42083 Bugatti Chiron - MODs and Improvements

[Wolf_Zipp]

I made a new test for the W 16 with 2 cranks

( only W4 .... not enough toggle joints )

Sorry, the last test was double V8

 

[Didumos69]

I built my front suspension MOD. I made one error in the LXF-file. I used friction pins where the extra wishbones are connected to the vertical 5L thin levers, where it should have been frictionless pins. I fixed that in the LXF-file.

I checked it's strength and I think it's good. With a weight of over 1500gr it only just starts to compress, the wishbones are flat at a weight of over 2000gr and the suspension is fully compressed at about 2800gr. Does anybody know what the weight of the Bugatti is and how it's divided over the front and rear axles? The only thing I'm not completely happy with is the rigidity of the bent liftarms sticking the top. Will see if I can improve that.

Edited June 9, 2018 by Didumos69

[Didumos69]

On 6/4/2018 at 10:43 PM, DugaldIC said:

It does work I'll post up some corrected pictures in a few. 

Wow, that's what I meant. Even less parts?

[lcvisser]

On 2-6-2018 at 11:42 PM, Didumos69 said:

In the figures below minus means the rotation direction flips, this was to check if reverse is actually reverse. The first gearbox in the chain has 4 positions, but toggles between 2 speeds. The second gearbox has 4 positions and 4 speeds.

[...]

 

Just wanted to say thanks for providing the renders and the calculations. Together the helped me finally wrap my head around how that pile of gears works   Fun exercise!

 

[Enantiomeer]

5 hours ago, Didumos69 said:

I built my front suspension MOD. I made one error in the LXF-file. I used friction pins where the extra wishbones are connected to the vertical 5L thin levers, where it should have been frictionless pins. I fixed that in the LXF-file.

I checked it's strength and I think it's good. With a weight of over 1500gr it only just starts to compress, the wishbones are flat at a weight of over 2000gr and the suspension is fully compressed at about 2800gr. Does anybody know what the weight of the Bugatti is and how it's divided over the front and rear axles? The only thing I'm not completely happy with is the rigidity of the bent liftarms sticking the top. Will see if I can improve that.

 

The car weighs ~ 2900 gram. I don't have two scales so I can't check reliably how the weight distribution is. What I did do was to put the front wheels on my scale and support the rear wheels so the car was level, and then turned it around. The indicated weight was 1460 g for the front and 1420 g for the rear.

 

With regard to the sagging of the front suspension I was thinking if you can pré-tension the springs by lowering the attachment points by ~ 0.5 stud this would solve the issue. If you look at the back suspension which works fine even though the springs are at a greater angle the distance between the attachment points of the springs is significantly shorter then for the front suspension.

Edited June 9, 2018 by Enantiomeer
typo

[DugaldIC]

Am I the only one to have this problem or at least notice it. With the Bugattis gearbox if the shifter is in drive the the pistons move but everytime I shift into reverse the pistons don't move at all?! Has anyone else had this issue? 

[brunojj1]

2 hours ago, DugaldIC said:

Am I the only one to have this problem or at least notice it. With the Bugattis gearbox if the shifter is in drive the the pistons move but everytime I shift into reverse the pistons don't move at all?! Has anyone else had this issue? 

I´m having exactly the same issue, has been reported in some reviews as well. My 4y old son doesn´t care about the gearbox, he´s happy about the blue color, speed key and handbag instead .

Regarding the suspensions: I have tan 3L pins installed in the front. At the rear all original - and it´s sagging after being pushed. This way I have similar heights on both axles. Haven´t put the stickers onto the car yet, maybe that makes some difference too 

[LvdH]

I think Paul told me something along of the lines of that the white clutch gear makes the lower gears hardly work... 

[Didumos69]

On 6/5/2018 at 4:44 PM, Didumos69 said:

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).

On 6/5/2018 at 7:26 PM, Erik Leppen said:

As for @Didumos69's gearbox… someone should really build it to test. If it's really working as I expect, I don't get how it can be that a whole design team paid to do this works a year on a model, and then a random dude on the internet fixes a cleaner-designed gearbox with fewer parts in at most a few weeks of his spare time (ignoring for the moment the years spent to learn the craft), while, seemingly, requiring one fewer new mould (I see no yellow extender).

I had to get back to this. I gave it a little more study and it turns out the modified 4-speed gearbox and the original low-high gearbox required different rotation directions for the wave selectors. So I changed the setup. Now they work in the same direction, but opposite to the original gearbox. To change that, the gerabox would have to be completely mirrored, but I don't regard this as a real replacement, more a thought experiment. As a side effect the gear ratios between the gearbox and the engine could be normalized, but that messes up the reverse ratio.

LXF-file here.

[Paul Boratko]

9 hours ago, DugaldIC said:

Am I the only one to have this problem or at least notice it. With the Bugattis gearbox if the shifter is in drive the the pistons move but everytime I shift into reverse the pistons don't move at all?! Has anyone else had this issue? 

 

7 hours ago, brunojj1 said:

I´m having exactly the same issue, has been reported in some reviews as well. My 4y old son doesn´t care about the gearbox

I was just checking out my wife's model, and it works perfectly in reverse... All I can think is that there is too much friction in your model's engine and the axle is turning inside of the white clutch gear...

[DugaldIC]

@Paul Boratko Strange, there's no friction. The model rolls just fine but in reverse but it doesn't work. I've built that gearbox twice now and same issue both times. 

[Paul Boratko]

The gearbox is irrelevant to the reverse gear...  It's just a 16 tooth gear on the main drive axle at the center shifter that drives reverse... If you have a standard 16 tooth gear on that drive axle and engage the reverse position on the shifter, it should apply a direct feed to the engine through the white clutch gear...

So either the axle is turning inside of the white clutch gear or there is a gear misplaced.. The reverse system in this car is very basic...

[Wolf_Zipp]

1 hour ago, Paul Boratko said:

 

I was just checking out my wife's model, and it works perfectly in reverse... All I can think is that there is too much friction in your model's engine and the axle is turning inside of the white clutch gear...

I have no Bugatti, but it interested me , how the original build is. I read often about the friction in the engine. So I build it from the the Pictures..

I feel low friction in the engine , when I follow the Primary rules of Lego technic :

Don´t press the beam with the gearwheels !

When I press 1 beam with the gear at the top V8 , I get friction !

 

[efferman]

The engine has indeed low friction. 

[Didumos69]

1 hour ago, Paul Boratko said:

So either the axle is turning inside of the white clutch gear or there is a gear misplaced.. The reverse system in this car is very basic...

Just to illustrate the basic reverse system. Here you see the whole drivetrain. The DNR is at the front and the red clutch gear at the very front is supposed to route the engine to the main drive shaft running from front diff to rear diff, right underneath the DNR driving ring.

Edited June 10, 2018 by Didumos69

[jb70]

I did my first MOD on the HOG steering. It is easy to operate, includes a turning steering wheel, only needs a few parts and fits nicely to the design of the car.

For me a must-have to be able to move the car.

 

 

[nmono]

Nice MOD it blends in very nicely!

[emielroumen]

10 hours ago, jb70 said:

 

 

Very nice! I hope I can get my hands on the set below 300 euro this year. This mod is a must have.

Edited June 11, 2018 by emielroumen

[Kumbbl]

7 hours ago, nmono said:

Nice MOD it blends in very nicely!

Indeed Thank you for sharing - now one of the two major flaws is fixed - Now if we would get a better front suspension too the model would be already really good and quite useable...

[chox]

My news mod for the gearbox to fix 1 -> 8 and 8 -> 1.

[youtube]https://youtu.be/tVnS0abE7KY[/youtube]

[stevenhalim]

Yey, seems that all my major initial MOD lists have been all addressed (simple torsion bar solution by DugaldIC, Didumos69, HOG solution by jb70, 1->8 and 8->1 limiter by chox just now).

By the time I get my own copy all these major issues will be gone :).

[Didumos69]

5 minutes ago, chox said:

My news mod for the gearbox to fix 1 -> 8 and 8 -> 1.

That could have been done much more elegant by skipping the gears at the back of the low-high gearbox. Those gears become obsolete when you have a 8<->1 gearblock.

[chox]

4 minutes ago, Didumos69 said:

Cela aurait pu être fait beaucoup plus élégant en sautant les vitesses à l'arrière de la boîte de vitesses à faible élevée. Ces rapports deviennent obsolètes lorsque vous avez un 8 <-> 1 gearblock.

Yes, but the paddles while driving would still be functional.
Except with my mod, the pallet to mount the reports locks in 8 th speed ;)

[Didumos69]

11 minutes ago, chox said:

Yes, but the paddles while driving would still be functional.
Except with my mod, the pallet to mount the reports locks in 8 th speed ;)

No, also with my mod, the paddles won't be able to move further. The perpendicular connector attached to the low-high gear selector confines that selector to 2 positions only, just like your approach. My main point is that when you have an 8<->1 gearblock, it would be a pitty not to remove the gears in the gearbox that have become unnecessary. And removing those gears creates space for the gearblock.

Also, your solution relies on slack in the 8t gears. The blocking axle with the 2L red levers can only rotate 45, maybe 60 degrees, where the gear selector should be allowed to move 90 degrees.

Edited June 11, 2018 by Didumos69

[chox]

5 minutes ago, Didumos69 said:

Non, aussi avec mon mod, les palettes ne seront pas en mesure d'aller plus loin. Le connecteur perpendiculaire attaché aux limites de sélection basse vitesse haute que sélecteur 2 positions seulement, tout comme votre approche. Mon point principal est que lorsque vous avez un 8 <-> 1 gearblock, ce serait vraiment dommage de ne pas retirer les engrenages de la boîte de vitesses qui sont devenues inutiles. Et la suppression de ces engins crée un espace pour la gearblock.

oh yes, exctly!