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View Full Version : Two Monster Truck motors in a ZZ, you gotta see this!


'Vette Nerd
06-19-2006, 06:42 PM
I have finally figured out how to put two MT motors in a ZZ, and it works.:D I still have a little bit more work to do before I can get it work properly, and it's a serious hack job, but hey, it's works. I still don't know if I need to dual cell it for any real speed. I Also need to do a better job on the wiring and really need to make a gaurd for the back of the third yellow gear to reduce the wobbling. If anybody has any tips or suggestions on how to make this monster better, that would be appreciated, maybe some of you pros already did this mod. I got some good pics for ya to see, you'll notice I accidentally had the blue and yellow wires wired in reverse at the time.
Man this puppy was tight and tedious work!

buffalo beans
06-19-2006, 07:23 PM
Oh my hanna that is so freakin awsome. Must have taken alot of time. Yeah a dual cell would make it run better or else try to do a tri cell that would be cool.

Snake Mod
06-19-2006, 07:53 PM
I have already done a SS mod but I think this would have killer torque. If you have 2 SS motors, it would lower the center of gravity alot you might wanna quit/redo this job, becuase i bet if you were to fall backwards, wellll...you know the rest.

Edit:Man that yellow gear looks pretty cool

Jazz32
06-19-2006, 08:05 PM
Ok, this makes me really confused. You are using two yellow motors at 18000 rpm. You are using the orange gear to drop the rpms around 6000rpm. On top of that, you're gearing it down again to the bottom motor around 2000rpm. That motor is going to fight the first one because it wants to go 18k.

And all of this is going to a regular zz gear set up. This is not going to increase speed at all, it will hinder it greatly.

Also, since the motors are going to fight each other, your battery life is not going to be very good at all.

To hook up 2 motors, they need to be on the same gear ratio as the drive axle and have as closely matched rpm ratings as possible.

If you're looking for torque, mount the orange gear on the regular transfer gear and hook up both motors with the same pinion to that one. If you're looking for speed, put a blue gear on both motors and mount them both on transfer gear directly (not via the smaller gear in the middle).

I have a zz that direct drives the axle gear and there is way more than enough power to do that. Lower gearing really isn't necessary for a car.

I'm sorry, but I don't think this is going to work.

'Vette Nerd
06-19-2006, 08:40 PM
Response:
1.Yeah, this sucker took a week to do, I'm still surprised it could actually be wired up.
2. The three 'layers' of super glue gel and two layers of super glue I used on both the motors and extra transfer gear rod is to ensure they don't come off.(You would have use a hammer to break them off or pick the glue off with a knife.) But your right Snake mod, all that weight in the back wouldn't let it climb steep angles without falling backwards.:eek: the yellow gear was from my Zcar since I ran out of blue gears.
3. I didn't quite think about that jazz, I barely understand gear ratios and all that other stuff. But I guess I forgot to mention that I wired up the second motor in reverse so that it can add its motion to the first one, so the motors don't fight each other, at least that, but even then it still won't have speed, as you said. But I never thought of doing what you just mentioned, that's cool, I'm definitly gonna' do that since I'm lookin' for speed. Should have some pics soon. Thanks for saving me the time and trouble of trying to making this hack job work.

frizzen
06-23-2006, 11:49 PM
Vette, Jazz was saying that your blue gears have 6 teeth, the yellow gear has 7. IT NO WORK!

You are using 2 motors of the SAME speed rating, yet you have one motor connected to the other using DIFFERENT gear ratios, the motors WILL fight each other and any possible gains will be cancelled or made worse than if it were just a single motor. Your orange idler is an 18 to 7, just like the ZZ green.

For reference:
- Blue idler is an 18 teeth to 6 teeth (3:1 ratio).
- Green idler is an 18 teeth to 7 teeth (2.57:1 ratio)

So, 3:1 does NOT equal 2.57:1. Therefore, your motors WILL be fighting eachother, just like Jazz said.

-- EDIT

I just realized you're doing some really, um... interesting, gearing. Uh, wow. :eek: You really don't get gear ratios do you?

Ok, let's start at the pinion of the top motor: 7 teeth
that meshes with an 18 tooth. (2.57:1 reduction)

...is mounted to a 7 tooth that meshes with an 18 tooth. (2.57:1 reduction)

...which is a motor pinion (despite the other MATCHED motor already having a 6.60:1 reduction)

Which has the 18t gear meshed with an 18t gear (1:1 ratio)

which goes into the stock blue drivetrain. 6t to 24t (4:1)

Which is really just a huge mess!

Your Top motor sees: 67.848:1
Your Bottom motor sees: 26.4:1

No, they aren't fighting eachother at all! :rolleyes:

'Vette Nerd
06-24-2006, 08:00 PM
Thanks for the info Friz, I haven't been noticing until just recently how much gear ratios have an effect on performance, interesting stuff. I've actually ran this zz last week before I picked the MT motors off, it worked, but it was dirt slow(like using the green zz motor and blue gears in a 1st gen, but slower:eek:!) I would've had to do more work and dual celled it before I'd get any real speed, and I wasn't about to waste time doin' that if there are better and more efficient setups, like what Jazz mentioned. Your info is really helpful Friz, thanks.:D
EDIT:Although Jazz, I have a question, I know how to mount the first motor onto the drive shaft, but how am I going to mount the second motor to it without removing the rod holding the first transfer gear or is this just nessesary for making room for the second motor?