Didumos69

Aha, so you're talking about moving the point where the springs attach to the bottom suspension arm towards the wheel. But how? I don't see any options.

I think I understand correctly, but you're still mistaken. Yes the wheels will have less leverage, but the shocks would attach to the suspension arm at 1/3 of the overall suspension arm length, where it originally was 1/2 of the suspension arm length. So the moment of force invoked on the spring would increase by 50%. By bringing the hinged point closer to the wheels and the point where the spring is mounted, you're in fact creating a more effective lever to compress the spring. Imagine the hinged point would move so much it would almost coincide with the point where the spring invokes force: The wheel would be practically free to move, almost without compressing the spring at all.

It would make things only worse. The shock would be mounted even closer to the bottom pivot. Changing the front to use 6L suspension arms would be a better approach (also suggested by @Erik Leppen in the MODs and Improvements thread). That allows for moving the pivot away from the wheel. The U-joints would have to be replaced with CV-joints. EDIT: Explanation: Draw a line through the rotation point of the suspension arm to which the shock is mounted, orthogonal to the length of the shock. The distance between the rotation point and the shock defines the 'arm' and the longer the arm, the bigger the moment of force, the stronger the suspension.

We have third party tires, we have third party RC, now we need thrid party shock absorbers! Or would it be illegal to make copies of original LEGO parts?

This all depends on whether there is someone who takes up the task of putting all mods together. I will stick to some occasional mods this time. Would indeed be nice to fix this, but introducing 2 extra meshes is going to introduce more friction and backlash. And adding an extra clutch gear is even worse.

Thanks, but I'm afraid they can't afford me. Cool! Are you following the steps in terms of groups in LDD? They will show you how to install the body, albeit assembly by assembly. This one: https://bricksafe.com/files/Didumos/4wd-rc-buggy/Greyhound - 4WD RC Buggy - Bld.lxf

Yes, it needs to be built before we can draw real conclusions. The whole gearbox works at a higher speed (9/5 times the speed of the original), which is the only downside I can think of.

I used this one - with small modifications - as a replacement 4-speed gearbox for the Bugatti transmission and reduced the complexity. See:

After some tinkering I managed to reduce the Bugatti transmission complexity. It uses two meshes less in each gear and it has one clutch gear less involved in transferring drive on an axle with different speed. The gearbox is also narrower and shorter and has a 8th-to-1st gearblock. All its clutches are perfectly aligned, which allows for a more elegant housing as well. The whole transmission has practically the same ratios as the original (only 2nd and 6th gear change slightly from 0.286 to 0.268 and from 0.794 to 0.744 respectively). LXF-file here.

Small update to avoid bending in the longitudinal drive shafts. The LXF-file is updated as well as the LDR-file. Parts list is updated too (click to enlarge):

I somehow feel I am in both camps. With the Porsche I felt the urge, if not the Technic necessity, to make it work. It was the whole reason why I bought that model. I wanted to know the exact reaons behind the flaws. After that, I started working on my rugged supercar and it felt like a revelation. I had complete freedom to live up to my own standards. So I started to hate the Porsche. When I took it out of the cabinet to show it, the carefulness I had to abide, the sloppy panels, I really hated it. But over time I started realizing what a great learning experience the Porsche has been for me. Without that experience, I could not have made my rugged supercar. So the fact that it was flawed had its good side and its bad side. But now with the Bugatti, I somehow feel tired of fixing flaws. So I'm not buying.

It would help of course, but I think you would have to remove at least 300 to 500gr if not more. My rugged supercar weighs 2kg and has a suspension geometry that is stronger than this Bugatti and only has just enough strength in the front (without torsion bars). I reckon this model weighs around 3kg. +1. @Erik Leppen explained this once very nicely. Draw a line through the rotation point of the suspension arm to which the shock is mounted, orthogonal to the length of the shock. The distance between the rotation point and the shock defines the 'arm' and the longer the arm, the bigger the moment of force, the stronger the suspension. In a setup where the shocks are squeezed between two parallel suspension arms, you can derive the arm length by translating the shock along the suspension arms upto a point where the upper end of the shock coincides with the rotation point of the upper suspension arm. This is the case in my rugged supercar: That would indeed be strong, but I don't like the fact that you almost can't see the shocks.

I meant the vertical black liftarm above the torsion bar, or was that what you tried? It's a bent one I think.

@DugaldIC, why not use this part with the axle sticking behind the black liftarm?

When you build it, please be sure to align the orange gear selectors and the 2l lever with towball (the low-high switch) as in one of these examples. Otherwise you might end up with a wrong sequence, like for instance in the Zusammengebaut review. More in this post.

But that space is quite convenient if you would want to route the main shiftshaft (!) to the spoiler.

In fact the Bugatti has such a 4-speed gearbox. The 8-speed gearbox is built up from a 4-speed gearbox and a low-high gearbox.

The zusammengebaut review reports a wrong gear sequence: " 1. Gang → 6. Gang → 7. Gang → 8. Gang → 5. Gang → 2. Gang → 3. Gang → 4. Gang." But they made a mistake with the 2L lever with towball. With the 2L lever positioned as in the image below (from zusammengebaut), the 4-speed gearbox (in the background of this image) should be in its 1st gear, but it is in its 2nd gear. This means that when you switch the 4-speed gearbox from its 1st to 2nd gear, the high gear of the low-high gearbox (in the foreground of this image) is immediately engaged. So, effectively this switches the entire gearbox from 1st to (2+4=6)th gear. To make it work, the orange gear selectors and the 2L lever with towball should be aligned properly. The foreground of the render below shows the only correct aligment of the 4-speed gearbox with the 2L-lever with towball pointing to the upper-right side. The 4-speed gearbox is in its 4th gear. In the background of the render, the low-high gearbox is in its low gear, which corresponds with either of the two vertical gear selector positions. However, the low-high gearbox might as well have been in its high gear, which corresponds with either of the two horizontal gear selector positions. The 2L-lever with towball is in position to switch the low-high gearbox when an up-shift occurs (the right paddle shifter under the steering wheel is for up-shifting). Such an up-shift will switch the 4-speed gearbox from 4th to 1st gear. In the render, with the low-high gearbox in low gear, this means the entire gearbox is switched from 4th to 5th gear, which is the desired result. If the low-high gearbox had been in high gear, the up-shift would have resulted in an 8th to 1st shift of the complete gearbox. The brothersbrick review shows the correct alignment. The low-high gearbox is in low gear and the 4-speed gearbox is in 4th gear.

No, that will make it even softer. See mods and improvements thread.

Maybe they used friction pins as a last resort to at least keep the model up when it sits still.

Reminds me of this explanatory illustration from @Erik Leppen.

Great idea, I don't know how difficult it is to route the main gear shifter axle in the center all the way to the back.

Here's an 8th to 1st and 1st to 8th gearblock attempt.

@Appie, @Jeroen Ottens, @Pvdb, I think @Appie's idea for a gearblock should work. With a proper gearblock for avoiding 8th-to-1st gearshifts, only the front two clutch gears are needed in the 1st (right) gearbox, because that gearbox only needs two of its 4 positions (in the original it uses all 4 positions, but toggles between two speeds). Leaving out the other 2 clutch gears in the back and the 16t gear they mesh with, creates space for exactly that gearblock. In the background the original, in the foreground the mod. The piece sticking out at the top side is a 4x2 liftarm. For this to work properly it is required that the orange gear selector for the first gearbox and the 2l lever with towball inserted that switches the 1st gearbox have the right orientation: There should always be one of the two remaining clutch gears engaged. @Kumbbl, in fact the gear selector axle of the first gearbox counts the cycles of the gear selector axle of the second gearbox. But it will be hard to have this flow back to the DNR in order to avoid switching to reverse in other than 1st gear.

In fact the gearbox has 16 different positions. It is build from a sequence of 2 gearboxes. The first has 4 positions, but its 1st and 3rd gear have the same ratio and its 2nd and 4th gear too. The second gearbox has 4 ratios, one for each position. So all together it has 16 positions, but when you iterate over them, you'll run through the eight speeds twice.