TRICK IN THE BOOK (the Black Book, for those of you in the know or with long memories!!) thrown at it, above the mid 70s for peak watts. Fine for bashing, crap for racing.
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Last edited by Buckaroo; 02-01-2011 at 07:12 PM.
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Old 02-01-2011, 08:14 PM   #14
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lets face it brushed is the thing of the past.... brushless is to cheap to get into as the cheap stuff still works just as good as the dear stuff for a new guy to brushless.... There is no point in having all the power in the world if you cant drive.

If u read any manual for a kit or any car you buy it says in it somewhere " dont change the basic setup until u can drive around the track consistently and no crashes"
Then get the go fast gear and tuning the chassis is the next thing...

So comparing brushed to brushless you cant for so many reasons. Honnestly they should never be compared full stop.
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Old 02-02-2011, 08:23 AM   #15
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Quote:
Originally Posted by Dadic 78 View Post
Hey guys, sorry about the noob-ish question but I can't find the info I'm looking for via search...

I've been bashing nitro's forever, and decided to get into some indoor onroad electric racing for the winter to keep my friday nights busy. The group I'm running with seems to run 17.5 brushless motors, and brushed motors. I'm just not sure what type of brushed motor they run that competes with a 17.5T brushless. Can anyone elaborate on this for me?

I have a brushed setup kicking around, (stock motors, ESC, NiMh's) and that's why I figure I'll use it. Just cheaper (for now) so I don't have to make the swap to brushless. Maybe do that next year...

If you can suggest a good motor to run that would compete with these guys. We're running 1/10th 4WD TC's on carpet. Winding course, not an oval. I'll be running a Cyclone TC.

Thanks everyone!

A 17.5 brushless with a timing advance ESC will run about the same speed as a 12T modified motor would.
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