Help with Reedy 9.5 sonic
 

Hey guys, I am wondering about my new motor I have. I feel like it should have more power kinda in reserves if needed type thing. I understand there are many things that affect this. My ESC is a lrp sxxv2 and my gears right now are 87/17. Ive been crunching some numbers and I wanna try 87/19 to give me a closer wheel to gear ratio of 1:1. My first race this weekend my esc was getting hot but motor was only warm. I turned my timing up yesterday to 45 all of the way and test ran it for 6min. Its still warm and at 115 degrees. The reason im concerned is say for instance there is a quad and you just double double them at my track. I get to the second double and not enough speed or power to double second one. I dont have experience with this motor but maybe it just runs smooth and i need to mess with gear ratios more. Any help is appreciated

We really need more info about your RC, and the size of the track where you use it to know if your gearing is correct. Jacking the timing way up can increase speed, but it will cost you alot of grunt you might need to get over a jump. A 9.5 motor is certainly more power than many 10th scale RCs need, but it may not be adequate for a heavier truck.

instead of giving us your spur and pinion why not just crunch out the numbers and give us an FDR. Looking at your motor temps, im assuming you are not hitting the sweet spot of the motor where it makes full power.

Hey guys, Sorry about lack of info. Its on a FT SC10. My FDR is 13.35. I know If i put a 20 pinion on it then my tire to gear ratio will be closer to 1:1. What do these FDR #'s mean? Is it the larger the FDR the more top speed you have?

I ran 87/21 with a 8.5 so with your 9.5 you might want to be in the 21-22...23 range for pinions, all depending on track size.

FDR..only matters if you're trying to compare gear ratios between vehicles that have different internal tranny ratios (Losi vs. AE)

SC10 guy talking ratios to an SC10 guy, there's no need to do the extra math.

I found someone posted: Higher FDR = more acceleration, less top end
Lower FDR = less acceleration, more top end.

ok thanks racer, I thought i should start at 20 and go up and see how it feels. I turned the timing up to 45. Should I turn that back down before I trial 20,24 pinions. Timing makes the motor get up to high rpm faster doesnt it?

Yes, Like others have said, boost will kill your low end so turn it way down or even off to start. Running a 9.5 unless its a big outdoor track should be plenty of motor.

I don't know of anyone who adds timing (on the motor or the esc) when running mod motors. Maybe on a huge track or maybe to take away some bottom end snap on a loose track but it's not really that common, as far as I know. Find the right gearing and you should have plenty of power.

esc's are most efficient at WOT, if you spend 90% of your lap at half throttle esc temps may increase from that as well..IIRC

+1 good advise. I see so many people have a way bigger motor and always run into heat issues because they are turned down so much...Just get a motor you can control, de-tuning a little per track is ok but dont try to de-tune a 8.5 to a 13.5 you will have problems with heat and it wont be very smooth either.

Sounds good, I guess what i am trying to do with this motor is get a little more acceleration out of it. Someone mentioned going up pinion gears in the 20-23 range. That is going to make my truck pass cars on the highway isnt it? Higher FDR# higher top speed. Im trying to find the delicate balance of power from this motor regardless of track size. If i cant have enough power to get over the second double then It should be because its geared to high.

45 is a lot of physical timing for a Reedy. I have found anything over about 38-39 just gets hotter without going any faster. Back it down to 35 or so and go up a few teeth on the pinion.

Get all that stupid 1:1 ratio crap out of your head. I have read the original article that whole idea came from at it's the biggest bunch of bull I have ever seen.

You can dramatically increase the speed of you brushless motor using less power.

First, you need to find the power band on the motor with zero timing and zero esc timing.
Using a chassis dyno (under a load 2X chassis weight) add gear until amp draw falls as Rpm stays relatively high.

Next, add esc timing until Watts or Power reach around 100 range or until
max Rpm at min amp draw is reached.
This is max efficiency on the motor.
If the amp draw is to low you can increase motor can timing slowly by one degree at a time to desired amp draw. Like a fine tune adjustment.

Also, Rpm points are very important, lower Rpm points increase spool up times and adds to increase amp draw.
I like to start in the middle, and try different ranges.

I use the same lipos/esc in a race as I do to dyno.
This will give you the amount of amps to draw by the amount of voltage drop on the battery. (Internal resistance)

You can use the track as a dyno with an on-board watt meter in the vehicle will do the same thing but will take alot longer to do.

and you think he not only understood all that but is actually going to do it not even knowing all about gearing and timing....

What off road mod. racer on the planet actually goes through all that besides you.:weird: