Is this motor ok?

[Spunkybob]

Hi all.

I picked up a twin hammers second hand with no motor. I out in a 20t hpi brushed I had laying around but its very slow.

I have a 120amp brushless turnigy trackstar turbo esc with a 21.5t motor that I used for VTA Onroad which I don't do anymore.

Would this motor be ok with turbo timing? Or will I lose slow speed crawling ability?

How would the below motor go? I want to be able to go fast but still crawl through the bush/up creeks etc.

Turnigy TrackStar 9.5T Sensored Brushless Motor 4120KV ( (AU Warehouse)

[dstaks]

You could use the 21.5t. Much better then that brushed motor, just try it and see how you like it. Put some boost on it. I'm going to run a 13.5

[Sr.Irie]

Originally Posted by Spunkybob

Hi all.

I picked up a twin hammers second hand with no motor. I out in a 20t hpi brushed I had laying around but its very slow.

I have a 120amp brushless turnigy trackstar turbo esc with a 21.5t motor that I used for VTA Onroad which I don't do anymore.

Would this motor be ok with turbo timing? Or will I lose slow speed crawling ability?

How would the below motor go? I want to be able to go fast but still crawl through the bush/up creeks etc.

Turnigy TrackStar 9.5T Sensored Brushless Motor 4120KV ( (AU Warehouse)

I am running this motor and it works great for what I want it to do and I think that one would do fine also. For me the 4150kv 5Tis perfect. To much power, goes to fast, and cheap also, so if I kill it in the mud and water not as big of a deal. I also Have run many HK brushless sensored motors and have had good luck with them.

[Spunkybob]

Thanks Sr.Irie

Would my ESC run a 550 motor? Turnigy Trackstar 120A Turbo

From my understanding a 550 motor is longer, slower but way more Torque then a 540?

I have been running my 21.5 with +35 timing set on the ESC but I feel its getting too hot.

[Sr.Irie]

Your ESC should have no problem with it, I think that even may be what HK recommends for it.

Your getting hot allot to do with the timing set so far advanced. You will not need to set the timing so far to get the speed with the 4150KV, it will go plenty fast. If not just give it more gear, it has more than enough torque for the TH. My truck will crawl as slow as you want, barely moving to about 25mph in second. I had it at one point geared to do 37.8 (fastest I have got on GPS) but that was to tall for real crawling. But I set it up that way to go to the dunes and it had no problem with heat in the sand.

[Spunkybob]

Thank you, id say that is a go then.

the 21.5 crawls well its just the speed its lacking when i want it.
What pinion size did you run?

[Spunkybob]

Ok, I am ready to order a new motor now.
I know Sr.Irie mentioned the 550 motor but I am having trouble locating a 5mm 48P pinion gear in Australia (That doesn't cost ridiculous money)

How easy (hard) would it be to convert it to 32p?

IN saying that, would a 13ish turn brushless be good for low end but still give me speed when i feel like bashing?

[Lochrie2]

I run the Tekin Redline 13.5 with 26t pinion and a 76 spur for me its a great combo for crawler and basher

[Sr.Irie]

Originally Posted by Spunkybob

How easy (hard) would it be to convert it to 32p?

There used to be a part number for a 32p spur that was a direct fit but I am pretty sure they stopped making it. I am sure it would not be hard to modify one to fit, but personally I would not run 32p though.
Why wouldn't you order it at the same time as the motor from HK they have them cheap.

[Spunkybob]

Originally Posted by Sr.Irie

Why wouldn't you order it at the same time as the motor from HK they have them cheap.

The don't seem to have stock of ANY 48P 5mm pinion in the Australian store :(
ps, I'm thinking the 5.5T 550 because its on sale now for $32

When you say its "too fast" do you limit it at all or just not full throttle, how does the drive train go with it?
Are you running the stock size 28T pinion?

[Sr.Irie]

Originally Posted by Spunkybob

The don't seem to have stock of ANY 48P 5mm pinion in the Australian store :(
ps, I'm thinking the 5.5T 550 because its on sale now for $32

When you say its "too fast" do you limit it at all or just not full throttle, how does the drive train go with it?
Are you running the stock size 28T pinion?

That sucks, I guess I should check before typing, I agree they are to much everywhere else.

I run a 26T, 28T and a 32T, along with quite a few different spur gears depending what I will be doing. No I do not limit it and use it all. But if you would like to limit it you can just turn down the throw of the throttle on the radio after setting the speed control to limit it, if speed control is not programmable. What I mean to fast is you really must be driving it when its taped out. When you start getting I would say 22MPH(mine did 18MPH stock) and above the suspension needs to be right and when it is right, it is still a hand full. It is like driving a real U4 truck taped, steering input is critical. With any of my gear ratios my TH will do a standing back flip on asphalt or high traction stuff, to give an idea of the power. The drive train holds up very well when driven properly or with thought. I am sure if it was all bound up and I just gave it the beans without thought, I could break something.

The 5.5 would still be plenty for the truck.

I have competitively raced off-road buggy, off-road truck, pan car road course, carpet oval and dirt oval. I would say I have to pay attention and drive my TH more than all of them. That is the way I like it, it is a challenge.

[lonleycreeper]

Irie has it right, I raced AE buggys and truggys in the mid 90'sand suspension setup and throttle control are key to these little U4 buggy.

I just sold my 2wd slash that did 45 ish mph, replaced with my little twin hammers, that does 25ish mph same power plant just geared a lot lower. I have way more fun with the twin hammers.

My setup...
A arms level, 0° toe, 2° front camber and the rear a bit higher than the front, soft bar rear and none up front, stock shock oil, works good for me.

As far as the screws the trans screws were the worst. I recommend a good set of drivers before continuing your build.

[Spunkybob]

Thanks guys, looks like I'm going to have a little bastard on my hands :P
I can only run 2s on my ESC so i guess that will limit it anyway.

As long as I can still rock crawl I'm happy also.

I always though the lower turns the less torque, so I'm guessing with the 550 it doesn't matter and ill have all the torque I need without the motor getting hot.

[JohnRobHolmes]

Brushless does not lose torque with lower turns. Kv does not change the stall values or efficiency curve. For any given voltage the low turn motor will actually produce more torque.

Be sure to get sway bars. That motor is incredibly overkill.

[Spunkybob]

Originally Posted by JohnRobHolmes

Brushless does not lose torque with lower turns.
Be sure to get sway bars. That motor is incredibly overkill.

I had no idea that brushless did not lose with lower turns... ok, so maybe ill stick to the 540 10-13t then. shoud I look at the turn or the KV? seems that motors of the same turn have different KV values.

I want it be still be controllable on sand etc.

Would lower turns affect the heat while climbing though?

[JohnRobHolmes]

Faster motors need more geardown to control the wattage. Kv is typically more useful, if given. For example, my trailmaster two pole motor is 8.5 turns for 3100kv. A race style motor would be 13.5 turns around that speed.

[Sr.Irie]

Originally Posted by JohnRobHolmes

That motor is incredibly overkill.

Yes Sir it is

[Spunkybob]

So this motor would be good then.

Specs:
Can Size: 540
Turns: 10.5
RPM/v: 3730kv
Sensored: Yes (Standard 6 pin harness)
Max voltage: 7.4 (2S)
Max Current: 45A
Max Watts: 320w

[JohnRobHolmes]

13.5 will be more crawl oriented with wheelspeed.

[Spunkybob]

Originally Posted by JohnRobHolmes

13.5 will be more crawl oriented with wheelspeed.

Ok thank you. I had a look at your site and if you were in Australia
would a 13.5 be faster then my 21.5 with 35% timing on the ESC?