problem with Blitzer, xr10, SP17.5 and 2s lipo. Help!

[lordbigsack]

Hi, i was wanting to make my blitzer perform a little better than stock.  I've installed a HobbyWing xr10 ESC, Speed Passion 17.5T sensored brushless motor and a 2s lipo battery.  It all seems to work except the performance doesnt seem much better than stock motor, tble2 and nimh.

The motor seems to increase RPM up to about 2/3 throttle but doesnt improve from there.  It's like the last third of the throttle doesnt do anything.  It seems to 'hiccup' and then just carry on at the same rpm for the final third. 

I've tried calibrating the ESC but it hasnt made a difference.  I'm new to brushless, sensored and lipo - any help/thoughts appreciated.  I Don't want to go back to my LHS and find out its something obvious i should have known all along

 

 

[Juggular]

Unfortunately 17.5t isn't supposed to be much better.  13.5t would be better.  Even though XR10 is a 60A ESC, it has a fan. I'm cautiously hopeful that it could handle 10.5t?  

 

[lordbigsack]

just seems weird that RPM doesnt increase over two thirds throttle.   Even the stock motor spins up on the final third of throttle, wondering if the motor ,and or, the ESC has a fault

[Howards]

Try it with the tble02 - it will be fine with it just make sure the lipo doesn’t dump.

[Aerobert]

Did you set the throttle end points for the new ESC?

[catman79]

Is the esc set to run in sensored mode and not sensorless?

[lordbigsack]

18 minutes ago, Aerobert said:

Did you set the throttle end points for the new ESC?

yeah the calibration on the ESC / transmitter did that.

2 minutes ago, catman79 said:

Is the esc set to run in sensored mode and not sensorless?

Docs say it will run with whatever is present.  I'll have another read and see if there is anything else to dowith it

36 minutes ago, Juggular said:

Unfortunately 17.5t isn't supposed to be much better.  13.5t would be better.  Even though XR10 is a 60A ESC, it has a fan. I'm cautiously hopeful that it could handle 10.5t?  

 

Maybe i was just being too optimistic on a 17.5,  perhaps a 13.5 would have been a better bet.

 

I'm at the point where i need to extend the power cables and didnt want to get on with it if i was going to have a returns situation with the LHS.  Although i've soldered the posts to the power and the motor mounts so it might be too late anyways...

 

 

 

[howaboutme]

Blitzer is 2wd, right? 17.5t is standard for 2wd brushless setup. I have the same ESC w/ 17.5T (mine is HW) on my RC10 and it flies. My first thought is end points but if you've done it correct then something else is wrong. How do you connect your ESC to motor? Are you direct solder? If so, do you have a bad joint? Gearing is wrong? I'd test each of the electronics on another car if you can. Is the lipo old? Puffy? Do you know it's IR? So many factors.

[catman79]

I’d just take the whole thing to your lhs, they are the experts and will be able to give it a look over and see if anything is wrong. 

[Jonathon Gillham]

3 hours ago, lordbigsack said:

Hi, i was wanting to make my blitzer perform a little better than stock.  I've installed a HobbyWing xr10 ESC, Speed Passion 17.5T sensored brushless motor and a 2s lipo battery.  It all seems to work except the performance doesnt seem much better than stock motor, tble2 and nimh.

The motor seems to increase RPM up to about 2/3 throttle but doesnt improve from there.  It's like the last third of the throttle doesnt do anything.  It seems to 'hiccup' and then just carry on at the same rpm for the final third. 

I've tried calibrating the ESC but it hasnt made a difference.  I'm new to brushless, sensored and lipo - any help/thoughts appreciated.  I Don't want to go back to my LHS and find out its something obvious i should have known all along

 

 

What gearing are you running.  In a 2wd buggy you could run an FDR around 5 - 5.5 with a 17.5T motor (but check the temp of the motor).  I suspect the Blitzer can't be geared low enough to make use of the 17.5T motor.  A properly geared 17.5T is fast, and on the right surface (ie, low grip) will be as quick as a mod buggy running a boosted 8.5T motor.

To me it sounds like the motor is spooling to max rpm at 2/3 throttle, its just not working hard enough.  Needs a bigger pinion and/or smaller spur.

You could increase the timing on the motor endbell, just crank it all the way to max and check it after a minute or 2 running.  If its hot, wind the timing back, but with it being so undergeared you will probably be able to run it close to max, if not max.  Those Speed Passion motors don't have crazy advanced timing anyway like modern motors do.

The limited gearing on most Tamiya buggies mean a 8.5T - 13.5T are the sweet spot, but then they are much faster than the buggy was designed for.  Some like the Top Force can handle the power, but something like a Boomerang is really at its limits on a 13.5T.

[lordbigsack]

On 6/8/2020 at 12:39 AM, Jonathon Gillham said:

What gearing are you running.  In a 2wd buggy you could run an FDR around 5 - 5.5 with a 17.5T motor (but check the temp of the motor).  I suspect the Blitzer can't be geared low enough to make use of the 17.5T motor.  A properly geared 17.5T is fast, and on the right surface (ie, low grip) will be as quick as a mod buggy running a boosted 8.5T motor.

To me it sounds like the motor is spooling to max rpm at 2/3 throttle, its just not working hard enough.  Needs a bigger pinion and/or smaller spur.

You could increase the timing on the motor endbell, just crank it all the way to max and check it after a minute or 2 running.  If its hot, wind the timing back, but with it being so undergeared you will probably be able to run it close to max, if not max.  Those Speed Passion motors don't have crazy advanced timing anyway like modern motors do.

The limited gearing on most Tamiya buggies mean a 8.5T - 13.5T are the sweet spot, but then they are much faster than the buggy was designed for.  Some like the Top Force can handle the power, but something like a Boomerang is really at its limits on a 13.5T.

Thanks for responses, i'm running the standard gearing on the blitzer, it can take a 2 tooth larger pinion which if i've understood right would make a difference to the top speed.  Motor is never hot!  I bought what i thought was the right 15 tooth pinion but when it came the gap between the teeth was way too narrow.  I think this is the right one -  https://www.modelsport.co.uk/tamiya-rm-15t-pinion-gear-58256/rc-car-products/391028 

 

I must confess though it is quite a bit faster than the stock can already.  To my embarrassment when i originally tested it was on wet grass - at dusk.  Once it dried up the performance improved dramatically, pulling monster wheelies (something else to content with) on part throttle.  

 

 

[Biz73]

Which XR10 is it? Pro, Stock Spec, or Juststock? Do you have the program card? There are a lot of settings that you can experiment with to get it running how you want. You can turn down the punch setting to help with the wheelies.