Let's talk about performance!

[Zerobricks]

So to continue testing, I upgraded the light 4x4 with 2 more motors, stronger differentials and a reinforced driveline:

The front axle is still free to sway, though i did install some limiters to keep the suspension going too far up and knocking out the steering links:

No space for a bed in the back, due to the motors which are placed in a V shape, exactly as in my Acura NXT:

Another detail shared with Acura NXT is the gearbox, though this one has a higher gear ratio and fits perfectly with the motors inside a 11x15 frame:

 

And how does it perform? Compared to the light, this medium heavy model gained some 200 additional parts and around 250 grams, so it weighs around 1 kilogram.

So, the power went up by a factor of 2x, while the weight increased "only" 25 %, further proving that the more motors, the higher the power to weight ratio. Speaking about that, it increased from 400 grams/motor to some 250 grams/motor, which is nearing the Wildcat 6x6's 208 grams/motor.

Outside performance is quite good, it has no issues running in high gear (unlike the light version) and is capable of doing jumps with ease, though not quite at the same level (literally) as Wildcat 6x6.

Here's a comparison gif of both models on the same jump:

You can see the medium offroader managed to get the front wheels off the ground slightly, but not the rear ones. That might be due to a longer suspension travel compared to the Wildcat 6x6. Also another thing to remember is that Wildcat 6x6 is much longer, so it had more room to push itself up the hill.

I think I will do a video on this topic, where I can go more into the details of the models and what I've learned from actually building and comparing the various models.

Edited August 21, 2022 by Zerobricks

[Daniel-99]

Nice progress! Version 2 is way cooler then V1, and I appreciate the new transmission, though the bodywork can be slightly improved .

What is the weight distribution of Version 2?  

 

 

[Zerobricks]

17 minutes ago, Daniel-99 said:

Nice progress! Version 2 is way cooler then V1, and I appreciate the new transmission, though the bodywork can be slightly improved .

What is the weight distribution of Version 2?  

 

 

Thanks. It's slightly front heavy, that's why it has 6 shock absorbers in the front. The only drawback of the new transmission is that's all exposed. I'm thinking of adding some panels to protect the transmission, raising the suspension and making the rear axle also pendular. 

[Daniel-99]

54 minutes ago, Zerobricks said:

Thanks. It's slightly front heavy, that's why it has 6 shock absorbers in the front. The only drawback of the new transmission is that's all exposed. I'm thinking of adding some panels to protect the transmission, raising the suspension and making the rear axle also pendular. 

I see. The visible disadvantage of big gears is their size, though they are very neat gears in terms of transmission efficiency. Also it is worth noting, that raised suspension will cause more stress at the CV joints, especially an the front axle. Which hight you are trying to achieve with the ground clearance? My tests showed that the outdoor car needs at least 3 studs.

[Zerobricks]

6 minutes ago, Daniel-99 said:

I see. The visible disadvantage of big gears is their size, though they are very neat gears in terms of transmission efficiency. Also it is worth noting, that raised suspension will cause more stress at the CV joints, especially an the front axle. Which hight you are trying to achieve with the ground clearance? My tests showed that the outdoor car needs at least 3 studs.

Currently I have some 5,5 studs under the axles and 6,5 studs under the gearbox. I'm also thinking of raising the egarbox by a stud and using red differentials as a high gear.

[Daniel-99]

16 hours ago, Zerobricks said:

Currently I have some 5,5 studs under the axles and 6,5 studs under the gearbox. I'm also thinking of raising the egarbox by a stud and using red differentials as a high gear.

5,5 studs sounds very good! 

[Daniel-99]

I wanted to build a fast car with "normal" hubs and 4 x Buwizz motors. Here are the first results.

 

Currently it has 2 Buwizz motors on the front, but I will add two more motors to the rear at September.

Specs:

• Buwizz motors for propulsion
• 3S Lipo for power
• RC control system
• independent suspension
• custom wheel hubs with metal bearings and metal U-joints
• positive caster on all wheels
• 95 mm RC wheels
• minimalistic transmission

This is only the first draft of the chassis, the bodywork will be added later, and it will clearly increase the total weight. To deal with extra weight, I will install two more Buwizz motors. I will try not to exceed the limit of 1,7 kilos. Current chassis drive very smoothly. Thanks for the metal bearings and Buwizz motors which have a very low friction. It drives so smooth, that it requires the braking system! 

Such layout is very efficient, but does not allow to drive slow due to the specifications of motors. So such chassis wont be able to perform at trial or extremal off-road. It it applicable for fast driving at the rough terrain such as country roads. So the layout with 2 speed gearbox has it`s own benefits, though it can not be that efficient.

Here is a short driving test: 

 

 

Edited August 23, 2022 by Daniel-99

[FriedlS]

1 hour ago, Daniel-99 said:

I wanted to build a fast car with "normal" hubs and 4 x Buwizz motors. Here are the first results.

 

Currently it has 2 Buwizz motors on the front, but I will add two more motors to the rear at September.

Specs:

• Buwizz motors for propulsion
• 3S Lipo for power
• RC control system
• independent suspension
• custom wheel hubs with metal bearings and metal U-joints
• positive caster on all wheels
• 95 mm RC wheels
• minimalistic transmission

This is only the first draft of the chassis, the bodywork will be added later, and it will clearly increase the total weight. To deal with extra weight, I will install two more Buwizz motors. I will try not to exceed the limit of 1,7 kilos. Current chassis drive very smoothly. Thanks for the metal bearings and Buwizz motors which have a very low friction. It drives so smooth, that it requires the braking system! 

Such layout is very efficient, but does not allow to drive slow due to the specifications of motors. So such chassis wont be able to perform at trial or extremal off-road. It it applicable for fast driving at the rough terrain such as country roads. So the layout with 2 speed gearbox has it`s own benefits, though it can not be that efficient.

Here is a short driving test: 

 

 

Wow, nice work! But why don’t you use a rc motor (brushless)? 
 

e.g.:

 

[Daniel-99]

2 minutes ago, FriedlS said:

Wow, nice work! But why don’t you use a rc motor (brushless)? 

I saw your brilliant trophy truck! Yes, brushless motors are on the next step in the hierarchy of electric motors, they provide such a torque an speed which can not be achieved with Buggy motors ;-). Currently I don`t have a brushless motors set-up for Lego, but I will look forward to get one! 

[Aerolight]

My m motors with new internals running off buwizz 3 (2-one each) in my direct drive buggy would smoke these - looks to be twice as fast and powerslides on tarmac

The problem i had was sheering the axles and after some abuse one of the motors planetary gearboxes exploded but since i extended the axles to provide a cush drive effect this has not been a problem.

I have been wanting to film it for months but was scared of wearing out the motors before using them in the plane, but will probably just do it anyway bored of waiting.

The buggy has front and rear anti roll bars (when disconected it just flips) brick built frount hubs and progresive suspension; to make up for the lack of dampers when doing jumps.

[shroomzofdoom]

On 8/15/2022 at 5:22 PM, Zerobricks said:

 

And of course the planetary hubs have their own weaknesses:

• Lower ground celarance compared to planetary hubs
• Higher initial friction
• Harder to integrate into the model
• No user-replacable components - once it's worn out there's notinh to replace, you can only buy a new one

You forgot the part about the wheels falling off :-) 

The ability to feed a central axle through the drive gear on the portal hub and use that plus the 3 hub stubs to keep the wheel on is indispensable. This reason right here is why I stopped trying to incorporate them into models. Of course, I do wind up twisting quite a few 8L stop axles but I buy them 100 at a time now.

Edited October 7, 2022 by shroomzofdoom

[bg3305]

Hi. Is adding the number of motors the best solution for motor overheating issues? Does adding a motor completely prevent the motor from stopping due to overheating? Or does it just delay the time the motor stops? I needed a car that could run fast for a considerable amount of time, so I used two Buwizz motors and two Buwizz units. However, after a few minutes of continuous operation, the car stopped due to overheating of the motor. The body weighed around 900g, and no gears were used except for differential gears. So, I want to know the solution for this problem. Thank you.

[Mikdun]

In general when you add motor you reduce load on the current one (and reduce heat dissipation per motor).

If it will eliminate the problem completely - it's not possible to tell, for sure it will heat up slower.

[Zerobricks]

4 hours ago, bg3305 said:

Hi. Is adding the number of motors the best solution for motor overheating issues? Does adding a motor completely prevent the motor from stopping due to overheating? Or does it just delay the time the motor stops? I needed a car that could run fast for a considerable amount of time, so I used two Buwizz motors and two Buwizz units. However, after a few minutes of continuous operation, the car stopped due to overheating of the motor. The body weighed around 900g, and no gears were used except for differential gears. So, I want to know the solution for this problem. Thank you.

It really depends a lot on your model, especially gearing ratiom size of wheels used and in what terrain you drive it. I have a feeling you're talking about a 42160 BuWizz MOD, am I right?

[bg3305]

1 hour ago, Zerobricks said:

It really depends a lot on your model, especially gearing ratiom size of wheels used and in what terrain you drive it. I have a feeling you're talking about a 42160 BuWizz MOD, am I right?

Yes, my car is based on a 42160 MOD. The size of the vehicle and wheel, etc. is the same as or similar to a 42160 MOD. And I tested in the home. When I made a 42160 MOD, I didn't know about this problem because I didn't drive it for a long time. By the way, I tried to drive it for a few minutes with the chassis to check its reliability while making my own car, and this problem occurred. I found out from your article that adding a motor is a way to solve this problem, but it's a dilemma because I want to secure a long time to run.

[Zerobricks]

I had a support ticket like that, might be the same person, even. What I'd do is replace differentials with the red one and remember to lubricate the driveline!

[bg3305]

On 8/21/2024 at 7:49 PM, Zerobricks said:

I had a support ticket like that, might be the same person, even. What I'd do is replace differentials with the red one and remember to lubricate the driveline!

Maybe. I asked the same question on the Buwizz homepage. After replacing the differential gear with a red one and running continuously for about 4-5 minutes even though I used the lubricant, the vehicle stops due to motor overheating. It doesn't seem to solve it just by lowering the gear ratio.

[Zerobricks]

Check that the tires are still on rims correctly! They tend to slip a lot off in the 42160.