A new toy for me!

[sikeston34m]

Hey Linc,

I'm Brain Storming again. LOL

Correct me if I'm wrong, but since the new E maxx has a Revo Style Slipper, won't the Revo Mod 1 Spur fit this?

Let's go with the 40 tooth Mod 1 Revo Spur. I notice Mike has those in stock. While we're ordering, let's get us a 25 tooth Mod 1 Pinion gear and maybe a 20 tooth Mod 1 as well.

Then let's turn to AXI for a 2826/10 Outrunner motor. The motor shaft length is exactly 20mm! Perfect for this. Let's get a motor cooling fan too.

I know this is a bigger heavier truck than the Redcat but now we've got gears AND a good slipper.

Here's some gear figures that I put together.

Stock E maxx

68 tooth spur 19 tooth motor pinion 3.58:1 gear ratio

If the motor spins 20,000rpm, the tranny input shaft is spinning 5587rpm

Revo

AXI 2826/10 GOLD LINE 920kv 3-5 Lipoly current capacity=42amps/60s

40 tooth Mod 1 spur 25 tooth pinion 1.6:1 gear ratio

4S Lipo = 14 volts under a load 12,600rpm @ 900kv

7875 input shaft rpm with a 25 tooth pinion.

6300 input shaft rpm with a 20 tooth pinion

I'm really tempted to try this setup.

I wonder what the gear ratio is inside the tranny from input shaft to output shaft?

I'm thinking gearing it high like this will be best because the outrunner will make so much more torque than both the Titans. Then add the 2 speed kit to the equation. We've got Gears!

What do you think Linc?

[lincpimp]

Originally Posted by sikeston34m

Hey Linc,

I'm Brain Storming again. LOL

Correct me if I'm wrong, but since the new E maxx has a Revo Style Slipper, won't the Revo Mod 1 Spur fit this?

I wonder what the gear ratio is inside the tranny from input shaft to output shaft?

I'm thinking gearing it high like this will be best because the outrunner will make so much more torque than both the Titans. Then add the 2 speed kit to the equation. We've got Gears!

What do you think Linc?

Revo spurs will fit, not sure if the tranny has enough clearance for the out runner with the 20t pinion, so i stuck with the 25 for my number crunching.

Ok, intelligent guess says that the internal ratio is 33/18, or 1.83:1. All guesses referenced from the new emaxx parts list on the traxxas website, hope it is correct.

This appears to be slightly lower than the old emaxx second gear. That coupled with the use of 14 cells would account for the higher speed while still using the same diff ratio, tire height and motor kv.

Traxxas is smart, they reused the idler gear, still 20t but steel now. Good cheap way to up grade an old emaxx tranny!

Motor kv on the titans must be arround 2200, yeilding 35mph on 14 cells. This sounds too high, as most belive the motors to run around 20k rpm on 14.4, which would be 1400kv or so. Heres the speed calc for the stock setup, my best guess on motor kv:

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.83
Other Ratio: 1
Spur Tooth Count: 68
Pinion Tooth Count: 19
Total Voltage: 16.8
Motor KV: 2200
Tire Diameter (inches): 5.75
Spur/Pinion Ratio: 3.58 : 1
Total Ratio: 18.64081 : 1
Tire Circumference (inches): 18.06 inches (458.83mm)
Total Motor Speed: 36960 RPM
Vehicle Speed: 33.92 MPH (54.48km/h)

Now here is your proposed setup with the 25t pinion:

Differential Ratio: 2.8461538461538462
Transmission Ratio: 1.83
Other Ratio: 1
Spur Tooth Count: 40
Pinion Tooth Count: 25
Total Voltage: 14.8
Motor KV: 900
Tire Diameter (inches): 5.75
Spur/Pinion Ratio: 1.6 : 1
Total Ratio: 8.33354 : 1
Tire Circumference (inches): 18.06 inches (458.83mm)
Total Motor Speed: 13320 RPM
Vehicle Speed: 27.34 MPH (43.92km/h)

Looks to be a bit slow on 4s with that combo, but most likely not too far from stock. Would be better on 6s, at least for me.

Give it a try Sike, and let me know what you think. My math may be wrong, but I checked it a few times?!

[sikeston34m]

If the Mesh will line up right, we could use a 36 tooth spur instead.

The would give a 1.44 ratio instead of a 1.6

This outrunner will make about 900 watts, so I'm thinking the acceleration should be there.

Another option would be to go with the 2826/8 motor. It's a higher kv at 1130kv.

The mod 1 gears are alot tougher than the 32 pitch gears aren't they?

[sikeston34m]

Put those two setups on equal voltages please.

[lincpimp]

Originally Posted by sikeston34m

If the Mesh will line up right, we could use a 36 tooth spur instead.

The would give a 1.44 ratio instead of a 1.6

This outrunner will make about 900 watts, so I'm thinking the acceleration should be there.

Another option would be to go with the 2826/8 motor. It's a higher kv at 1130kv.

The mod 1 gears are alot tougher than the 32 pitch gears aren't they?

Mod1 is quite a bit stronger, the 36 tooth would help. I only had the voltage set on 14 cells to try and figure out the titans kv. Traxxas claims 35 mph so I figured I would run the numbers. $s will actually hold its voltage arounf the 14.8 mark unless the lipos are crappy! Are you set on 4s or could you go higher, 6s would be killer and allow you to gear down some, which seems to help regardless of the motor type.

Not sure if you noticed, but the chassis braces are set wider on the new emaxx than the old one. Maybe a direct to diff setup would fit? An idea?!

[sikeston34m]

Originally Posted by lincpimp

Mod1 is quite a bit stronger, the 36 tooth would help. I only had the voltage set on 14 cells to try and figure out the titans kv. Traxxas claims 35 mph so I figured I would run the numbers. $s will actually hold its voltage arounf the 14.8 mark unless the lipos are crappy! Are you set on 4s or could you go higher, 6s would be killer and allow you to gear down some, which seems to help regardless of the motor type.

Not sure if you noticed, but the chassis braces are set wider on the new emaxx than the old one. Maybe a direct to diff setup would fit? An idea?!

I plan on using the Quark, so 6S is an option. Motor temps are going to determine if 5S or 6S will be the "settling" point.

Here's the 2826/8 wind on 4S with a 36 tooth spur
Differential Ratio: 2.84
Transmission Ratio: 1.83
Other Ratio: 1
Spur Tooth Count: 36
Pinion Tooth Count: 25
Total Voltage: 14.8
Motor KV: 1130
Tire Diameter (inches): 5.75
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 1.44 : 1
Total Ratio: 7.48397 : 1
Tire Circumference (inches): 18.06 inches (458.83mm)
Total Motor Speed: 16724 RPM
Vehicle Speed: 38.23 MPH (61.4km/h)
Effective Speed Rate: 2.58mph/V (4.15kmh/V)
Effective KV Value: 1130

Here's the 2826/10 on 6S with the 40 tooth spur
Differential Ratio: 2.84
Transmission Ratio: 1.83
Other Ratio: 1
Spur Tooth Count: 40
Pinion Tooth Count: 25
Total Voltage: 22.2
Motor KV: 920
Tire Diameter (inches): 5.75
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 1.6 : 1
Total Ratio: 8.31552 : 1
Tire Circumference (inches): 18.06 inches (458.83mm)
Total Motor Speed: 20424 RPM
Vehicle Speed: 42.02 MPH (67.49km/h)
Effective Speed Rate: 1.89mph/V (3.04kmh/V)
Effective KV Value: 920

I think it would kick Arse!

[lincpimp]

Sounds like a good setup, either way. My Emaxx will stay stock until I can finish the other conversions I have sitting around. Going to convert a Losi aftershock and use an 1100kv kb45 inrunner on 9s lipo thru a hv85 esc. Stock tranny and 2 speed so it should be plenty fast!

[aqwut]

Originally Posted by lincpimp

Sounds like a good setup, either way. My Emaxx will stay stock until I can finish the other conversions I have sitting around. Going to convert a Losi aftershock and use an 1100kv kb45 inrunner on 9s lipo thru a hv85 esc. Stock tranny and 2 speed so it should be plenty fast!

YES.. it's plenty fast.. I'm running the 1000KV on 12S 3700mAh Lipos on my LST...... and it's super duper fast... but snow is melting fast.... I will get videos on a nice day...

8S1P 5000mAh 25C Lipo & 1800kV KB45 on MGT, and 8S1P 5000mAh 25C Lipo & 1000kv KB45 on GST 7.7...

Those KB45 are just great motors for the price... just gettin' the pinions sucks monkey butt... but thank God I got myself a lathe...