Didumos69

I gave the shifter a little more space, because the drivers need to be able to move vertically. I think the drivers need to be tied together with 2 white silicon bands. I uploaded the updated LXF-file here.

Did you test this with the gearbox mode only, or also with the original gearbox? The incomplete gearshift doesn't sound like something specific to the modded gearbox, because the whole shift mechanism hasn't changed. As for the friction; in the modded gearbox friction should actually be less than in the stock build. It would be valuable if you could share your experience with both the modded and the original gearbox,

I think the gearbox could move 2 studs to the back, but it requires rework on the rear axles. I'm willing to do that, but it would mean I am once again changing the work of someone else, @Aventador2004 in this case. An other approach would be to simply remove part of the rear axles, so I can move the gearbox backwards and let @Aventador2004 figure out how to fix the rear axles. Perhaps @letsbuild could give direction in this matter. That would indeed be something that needs testing. In LDD it can rotate far enough, so I'm optimistic.

To start with you can use Ctrl-K to make screenshots without the ugly background in LDD. I'll come back with a more extensive answer later.

I have been working on integrating the gearbox. I redid the housing, because in the existing chassis, I only needed to add a few beams to support all axles. I also made a small change to the layout: I skipped one of the central red clutch gears to keep enough space for the engine crankshaft. I tried to put the gearbox as much to the back as possible. I think I could move it backwards 2 more studs, but that would mean the rear axles would need to be completely redone. Btw, in the current build there is enough space for a V12, so I changed that too. If this is not okay, I'll switch back to the V8. The shifter is a different story. To be honest, I don't like Charbel's shifter at all. The main issue I have is that the belt wheels to which the drivers are attached, can only be supported at one end, which effectively means the shift lever can also be supported at one side only. That gives a lot of undesired bending. So I have been playing with this a little in LDD, but this needs to be explored in real life before we can draw any conclusions. The idea basically boils down to this: The 5x7-frame has a 90-limiter inside and a square 2x2 brick. I extended the square brick with plates so it measures exactly 2 studs. The lever is placed on a half stud offset, so the drivers almost collide with the square brick in idle position. The 90-limiter uses two white silicon bands and the drivers are also tied together with a white silicon band around the yellow bushings. The LXF-file can be found here.

I'm working on integrating the gearbox. I will post details later today.

I don't care about sets, I love the Technic theme for it's parts only, especially the basic parts. They're brilliant. Only atoms are more versatile (cited freely from @Blakbird).

For the stock build, yes:

Can you lower the upper U-joint now? Then the angles of the two U-joints will be more equal. EDIT: Also, when you rotate one of the U-joints by 45 degree, the 2 U-joints will together approximate a constant velocity joint. That will give the gear-indicator more even steps. When both U-joints make the same angle, they will function as a perfect CV-joint.

Sorry for being a bit firm on this. Our gearblock is already quite far from the paddle shifter. This is also why I think it's even better to use a perpendicular axle-pin connector instead of the orange (ox)-piece @jb70 is currently using. A perpendicular axle-pin connector is slightly wider and bumps into the gearblock slightly earlier.

I did think of that, but I don't think it's a good idea. It would block the driving rings, but I fear it would allow for too much rotation to actually prevent an undesired shift. Especially when I realize that the 90 degree limiter is all the way in the paddle shifter unit. But more importantly, the wave selectors - which can be regarded as a kind of worm gear - would translate, if not amplify, the rotational force into a longitudinal force applied to the gearbox housing. In other words, you would end up building a very sophisticated mechanism to drive apart the beams to the front and back of the driving rings, with undesired friction in the gearing at the other side of those beams as a result. I'm convinced that blocking the rotation directly, which has a much bigger chance of actually avoiding a paddle shift, is the better approach. Certainly from a mechanical point of view. And I don't think blocking the rotation is that much more complex compared to blocking the driving rings.

@kbalage, that seems like a very plausible explanation, If you take into account the number of gear meshes (engine to diffs) directly involved in each gear: R::4, 1st: 11, 2nd: 15, 3rd: 11, 4th: 15, 5th: 13, 6th: 17, 7th: 13, 8th: 17. People may be happy with the drivetrain, but I think this is ridiculous. These.numbers do not even take into account all other meshes that are not directly involved, yet always active. Two driving rings actually only need a red clutch gear at one end if a 1-8 gearblock was added in the stock model. So at least two dummy gear meshes would not.have been needed.

That's a very cool paddle shifter! I think I know what your nifty gearbox secret is .

I say high five @jb70! Great work! The housing could have been even more elegant without the need to fit it in the rest of the Bugatti. The main gain though, is having 2 less gear meshes in each of the 8 speeds. I know @ttoobbyy has been sharing ideas on connecting the shift axle.to the rear wing, but I somehow have the feeling that these free holes in the center of the gearbox could be used to route the center shift axle to the back. To make such a thing work, the mechanism of the rear spoiler should be practically without friction. Also, such a connection should have the least lag possible. Preferably only one gear mesh. If we could somehow replace the liftarm above the rear diff (the one with holes placed vertically) we can extend the center shift axle all the way to the back of the rear diff.

Cool! And is the sequence okay now? I do think it would be nice if the 16t gear at the back could somehow be secured better. In general I would prefer gears to be supported.at both ends. I would think there is some space above the 5x7 frame around the diff and the 13L lbg liftarm right in front of that frame.

I managed to reverse the 4-speed gearbox, so it works in the same direction as in the orginal. The update roughly boils down to switching the input and output axles of the 4-speed gearbox. This means there are now 3 red clutch gears at the front of the gearbox, just like in the original. It also has a better overall ratio. The overall input / output ratio is slightly smaller than the original, but that brings 1st gear ratio closer to reverse ratio. In the original build reverse has a much smaller ratio than 1st gear. The slightly smaller overall ratio can be compensated for, by using 2 16t gears for the engine (see renders). You can find an LDR-file here and an LXF-file here. In the digital file and in the renders the gearbox is in 4th gear. If there is no space for the 2x4 liftarm at the back of the gearbox, a 13L liftarm could be installed right above the two 7L liftarms.

Sorry for answering. The issue is that the wave selectors of the 4-speed gearbox and the low-high gearbox need to rotate in the same direction for an up-shift. Now, with only 2 clutch gears in at one end of the low-high gearbox and a gearblock at the other end, the required up-shift direction is from bottom driving ring to right-side driving ring. The only way to change the direction is either to swap the driving ring ratios, or to use one clutch gear at one end of the low-high gearbox and for the other driving ring a clutch gear at the other end. The first is not an option, because the gears would stick out too much and collide with the engine.

Yes, moving the gearblock does not make a difference, I should have known. Reversing the 1-4 gearbox can be done by swapping the 16t-20t mesh at the backside, but that would give a much higher input/output ratio of the complete gearbox. The engine would need to be geared down, but that will also affect reverse. The low-high gearbox can be reversed by moving one of the red clutch gears to the front and by rotating the wave selector by 90 degree, but that would require the gearblock to move to another spot. Also, reversing the low-high gearbox would require the shift direction of the center shift axle to be the opposite from the original. But that could in turn be resolved by mirroring the entire gearbox from left to right. I can't make renders right now. I'll do that tomorrow. It's of course also an option to reinstall the original gearbox and only add the gearblock.

@jb70, what? I thought you were only going to figure out the gearblock, but you actually tried to fit in my entire gearbox idea. That's really cool! I do think this will still give a ratio difference between reverse and 1st gear. I also thought of a way to brace the upper 8t gear better. I'll post a render later tonight. I really appreciate your effort to really understand a mod and try to fit it in as good as possible. You even seem to think about how it fits in the build process.?

@Paul Baulch, I think this is exactly what I posted about two weeks ago. Nice to see it being buit! It uses all new parts! Only the use of 16t gears for the rotary catches is not perfect. But it could use knob wheels if the control axle could have a 45 degree angle.@ I especially like the fact that when one idler gear is engaged, all the other plain idler gears making dummy rotations. They are not involved in transferring drive.

The new 20t clutch gear (35185) is only euro 0.50 at Bricks&Pieces. I just ordered all new parts, plenty for the coming years.

You are really punishing this vehicle to the max! This switching between backward drive, forward drive, etc., is the way to break U-joints. Btw, what came loose with the 'boom'-accident? The 6x1 plates?

Not a PDF, but I will be doing photo sequence instructions. I'm a bit busy at work right now, so give me a few more weeks.

You're welcome! So you couldn't wait for the new parts either, haha. Feel free to share the BI, you're making me curious. People should only know that it's not a finished gearbox, it lacks a shifter and a 90 degree limiter.

Thanks for the info @Paul Boratko! To deal with the half stud difference and the 45 degree angle I was thinking of meshing the selector axle with a control axle using two 12t gears. I will then apply a 90 degree limiter to that control axle.