tripletschiee

42056 - Porsche 911 GT3 RS - MODs and Improvements

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About the bushes in the D+N+R-gearbox. They can actually be left out completely, so no bushes or half bushes at all. The 12T gear is locked up by other gears and the axle - with end-stop - is locked up by an adjacent 13L liftarm. I think it was DayWalker's model where I saw this first. But of course, the half bush in your image won't harm either.

I confirm that I removed all the bushes, and it was visible on one of my photos, you are right ! The idea was simple : reduce friction and let a little more spacing between the perpendicular axles.

Porsche_gearbox_7.jpg

Edited by DayWalker

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Has anyone made the Lego 42056 Porsche GT3RS in Lego Digital Designer? If so, could you please post the file. I want to experiment with the different mods before I apply them to my Lego GT3RS.

Edited by LegoExoticCarBuilder

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two small mods on the tail, the first one is a cleaned "B├╝rzel" and the second is a modified taillight cover

http://www.doktor-br...-Porsche-B-lxf/

For what I know Efferman had the best shot at it sofar. I had some problems with LDD crashing after moving the outer body, box 3 and 4, but box 1 and 2 are surely okay. Box 3 and 4 can be selected from the group's tab to move or remove them.

Btw, great thanks to efferman!

Edited by Didumos69

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Hi,

So I decided to use the space left over space from the original model to fit some motors and a battery box in. I replaced the drivers bag with the battery box then plugged an XL motor into the bottom and plugged a servo motor into the bottom too to steer the wheels.

I have yet to link the other side of the steering motor to the steering wheel but so far it looks pretty good!.

Here are the photos. I tried to make the mod as less invasive as possible so there are about 57 parts left over that will just go in my parts bins.

Here are the results so far: I put the bag inbetween the two seats by using the two spare holes on the back end of the rear 3x11 black panel.

800x452.jpg

800x452.jpg

800x1415.jpg

800x1415.jpg

800x1415.jpg

800x1415.jpg

800x452.jpg

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I wonder if it is possible to add power function (either 2 XL motors or 2 L motors) to drive the gearbox+wheels, after doing all the mods and reduced frictions.

I am still waiting for my box to ship but I don't think it will happen until August.

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@garymak/others who want to try:

I have tried putting 1L through gear train after applying most mods from didumos69 collection.

If the rear wheels are off the ground, all is well and you can see the differences of speed (and torque) between gear 1->4. You can see this in Jim's and Sariel's review.

If the rear wheels are on the ground, basically the car won't move at all due to its weight :(.

I tried 2L (hard-coupled) through gear train, no major improvement to make the car moves other than gear 1, crawling on gear 2-3, really no hope for gear 4 (torque too low).

After a while, the strain is too much and battery box protection kicks in and the entire system dies.

I tried 2L, on two battery boxes...

This makes the car heavier, it is more usable, but now the torque causes problem with some of didumos69 mods, especially the area where two longer axles that pass through red gears are split into four axles, each of these shorter axles only go 1/2 stud inside the holes.

This area will break under heavy torque... so can't be used for RC :(.

Changing gear midway when the car is running frequently jams the entire system :(... Or maybe I did things wrongly.

I initially want to make an RC gear shift system so that after rolling the car on gear 1, I can progressively make it faster to gear 2, 3, 4... This idea is put on hold for now.

At the moment I give up channeling the 2L on 2 battery boxes through the entire gearbox :(...

I now put the output directly to the differential and now it can move the entire car with reasonable speed :).

So basically, my 42056 is now a very very expensive medium-speed RC car :O.

Didumos69/Daywalker suggestion to make partial Ackerman Steering (can be automated with Servo motor) helps with steering though.

It is currently one of my smoothest Lego Technic RC in terms of turning capability. Maybe the new wheel with positive offset also helps too.

To make this set's original feature (PDK gearbox) usable on RC system, need to wait for more mods involving PF to start appearing.

Hopefully there are more people who can come up with such PF mods :).

Bonus: We can also put PF light under the iconic 911 front light. It is cool :D.

Edited by stevenhalim

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Thanks for this clear and exhaustive report.

This area will break under heavy torque...

What exactly breaks? Does the gearbox split? Would it help to have lengthwise liftarms along the midsection of the gearbox?

EDIT: Like in my sturdy without body MOD:

400x225.jpg

Edited by Didumos69

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I think the whole drive train would have to be redone..... perhaps not. Need to look at the gearing. Don't have time to do it now..... but someone should compare the gear ratios of 42056 to Sheepo's Mustang. Both have around the same piece count (Sheepo's Mustang actually has more) and have two L motors for propulsion. Sheepo's Mustang is not going to break any land speed records.... but it looks like it runs just fine in all gears. Having built his model myself, I can also attest that there is a lot of friction in the gear box, just like 42056. Also, his has more motors...(steering, brakes, etc.) so I assume it would be heavier than 42056 yet runs fine on two L motors. My guess is the main differences are in the gear ratios......

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you see no difference to yesterday?

anyway the holes are filled, unfortunately no curved 7x3 panel

What tool do you use? MLcad from Ldraw has all the parts available? I am now almost finished with the model in MLcad. Especially the flex axles are a pain to get those right. This second front I like more than the first one. This little change on the nose makes the subtle difference.

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I did scan this post if somebody did try to get rid of the rubber bands in the Steering Block, I couldn't find one. After a few rounds I came up with this solution and it works pretty well.

In the first layer on top of the beam frame add 2 shock absorbers:

1468094737m_DISPLAY.jpg - 14680947371_DISPLAY.jpg

14680947372_DISPLAY.jpg

I still don't have the set myself so can't test if it works. I rebuild it myself with my own parts and it works well a bit strong when using extra stiff ones. The normal ones with black pins works better to my opinion.

Edited by aefferen

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It bothered me that the clearance of the final model was so bad. Especially in the front. That is why I decided to modify the front suspension. And this is the result.

800x1067.jpg

800x600.jpg

With this mod the front suspension has just about as much travel as in the rear, which is much better in my opinion.

Edit: I quickly discovered that the half pins limit the travel of the gear rack somewhat. Perhaps there is another way to secure the L-shape thin liftarms to the wishbone pieces?

Edited by ddeklerk

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It bothered me that the clearance of the final model was so bad. Especially in the front. That is why I decided to modify the front suspension. And this is the result.

800x1067.jpg

800x600.jpg

With this mod the front suspension has just about as much travel as in the rear, which is much better in my opinion.

Last week, I worked almost on the same geometry, since it is compatible with the Ackerman mod, but I did not finished it. Is the height of the front of the car a little bit higher with the body ? How much is the difference ?

The other advantage of this building is that if the rotation of the wishbones is the center of the 3x3 L gray parts, there is no parallelism issue in the ackerman geometry, but the effective strain of the spring is divided by 2... and so the variation of the height of the front due to the weight of the body ! Therefore, it is also possible to use 2 springs with such a geometry, instead of one !

Edited by DayWalker

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It bothered me that the clearance of the final model was so bad. Especially in the front. That is why I decided to modify the front suspension. And this is the result.

With this mod the front suspension has just about as much travel as in the rear, which is much better in my opinion.

Edit: I quickly discovered that the half pins limit the travel of the gear rack somewhat. Perhaps there is another way to secure the L-shape thin liftarms to the wishbone pieces?

I was already expecting you to come up with something.

I like the concept. Did you test it with body? There is more travel, but the resistance is less. I'm a bit affraid the weight of the body will completely compress the shocks. But like DayWalker already suggested, it could be extended with a second shock.

Can you make the half pins point inwards. Requires maybe a bit of stress on the suspension arm while putting them into place, but I even managed to put a 3L pin inside this type of suspension arm for the same purpose without damaging it. They are quite flexible.

Edited by Didumos69

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Currently busy with something different. I am still convinced that TLG had a brilliant opportunity to come-up with an upgrade of the steering

technology. So what I did I studied macpherson and other ones and studied the steering from this real Porsche. Conclusion is that we need a

Shock Absorber with a towball on top. Currently I am busy finishing the STL-files to have this produced by Shapeways. However this is easier

said than done. I made a picture impression. I am not sure yet if I need a tow ball on both ends. Any ideas?

14681385331_DISPLAY.jpg

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Currently busy with something different. I am still convinced that TLG had a brilliant opportunity to come-up with an upgrade of the steering

technology. So what I did I studied macpherson and other ones and studied the steering from this real Porsche. Conclusion is that we need a

Shock Absorber with a towball on top. Currently I am busy finishing the STL-files to have this produced by Shapeways. However this is easier

said than done. I made a picture impression. I am not sure yet if I need a tow ball on both ends. Any ideas?

Nice idea!

I wouldn't use a towball though. I'd say you need a pin or pin hole (facing downwards) at the bottom to be able to make the spring and wheel hub a solid unit. The wheel hub should then be able to rotate around the bottom of the spring. That"s also how real MacPherson setups work. The top of the spring doesn't need to change IMO.

Edited by Didumos69

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I like the concept. Did you test it with body? There is more travel, but the resistance is less. I'm a bit affraid the weight of the body will completely compress the shocks. But like DayWalker already suggested, it could be extended with a second shock.

Can you make the half pins point inwards. Requires maybe a bit of stress on the suspension arm while putting them into place, but I even managed to put a 3L pin inside this type of suspension arm for the same purpose without damaging it. They are quite flexible.

I did test it with the body yes. And the shocks are not compressed that much actually. Here is a comparison.

Before:

800x600.jpg

After:

800x600.jpg

And I cannot turn around the half pins on the suspension arms. Or if I would, I'd have to modify the way they are attached to the chassis. This is because the liftarm that the lower suspension arms are attached to would interfere with the half pins. Maybe this mod would work with the Ackerman steering mod, but I have not looked into that enough. And I would want this mod to work without any other mods too.

And for anyone wondering - here are the added parts.

800x600.jpg

I removed the four 3l axles with stops and half bushes, but those axles could just as well be used in place of the axles I used here. And the half bushes could be used in place of the 2l thin liftarms that I used. Both reducing the required parts even more.

Edit: As it turns out, the half pins are not as much in the way as I expected. That is at least when you have the stock steering limiters in place. That is to say the 3/4 pins attached to the gear rack hitting the orange (+o) liftarm. When the steering wheel is at either extreme position, the half pins from my mod only push the gear rack slightly and it does not limit the steering any more than the stock limiters.

Edited by ddeklerk

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Nice idea!

I wouldn't use a towball though. I'd say you need a pin or pin hole (facing downwards) at the bottom to be able to make the spring and wheel hub a solid unit. The wheel hub should then be able to rotate around the bottom of the spring. That"s also how real MacPherson setups work. The top of the spring doesn't need to change IMO.

I see your point and was doubting as well what to do. Finally I decided to stick with the 6.5L of this shock absorber. With your idea it has a length of 8.5L, longer but your idea gives more flexibility. Maybe I order both just to experience what is best.

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I did test it with the body yes. And the shocks are not compressed that much actually. Here is a comparison.

And I cannot turn around the half pins on the suspension arms. Or if I would, I'd have to modify the way they are attached to the chassis. This is because the liftarm that the lower suspension arms are attached to would interfere with the half pins. Maybe this mod would work with the Ackerman steering mod, but I have not looked into that enough. And I would want this mod to work without any other mods too.

And for anyone wondering - here are the added parts.

I removed the four 3l axles with stops and half bushes, but those axles could just as well be used in place of the axles I used here. And the half bushes could be used in place of the 2l thin liftarms that I used. Both reducing the required parts even more.

Edit: As it turns out, the half pins are not as much in the way as I expected. That is at least when you have the stock steering limiters in place. That is to say the 3/4 pins attached to the gear rack hitting the orange (+o) liftarm. When the steering wheel is at either extreme position, the half pins from my mod only push the gear rack slightly and it does not limit the steering any more than the stock limiters.

The difference is obvious! I forgot there was a liftarm inside the suspension arm, but apparently the half pins are not more limiting than the stock limiters.

I'm going to try to combine this with Ackermann steering in my ultimately playable build. That won't be straight forward, because my gear rack sliders also use the space where you mounted the shocks to the chassis.

Edited by Didumos69

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Here is perhaps an improved version of my former recommendation for the calipers in the front. To curve the rear calipers is fairly self-explanatory...... just use a bracket and the curved slope in the picture. Both are available in yellow. I like this design better than my other one..... you get to avoid using two 2L axles and don't have to deal with 1/2 1x4 liftarms. Pretend that the black piece (not the pin) is actually this piece:

http://www.bricklink.com/v2/catalog/catalogitem.page?P=15100#T=C

I could not find it in LDD

14682567891_SPLASH.jpg

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For people who made an ackerman mod, there is a very simple solution to double the front shocks : quite usefull since the front wheels are almost touching the body

Porsche_front_shock_1.jpg

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I have not tried an Ackermann mod, but does that not limit the steering? I mean, it looks like the grey shock gets in the way of the wheel hub.

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