42115 Lamborghini Sian MODs and Improvements

[jb70]

4 hours ago, stevenhalim said:

The red cardan shaft idea can be further extended a bit:
v0.15 page 12 step 10, the black 6M axle can be changed to red also :), and 
v0.15 page 45 step 1, although we don't have red 9M axle (as it is odd length), we can cheat by putting a red Technic bush after the Technic, Pin Connector Perpendicular 2 x 2 Bent as this small section is visible from below.
Now the entire red cardan shaft is really red, from front to back :)

Cool, I will change the black 6L axle to red, by that we also can leave out the red bush to avoid potential friction. And re-attach it to the front axle to cause some more friction? 

I think, we should leave the front axle as it is. Since the small visible grey part of the cardan shaft does not transmit any torque. This 9L-axle is a tricky part of the front axle. It was important for me, that you somehow can pull out the 9L axle before you disassemble the front axle from the chassis. If you don't, you need some brutal force and bend some beams to disassemble it. 

4 hours ago, stevenhalim said:

v0.15 page 23 step 21, the two orange wave selectors must be at that positions before adding the lime Technic Beam 1 x 2 Thick with Pin Hole and Axle Hole to combine the two gearboxes, otherwise the gear sequence is messed up
(yeah I did that mistake).

I will add a text in BI to "warn" the builder.

4 hours ago, stevenhalim said:

You remove the white 4L lightsaber bar that is really the only way to make the car has positive rake, without that both front and rear suspensions are "equal" = flat.
Let's find a solution to make the positive rake back?
I look at Sian's side view several times, the car do feel that it slightly pointed downwards (positive rake)

I already suggested to add a 1L beam to the 2L axle sticking inside the top suspension arm. That would have a similar and "sustainable" effect. Can you test and compare it to the 4L lightsaber solution?

4 hours ago, stevenhalim said:

The DNR selector, isn't it reversed?

Yes, I know about that. It was the same issue on the Porsche and Bugatti and every other Lego car, I know. I accepted that to be the Lego rule. To change it only in the Lamborghini would confuse me with my other cars. 

4 hours ago, stevenhalim said:

More important: My test drive currently show that first gear is a bit too excessive?
When I test drive it without the body, it works okay with the engine making very fast rattling sound :).
But after I put back the body (some weight added or I messed up something because of re-installation of the body), now gear 1 causes cracking sound somewhere -- haven't nail down the root cause

I am just building back the body and will compare it with my results in the next days. My test with the chassis only was fine also. From the theoretical point of view I do not see any negative issue by just adding weight to the car, unless the additional weight would really bend the structure too much to cause more friction. 

[Didumos69]

5 hours ago, stevenhalim said:

To Didumos09, feedback about the DNR selector and the first gear.

The DNR selector, isn't it reversed?
In real car

(front of the car)
R
N
D

But the current v0.15 is:
D
N
R

(I am aware that reversing it will be very difficult due to gear shifting mechanism so perhaps we leave it as such?)

You are right. Reversing this will be hard to combine with having the gearbox inside the frame and having Reverse use the center differential.

5 hours ago, stevenhalim said:

More important: My test drive currently show that first gear is a bit too excessive?
When I test drive it without the body, it works okay with the engine making very fast rattling sound :).
But after I put back the body (some weight added or I messed up something because of re-installation of the body), now gear 1 causes cracking sound somewhere -- haven't nail down the root cause

This picture should be gear 1, the first gearbox ratio is 1:1, the second gearbox ratio should be 24:16 (from wheel to engine) gearing up but the power crosses inside the blue clutch gear so there should be some friction there.

Gear 5 (which has the same setup in the second gearbox) is less smooth too, but the 12:20 * 12:20 (from wheel to engine) gearing down in the first gearbox).

Did I built something wrongly, some of my parts are not perfect and causes friction, or you are aware of this too?

The overall setup has a very high RPM of the engine in 1st gear. Slightly higher than the pimped up Bugatti. The idea is that it should be comparable to the Bugatti. However, the Sian has a higher input RPM in the gearbox than the pimped Bugatti, so more friction. My suggestion would be to gear down the drivetrain a little, preferably by replacing the 20:12 gears close to the diffs with 16:16.

If that doesn't help, then it could be an option to revert to the previous gearbox setup @jb70 had, the one with some gears outside the frame, but with Reverse using the center diff, with a different reverter in the DNR. That gearbox will follow the most simple path through the gearbox in 1st gear. But I'll leave that up to @jb70.

Edited June 29, 2020 by Didumos69

[stevenhalim]

7 hours ago, jb70 said:

by that we also can leave out the red bush to avoid potential friction. And re-attach it to the front axle to cause some more friction?

Yeah probably I will take the red bush out again haha, it is small friction but still a friction.

7 hours ago, jb70 said:

This 9L-axle is a tricky part of the front axle. It was important for me, that you somehow can pull out the 9L axle before you disassemble the front axle from the chassis. If you don't, you need some brutal force and bend some beams to disassemble it.

I use plier (small enough force, try not to damage the 9L axle too much) to detach it last time. Tricky indeed.

8 hours ago, jb70 said:

I already suggested to add a 1L beam to the 2L axle sticking inside the top suspension arm. That would have a similar and "sustainable" effect. Can you test and compare it to the 4L lightsaber solution?

I just tested it, the positive rake angle increased by too much, making front suspension becomes Bugatti-ish..., I think I prefer to sacrifice the 4L lightsaber... it is "official solution" :O.

 

8 hours ago, Didumos69 said:

You are right. Reversing this will be hard to combine with having the gearbox inside the frame and having Reverse use the center differential.

13 hours ago, stevenhalim said:

Ok DNR reversed as with many other LEGO cars

 

8 hours ago, Didumos69 said:

The overall setup has a very high RPM of the engine in 1st gear. Slightly higher than the pimped up Bugatti. The idea is that it should be comparable to the Bugatti. However, the Sian has a higher input RPM in the gearbox than the pimped Bugatti, so more friction. My suggestion would be to gear down the drivetrain a little, preferably by replacing the 20:12 gears close to the diffs with 16:16.

Last night I calculated (gearbox only, viewpoint: wheel -> engine)

Gear 1: 16/16 * 20 (tan)/16 (grey)-> gear up of 1:1.25 (this one jammed after the car gets heavier)
Gear 2: 16/16 * power goes out from red clutch immediately -> 1:1 this one has cleanest route of power from center differential to output, the smoothest in my opinion
Gear 3: 16/16 * 12 (black)/20 (blue at upper side) * 20 (tan)/16 (grey) * 8/8 (to sidestep one axle) -> out = 1:0.75 -> uses many gears but issue not as pronounced as Gear 1
Gear 4: 16/16 * 12 (black)/20 (blue at bottom side) -> out = 1:0.6 (power goes through the red clutch but the rotational difference effect not as pronounced as Gear 1)

Gear 5-8 repeats the second gearbox pattern above, but 16/16 at front changed to 16/16*12 (black)/20 (tan)*12 (black at the back)/20 (tan at the top) cross several idler gears all the way back to second gearbox, reduction of 1:0.36 from first gearbox. So Gear 5-8 ratio will be 1:0.36*1.25 or 1:0.45 for gear 5, 1:0.36 for gear 6, 1:0.27 for gear 7, and 1:0.216 for gear 8.
Within gear 5-8, gear 6 is the smoothest, gear 8 is the second smoothest, then gear 7, before gear 5 again (but since we have geared it down by 1:0.36, gear 5 is much better than gear 1

Didumos69, are these calculations correct?

So assuming we won't touch this gearbox setup again (it is still far cleaner than the stock build and save one more yellow gear middle ring extension piece like in Bugatti),
let's play with other parts like the 20/12 from front/rear differential to center differential
or 16 grey to 20 blue clutch (I think this is hard to change)
or the last one, 24 grey to 8 grey final speed up before the engine (the stock build is 20 to 12).
I will experiment :O

Btw, now that I can take some more photos, this is my roof mood that I hope included in pimped-up project book 2.
It is criticized again at https://www.brothers-brick.com/2020/06/29/the-lego-technic-42115-lamborghini-sian-fkp-37-rolls-in-the-good-the-bad-and-the-ugly-review/
"You have to make sure you’re actually grabbing the reinforced handle, though, because the roof body panels are a bit larger. Also, don’t make the mistake of grabbing the Porsche 911 this way (its handle is in the back) you’ll experience a catastrophic failure. I speak from experience."

With this mod, you can grab the first 3 beams and hold the 3kg Sian without it breaking (it stresses the 4 half pins but at least it doesn't immediately break)

[stevenhalim]

Ah so you really need to store the image elsewhere and just insert link to this forum.

Ok now bigger picture of my other WIP mod so that I can keep both Ackermann mod and NOT using gear rack limiter.
Ignore the color first as I don't have many 6M half beams in black left.
The red box was the location of black 15M beam.
This structure is clearly not as strong as one 15M beam but it serves the purpose of tying middle chassis with front axle and front axle with part of the nose section.
In this picture I pushed the inside of the wheel to max.
It should rub with the black 15M beam but by "halving it", it doesn't.

There should be stronger/cleaner solution but this one works for now.

[Didumos69]

3 hours ago, stevenhalim said:

Last night I calculated (gearbox only, viewpoint: wheel -> engine)

Gear 1: 16/16 * 20 (tan)/16 (grey)-> gear up of 1:1.25 (this one jammed after the car gets heavier)
Gear 2: 16/16 * power goes out from red clutch immediately -> 1:1 this one has cleanest route of power from center differential to output, the smoothest in my opinion
Gear 3: 16/16 * 12 (black)/20 (blue at upper side) * 20 (tan)/16 (grey) * 8/8 (to sidestep one axle) -> out = 1:0.75 -> uses many gears but issue not as pronounced as Gear 1
Gear 4: 16/16 * 12 (black)/20 (blue at bottom side) -> out = 1:0.6 (power goes through the red clutch but the rotational difference effect not as pronounced as Gear 1)

Gear 5-8 repeats the second gearbox pattern above, but 16/16 at front changed to 16/16*12 (black)/20 (tan)*12 (black at the back)/20 (tan at the top) cross several idler gears all the way back to second gearbox, reduction of 1:0.36 from first gearbox. So Gear 5-8 ratio will be 1:0.36*1.25 or 1:0.45 for gear 5, 1:0.36 for gear 6, 1:0.27 for gear 7, and 1:0.216 for gear 8.
Within gear 5-8, gear 6 is the smoothest, gear 8 is the second smoothest, then gear 7, before gear 5 again (but since we have geared it down by 1:0.36, gear 5 is much better than gear 1

Didumos69, are these calculations correct

Yes, this is correct.

3 hours ago, stevenhalim said:

So assuming we won't touch this gearbox setup again (it is still far cleaner than the stock build and save one more yellow gear middle ring extension piece like in Bugatti),
let's play with other parts like the 20/12 from front/rear differential to center differential
or 16 grey to 20 blue clutch (I think this is hard to change)
or the last one, 24 grey to 8 grey final speed up before the engine (the stock build is 20 to 12).
I will experiment :O

That is much appreciated! There will always be friction in these kind of gearboxes, because some patterns will go through many gears. If changing the 24-8 before the engine to 20:12 would make things acceptable, that would be ideal I think, changing the ratios close to the diffs will have more effect, because it gears down the whole gearbox. I will see if I can do something with the gearbox such that it uses more simpler patterns in 1st and 5th gears, but I think I explored most possibilities already. I have to say though, that the pimped-up Sian is not my project, but it's @jb70's. I just provide input. It's up to him to decide what should go in. And that's also how I like it to be.

Edited June 30, 2020 by Didumos69

[jb70]

Today I have finished building instructions until end of Box 4 and released v0.16:

https://bricksafe.com/pages/jb70/42115-pimp-up-my-lamborghini

 

16 hours ago, stevenhalim said:

Btw, now that I can take some more photos, this is my roof mood that I hope included in pimped-up project book 2.
It is criticized again at https://www.brothers-brick.com/2020/06/29/the-lego-technic-42115-lamborghini-sian-fkp-37-rolls-in-the-good-the-bad-and-the-ugly-review/
"You have to make sure you’re actually grabbing the reinforced handle, though, because the roof body panels are a bit larger. Also, don’t make the mistake of grabbing the Porsche 911 this way (its handle is in the back) you’ll experience a catastrophic failure. I speak from experience."

With this mod, you can grab the first 3 beams and hold the 3kg Sian without it breaking (it stresses the 4 half pins but at least it doesn't immediately break)

This MOD has been included. Thanks a lot to @stevenhalim for this clever solution.

 

We always like to reduce friction in any gearboxes, but in case of the rear spoiler I would like to increase friction. 

The stock design was not able to keep the spoiler in the uplifted position. It always went down a little, when handling and using the car. So this is my simple MOD to increase friction a bit to keep it in place. It is still working fluent to operate the spoiler lift mechanism by the handle before the passenger seat.

According to the total gearbox ratio discussed between @stevenhalim and @Didumos69 please be patient. I would like to verify the results in a real build by myself, but that may take another 1 or 2 days. I am busy on finishing the building instructions and verify them step by step with my real build. 

 

Edited June 30, 2020 by jb70

[Didumos69]

4 minutes ago, jb70 said:

According to the total gearbox ratio discussed between @stevenhalim and @Didumos69 please be patient. I would like to verify the results in a real build by myself, but that may take another 1 or 2 days. I am busy on finishing the building instructions and verify them step by step with my real build.

[Reeneman]

Many thanks to all of you for this great work so far. 
I got the Sian as a gift a couple of days ago, but I will wait with the building until the pimped instruction is released :)

[myvideo000]

6 hours ago, Reeneman said:

Many thanks to all of you for this great work so far. 
I got the Sian as a gift a couple of days ago, but I will wait with the building until the pimped instruction is released :)

Why? I would build the official version version version, order the required parts and then the pimped one. This way you can appreciate the mods much more and you have more to build. 

[Reeneman]

3 hours ago, myvideo000 said:

Why? I would build the official version version version, order the required parts and then the pimped one. This way you can appreciate the mods much more and you have more to build. 

I don’t want to dissemble the whole car again after building it. 
Beside work and other commitments I don’t have the time to do this :(

Edited July 1, 2020 by Reeneman

[RocketPuppy]

2 hours ago, Reeneman said:

I don’t want to dissemble the whole car again after building it. 
Beside work and other commitments I don’t have the time to do this :(

Just build it. These guys are going to be working on this for months/years. They'll release instructions for each major version, but they'll continually improve upon it. 

Build the thing, let it sit on a shelf for a few months, and see what magic these guys pulled off in the meantime. 

The 1:8 Supercars get a new release every 2 years. You have plenty of time to build, then disassemble the Sian. 

The pimp my Sian will still be here being continually improved during that time. 

Make no mistake. This project will be better than the factory Lego model. Right now it's more in the beta/prototype stage. Weaknesses will be found, simpler ways to do things will be discovered, and even more improvements to functionality and form will be implemented. 

While I have a few gripes about the Sian (overly complicated transmission, no Ackerman steering, hood wedge shape) , Lego did a much better job with the entire package of functions and appearance this time.  The pimped version will be better, but Lego really improved a lot of things, the Sian is a much nicer overall set than the 911 GT3 and Chiron that preceeded it. 

Edited July 1, 2020 by RocketPuppy
Typo

[jbuccino]

9 hours ago, Reeneman said:

I don’t want to dissemble the whole car again after building it. 
Beside work and other commitments I don’t have the time to do this :(

Speaking from personal experience (Porsche, Bugatti, Sian and about six other "improved" or RC MOCs) I have to agree with the suggestion to build the original right away. It is so rewarding to open a new Lego kit and work with the new parts and (overly) detailed instructions. Also I don't have the self-control to let a new Lego kit sit unbuilt. :-) I agree with you that taking apart the model is tedious and unrewarding. But once I start it goes way faster than I planned and I start anticipating the fun of the rebuild. I actually use the incremental releases of the modifications (no matter how small) as motivation to take apart a build. I buy Lego and work on MOCs not so much for display but the joy of the build.

Edited July 1, 2020 by jbuccino

[Reeneman]

Hmm I guess both of you are totally right :)

I was kind of spoiled in a positive way with the Bugatti that I bought earlier this year. The pimped instructions were far progressed and nearly final at that time, so I started with the pimped one.

I guess I will start building the Lambo in the next days but as well keep track of this great pimped project =)

Edited July 1, 2020 by Reeneman

[myvideo000]

I told you 

[jbuccino]

1 hour ago, Reeneman said:

Hmm I guess both of you are totally right :)

I promise you won't be disappointed. The build is so much fun. Enjoy! (And I think you just inspired me to take mine apart again just for the pleasure of building in some of the new mods.)

[astyanax]

6 hours ago, jbuccino said:

I agree with you that taking apart the model is tedious and unrewarding.

100% disagreed. I find disassembly very relaxing, and the OCDer in me loves sorting the bricks...!

[jbuccino]

1 hour ago, astyanax said:

100% disagreed. I find disassembly very relaxing, and the OCDer in me loves sorting the bricks...!

Interesting. I have lots of OCD tendencies but not that one. I never sort the bricks when disassembling. :-) But my wife always comes over and insists on doing it for me while I am starting the rebuild. I am just so anxious to start building that I'd rather find the parts as I go. And when it is a mod I go into my storage bins to find the changed additional parts.

[stevenhalim]

Hi all

On 6/30/2020 at 11:58 AM, stevenhalim said:

So assuming we won't touch this gearbox setup again (it is still far cleaner than the stock build and save one more yellow gear middle ring extension piece like in Bugatti),
let's play with other parts like the 20/12 from front/rear differential to center differential
or 16 grey to 20 blue clutch (I think this is hard to change)
or the last one, 24 grey to 8 grey final speed up before the engine (the stock build is 20 to 12).
I will experiment :O

Experiment results so far is a bit negative (for me) >.<

Gear 1 (the most problematic as it is the only one geared up) and it is associated Gear 5 (not so severe because of significant reduction in the first gearbox, but I can still feel friction) still problematic even if I change the front/rear differential from 20:12 to 16:16 (haven't try lowering it to 12:20 :O) or changing the final speed up before engine from 24:8 (3x) to 20:12 (stock build, 1.67x).

So the current problem is probably the setup of gear 1/5 in the second gearbox.

First comment: On page 13 step 12, there is axle 5L with stop.
Both of you (Didumos69/jb70) are risk averse towards this setup right?
This is part of the sequence of axles that will transmit power in gear 1+5
I have tried changing it to 5L without stop but the friction is still there though.

Second comment: This red 4L axle highlighted pops out when I encounter that gear 1 friction issue.
I have tried changing the bracing so that it won't pop out (change to 3L and use another part to block it), but the force of gear 1 still tend to want to pull this axle out.

So at this stage, I stop my experiment and do my (real) day work instead of tinkering this (although working from home) :O.

jb70, I want to hear your real life experiment with gear 1 too using strictly v0.16 build.

Until we collectively figure out how to resolve this, my current stand is... "avoid gear 1" for now...

[Didumos69]

Thanks @stevenhalim! Did you test these changes with the gearbox only or installed in the complete model / chassis?

I suspect there is friction somewhere down the line towards the engine. 1st and 5th gear would be the most sensitive to such friction.

Edited July 2, 2020 by Didumos69

[stevenhalim]

8 hours ago, Didumos69 said:

Did you test these changes with the gearbox only or installed in the complete model / chassis?

Both, but didn't help for now

8 hours ago, Didumos69 said:

I suspect there is friction somewhere down the line towards the engine. 1st and 5th gear would be the most sensitive to such friction.

Probably, so I am now waiting for other testers to see if this is my case only (I did something wrong or some of my parts not good) or there is design issue with gear 1 or 5.

I just tried two more things:
a. Change wheel to gearbox ratio from 20:12 (stock build) to 16:16 (better but gear 1 and 5 issue are still not resolved), or 12:20 :O (slightly better but gear 1 and 5 still the most jittery gear).
Of course at this point, the engine moves very slowly especially on the 8th gear... probably not the route to take

b. Temporarily remove center differential :O as this also stressed (it bulges a bit under heavy stress) when I try to rotate the wheel by hand upside down on first gear.
Not really helpful either.

So my current suspicion is the difference of rotational speed between red clutch gear (that transfer power from first gearbox to second gearbox) and the 1.25:1 gearing up in gear 1/5 that makes the powered axle that goes inside that red clutch gear rotates 1.25x faster than the one outside... hm...

Let's wait for other early tester feedback then.

[astyanax]

Is there any appetite to see if there's a way to fit glow-in-the-dark bars as headlights? (As seemed to be suggested -- for a fleeting moment -- in the reveal video.)

Problem of course is that this color only comes in 4L bars so it may be hard to mount them without having them look too short.

[jb70]

I have now finished building instructions with v0.17:

https://bricksafe.com/pages/jb70/42115-pimp-up-my-lamborghini

And I tested all the new features in a real build. And I must say, I am very excited with the results! 

In my build the new gearbox and the V12 engine run smooth as butter. Even better and smarter to push the car in 1st gear compared to the Pimp up my Bugatti, although we have increased engine speed a little bit (14% more RPM as the Bugatti). 

@stevenhalim I am sorry, but also happy, that I could not confirm your test results with problems in 1st and 5th gear. If all the other gears run smooth in your build, there must be some problem in your build with the gears involved in 1st and 5th gear. You should check and maybe rebuild that section.

Edited July 2, 2020 by jb70

[Filthy Fox]

@stevenhalim  Your friction problems may be due to slight variations in parts from the factory. That's what has happened to me, as my Sian doesn't work well in a certain gear, and I've ruled everything, I mean everything, out. It's truly tragic, this problem can especially show in complex gearboxes.

[suffocation]

I think the stacked frames may be an issue. Stacked frames don't quite measure up to their theoretical height, so e.g. four stacked frames will measure a fraction of a mm less than four studs, which is more than enough to generate unwanted friction, especially between bevel gears.

[Didumos69]

9 hours ago, jb70 said:

I have now finished building instructions with v0.17:

https://bricksafe.com/pages/jb70/42115-pimp-up-my-lamborghini

And I tested all the new features in a real build. And I must say, I am very excited with the results! 

In my build the new gearbox and the V12 engine run smooth as butter. Even better and smarter to push the car in 1st gear compared to the Pimp up my Bugatti, although we have increased engine speed a little bit (14% more RPM as the Bugatti). 

@stevenhalim I am sorry, but also happy, that I could not confirm your test results with problems in 1st and 5th gear. If all the other gears run smooth in your build, there must be some problem in your build with the gears involved in 1st and 5th gear. You should check and maybe rebuild that section.

This is great news!

6 hours ago, Filthy Fox said:

@stevenhalim  Your friction problems may be due to slight variations in parts from the factory. That's what has happened to me, as my Sian doesn't work well in a certain gear, and I've ruled everything, I mean everything, out. It's truly tragic, this problem can especially show in complex gearboxes.

@stevenhalim, what @Filthy Fox is saying makes sense. You should also check for bent axles:

On 6/23/2020 at 1:59 AM, allanp said:

Many people might not have this problem, but we are so close to the edge of being barely functional due to these over-complex designs that any barely noticeable manufacturing flaw can cause this to happen. I noticed when a lot of people were having problems with the 42009 outriggers barely moving that some axles straight out of the box were ever so slightly bent. So I built an axle tester by placing a bunch of 1x2 Technic bricks next to each other on a 2x8 brick. Half the axles fell straight through but many of then fell slowly and many didn't fall through at all. After building 42009 using my tester on every axle the outriggers worked as well as I've seen in any video (not great, but they worked). Tiny imperfections like this caused some people to have the issue, and some people not to.

Source.