Upgrade to a Lehner... Which One? - RC-Monster Forums

jhautz · **Upgrade to a Lehner... Which One? -** 07.28.2006, 02:49 PM

OK I think Im ready to upgrade to a Lehner 19 series motor in my E-Revo. I want to find a setup that will be able to run my entire 8000mah 5s lipo packs in hard bashing conditions with out stoping to let the motor or ESC cool down. I'm lookin for advice on which size and wind to choose. I want to get the best setup I can at this point I'm tired of always walking the line with heat. Granted I don't want to replace everything. Just the motor. Cool and Stable is my goal. However, I would like to make sure I keep at least 40-45 mph as a top end. I bash w/ nitros frequently and still want to be able to keep up on the top end.

Here is my current setup. I would like to be able to just keep the setup I have and put in a new motor, spurs and pinions.

E-Revo G-Maxx chassis w/ Gmaxx Motor Mount
580C-9XL
Quark MonsterPro 125 w/ heatsink and fan
2 Speed Emaxx Tranny - Ultramaxxed
70/24 32P Gearing
RRP Slipper Kit (I have a Strobe in the package still, will be upgrading with this rebuild)
TrueRC 8000mah 3s + 2s Packs.
RRP- Rear Diff gears w/ Aulm. Cups and Case
MIP CVD Rear / Stock Sliders Front
Dual 5925MG steering Servos
M8 Radio w/Spektrum

I am planning on continuing to run the 5s packs for the most part, I would however like to be able to run a 6s setup ocasionally (just for showing off to the nitro guys).

My initial thoughts are to go for the 1950-7. I am a little concerned about the sheer size of the motor. Looks really big and really heavy. Would a 1940 can due just as well for me? I don't really want ot get into making support brackets for the back of the motor and such.

Just looking for some input to make sure I make the right choice. To me this is a lot of cash to drop on just a motor, so I want to make sure I make the right choice.

squeeforever · 07.28.2006, 04:06 PM

I would choose the 1950/8 if you plan on going with 6S sometimes. It should run cool and fast.

jhautz · 05:10 PM

Do the charts for Lehner show loaded or unloaded kv #'s?

Also what kind of gearing would I want to run w/ that using a 51t Spur?

neweuser · 05:49 PM

Loaded. on a revo, not quite sure, but maybe 18/51 should be a good start.

squeeforever · 07.28.2006, 05:51 PM

I would try 16 and 18 to begin with.

jhautz · 07.28.2006, 06:21 PM

My calculations say that the 1950/8 on 5s with 18/51 gearing is only a 37mph setup. I am planning on running 5s 95% if the time. I'm thinking that the 1950-7 sounds like a better perofmrnace setup. How much diferance in heat would there be between the 2?

WOuld a 1940/9 be worse. Its kind in between the other 2 as far as KV rateing.

MetalMan · 07.28.2006, 05:58 PM

I think Mike used the 1930 in an E-Maxx or Revo of his, so the 1940 should be enough.

squeeforever · 07.28.2006, 07:55 PM

The 1940 would run hotter. The 1950 is the way to go. Which wind is up to you.

MetalMan · 07.28.2006, 08:02 PM

Quote:

Originally Posted by squeeforever

The 1940 would run hotter. The 1950 is the way to go. Which wind is up to you.

But how much hotter? I would think the 1940 should be enough, is it not?

squeeforever · 07.28.2006, 08:19 PM

Not sure but the 1950 will handle the heavy truck for sure. Keep in mind that the G2R's aren't light by any means.

jhautz · 07.29.2006, 11:41 AM

What about a Hacker C50-9XL? Its a 1804kv motor about the same size as the Lehner 1950. Anyone have an idea how well that would run on 5s?

squeeforever · 07.29.2006, 01:28 PM

Not much better than a Feigao 9XL....There pretty much identical inside. It migh run cooler than the standard. About the same as the C version...

jhautz · 07.31.2006, 09:10 PM

So on 5s will I have a problem with heat with the 1950-7. Or am I better off playing it safe and going 1950-8. I just feel like the 8 will not get to 40 on 5s.

RC-Monster Mike · 08.03.2006, 10:39 AM

Quote:

Originally Posted by jhautz

So on 5s will I have a problem with heat with the 1950-7. Or am I better off playing it safe and going 1950-8. I just feel like the 8 will not get to 40 on 5s.

Either motor will easily reach 40-50 mph on 5s Lipo. Just a matter of gearing.

jhautz · 03:04 PM

So gearing up a 1950-8 will not cause excessive esc heat? The whole reason I want to upgrade is to avoid heat. I feel like Im constantly walking the line of to much heat in either the motor or esc.

On 5s (18.5v) the 1950-8 will only be spinning at around 30k rpm. The 1950-7 will be at about 35K rpm. Will I have a problem with the 1950-8 not hitting its sweetspot ''powerband'' at only 30K rpm?

Which of the 2 would be better for nice cool running and 40-45 mph but still have nice punch? Any sugested gearing for the 2 motors for 40-45 top end on 5s? I'm running a Gmaxx revo with an emaxx tranny and revo diffs and a Quark 125.

My calculations say that it would need to be arond 51/18-20 on the 1950-7, and 51/20-22 on the 1950-8 to reach 40-45mph on 5s. Does this sound reasonable?