Lehner 2240
 

Here is a short, low quality vid of my one E-maxx. The power system was a Lehner 2240 motor and Schulze 32.80 speed control with 24 worn out cells. The truck has a 1/8th buggy center differential.
This was the first run with the diff. I see that the truck needs new cells and much heavier oil in the center diff(40,000 now).
My Eagle tree system recorded watts over 2600!

Sorry for the poot quality of the vid.

http://www.rcpics.net/img/49861

Here is a picture of the center diff.

http://www.rcpics.net/img/49862

Thank you,
Promod

What kind of speed did your eagle tree record with that setup (if it records speed)? Definately cool. We are working on a center diff/slipper setup currently. What diff is that (kyosho mp5?)? The plastic gear is a nice feature to be easy on pinion gears.

Mike,
I don't have the Eagle tree set up to record MPH. It is the same motor and speed control that went 70 mph. But this truck with the center diff and G-maxx chassis is close to one pound lighter than the 70 mph truck.
It is an ofna diff but I'm not sure which one. The spur gear is the same one used on the strobe slippers.

Thank you,
Promod

So a 51 tooth spur? Cool. Do you or have you done any rough off roading with that setup (racing on a track, for instance)? I am curious how well the diff holds up without a slipper.

That's a great idea! What tooth pinion gear are you using? In addition, is that a 2240 12 turn? With a "center diff", if you held the rear tires, do the front spin x2 as fast? I'm no familiar with 1/8th scale. Thanks!

Oh, one more question - I notice you only use 4 shocks too - which shocks are those? I'm using the stock ones and even with 100 weight oil, the plastic bodies expand too much and don't dampen very well.

:eek: What does your truck weigh? I think I am going to have my gmaxx go on a diet.

Those are Ofna 9.5 shocks. cheapest way to get them;

directly from UE, 67 dollars /4 pieces.

I use 4 of them on my heavy weight savage.

FANTASTIC bytheway..

SUPERB centerdiff..!!!! Are you willing to share what particular parts you used?

Do you think a plettenberg bigmaxx is able to pull this with this lower gearing ratio?

What 2240 do you use? How does it drives on 16 or 18 cells? does it stay below the 100A on a cellcount like that? (perhaps i can use the 18.97 controller on it..?)

Mike,
Yes it is a 51T spur. I've never ran it on a track just in the yard. Wouldn't the center differential act as the slipper clutch?

lipomax,
I'm using a 15T pinion gear. Final drive ratio is 11.25:1. It would be the same as a stock E-maxx geared 30/69 in 2nd gear. The motor is a Lehner 2240/12. With the center diff the rear tires don't spin any faster. There is no gear reduction in the center diff. The center diff can be "tuned" with different weight oil. This is suppose to help the truck handle better for racing. But the reason I installed the center diff was to save weight and have a much higher gear ratio for future speed runs. The shocks are UE Supershocks.

rc4x4nut,
The truck RTR but no cells weighs less than 7 1/2 pounds. The center diff saved almost one half pound over the ultramaxx tranny I was using. The 2240 motor alone weighs 1 1/2 pounds.

Thank you,
Promod

Do you know how much current it draws on 16 or 18 cells?

Serum,
Here is the center diff used.

http://cgi.ebay.com/ws/eBayISAPI.dll...957238305&rd=1

Here is where I got the custom rear drive shaft.

http://www.rcalloys.com/

The rest was just fabrication. It really was not that hard.

Never tested a Plettenberg so I really can't say. I've got a 2240/10 running 18 cells in another E-maxx. It spikes to 107 amps but pulls 60 to 80 amps normal. So the 18.97 should work fine.

Thank you,
Promod

Thank you! here is one upcoming 2240/10 driver then!!!!!

How fast does it goes on 18 cells?

What gearing ratio are you using with this setup?

Perhaps i could also drop in a 9918 for this 2240/10 then

I really love that eagletree system..

The diff would act as a slipper, unless the front and rear wheels happened to land at the same time (which could happen a bit on a track). The reduction is also tricky with just a center diff (tall ratio requiring slow motors), and the mod1 pitch is not run of the mill. My design uses the top shaft of the e-maxx tranny (and therefore the stock slipper clutch/spur gear) with a center diff. The reduction is similar to the stock tranny (actually a little more reduction), but lighter and the tuning abilities of the center diff.

Lipo- - Yes, if you hold the front, the rears will spin faster, just like any diff. The only reduction is the pinion/spur as promod suggested, but the diff works like any other diff otherwise.

Fill up that sucker with 300K.. It still would not wheelie..

What gearing ratio is on your 18 cell maxx? How fast is it?

And does the mod 1 strobe gear fits on the gearbox 1 on 1?

This motor will run over 60 mph on 18 cells. I use 20/51 gearing for bashing.

Here is a vid of a different E-maxx. It is the 2240/10 on 18 cells. This truck is heavy weighing over 12 pounds RTR with cells.

http://www.rcpics.net/img/49947

Thank you,
Promod

You think it is able to pull the centerdiff mod to?

What gearing ratio are you having with this setup? is it with the 13/43 diffs or the stock diffs?

60mph.................... It simple is too much.. ;)

If the truck was light I think it could pull the center diff mod. I'm using UE diffs the ratio is 3.31.

Thank you,
Promod

Promod;

Why don't u use a UBEC from kool flight? it's a lightweigt truck, and you still are using an heavy 5pack..? And, one other thing, can you turn the 2240 by hand? do you feel the magnetic resistance? And how did you use the 2240? in normal or in bridged configuration (stern, as the Germans call it)

Mike, about that centerdiff holding up;

It is the same principle as the savage diffcups. I ordered one centerdiff, I will show you the pictures on how to make the diff bullit proof.. (i use it in my savage too, and it works like a charm..)

The standard gears that ofna uses aren't the best, so i probably replace them with good molded HPI gears. This diffcup uses also a metall output. (unlike the savage cups) It is a good diff. I will fill mine with 300K silicone..

I will shoot pics of the modificitations.

Serum,


The 6 volt receiver pack I use weighs a little more than 2 oz. Was going to try the Ubec but never got around to buying one. The 2240 turns over easy just like the Hacker. Both 2240s are in normal configuration.

Thank you,
Promod

Thank you!

The gears in the centerdiff are silver of colour right? Not gold/silver, but really silver?

I truely like the centerdiff in this simple form on the gorrilamaxx frame!

With the 20/51 what is the gearing ratio of the 2250/10?

I'm not sure what color they are. when it was apart to put the diff oil in I didn't really look.
The final gear ratio with the E-maxx tranny in 2nd gear with 20/51 would be 14.5:1 .

Thank you,
Promod

Okay, i ordered the diff, so i will see..

How far does the voltage drop on you 18 cell pack when geared for the 60mph? And what gearing are you using with the 60mph maxx?

And what batteries did you used?

With the E-maxx transmission and UE diffs the truck was geared 30/51 for speed runs. I haven't made any speed runs with the Eagle tree system yet. But making "speed runs" in the yard was seeing voltage droping from 24 volts to 17 volts. The cells are cheap matched E-bay cells.

Thank you,
Promod

I thought you made the 60mph truck run on 18 cells instead of 20? or is it on that 24 volts on 18 cells?

Sorry for all the questions mate, just trying to figure out what motor to buy..

Thanks in advance..

That is 24 volts on 18 cells.

Thank you,
Promod

That's not a too bad voltage drop, geared that way and still pushing out .95volts! (that must be in the 80-90 amp range i guess..) not bad for not the best cells.. Where they the GP3300, the yellow and the green? (not the red/improved?) Factory matched?

They are the red cells and where matched by someone on e-bay. I guess they were setting in shed to long because they are only charging to right over 3000 mah. But still getting almost 15 minutes run time.

Thank you,
Promod

Promod, when making those speed runs in the yard, when the voltage dropped from 24 down to 17 - was that during the peak amp draw? What kind of peak amp draw are you seeing? Have you seen occasional peaks that are WAY too high? Generally, I see peaks at 1300 watts with 6s lipo, 1700 watts 8s lipo. But occasionally, it'll pick up spikes that are more than double the usual amp draws. Of course those peaks depend on motor and gearing, but what kind of peak amps are you pulling? Can you post the .cdr file?

Promod: Sorry to be asking soo many questions - I'm just wondering because I've never had the opportunity to test my eagletree system on NiMH - just LiPos.

Here is one on 24 cells. I hope this works.

Thank you,
Promod

Here is amps.

Here is watts. One note these 24 cells are very old.

Thank you,
Promod

Here's one with 8s in first gear using a Basic 2700 motor geared 18/66 stock tranny and diff.

Here's the watts

Here is the 2240/10 on 18 cells.

Here's the amp graph

2240/10 18 cells.

2240/10 18 cells watts.

Thank you,
Promod