jb70

IMO the original design has a big mistake: the gear sequence is wrong: If you switch to a higher gear, the engine speeds up. Everybody knows, that in real cars the engine speeds up, when you switch to a lower gear. The reverse gear had a gear ratio similar to 4th gear and did not have any impact on Hi/Lo switch. So I totally redesigned the complete gear train. And as a side effect I could get rid of the 4 universal joints to connect the gearbox. Now the gearbox is directly connected to the DNR switch with straight axles, avoiding friction and torsion in the gear train. MPD file and PDF instructions have been published on rebrickable.com: So pimp up your Landrover, if you like!

If you have the time, I would recommend to build the original version, first. The original building instructions have a lot of additional info about the model and the real car. And listening to the podcasts while building is a great building experience! Play with the final car and then rebuild the pimp-up version to feel the value of the improvements.

I successfully tested the new gearbox with center diff in the Pimp-up-my-Bugatti. Some minor modifications were necessary: Some minor changes in the chassis to get the new gearbox fit in The housing of the gearbox was blocking to the chassis during marriage Fixture of gearbox to chassis was too wobbly changed rubber band fixture to have a smooth change between 4th and 5th gear So finally the gearbox looks like this: And Pimp-up-my-Bugatti v1.5 is released: Have fun to pimp up your Bugatti, if you like!

Thanks to @SNIPE 's great idea and inspiration I think, I finally found a solution how to integrate a center diff into the main power train inside the gearbox, that fits into the Pimp-up-my-Bugatti design and keeps the well balanced sequential gear ratios from @Didumos69 's proved solution: I needed to add an additional gear pair (12t/20t) at the front side of the gearbox and in the high/low-part of the gearbox I changed two gear pairs from red clutch gears (12t/20t) to the new blue clutch gears (12t/20t) to compensate the total gear ratio of the gearbox. These changes were necessary, because the center diff now couples into the gearbox by a 1:1 ratio (16t/16t). In the original design it was a 1:3 ratio (8t/24t), which now has to be compensated. Without theses changes the reverse gear, which bypasses the gearbox would have been ranged near 5th gear, much too fast for a reverse gear ;-) This design results in the following gearbox ratios (from gearbox in to gearbox out): 1st gear -1,33 2nd gear -1,67 3rd gear -2,22 4th gear -2,78 5th gear -3,70 6th gear -4,63 7th gear -6,17 8th gear -7,72 reverse gear 1,21 Up to now I only did a digital build. Next week I will test it in a real build. And if the design passes the tests, Pimp-up-my-Bugatti v1.5 will be on its way...

@SNIPE Yes, I checked your last link. But, placing the center diff between engine and power train axle in the F-N-R selector does not have any effect to balance torque and speeds between front and rear axle. In your solution the center diff can only manage torque and speeds between engine, gearbox and wheels. But front and rear axle are still strongly coupled by the main power train axle. That may still work fine, but doesn't have the desired effect of a center diff. If you want a working center diff to manage torque and speed between front and rear axle, you must place it inside the power train axle between front and rear axle. Nevertheless, the way how you designed the diff into the F-N-R selector and the existing environment, well done! Your gearbox looks very nice and compact. When I did count correctly from your photos, I calculate the following gear ratios: 1st gear -1,25 2nd gear -1,00 3rd gear -2,08 4th gear -1,67 5th gear -1,56 6th gear -1,25 7th gear -2,60 8th gear -2,08 So, I think, the gearbox will work and shift, but not really sequentially. Maybe our gearbox hero @Didumos69 can have a look on it?

@SNIPE. That's a very good idea to add a center diff to the Bugatti. Without a center diff the power train loads a lot of torsion. But, I think your solution does not work, because you placed the center diff only between the engine and the power train axle. So the power train axle still builds up a fix connection between the front and back differentials: To get it work, we need to place the center diff inside the power train axle and connect the housing of the center diff to the gearbox. Something like that: I need to think about how the gearbox can be redesigned so that center diff fits in...

I found a solution to avoid blocking of the belt as @Ngoc Nguyen showed in the upper picture: More details and building instructions are available on https://rebrickable.com/mocs/MOC-24566/jb70/42055-smooth-bucket-wheel-excavator.

When rendering technic liftarms with POV ray, I think there is a bug in LGEO. The axle holes are only visible in the half of the part: . Does anyone see the same problem? - Or have an idea how to fix this?

Yes, the gearbox (or to be precise: the paddle shifter) has been inverted compared to the original 42083-1 as you can see in this previous post. Note that in low gears you have fast engine at low vehicle speeds and in high gears slow engine at high vehicle speeds. And do you really pull or push the paddles?

No, the gear indicator should go from far left (1st gear: means fast engine at low vehicle speed) to far right (4th gear: means slow engine at fast vehicle speed). If your engine doesn't move in that gear sequence, you should verify your gearbox. Please check the correct 90° position of the orange 2L beams on step 41 page 30. They should align with the dark gray driving rings exactly, as shown in the instructions: Left driving ring is engaged to the front red gear. Right driving ring is idle in the middle position. And while mounting these orange 2L beams, take care to keep the position of the gear indicator as shown on step 30 page 17. This will indicate 4th gear. Yes, this is normal. There is some backlash in the gearbox. Each gear pair causes a little bit of backlash. There are many gear pairs between rear axle and engine, so it sums up to a few centimeters of moving the car, until you notice the engine to move. Yes, this is normal, too. You may always shift all 4 gears in any state of the DNR switch. The DNR switch only switches the direction of the engine between (D)rive forward, (N)eutral and (R)everse.

@adultlegouser, Thanks for your review! I have updated part list and building instructions as you suggested.

And I did some MODs on the front axle: 1. Added Ackermann steering. It only has a little effect because of the reduced wheel angle (limited by tires and CV joints), but it is a noticeable improvement in playability. 2. Reinforced front axle and suspension I replaced the yellow 1x5 thin beams by black 1x5 beams with axle holes and replaced frictionless pins by axles. This gives more stiffness to the front axle. And I added some reinforcements to fix the front axle better to the chassis. The benefit is a noticeable better suspension and a little bit more clearance of the front body. These updates with part lists and building instructions are available on Rebrickable: pimp-up-my-bugatti v1.4 Have fun to pimp up your Bugatti, if you like!

Finally I found a clue for an easy to use HOG lever to operate the spoiler and air brake: You can now operate the black lever smoothly between 0° (pointing back) an 90° (pointing right) to lift and lower the spoiler in normal mode. If you push the lever further to 135°, the spoiler goes into air brake position. Returning the lever to 0° position sends the spoiler back to home. Operating the lever between 0° and 135° perfectly fits in the gap between the dark blue panels. If you like to use the speed key to operate the spoiler, you're fine: It still works as it used to be. With this MOD i took back the change of the air brake from @nerdsforprez in v1.3 and returned to the friction pins in the air brake as in the original design from Lego designer Markus Kossmann. With the friction pins there is a better and clear difference between the two modes: lifting and lowering the spoiler air brake

I have uploaded additional part lists with the different parts between Pimp-up-my-Porsche v1.3 and v1.4: - If you already have build v1.3, here you will find the different parts and a rebrickable part list or bricklink part list with the additional parts you need to build v1.4. These part lists can be imported on rebrickable or bricklink. Have fun to pimp up your Porsche!

Hi @DayWalker, thank you for this cool MOD! I like your technical adaption of an anti-roll bar. It works perfectly and it looks really cool! I have integrated the new front and rear axles into Pimp up my Porsche v1.4 with new part list and building instructions. Ackermann steering, geometry and clearance of your front axle work similar to our previous solution by @Didumos69 and me. But your design is clearer, easier, with less friction and geared down a bit leading to better playability. I generally kept your design, just replaced the 90° connectors with round elbows. This widens the gap between anti-roll bar and tires. And it looks cool! Added a limiter to the gear rack changed some colors

Hi Erik, Great work! I really enjoy your idea and am looking forward to build it. Your work may result in a lightweight Bugatti Chiron (as one would expect from a sportscar ). If I compare my pimped-up Bugatti with the pimped-up Porsche I feel like the "heavy" Bugatti is made for straight-on roads at high speeds while the "light" Porsche is made for curvy racetracks. The Porsche just feels lighter to drive. This feeling may result in different things like: Bugatti has 4WD without middle differential compared to the Porsche with 2WD (maybe you could add a middle differential to your design?) Bugatti does not have Ackermann steering compared to the Porsche (your design looks to may have Ackermann steering or at least it should be easier to integrate as in the original design, because you reversed the steering to have the rack behind the wheels) Bugatti has 8 gears and 16 cylinders compared to the Porsche with 4 gears and 6 cylinders (OK, that used to be, but i am interested how your 16 cyl. engine will work compared to the original one) Bugatti has more weight than the Porsche (that may still remain because of the more features like 4WD, 8 gears, 16 cyl., but maybe a benefit without paddle shifters and for sure by optimizing the frame) So finally I think, there is a lot of improvement potential based on your solution compared to the existing Bugatti MODs. I am little bit worried, if you would loose too much stiffness in your design, because I think the original Monocoque is extremely hard (I liked that), but let's see... So a am very interested to follow your work! If you are looking for a place to share .mpd, please look at https://bricksafe.com/. For the CAD I would recommend LDCad. I also started with MLCad but I changed to LDCad while designing my pimped-up Bugatti. If you are used to use MLCad, this will be a change. But after a few days of learning (there are good tutorials) you will be much more efficient, because it supports real 3D CAD with part snapping.

Pimp up my Bugatti v1.3 has been released and includes the air brake fix from @nerdsforprez. Thankx for your contribution! For those who have already build the Bugatti, these changes can easily be made afterwards: unmount the grey bumper parts that are mounted on page 262 step 51 unmount the black panels that are mounted an page 260 step 49 by pulling out the grey pins from page 258 step 48 add the black ball pins from page 208 step 21 exchange the 2 blue long pins by 2 tan frictionless long pins like on page 203 step 7 remount everything and you are finished.

@nerdsforprez, great Idea! In Episode 6 oft the Bugatti Chiron podcasts LEGO designer Markus Kossmann tells why he used friction pins: to combine two motion sequences (lifting and tilting the spoiler) with one technic axle for the speed key. But your solution is still a worthy improvement. By just replacing 2 friction pins by frictionless pins there still remain some friction pins in the spoiler mechanics. In the result Markus' idea still works, but with less friction. I tried it today and it works smoothly, but with one disadvantage: With less friction the spoiler may tilt to ~90° and when returning the spoiler from this position to idle, it may block with the body frame and not return to idle position. But I found an easy solution to fix that issue by adding two ball pins to the dark blue 3x5 liftarms. The ball pins give a tighter bearing to the liftarms and prevent the spoiler to tilt ~90° so it doesn't block anymore. Now the air brake MOD works excellent! Yes, I will do this soon!

@Scot-e-dog, when I first built my Bugatti, I had a similar experience. In my case there was a loose pin in the middle console after the marriage process. The grey liftarm was not really connected to this blue pin with pinhole and by that it caused a lot of direct friction onto the mesh with the white clutch gear inside: Please check this area in your case. To avoid this issue, I modified the structure around this gear mesh in the Pimp-up-my-Bugatti MOD like that:

Here you are: Pimp up my Bugatti v1.2

@stevenhalim, yes, also the real Bugatti Chiron has the "+" paddle on the right hand side: I found an easy solution to reverse the paddle shifter. Just move the knob gear in the paddle shifter unit to the top. That solves the issue. Now you can shift up by pulling the right paddle:

Finally I solved the "wabbly door issue" by using only these addional parts and flipping 3 dark azure 2x4 liftarms on each door: The hinge on left side is similar to the 42056 Porsche GT3 RS and adds stiffness to the doors. And I found a clever solution for a self-locking and self-opening door-lock (right side). I am very proud of this !. See this video for details. This solution gives us stable doors locking themself with a nice cloc-sound as it used to be for a Bugatti. It fits well into the original design and keeps the doors in their desired postion aligned with the dark azure body parts behind the doors: I have updated part list and building instructions of Pimp up my Bugatti v1.1.

The function of the paddle shifters in my pimped-up version is exactly the same as in TLG original 42083. But indeed I was asking me the same question allready. In my real car (Audi A6) shifting up is on right hand paddle and shifting down on the left hand. But I am not sure how the real Bugatti or Formula 1 cars handle this. If you push (not pull) the right paddle, it will shift up. But nevertheless it no more important for me, because I use the gear indicator for more convenient shifting instead of the paddles.

Yes, it was some hard work in the last weeks. But I enjoyed the work, especially the good ideas and exchange in this forum.

The first release of the "Pimp up my Bugatti" project is available on https://rebrickable.com/mocs/MOC-16181/jb70/42083-pimp-up-my-bugatti. Thankx for your contributions and have fun to pimp up your Bugatti!