42056 - Porsche 911 GT3 RS - MODs and Improvements

[JunkstyleGio]

 

My Martini-Racing Porsche in finally done..

(Withe a little help from LDD, LDDtoPOVray, POVray and Gimp2)

[Edwin Korstanje]

Very nice my friend.

Spoiler

 

 

[Ngoc Nguyen]

Is there any MOD that allows detaching the body more easily?

[t12ung]

19 minutes ago, nguyengiangoc said:

Is there any MOD that allows detaching the body more easily?

Jetro made one such MOD...

http://www.eurobricks.com/forum/index.php?/forums/topic/133688-review-42056-porsche-911-gt3-rs/&do=findComment&comment=2574774 (End of Page 3 of this thread)

On 10/15/2016 at 10:06 PM, nerdsforprez said:

Are these lifelites with just the effects turned on?  At the bottom of most LED sets there are options to do lots of different effects.  I just didn't have mine turned on. 

I've no idea. I just happened to come across this video and thought you might be interested 

Edited October 17, 2016 by t12ung
Direct Link doesn't seem to work

[Ngoc Nguyen]

Is there any MOD to prevent gear shifting in R gear? I knew one from MaxSupercar, but it involves a custom panel and isn't very compact.

[Didumos69]

1 hour ago, nguyengiangoc said:

Is there any MOD to prevent gear shifting in R gear? I knew one from MaxSupercar, but it involves a custom panel and isn't very compact.

I have this one still laying around (based on ideas from MaxSupercars and Appie), but it's certainly not compact and I never tested it and I don't know whether the 15L liftarm has enough movement underneath the 3x11 panel, but it should come close. It does fit with all minimal fixes from the unofficial errata though. The LXF-file also contains the errata and HoG steering.

I deliberately left out the reverse gear shifting block from the errata and from my ultimately playable version because it takes up a lot of space and still allows to shift from 4th gear to neutral and back. I think the better way to fix the reverse gear shifting would be to actually bypass the gearbox in reverse. But that would be an advanced MOD and as it adds to realism it should IMO also make sure the gearbox is not engaged when in neutral. That would require the order to be engine->D+N+R->gearbox. Right now it is engine->gearbox->D+N+R.

Edited October 18, 2016 by Didumos69

[OzGadget]

This set needs a driver, something to occupy the cabin otherwise it looks bare.

Nick from the Galidor series looks great standing next to it, but he cannot fit inside the cabin. 

https://flic.kr/p/LjGYbJ

I have come up with a work-in-progress driver. Inspired by The Stig & borne from a Minecraft design, I have come up with a driver.

Here you see them sigh in the car;

https://flic.kr/p/LVs1cY

Here is what it looks like with the door open;

https://flic.kr/p/M3bQka

And their is what they look like out of the car.

https://flic.kr/p/LV5iaV

The driver is held in place by a 1x3 that sits into the groove opening of the bucket seat. 

As I mentioned before, it is a work-in-progress & I will be looking at making it more realistic and introducing curves in the design.

 

[Ngoc Nguyen]

@Didumos69 Are there any simple MODs to increase ground clearance of the front wheels? Thanks!

[Didumos69]

3 hours ago, nguyengiangoc said:

@Didumos69 Are there any simple MODs to increase ground clearance of the front wheels? Thanks!

In my perception the most straight forward way to improve the front ground clearance was posted here, see first image below. To maintain a correct rake angle you may want to combine this with a very easy way to improve the rear ground clearance as well: see this post and second image below (btw, the latter post also shows the front axles that I use in my ultimately playable build, it also includes Ackermann steering and a gear rack slider). If that would lift the rear too much you could try combining it with mounting the rear shocks to the lower suspension arms one stud closer to the wheels.

Edited October 22, 2016 by Didumos69

[Ngoc Nguyen]

@Didumos69 Thanks for the suggestion. In the mod for the front gear, is it necessary to use extra 2 yellow springs? Is it possible to remove the two red springs from the place in the official instruction and use them in the place of the yellow springs instead?

Edited October 22, 2016 by nguyengiangoc

[Didumos69]

3 minutes ago, nguyengiangoc said:

@Didumos69 Thanks for the suggestion. In the mod for the front gear, is it necessary to use extra 2 yellow springs? Is it possible to use the two red springs instead?

I think that should be posible and it might actually turn out better. I needed the yellow ones in my ultimately playable build but in that case the strength of the stock shocks was reduced because I also used the full length of the suspension arms.

[I3Brick]

Hi guys,

Just wanted to post some feedback on some of the suggested mods. I've started building my set today and had planned to integrate 6 of the most basic, easy mods to improve functionality from the get-go. The mods were:

-          Blackbird's step 5 mod

-          Attikas change-over-catches-fix

-          Didumos69 change-over-catches extended with half a stud

-          Supertechnicman’s fix for the infinite gear shifting issue

-          Paul Boratko’s fix for the wrong gear sequence

-          Jetro’s MOD for easy unmounting/remounting the bodywork

 

I’ve not finished the model yet, but so far I’ve had an issue with 2 of the mods: Attikas’ and Didumos69’s changes to the change-over-catches. I implemented both from the start, but when I tried shifting, it wouldn’t shift smoothly at all. The yellow knob-gears in the steering wheel module kept skipping the full rotation, never really shifting the gears reliably. Some of the times they would push the thin end of the change-over-catch inwards, other times outwards.

So I undid Attikas change, which at first didn’t really improve matters, until I read a comment on his video on Youtube. The commenter (Elvis Chien) stated that he had similar issues to mine, and that when he reversed the mod to the original state it worked better for him, as long as he pulled the paddles long enough.

He said: “Try pulling the paddle until you think it's reached the limit then pull it harder,  you will notice that it can actually be pulled even further. Release the paddle, and the shifter is right at the correct position.”

This is exactly what happened to me. When you pull and it feels as if the paddle has reached its end, it actually just reached its furthest position against the thick end of the change-over-catch. If you pull just a bit harder, the change-over-catch will flex inwards just a bit more, giving just enough extra movement in the yellow knob-gears to provide a nice 90° shift in the orange XO pieces.

Seeing it in action makes you realize why they used the change-over-catches, even though at first you would think that in this position, any similar (and shorter) piece would do. But the knob of the knob-gear gets better friction from the stumpy end of the change-over-catch compared to another more rounded piece (or the other, thinner end of the change-over-catch).

I also undid Didumos69’s mod, because in my case I found it gave slightly more chances of double engagement. I’ll retry the effect once I’ve hooked up a motor though, to be sure.

I’m very happy the mods improved the functionality for a lot of you, but it seems that in my build, the original version actually works as intended (for now). My post is not meant as criticism of your mods, just as feedback. I’ve learnt a lot about the model and LEGO Technic in general from this thread and others about the same topic, so I wanted to share my own experience with you guys, as you’ve done with me!

Edited October 24, 2016 by I3Brick

[Didumos69]

1 hour ago, I3Brick said:

Seeing it in action makes you realize why they used the change-over-catches, even though at first you would think that in this position, any similar (and shorter) piece would do. But the knob of the knob-gear gets better friction from the stumpy end of the change-over-catch compared to another more rounded piece (or the other, thinner end of the change-over-catch).

I also undid Didumos69’s mod, because in my case I found it gave slightly more chances of double engagement. I’ll retry the effect once I’ve hooked up a motor though, to be sure.

Thanks for this extensive report. It's always good when people make their own analysis and try to understand what the exact problem is with the Porsche.

Still, if you want to get the shifting mechanism working properly, I strongly advice you to add the simple 90 degree limiter and remove the 8t gears that are supposed to reduce backlash in the shifting mechanism. That will make the biggest difference when it comes to reducing the chances of double engagement. And when you have that working, you can extend the change-over catches with half a stud again. That will reduce friction in the gearbox. Btw, I suppose you already know about the complete set of must-have improvements on Rebrickable.

P.S. I also wonder why they used change-over catches in the paddle shifter unit in the first place. They could have done with a more subtle stop-and-return setup which would have allowed for a shorter paddle movement at the same time:

 

Edited October 24, 2016 by Didumos69

[I3Brick]

That's a very nice redesign you made there of the paddle shifter, hadn't seen that one yet! Seems to be a bit neater indeed, compared to the version with rubber XX  pieces and the change-over-catch. But in that particular design, I do now understand their reason for the piece I think, having seen it operate in real life.

I do know about your ultimate version, thank you very much for the PDF instructions! They helped me to understand a lot of the problems the set has and how the modifications work. I spent half a day studying all threads and your instructions to get a clear idea about the mods and improvements :-D (wasn't always easy, since the names of the mods were sometimes not unique in all threads or forums).

The 90° limiter I purposefully omitted in my list of to-implement mods, it was too much of a 'change'. I wanted to avoid mods that required medium or big changes during my first build. But it's a very elegant and effective solution based on what I've seen and read. If it turns out that for my purposes my build doesn't work well enough, it will probably be the first mod I'll add to the build. But since for now I only intend to display the model and once in a while hook up an L-motor to the fake engine to show the functioning of the gearbox (with the wheels off the ground), I hope it won't be necessary.

I did just now put your 'half stud extension' mod back in, I had completely forgotten the reason behind it (thought it was more related to the double engagement, but as you rightfully reminded me it was about reduction of friction). Thanks for the reminder!

[t12ung]

On 10/22/2016 at 1:15 PM, Didumos69 said:

In my perception the most straight forward way to improve the front ground clearance was posted here, see first image below.

I don't suppose anyone has tried this MOD on the stock model? Would be good to know how the suspension feels and whether it collides with the 7M Beams underneath.

[I3Brick]

I was wondering if anyone has a suggestion for the following: I want to motorise my model, but only require it to function when the wheels are off the ground. The point is to show off the gear shifting function by seeing the wheels turn slower or faster when shifting. Since having the car resting on its wheels adds too much weight (requiring big motors and potentially running into issues with the drive train/wear and tear), and since I don't want to have a fully RC model, this should be less complicated than a fully RC model. I don't mind if the motor is external to the car. The most convenient spot I found so far to do this is at the back.

My plan is to extend the axle marked in red on the picture (passing through the lowest of the two grey gears used to make the engine turn) with one stud. That way I can connect an axle connector with L-motor to it when I want to show the functionality, and I can easily remove (and hide) the motor when the car is on display. That would mean I'd have to split up the long black 15 stud beam of the rear bumper from step 597 into two smaller beams, so that the axle could pass through. Not sure what the overal impact will be on the sturdiness of the rear bumper if I do that, it seems to be a rather structural element.

Any suggestions for the 'connection point' of the car and the motor? I am hoping that with the car off its wheels, a single L-motor will suffice to operate the entire drive train without causing too much wear and tear to all the gears. I'm not going to be running the car like that for long periods of time, but there's still a lot of gears involved. Thoughts and tips are welcome.

PS: I did see the video posted by schraubedrin on page 13 of this thread. It looks like one of the easiest ways to connect an L-motor, but it connects to the rear wheels directly, meaning that you will only see the speed differences of shifting in the engine pistons. Those are hard to see, less spectacular and you can only apply this when the chassis is removed. I'd prefer a method that works with the chassis on as well.

PSS: I also know stevenhalim tried connecting an L-motor and it worked with wheels off the ground (allbeit with Didumos69's mods, which I haven't all implemented), but I've got no idea where exactly he hooked up the motor and if anybody else tried doing this.

Edited October 24, 2016 by I3Brick

[Didumos69]

14 hours ago, I3Brick said:

The 90° limiter I purposefully omitted in my list of to-implement mods, it was too much of a 'change'. I wanted to avoid mods that required medium or big changes during my first build. But it's a very elegant and effective solution based on what I've seen and read. If it turns out that for my purposes my build doesn't work well enough, it will probably be the first mod I'll add to the build. But since for now I only intend to display the model and once in a while hook up an L-motor to the fake engine to show the functioning of the gearbox (with the wheels off the ground), I hope it won't be necessary.

I get it. I visited Lego World last weekend and there was a Lego fan demonstrating the Porsche. He used a motor to show the shifting mechanism and after a few shifts the entire setup stalled because of double engaged gears. I hope you'll do better .

Good luck and have fun building!

Edited October 25, 2016 by Didumos69

[t12ung]

13 hours ago, t12ung said:

I don't suppose anyone has tried this MOD on the stock model? Would be good to know how the suspension feels and whether it collides with the 7M Beams underneath.

Actually, I had a closer look at the model in LDD again and tried to add this to stock build, besides what you see in the image above relating to this, you need to replace the brown cross axle with stop and grey bush with a 3M cross axle when connecting 3x3 90 deg lever to the ball cups (x2).

Then there's an issue connecting the horizontal 11M beam because the existing red gear shift connector is blocking it. It connects a 4M cross axle with stop to an 8M cross axle.

I think replacing the axles with 8M with stop and 4M should do as a workaround?

[fred-eric]

On 24/10/2016 at 10:44 PM, I3Brick said:

I was wondering if anyone has a suggestion for the following: I want to motorise my model, but only require it to function when the wheels are off the ground. The point is to show off the gear shifting function by seeing the wheels turn slower or faster when shifting. Since having the car resting on its wheels adds too much weight (requiring big motors and potentially running into issues with the drive train/wear and tear), and since I don't want to have a fully RC model, this should be less complicated than a fully RC model. I don't mind if the motor is external to the car. The most convenient spot I found so far to do this is at the back.

My plan is to extend the axle marked in red on the picture (passing through the lowest of the two grey gears used to make the engine turn) with one stud. That way I can connect an axle connector with L-motor to it when I want to show the functionality, and I can easily remove (and hide) the motor when the car is on display. That would mean I'd have to split up the long black 15 stud beam of the rear bumper from step 597 into two smaller beams, so that the axle could pass through. Not sure what the overal impact will be on the sturdiness of the rear bumper if I do that, it seems to be a rather structural element.

Any suggestions for the 'connection point' of the car and the motor? I am hoping that with the car off its wheels, a single L-motor will suffice to operate the entire drive train without causing too much wear and tear to all the gears. I'm not going to be running the car like that for long periods of time, but there's still a lot of gears involved. Thoughts and tips are welcome.

PS: I did see the video posted by schraubedrin on page 13 of this thread. It looks like one of the easiest ways to connect an L-motor, but it connects to the rear wheels directly, meaning that you will only see the speed differences of shifting in the engine pistons. Those are hard to see, less spectacular and you can only apply this when the chassis is removed. I'd prefer a method that works with the chassis on as well.

PSS: I also know stevenhalim tried connecting an L-motor and it worked with wheels off the ground (allbeit with Didumos69's mods, which I haven't all implemented), but I've got no idea where exactly he hooked up the motor and if anybody else tried doing this.

 

You can put a small motor in front of the car. I replaced :

on step 107 the Axle 2 Notched with a 3 one,

on step 112 the Liftarm 3 X 5 Perpendicular H-Shape Thick with two Liftarm 1 x 3 Thick

and I use a Plate, Modified 2 x 2 with Pin Hole to hold the motor.

This is not perfect because in this configuration, you change the speed of the motor...

 

[Didumos69]

On 25-10-2016 at 11:58 AM, t12ung said:

Actually, I had a closer look at the model in LDD again and tried to add this to stock build, besides what you see in the image above relating to this, you need to replace the brown cross axle with stop and grey bush with a 3M cross axle when connecting 3x3 90 deg lever to the ball cups (x2).

Then there's an issue connecting the horizontal 11M beam because the existing red gear shift connector is blocking it. It connects a 4M cross axle with stop to an 8M cross axle.

I think replacing the axles with 8M with stop and 4M should do as a workaround?

 

Yes, that would for sure be a workaround. Btw, here is the LXF-file of this MOD, but I see you already sorted it out yourself.

[I3Brick]

Been continuing my build of the Porsche, and the conundrums keep pilling up :). I applied Paul Boratko's switch of the gearbox sequence (steps 267-269). Right after completing that step, I tried out the gearbox again to make sure everything still runs smoothly. Connected an L-motor for a test and gave it a spin. In the 2d gear the gears give so much friction that the gearbox stalls. Even when manually trying to rotate the wheels you get this effect. I believe I've read about gearbox friction issues in that gear before, but the weirdest thing is that when I reconstruct the gear sequence to the original version of the manual (1 - 3 - 2 - 4) the friction is severely reduced and the L-motor manages to run through all gears without stalling. Without the 3 axles of steps 267-269, everything goes smoothly in every gear. But once I add those 3 axles in Paul's configuration, one particular gear gives an abnormal amount of friction. I believe it's the two black gears added in these steps that somehow don't revolve with the same speed or something, it's really an excessive amount of friction compared to the original version of the manual, and that just when adding these 3 axles in that order.

Has anybody else experienced this behaviour before? It would almost look like the original version has a much smoother gearbox than the mod (albeit in the wrong order). I'd find it hard to believe, after all the reports of people here who've applied the mod without adverse effect, but I'm a bit baffled as to why this would give so much more friction than the original version on this particular gear. 

 

Edited October 31, 2016 by I3Brick

[Didumos69]

14 hours ago, I3Brick said:

Been continuing my build of the Porsche, and the conundrums keep pilling up :). I applied Paul Boratko's switch of the gearbox sequence (steps 267-269). Right after completing that step, I tried out the gearbox again to make sure everything still runs smoothly. Connected an L-motor for a test and gave it a spin. In the 2d gear the gears give so much friction that the gearbox stalls. Even when manually trying to rotate the wheels you get this effect. I believe I've read about gearbox friction issues in that gear before, but the weirdest thing is that when I reconstruct the gear sequence to the original version of the manual (1 - 3 - 2 - 4) the friction is severely reduced and the L-motor manages to run through all gears without stalling. Without the 3 axles of steps 267-269, everything goes smoothly in every gear. But once I add those 3 axles in Paul's configuration, one particular gear gives an abnormal amount of friction. I believe it's the two black gears added in these steps that somehow don't revolve with the same speed or something, it's really an excessive amount of friction compared to the original version of the manual, and that just when adding these 3 axles in that order.

Has anybody else experienced this behaviour before? It would almost look like the original version has a much smoother gearbox than the mod (albeit in the wrong order). I'd find it hard to believe, after all the reports of people here who've applied the mod without adverse effect, but I'm a bit baffled as to why this would give so much more friction than the original version on this particular gear.

After applying Boratko's fix I also experienced the biggest issues in 2nd gear and also others reported on the same issue. There's a known issue with the red clutch gears that are not actually involved in one of the two clutches - the ones lined up between the normal 16t gears just in front of the actual gearbox. There is always one of them involved in transferring drive, which gives problems when its axle is forced into a very different rotation speed. Reasoning from the gear ratios in the gearbox I arrived at the following conclusions with respect to the RPM ratios between the mentioned red clutch gears and their axles for the situation with Boratko's fix:

• 1st gear, right clutch gear involved, gear / axle RPM ratio is 1:1
• 2nd gear, left clutch gear involved, gear / axle RPM ratio is 1:3
• 3rd gear, right clutch gear involved, gear / axle RPM ratio is 25:9
• 4th gear, left clutch gear involved, gear / axle RPM ratio is 1:1

So in 2nd and 3rd gear the axle of the involved red clutch gear rotates almost 300% faster or slower than the gear itself, Taking into account that the clutch gear will be pushed against its axle as it transfers drive, it's not strange that this causes severe friction. Especially in 2nd gear when the engine needs to rotate faster than in 3rd gear. Now let's see what the ratios are when we don't apply Boratko's fix:

• 1st gear, right clutch gear involved, gear / axle RPM ratio is 1:1
• 3rd gear, left clutch gear involved, gear / axle RPM ratio is 5:9
• 2nd gear, right clutch gear involved, gear / axle RPM ratio is 5:3
• 4th gear, left clutch gear involved, gear / axle RPM ratio is 1:1

These ratios are much better compared to the situation with Boratko's sequence fix. Especially 2nd gear, which has to work harder than 3rd gear, has a much better ratio. I think this explains the difference you're experiencing.

Actually, this would make the explanation given by TLG for having the 1-3-2-4 sequence partly correct. They said: "Too many gears are engaged at the same time and smooth running with all those tolerances is just not possible." Indeed, the 1-3-2-4 sequence allows for a more smooth running of the whole drive train. However the first part of the statement remains to be untrue, because in each gear all axles rotate and in each gear the same number of gears is involved in transferring drive from input to output.

Btw, as you probably already know, a way to avoid red gears from transferring drive on axles rotating at different speed has been described here and is also part of the unofficial errata.

Edited November 1, 2016 by Didumos69

[I3Brick]

Thanks for the extensive reply Didumos. That makes sense.

I had already read about those ratios and had indeed seen your mod to replace the red gears. But it's only now in experiencing the issue myself and you reexplaining the gear ratio problem that the pieces of the puzzle (or should I say gears) come together :-D. Not that I didn't believe your mod was useful, I just hadn't understood the exact issue it solved. Since you've provided the pictures to add in your mod for the red gears mid-build (at the steps I'm currently on), I'll give them a go and hope it solves the issue! I'll report back on my findings afterwards.

BTW, I can confirm your statement from one of those threads: "Also in my case 2nd gear has more friction when driven by differential than when driven by engine axle. Still nothing drastic, but there is a difference." Still find that weird as well, since you're still moving the same gear train, but that issue should be mostly solved as well when applying your mod.

Thanks a lot, a troubled model is at least teaching me a lot about gearboxes, thanks to you and the rest of the community :-).

 

UPDATE: I applied your mod for the axles and red clutch gears and now it indeed functions smoothly. It's amazing how much friction free running gears that are brushing up against an axle at different speeds can have . Very surprising. I tried hooking up an L-Motor to the gear box (not the differential) and it worked smoothly in all gears. Still using the original paddle shifter, without the 90° limiter or inverted change-over-catches.That worked smoothly still as well, so at least TLG got that right enough. Although I'm sure the modded version with the limiter and reduced friction in the selector mechanism will work with less force.

While disassembling the gearbox to make the changes I did notice one thing that made me less happy: very fine deposits of what I presume to be plastic dust on one of the axles of the gearbox (not one of the axles to be replaced by the mod). I've only been using a motor to test the setup very briefly for a few times, but clearly with so many gears (and the occasional stalling) you will wear things out quickly. It were only very fine spots, that showed rather well since it was light grey dust on a dark grey axle, so it wasn't disastrous yet. But I'm not so sure anymore that I'll be hooking up a motor anytime soon. I'll be able to show the effect of shifting gears on the fake engine by pushing the car, that will have to suffice I think.

Edited October 31, 2016 by I3Brick

[Didumos69]

2 hours ago, I3Brick said:

...

You're welcome! Good to know that this mod made a difference, also in your case. I appreciate you taking the time to make your own exploration - or should I say investigation - and to share your experiences. I'm affraid most people building this set don't really bother how the model behaves. This way it becomes a great learning experience, just like it was for me when I built this set back in June. And it's good to get some confirmation that at least some of my conclusions on this set actually make sense.

About the plastic dust; that's quite common, I even have it in my build without ever having used a motor. I don't worry much about it. I even tend to believe it gives the effect of dry lubrication, but maybe that's wishful thinking.

Edited October 31, 2016 by Didumos69

[t12ung]

On 10/22/2016 at 1:15 PM, Didumos69 said:

In my perception the most straight forward way to improve the front ground clearance was posted here, see first image below.

So I tried adding this to the stock model over the weekend. Am I right in thinking that this little MOD only serves to stiffen the existing front suspension only and doesn't actually give it any extra ground clearance? I've not put the chassis on yet but it feels VERY stiff with the added

@Didumos69 I had actually used the LXF file from your minimal errata and assumed the front suspension was stock model, but it's not  - It has a steering HOG built into it so workaround I had suggested for stock model wouldn't apply. Looking at the LXF file you just posted of this front section, there actually isn't a conflict with the  as it's positioned above the additional

@nguyengiangoc Did you try removing the existing front red shocks from original BI and use them with this MOD instead? If so how does it feel comparing to original set up?

 

Edited November 2, 2016 by t12ung
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