Mustang Shelby GTEX AWD (42138 MOD)

[Zerobricks]

Few months ago I modified the set 42138 with one BuWizz motor for driving the rear wheels, one PU motor for steering and a BuWizz 3.0 to power the model.

This MOD was really fun and all BUT, deep inside I knew I can do better, especially after being inspired by upcoming Bolide (and a bit frustrated by it's lack of AWD).

So after a lot of trial and error, fiddling and trying literally all kinds of component placements, I came up with the following MOD:

So you may be thinking, It's a different color, so what?

It has a fancy diffusor, spoiler and a few body mods but what's different?

Well... The answer hides on the underside photo:

Yes, this small 1:16 model has all wheel drive with differentials! Not only that, but the rear axle allows for torque vectoring which allows me to fine tune handling, especially adjusting understeer/oversteer.

The model has been assembled and tested with real bricks, I will post more media soon. AllI can say for now is that performance is excellent, there is plenty of torque to spin all 4 wheels and it can even do AWD powerslides.

[FriedlS]

Looks interesting! 😊👍

[2GodBDGlory]

That's a very interesting method of connecting the motors! You're basically directly controlling the rear wheels from the motors, and then using the rear differential as an adder to send their average power to the front, if I understand correctly. That torque-vectoring sounds neat! Looking forward to seeing a video!

[Thirdwigg]

I love when a design goes so far above and beyond what is needed. I definitely want to see all four wheels spinning out when it's built.

[brunojj1]

Jerry, you have outdone yourself once again, all due respect, man !! The doubled-down-drivetrain is insanely genious to say the least!

So how do you distribute / differentiate the commands in order to regulate the power outputs for both buggy motors? I fear you´ll need to replace the usual CV-joints which connect the rear to the front axle by metal parts. But it must definitely reach a speed beyond 20km/h! Can´t wait for the video!

[msk6003]

I already made 4WD 42138 mod but differential is another story. good!

[gyenesvi]

That already has insane speed with one motor, what could it do with two? I'm tempted to build this, are the instructions out for the 1-motor version?

I love the way the possibility of torque vectoring is implemented, especially that it has AWD through the differential at the same time. Are you planning to actually implement it in software? In the Buwizz app?

[Zerobricks]

9 hours ago, brunojj1 said:

Jerry, you have outdone yourself once again, all due respect, man !! The doubled-down-drivetrain is insanely genious to say the least!

So how do you distribute / differentiate the commands in order to regulate the power outputs for both buggy motors? I fear you´ll need to replace the usual CV-joints which connect the rear to the front axle by metal parts. But it must definitely reach a speed beyond 20km/h! Can´t wait for the video!

 

50 minutes ago, gyenesvi said:

That already has insane speed with one motor, what could it do with two? I'm tempted to build this, are the instructions out for the 1-motor version?

I love the way the possibility of torque vectoring is implemented, especially that it has AWD through the differential at the same time. Are you planning to actually implement it in software? In the Buwizz app?

Thanks! Instructions for a single motor version are on the BuWizz website. The BuWizz app allows for torque vectoring using skid steer module. Setting the tracked steer module to 0 will cause the model to understeer, and 0.20 will make it oversteer, so currently I have it set at 0.10 I will demonstrate the effect in a video. Regarding the speed, I think it won't be that much faster than a single motor MOD, but it does have a higher acceleration, controllability and better braking performance. Because the wheels are so small and the car is so light, there have been no broken CV/cardan joints so far.

[Jundis]

I'd be very curious about the torque vectoring, too! Expecially how it's combined with the steering motor.

Just a littel question: Why did you use the new diff in the front? Doesn't seem that you have any problems concerning space....?

[Zerobricks]

3 hours ago, Jundis said:

I'd be very curious about the torque vectoring, too! Expecially how it's combined with the steering motor.

Just a littel question: Why did you use the new diff in the front? Doesn't seem that you have any problems concerning space....?

I just use the same slider as for normal center steering for the skid steering module, I have used this technique in almost every model that has independent driving motors. The reason for the new diff is that the CV joints in front hubs can accept 1,5 module axle length, so the diff was offset by half a stud, so that one side has a 3 studded axle and the other 4 studded axle. Now since the diff is offset, it would mean the input axle would also have to be offset, but by using the new diff, which has a thicker gear, that was not necesssary.

I hope these pictures clear it up:

Edited December 9, 2022 by Zerobricks

[brunojj1]

2 hours ago, Zerobricks said:

I just use the same slider as for normal center steering for the skid steering module, I have used this technique in almost every model that has independent steering motors. The reason for the new diff is that the CV joints in front hubs can accept 1,5 module axle length, so the diff was offset by half a stud, so that one side has a 3 studded axle and the other 4 studded axle. Now since the diff is offset, it would mean the input axle would also have to be offset, but by using the new diff, which has a thicker gear, that was not necesssary.

That´s another genious solution of yours which I admire !

[gyenesvi]

4 hours ago, Zerobricks said:

The BuWizz app allows for torque vectoring using skid steer module. Setting the tracked steer module to 0 will cause the model to understeer, and 0.20 will make it oversteer, so currently I have it set at 0.10 I will demonstrate the effect in a video.

Oh, that's a nice trick to control two modules with the same slider!

4 hours ago, Zerobricks said:

The reason for the new diff is that the CV joints in front hubs can accept 1,5 module axle length, so the diff was offset by half a stud, so that one side has a 3 studded axle and the other 4 studded axle. Now since the diff is offset, it would mean the input axle would also have to be offset, but by using the new diff, which has a thicker gear, that was not necesssary.

That's a great solution to that half stud problem, I guess the axles could otherwise slide out from the diff and into the CV joint.

[Zerobricks]

11 minutes ago, gyenesvi said:

Oh, that's a nice trick to control two modules with the same slider!

That's a great solution to that half stud problem, I guess the axles could otherwise slide out from the diff and into the CV joint.

Thanks. I think it would also be really useful for @Fosapifi's Tesla truck too.

Exactly, I had to get 8 stud total long axle length between the CV joints so they don't slip out of the differentials.

[Jdrewg]

I'm curious: what are you using to design with? Stud.io? Or?

[Zerobricks]

3 hours ago, Jdrewg said:

I'm curious: what are you using to design with? Stud.io? Or?

Lego Digital Designer, with custom additional bricks, see this topic for more details:

 

[Zerobricks]

Unfortuantely haven't yet managed to record a video of the model due to the bad weather conditions preventing me to test the top speed outside.

BUT I did took some indoor photos of the phsysical model, hope you like them:

[Zerobricks]

So here are some proper photos of the little beast:

Some additional technical information:

• Number of parts: 724
• Weight: 650 g
• Size: 28 x 12 x 8 cm
• Top speed: 17,5 km/h

And finally a video where I showcase and explain in detail about the model:

 

As mentioned in the video, i think this MOD/MOC came out really great and I can't wait to further develop and improve the whole 1:16 scale AWD concept.

[Davidz90]

Wow, that's a lot of power! Extremely impressive.

[gyenesvi]

The adjustability of the under/over-steer looks pretty cool!

The only thing I don't get is why the two U-joints are needed in the drivetrain? What causes a level difference between the front/rear axle? Is there a difference in the wheel diameter?

[Zerobricks]

Thanks for the praise. The front axle is half a stud offset, lower than the rear to give the model a rake. 

Edited December 27, 2022 by Zerobricks