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Old 01-23-2009, 08:27 AM   #181
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got a question. I am running 21.5 lipo with an lrp tc spec. geared at 4.21 my car comes of the track at 92*. Do I really need the heatsink and fan on the esc can I do away with one or both? I have not temped the esc since I have thought about doing this. just wondering if anyone else does it.
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Old 01-23-2009, 08:40 AM   #182
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Quote:
Originally Posted by cliferton View Post
got a question. I am running 21.5 lipo with an lrp tc spec. geared at 4.21 my car comes of the track at 92*. Do I really need the heatsink and fan on the esc can I do away with one or both? I have not temped the esc since I have thought about doing this. just wondering if anyone else does it.
Cooler electronics are always better, but that's plenty cool. You would be just fine without the fan, and maybe the heat sink as well.
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Old 01-23-2009, 09:40 AM   #183
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Try a couple friends temp gun. It sounds like yours is miscalibrated.
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Old 01-23-2009, 09:49 AM   #184
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I don't think so, I'm running a TA05 tub car with no fans or heat sink and about 1050 grams overweight with the 21.5 lipo geared at 4.2 and come off the track at 94* after a run. This was checked with my temp gun and two others.
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Old 01-23-2009, 01:05 PM   #185
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TC3 chassis setup for VTA? im running a 21.5 and lipo and very happy with the speed, handling not so much.
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Old 01-23-2009, 01:07 PM   #186
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I'm not suggesting you touch any motor after racing, but is it warm to the touch? If it is truly reading 94, then that is cooler than the average person's mouth. I wouldn't suggest putting your finger into your mouth at the track either unless you like the taste of traction compound.

I don't doubt that the motor is coming off reasonably cool. If the ambient temperature of your track is low, that could explain some of this. However, I've yet to see a car geared at 4.2 that came off the track I race at temp that low. Granted, I race at a tight indoor track that requires you to be on/off throttle for the entire run. A large flowing track will usually result in cooler motor temps than a tight technical track or an asphalt parking lot track during the summer time.

This leads to the question of proper calibration of a temperature sensor. Most IR sensors have to be calibrated to the type of surface they are reading. I'm not going to claim to understand this, but this is called emissivity. Here is an section from the Duratrax Flashpoint Infrared Temperature Gauge (http://manuals.hobbico.com/dtx/dtxp3...ual-v1_1.pdf):

Quote:
Emissivity is the way that any object emits heat
energy into the air. Emissivity is always rated by a
numerical value. Different types of materials have
different emissivity values. An object's emissivity is
dependent on its surface condition, material type,
temperature and wavelength of temperature
measurement. Adjusting the infrared temperature
gauge to compensate for the emissivity values of
different objects is the key in getting the most
accurate temperature readings.

Last edited by IndyRC_Racer; 01-23-2009 at 01:33 PM.
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Old 01-23-2009, 03:11 PM   #187
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Quote:
Originally Posted by IndyRC_Racer View Post
I'm not suggesting you touch any motor after racing, but is it warm to the touch? If it is truly reading 94, then that is cooler than the average person's mouth. I wouldn't suggest putting your finger into your mouth at the track either unless you like the taste of traction compound.
Now you tell me, I had to find out the hard way!
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Old 01-25-2009, 02:41 AM   #188
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If you're running a pre-T2 Xray chassis in VTA I've just listed up a like-new one-way diff at http://www.rctech.net/forum/r-c-item...ml#post5338228 if you've been wanting to give one a try. I bought this for the only Xray I ever owned, a 1/12 sedan, that I ended up selling before I ever ran it.
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Old 01-25-2009, 09:16 PM   #189
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I am running a TC4 with a 21.5 brushless and am wondering what other people are using for gears to reach the 4.2 FDR. Are you using 64 pitch or 48 pitch and which ones (i.e. 81/48 64p, 69/41 48p)?

Thanks
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Old 01-25-2009, 10:16 PM   #190
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Originally Posted by lp3233 View Post
I am running a TC4 with a 21.5 brushless and am wondering what other people are using for gears to reach the 4.2 FDR. Are you using 64 pitch or 48 pitch and which ones (i.e. 81/48 64p, 69/41 48p)?

Thanks
I'm just setting my TC3 up right now with the 21.5 and I'm using the 48p setup.
I have both the 72t and 69t spurs and currently a 40t and 38t pinion. I wanted the 39t also but it was out of stock. I prefer the 48 pitch as it's less susceptible to damage IMO.

I didn't see a 41t pinion for sale at SpeedTech RC but maybe you've seen a different source?

From what other's are saying it doesn't seem like you need to go all the way to 4.2 anyway.
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Old 01-26-2009, 06:58 AM   #191
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I believe A-Main has a 41 tooth 48p pinion. Thanks for the info. Did you have any fitment issues with the pinion. I have 69 48p spur so I may try that.
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Old 01-26-2009, 08:48 AM   #192
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Has anyone had any luck trying to recycle their HPI rims? I have a couple rims that are in excellent condition, the sidewalls of the tires are starting to split.

Will the old boiling the rims/tires trick work?

Thanks!
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Old 01-26-2009, 08:54 AM   #193
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I realize this answer is not for 48 pitch gears, but as long as I've paid attention when setting my mesh on my TC3, I've never had any issues with gear mesh using 64 pitch gears.

The simplest (and probably cheapest) way to reach the 4.2 FDR for a TC3/TC4 is to use an 84 tooth spur and a 50 tooth pinion in 64 pitch. This is exactly 4.2. If you plan on only running 4.2 you would only need to buy 1 spur and 1 pinion.

84/50 * 2.5 = 4.2

If you use a tub chassis TC3 you will have to remove some of the webbing or chassis support that will be underneath the pinion gear. I just setup a TC3 for VTA and used a grinding stone/wheel on my dremel and it only took me a few minutes to remove the material so the pinion would not rub the chassis.

The smallest 48 pitch spur that I'm aware of is a 60 that is made by Robinson Racing. It is available on Tower Hobbies (http://www3.towerhobbies.com/cgi-bin...?&I=LXEY18&P=7). The "fastest" you can go with that gear is:

60/35 * 2.5 = 4.286

Last edited by IndyRC_Racer; 01-26-2009 at 09:20 AM.
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Old 01-26-2009, 12:07 PM   #194
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Quote:
Originally Posted by IndyRC_Racer View Post
I realize this answer is not for 48 pitch gears, but as long as I've paid attention when setting my mesh on my TC3, I've never had any issues with gear mesh using 64 pitch gears.

The simplest (and probably cheapest) way to reach the 4.2 FDR for a TC3/TC4 is to use an 84 tooth spur and a 50 tooth pinion in 64 pitch. This is exactly 4.2. If you plan on only running 4.2 you would only need to buy 1 spur and 1 pinion.

84/50 * 2.5 = 4.2

If you use a tub chassis TC3 you will have to remove some of the webbing or chassis support that will be underneath the pinion gear. I just setup a TC3 for VTA and used a grinding stone/wheel on my dremel and it only took me a few minutes to remove the material so the pinion would not rub the chassis.

The smallest 48 pitch spur that I'm aware of is a 60 that is made by Robinson Racing. It is available on Tower Hobbies (http://www3.towerhobbies.com/cgi-bin...?&I=LXEY18&P=7). The "fastest" you can go with that gear is:

60/35 * 2.5 = 4.286
I'm building another tc4 but w/ 21.5. I'll be using 88/52 for frd 4.23. I just hope they fit w/o too much trouble...it's a tub chassis. Up to a 54 would fit in the tc4FT car, but it's alittle too stiff to run TA.

thanks for trhe 60/35 info! I have had problems w/ 64p & rocks outdoors and will go back to 48p for the outdoor/summer season.
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Old 01-26-2009, 02:11 PM   #195
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Originally Posted by cutjo3 View Post
Has anyone had any luck trying to recycle their HPI rims? I have a couple rims that are in excellent condition, the sidewalls of the tires are starting to split.

Will the old boiling the rims/tires trick work?

Thanks!
If your not using the tires again, I'd try acetone first. Boiling or baking may warp the rims.
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