My e-revo brushless edition build - Page 10 - RC-Monster Forums

mistercrash · 02:00 PM

Thanks guys, I went racing this weekend but couldn't convince myself of running this body yet.

I am wondering after this weekend's race. After a 15 minute main, running Neu 3900 mah 4S in parallel, geared for 40 mph, My whole system was pretty hot. Motor 185, ESC 165 and batts 130. Ambient temperature was in the mid 80s, I have holes in the body for ventilation. The track has a new layout with two long straights that lets the MMM breathe almost to max rpm. Could it be that the CD, which always unloads to the front a bit more to prevent wheelies, puts too much strain on the system because it revs too high a lot of the time especially if the CD unloads too much in certain parts of the track? Because of the loss of traction due to the CD unloading, I think more throttle input is applied trying to get the same amount of acceleration as with a solid axle in the tranny. Does this make sense? I know my gearing is fine, I absolutely know that my drive train rolls very freely with no biding anywhere.
I seriously think that with the MMM's torque, a CD may not be beneficial and a solid axle with better throttle control might make me faster with lower temps and less strain on the MMM and batts.

What is everyone's take on this?

sjcrss · 07.06.2009, 05:17 PM

MC, im not sure what to tell you about the CD, im running the 50k, and my front end stays down pretty well, as long as i don't get heavy on the throttle...what is the gear ratio for the LST2 diff that you made into a CD?.....that could effect the overall ratio possibly...just a thought is all...

mistercrash · 07.07.2009, 11:25 AM

Next time at the track, I'll try a couple things. First, I will gear down to 35 or 36 mph instead of 40 and see what happens. I want to try thickening the CD a bit, maybe mix 50k and 100k to get around 70 or 75k. Finally I will try a solid axle to see how the truck handles.

mopar1994 · 07.07.2009, 12:27 PM

hey mistercrash, what weight diff oil are you using in your lst2 diffs and what gearing are you using?

mistercrash · 07.07.2009, 11:06 PM

Right now I'm running 10k front and 5k rear. I use 54 spur and 22 pinion. I will try 56/20 next time.

shaunjohnson · 07.08.2009, 08:14 AM

well mrcrash..
following in your footsteps ive begun the mods to my revo (2.5, 3905 convert)
yesterday the imperial screws i needed finally arrived and i put in the threaded inserts to the bulkheads

bet it's loads stronger now.

and so far for the record ive had about 2.5 hours racetime on the summit driveshafts and they are showing minimal ware

just a note on the summit shafts tho...there are 2 grub screw threaded holes in the CV's..yet the summit shafts only come with enough parts to put the grub screw in one side only, so if when you do the driveshaft conversion (seems like a good idea to me) try and get some extra grub screws, i have a hunch that they are the same grub screws that come in 32p pinion gears (5mm shaft ones)

gotta save up for the diffs now to copy you some more

ive only got stocker E-revo diffs (CD too w/ ofna 500k) and i bet they suck compared to the LST diffs.

has anyone tryed the Torsion diffs from ofna or the Losi smart diff in their revo?

shaun

brushlessboy16 · 07.08.2009, 11:23 AM

MC your the man, been using your revo as inspiration for mine.. started life as a 2.5r, getting the 3.3 chasis and body, e-revo trans and lst diffs.... not much of the original truck will be left

also thanks to all the other who inspired my inspiration, linc, sjrss(sp), etc.

BL_RV0 · 07.08.2009, 02:28 PM

Quote:

Originally Posted by brushlessboy16

also thanks to all the other who inspired my inspiration, linc, sjrss(sp), etc.

How do you inspire an inspiration?

sjcrss · 07.08.2009, 04:13 PM

Thanks for the words of inspire of inspiration, as to B.boy's question about the smart diff, I've been kicking the idea around about putting on in my erevo, using the mod ring gear that i came up with, but i have been talking to the gassers, and they have told me that the springs fail sometimes, and honestly, there is a whole lot of stuff to remove , just to replace the springs in the CD, for now..I'm running 50k in the CD for now...but i will see about the other..I havn't fully committed to it yet....however, myself and MC have info for anyone who want to do the mod to the CD for the erevo....also a great big thumbs up to you MC, for keeping the thread alive, along with the variations of the original design....

shaunjohnson · 07:26 AM

Quote:

Originally Posted by brushlessboy16

MC your the man, been using your revo as inspiration for mine.. started life as a 2.5r, getting the 3.3 chasis and body

why get the 3.3 chassis?
in MY experience hte 2.5 chassis handels better...well on the race track at least, dunno why the 3.3 chassis is always considered to be supirior.
i reckon the best setup you can have on a nitro revo is a 2.5 chassis and mod it to take a rear break kit and CD!! OMG it goes soo much better than the 3.3 w/ CD and rear brake

so i used the same principle and use a 2.5 chassis and a CD.

guess it's every man to themself.

as for center diff..i run ofna 500k in the yuckey traxxas diff and my temps are ok
i'm geared for 45mph ish on 5s w/ the MMM 2200 combo and after the highest load bashing i can dish up the MMM fan only comes on for about 3 secs and motor never gets to 120.
even after a 30 min main race the whole system is cool (120 max motor).
so i dont think the un-loading CD is causing the issue.

mistercrash · 07.09.2009, 10:47 AM

Well I never thought this would happen but my 8th scale center diff failed. The diff cup broke. I think it is my fault because I turned down the cup a little bit for more clearance which I'm sure weakened it. So I replaced it with a new unmodified cup and I went to extremes and put 100k in the diff and will see how I like it.

This is what I did to the cup before. The stock cup on the right and the modified on the left. Not a good idea as the whole center part of the diff cup broke off.

rawfuls · 07.09.2009, 05:11 PM

Are there no alu cups?

sjcrss · 07.09.2009, 06:16 PM

I don't think a aluminum cup is needed, i think what is happening, is when MC, does a small modification, like trimming or something ( don't get upset on me), this tends to weaken the part, I have been running my same original 1st prototype 1/8 hyper CD, and havn't had a single issue at all, not even a small one, I inspected the whole thing this weekend when I switched out the 30k for 50k fluid, and saw no visual wear in the cup, gears, modded shafts or reng gear, the bearings all rolled freely as well.

rawfuls · 07.09.2009, 06:49 PM

That too...

mistercrash · 07.10.2009, 11:13 PM

I haven't had a chance to try the truck on the track but I'm liking how it handles on the street and grass with 100k in the CD. With some throttle control, accelerations are better than before with less unloading to the front. I'll keep on running it to see if I will stay with 100k. Up to now, it's good. I don't think I will ever try to go higher though.