Performance difference between a 17.5 and a 13.5
 

Hello All,
While pretty well versed in brushless motors for E flight I am a newbie when it comes to BL motors in cars so looking for some guidance.

I have a TT02 that I am running with a old Novak Sport 17.5T motor and a Justock ESC. I have it geared with a FDR of 4.33:1 and it goes alright but being a motor head I wonder if it would be more fun if it was a bit faster. I do like the torque that I get with the 17.5 and I get an easy 15 minutes of duration out of a 4000mah pack.

If I was to switch to a 13.5T motor and gear it appropriately how much of a difference would there be in torque (acceleration) and top end over the 17.5? Any guesses on how much of a hit I would take in duration?

I am not racing, I drive the car 90% of the time on two tennis courts (70' straight?) and set up a little course with field markers. These tennis courts are not all that well used or maintained so the surface is not that sticky.

Thoughts?

Thanks.

Cheers,
Jim

For that car the difference between 13.5 and 17.5 is a pretty good jump in power. But it is by no means "too much" power. I actually felt like I could have used more power out of my TB03 when I was running 13.5, but then you have to consider driveline components too. Going too big in these cheaper on road cars can munch gears if you're not careful. I would stay above 10.5t with that being said.

As far as torque goes, it should be roughly the same between the two, but of course you'll notice far more top end with the 13.5. I can't speak of the runtime you'd get with 13.5, but I would guess maybe a 3 minute decrease? But that's just speculation.

That is good to hear.

I went down "to much power" road with a 1:18 scale truck and while it is stupid fast it is not very driveable and a maintenance nightmare.

I may have to keep my eyes open for a decent used motor to try out.

Thanks.

Cheers,
Jim

You will feel much of the difference between regular 17.5 (blinky) vs 13.5T (blinky).
In case of newest, outlaw with right timing 17.5T i.e. MM Fleta Sting would be very close to blinky 13.5 in terms of top speed.
Running time is pretty similar. In my case on large asphalt track 5min of race means 1800-2000 mAh

13.5t is a quicker, less torquey motor. The 17.5t is slower but more torquey.

I don't thnk there is that much difference between a 13.5 and 17.5, especially if bashing. Modern 17.5s are not slow. You would need to go to a modified motor to start to notice an obvious difference

A bigger factor for you is probably the age of the motor - the original Novaks had a weaker rotor than current motors, and the your gear ratio - there is probably scope to gear up a bit, although the TT-02 is quite limited.

You will probably find a faster brushless motor easier to gear in a TT-02. Bear in mind that a faster motor might start to push the mechanical limits of the car - Tamiya developed it for their sealed brushed motors which are a lot slower.

I have the "High Speed Gear Set" and running 64P gears as well as an adjustable motor mount so I can hear as low as the low to mid 3's and on up to 8+ so gearing is not the issue.

I am aware the motor is 8 years old and probably not fast as the current generation motors.

Do you guys think I would be better off picking up a more modern 17.5 or a modern 13.5. How much effect does motor timing have on overall performance?

Thanks.

All one's manufacturer engines cost about the same - windings does not matter. Buy 10.5, set timing and you would be happy ripping off gears out of your tt02 ;):):)

oooold thread but Google don't care!
 

Just thought id put in some tested numbers to anyone ending up.here by way of Google's blindness to post dates, and therefore making an old post relevant.
I have SEVEN variations of the ole' TT-02 cars.
I have three Trackstars in some. 7.5t(fast bash), 9.5t(drift), and 13.5t(rally/onroad bash).
If you build your diffz with some proper techniques you have absolutely NOTHING to worry about. If you need help there go check out nbTMM's post on TamiyaClub, (post topic title: TMM'sTMM's TT02 / TT02B Garage),
and you wont go wrong, you can also use tt01 gears and diff case but just using TMM's instructions will have you a solid set of diffs. I have had a Ruddog RP542 4.5t in one of my customized TT-02 cars for about 2 years now and no clicking, no breaking of gears, or parts....but to be fair it has CF shock mounts, spring steel CVDs, alloy center driveshaft or propellor shaft, etc.
When things break its an excuse to go shopping!
Anyway, i like the 13.5t TT-02 best. It has a Trackstar 80a Tirbo esc in it and its It's hell on wheels, plenty take off power, top end and runtime. i sawed off the top and bottom of the front hubs to get rid of the silly plastic bushing mounts, i cut it to within 0.5mm of the ball and then shimmed and placed titanium 0.45mm spacers and then screwed it down with tutanium screw, socket head top button head bottom. Then installed titanium beveled spacers mounted one each front and rear where the single screw goes in dead center of the lower bumper mount. This created a bump stop that shoots sparks just so sweetly, and the Aarms and bottom of hard chassis barely have road rash! The road has rash instead! This is great for badhing but maybe not racing...thats what a Down Stop Droop Plate is for!!!
I have an R1 Wurks 17.5t in another tt02, running hobbywing 10bl60 sensored or the older 60a sensored hobbywing esc the older model with the blue heatsink and the esc is square... the new 144001 brushless 45a esc is based on this and they look similar. Anyway she scootz and is fun but its just not the same as the 13.5t. i. I would not even enjoy racing it 17.5t blinky because its just not fun imo. i even tried a Skalar 21.5t and that was miserable...just so slow motion no matter how i geared it it just felt like i was driving a wet blanket!!! 7.5t uf you know what your doing when building the diffz, 13.5t if u dont but you at least follow TMM's build guide (especially about the diffz) and if you think them is to hot for u to handle go get you a a boxed combo TT-02 with the Torque 550 can motor and let it rip! 😉