Novak HV 4.5 system problems

[JThiessen]

I recently installed a brand new HV 4.5 system in my Revo. At the same time, I removed the diff's and filled them with 90W.
After putting it all back together, it runs great on the bench - balloons the crap out of the tires. However, when I set it down on the ground, it cogs and glitches like crazy - to the point that it wont run. I did manage to run a 30 foot loop with it, but it had the top speed of about half a stock emaxx.
I removed the front and rear drive shafts individually to see if one of them was binding, no luck. I then pulled the tranny (Emaxx with G-Maxx single speed conversion) to see if something was blown in there. Nada. (I took that opportunity to finally install the steel idler thats been in my tool box for a year).

I'm at my wits end, prior to taking it back to my local LHS (thankfully I bought from them, so returns shouldnt be an issue).

Any thoughts????

[BrianG]

What is your gearing set at?

[JThiessen]

Just off the top of my head, I think its about 70/20.............now that I'm typing this, I don't know for sure what spur I have on there. I have the Robison Racing Slipper System that I used with my Fiego 10L (which ran great on there till I fried everything). So it's likely either a 66 or a 72. But I'm almost certain its a 20T Spur. I'll look tonight when I get home.

I didnt even think that the gearing could have been off that far. I have quite a few different Emaxx pinions. Can they be used on an RR slipper set up?

Does switching the diff lube to 90W add much to the resistance of the truck?

[suicideneil]

Theres no way a sensored system should glitch like that, unless there is serious radio interference- what radio are you using? As for gearing:


Its the final drive ratio that is most important (since you are running an emaxx tranny but revo diffs). I would say chuck your numbers into BrianGs calculator and see what it says; just bear in mind your tire diameter if it is larger than stock, and the weight of the truck rtr (stock emaxx is 9lbs I think).

[JThiessen]

Originally Posted by suicideneil

Theres no way a sensored system should glitch like that, unless there is serious radio interference- what radio are you using?
........ just bear in mind your tire diameter if it is larger than stock, and the weight of the truck rtr (stock emaxx is 9lbs I think).

I've tried both my Spektrum System and the stocker Traxxas radio/recievers. Same exact result.
Tire dia is slightly smaller than stock - using pro-line's.
Weight should be right at or a little less than Emaxx.

I'm hoping its the gears.

[crazyjr]

I think you are waaaaaaaay too overgeared, I ran 12/72 on a 4400 with no problems

[JThiessen]

I just checked and its 20/66. My Emaxx, with the same set up, is 15/72 and it runs good - never gets even the slightest bit hot. I was actually planning on gearing that one up a little. I'll try a lower gear on it, and see if it helps. But it seems to me that even at 20/66 it shouldnt cog that bad.

[BrianG]

From what I've read, the HV systems are sensitive to gearing, so don't discount that just yet. You have nothing to lose by trying it...

[ClodMaxx]

sweet MOTHER you have that HV system geared way higher than it should be!

i had a 4400 system with a 6.5 rotor for over a year in my maxx, geared with a 70t spur and 13 tooth pinion, with dual 7 cell packs. temps were in the 120's for the motor and esc, and the batts were at around 100 degrees. if i went up to a 15t pinion with the 70t spur, everything shot up about 15-20 degrees.

you have an enormous gear ratio difference between your maxx and your revo. your maxx is set up for a hv system. your revo is geared to thermal. in no time.

[JThiessen]

Yes, it was geared way too high. But seeing as I havent ever run it, I havent thermaled it. Like I said before, when I first put it in, I had problems with the forward/reverse being backwards, and I didnt get the differential flipping done until a week ago.

I tried gearing it down, went to 15/66, and still nothing. I also tried lifting it off the ground, but still didnt get anything this time.
When I squeeze the trigger, sometimes there is a small lurch, but most of the time nothing (forward or reverse). If I keep the trigger squeezed, I can see the motor twitch a little, and hear it clicking. I watched the lights on the ESC once when i did this, and I got 6 flashes of the green and blue lights. I looked in the manual, and it doesn't say anything specific regarding that, except that it may have suffered a possible locked rotor, and refers me back to the ESC set up.

One other thing. When I first put the motor in, I may have run one of the mount screws in too far. I say may, because I dont remember for certain. I ended up stacking some washers under the head until I was able to trim them down.

[skellyo]

That's still way too high for the gearing. That's a 21.56:1 gear ratio with 2nd gear. Seeing as how Novak recommends no lower than 24.5:1, I'd say you still have a potential gearing issue.

[BP-Revo]

LOL that gearing might work if the motor had 2000KV, not 4800...

You need to drop to a 14T pinion at most...

my hvmaxx 4.5 died after one run of 18/72(iirc)
no thermal at all
just recharged and went out to run and it was lurching, or cogging

i am planning on sending it in to get replaced, as i feel its a very good system for racing, but i will stay out of long grass and never gear over 12/72


i just figured out my final drive ratios

1st version with revo trans close ratio and 15/40 was =18.9:1
2nd version g3r w/ emaxx trans in 2nd and 18/72 = 19.6

i am suprised it lasted the 15 or so runs it worked

which tells me that the center diff and lighter truck in version one helped me, it never thermalled and was about 1 pound or so lighter, but geared higher

when i get it back i will be geared 12/72
and i may also try to get the 6.5 motor for testing, and bashing

[Finnster]

FDR of 28:1..lol

For all the complaints of the Feigao motors, these seem even more tempermental.

I wouldn't run it again until you get the gearing way down. Be careful with the screws, the motor does spin freely? I'm worried its already fragged

[JThiessen]

Originally Posted by Finnster

FDR of 28:1..lol

For all the complaints of the Feigao motors, these seem even more tempermental.

I wouldn't run it again until you get the gearing way down. Be careful with the screws, the motor does spin freely? I'm worried its already fragged

Yes, the motor spins freely. I would've thought that the truck would have run, but just got hot with the higher gearing. But if it was the gearing, and it caused an issue with the 100 feet or so that its actually ran, then I agree with you on the tempermental part.
I thrashed the crap out of the one in my Emaxx in the sand over the weekend - and I bought it used from NL12 here a while back. It ran like a champ - brought the Maxx home broken!!!