Need advice for LRP Vector 8 motor application

[simplechamp]

And don't say get a different motor!

The only reason I have the LRP Vector 8 is because I got it for a hot deal, and I want to try sensored in my 1/8 on-road Jammin. I have heard they aren't really that suited for 1/8 but I figured in a mildly geared on-road app it might work out. The Jammin on-road will be very light too with lots of carbon including chassis.

The motor I have is the 2800kv. So here are my options:

1) 4S lipo, 46/13, approx. 41K RPM, 40mph, 11.7 total gear reduction, 1:1 rollout

2) 3S lipo, 46/17, approx. 31K RPM, 40mph, 8.9 total gear reduction, 1.35:1 rollout

My question is, which setup makes more sense? I have always been under the impression that 2-pole motors need to "wind up" to higher RPMs, and benefit from the higher gear reduction. The RPM seems high to me, but I would worry that the current load would be too high geared for 40mph on 3S with the lower gear reduction.

As I said before, I know this isn't the best motor for the job, and if it cooks, I am not really too worried about it. I just want to give it the best chance of success, maybe it can work out alright?

Any input is appreciated. Thanks for looking.

[snellemin]

I would only use 3s on that sucker, with the Fan! I run mine currently on 2s only without the fan with 30 degrees timing cheat mode with the MMpro.

I would use the timing inserts and use the one with the lowest timing. Then on 3s use a smaller pinion to compensate for the goofy small rotor, but make up the speed with the use of cheat mode, boost or Turbo....anything that increases timing at a certain rpm range.

[simplechamp]

So what part about the 4S makes it less desirable, the RPM is just too high? I thought the 4S would draw less current than 3S geared for the same speed?

I guess it's time to put my EagleTree to good use. I'll take current and temp readings for each setup and see how it goes.

[snellemin]

The 4s will be more efficient on paper, but that is extra weight in batteries over a 3cell. Save some weight and go faster with the use of cheat mode for example. You will be surprised as how fast that motor will go with an increase in timing.
For my sensorless slotless 2 pole motors I use 0-8 degrees of timing. For the goofy roar slotted motors I use 30 degrees to see some fun action.

Personally I'm thinking going with the 550 Ballistic with the 14mm rotor option for my next GTP.

[simplechamp]

OK I think maybe I'll try the Gens Ace 3S 5000mah 40C hardcase packs. And I'll also try with the 2x2S packs I have already just to compare the 3S vs. 4S on the EagleTree

[el tomaso]

Use that motor in a SC-truck or other 1/10's that need a little extra power. The KV is just perfect for 3s, I can't understand why anyone would run that motor on 4s.

TG

that is a 2 pole motor, so you need to max out the timing on the esc for it to run more efficiently, i used 5 degrees on the motor and max on the rx8(whatever that is) i was suprised it was slow and ran nuclear with the timing low and regular gearing, i boosted the timing and geared down and it ripped! and ran post nuclear lol

[simplechamp]

Originally Posted by el tomaso

Use that motor in a SC-truck or other 1/10's that need a little extra power. The KV is just perfect for 3s, I can't understand why anyone would run that motor on 4s.

TG

I don't have a short course or other 1/10 that needs extra power though. As I said in the original post I know it's not the optimal motor choice, it's more of an experiment.

Originally Posted by big greg

that is a 2 pole motor, so you need to max out the timing on the esc for it to run more efficiently, i used 5 degrees on the motor and max on the rx8(whatever that is) i was suprised it was slow and ran nuclear with the timing low and regular gearing, i boosted the timing and geared down and it ripped! and ran post nuclear lol

What was the setup you had the Vector 8 motor in?

I was thinking like you said, gear it with a higher reduction and rely on higher RPM (from voltage and/or timing boost). That's what I thought was best for 2-pole in 1/8 setups.

i had the 2500 kv in a Ve8 i think with a 16t pinion

[simplechamp]

On 4S or 3S?

4s probably would have been sweet on 3s