42056 - Porsche 911 GT3 RS - MODs and Improvements

[Appie]

@DayWalker

Yes, but doesn't that only apply to countersteering? For crab steering your Ackermann will be inverted (or does the real model have no Ackermann at the rear at all for crab?) 

Edited May 21, 2017 by Appie

[DayWalker]

For crab steering, I am not sure there is a difference. Ideally, all wheels should be parallel, and they are not what ever the building.

[Kumbbl]

On 4. Mai 2017 at 11:02 PM, jb70 said:

Thanx for all your good ideas in this forum!

I published my MODs to pimp up my Porsche including 314 pages building instructions on Rebrickable.com.

Have fun to pimp up your Porsche, if you like!

Just built this "Pimp up my Porsche" from @jb70 - very enjoyable build, great instructions (errorfree), incorporates all essential MODs you need to change the somehow mediocre retail 42056 in a really great set, now also functionwise:

- stronger front suspension (retail is much too weak) with much better geometry with less bump steer und Ackerman - also better steering lock 

- oustanding indexer so now gear-switching is now 100% reliable, so NO gearbox stalling anymore

- fixiert step-5 erfror in the BI and in Addition much better gear-arrangement in the gearbox for frictionless spinning of all gears - the car now runs absolute free and smooth when pushed even in 1st gear

- prevetning from endless gear-sequence (ie. now you can not switch from 4 to 1 or from 1 to 4

- correct gear-sequence

- reinforced chassis so the chassis does not bend even without body 

- HoG (essential for playablity)

- removeable body (essential for demonstration all the goodies)

This means all fixes from the errata of Didumos69 are apllied and in addition some important stuff from his ultimate playable Porsche - all compiled into great PDF-instructions, even for free! Many Thanks, @Didumos69, many thanks @jb70

One recommendation: i strongly recommend not to apply the pin-connector clutch but replacing this with a simple axle 4L! Cause of the now guaranted 100% reliable gear-switching there is no clutch necessary - in contrary: it could be that the clutch slips (e.g. in reverse gear) without any danger for part damaging - without clutch all is working like a charm and the pistons just fly ;-)

But this is the only change i have made - with exception of this the Porsche of jb70 is simply perfect: great to build and great to play. Kudos!

Edited June 5, 2017 by Kumbbl

[tomek9210]

18 hours ago, DayWalker said:

Well, in order to reduce the stearing radius, the outer wheels must have a higher radius, and not the contrary. This lead to the geometry depicted in the following picture., and for front wheels, it leads to position the tooth rack in direction of the rear wheels.

With 4 stering weels, the centre of turning circle should be between the front and rear wheels, and so, the tooth rack for the front rears should be in direction of the gearbox (and not the engine for the porsche)

The gear rack may be installed either behind or front of the axle. The thing is that for front axle with front mounted rack, its pivot points should be further from the center of the vehicle, so the line leaded through this pivot point and suspended wheel pivot point reaches the centre of the rear axle. The same rule applies to the gear rack mounted behind the front axle. Look here:

For steering in the rear axle, the lines leaded through steering pivot points and suspended wheel pivot points should meet in the centre of the vehicle. Ideally of course.

[Didumos69]

Yea, the gearrack could be positioned on either side of the axles to obtain Ackermann steering. However, when using the new Porsche wheel hubs, it is practically impossible to bring the pivot points more to the outside, which is needed when the gearrack is on the bumper side of the axles (that is, I tried this and could not get it to work).

Below you see some Ackermann steering setups.

Crab-steering - The left setup shows what crab-steering on the Porsche actually means:

• There is an imaginary third axle without steering to the back of the rear axles.
• I assume the steered rear axles steer with less angle than the front axles.
• The Ackermann effect for the rear axles and front axles need to work in the same direction.
• The Ackermann effect for the rear axles needs to be much stronger than for the front axles.
• Crab-steering requires less Ackermann effect for the front axles than in a situation without rear wheel steering.

Counter-steering - The right setup shows what couter-steering on the Porsche actually means:

• There is an imaginary third axle without steering in front of the rear axles.
• I assume the steered rear axles steer with less angle than the front axles.
• The Ackermann effect for the rear axles and front axles need to work in opposite directions.
• The Ackermann effect for the rear axles needs to be much stronger than for the front axles.
• Counter-steering requires more Ackermann effect for the front axles than in a situation without rear wheel steering.

So, all together this means Ackermann steering makes a lot of sense for steered rear axles and the effect is desired to be much stronger for the rear axles than for the front axles. Secondly, Ackermann steering for the rear-axles should work in opposite directions for crab-steering and counter-steerinf. Thirdly, the ideal Ackermann effect for the front axles is slightly influenced by crab-steering and counter-steering: Crab-steering requires a little less Ackermann effect for the the front axles; counter-steering requires a little more Ackermann effect for the front axles.

EDIT: Here's a better image.

Edited May 22, 2017 by Didumos69

[Jeroen Ottens]

37 minutes ago, tomek9210 said:

The gear rack may be installed either behind or front of the axle. The thing is that for front axle with front mounted rack, its pivot points should be further from the center of the vehicle, so the line leaded through this pivot point and suspended wheel pivot point reaches the centre of the rear axle. The same rule applies to the gear rack mounted behind the front axle. Look here:

 

For steering in the rear axle, the lines leaded through steering pivot points and suspended wheel pivot points should meet in the centre of the vehicle. Ideally of course.

I am not so sure about your ideal setup. If you would have Ackermann on both sides you can make them meet in the middle of the car. But I guess it depends on the handle characteristics whether or not that is the ideal point. Maybe a two-third / one-third ratio between the two axles is better. Or maybe you even need to place the virtual point behind the rear axle, or in front of the frontaxle (the last two are probably only interesting from an entertainment point of view). The point is, you can arbitrarily put it somewhere by changing the geometry of the steeringracks.
And none of this solves the question how to deal with the two steeringmodes...

 

Just now, Didumos69 said:

Yea, the gearrack could be positioned on either side of the axles to obtain Ackermann steering. However, when using the new Porsche wheel hubs, it is practically impossible to bring the pivot points more to the outside, which is needed when the gearrack is on the bumper side of the axles (that is, I tried this and could not get it to work).

Below you see some Ackermann steering setups for a 6-wheel vehicle. Forget the setup to the left.

Crab-steering - The middle setup shows what crab-steering on the Porsche actually means:

• There is an imaginary third axle without steering to the back of the rear axles.
• The real rear axles steer with less angle than the front axles.
• The Ackermann effect for the rear axles and front axles work in the same direction.
• The Ackermann effect for the rear axles needs to be much stronger than for the front axles.
• Crab-steering requires less Ackermann effect for the front axles than in a situation without rear wheel steering.

Counter-steering - The right setup shows what couter-steering on the Porsche actually means:

• There is an imaginary third axle without steering in front of the rear axles.
• The real rear axles steer with less angle than the front axles.
• The Ackermann effect for the rear axles and front axles work in opposite directions.
• The Ackermann effect for the rear axles needs to be much stronger than for the front axles.
• Counter-steering requires more Ackermann effect for the front axles than in a situation without rear wheel steering.

Now here you see the issue quite clear. In a car that has both modes the middle wheels of the middel picture are the same the rear wheels of the right picture (the other rear wheels are the virtual ones). And the gear rack is at a different location for both modes. So either you use two gearracks (which also automatically changes the direction of the steering angle). Or you use a straight setup (which effectively gives you a pivot point at an inifinite distance for both crab and counter steering.

Right?

[DayWalker]

3 hours ago, Didumos69 said:

EDIT: Here's a better image.

I was thinking about the "counter" solution, since our "Ackerman" mods leas to a center of the turning center that is located around the position of the seats : geometrically speaking, we can use the same systems as for the front rear with a small "error".

[DayWalker]

Hi guys,

Here is another mod. I have added a functionnal gear indicator on the dashboard, compatible with having a  front hog. The solution is based on a long tooth rack to transfert the position of the gearbox to the front part of the car.

Here is a photo of the system (note that the orange 1x2 liftarm should be under the tooth rack, but I changed it after I took the photos : when on top, it can touch 1x5 thin lifarm of the gearbox on 1st gear)

and how it can be inserted in the car (sorry, colors are different, since it was my test chassis...) for first gear. Note that the tooth rack penetrates the 4->1 gear solution, but when changing the gear, it goes further, and has no impact  ^ ^

and 4th gear :

As you can see, the tooth rack is shifted in direction of the front of the car by almost 3L. (To adjust the position of the rack, the 4th gear must correspond to the maximum extend of the tooth rack)

Under the chassis, we need to move few pieces to install the tooth rack :

And you can see that this solution is compatible with a top HOG :

... and TADA ! when inserted on the final chassis :

 

Edited May 24, 2017 by DayWalker

[Kumbbl]

On 23.5.2017 at 4:08 AM, DayWalker said:

Hi guys,

Here is another mod. I have added a functionnal gear indicator on the dashboard,..

 

@DayWalker Just implemented yur gear-indicator in a dummy-test-chassis (excerpt) and it works like a charm - but i'm wondering how you have mounted the driver seat - because the 12th tan bevel gear (which drives the 20th gear which in turn drives the gear rack) colides with the standard mounting point of the drives seat (a LBG 2x4 Liftarm thick)... could you please post a pic how yoz changed the driver seat mounting? Thanks a lot!

Edited May 24, 2017 by Kumbbl

[DayWalker]

59 minutes ago, Kumbbl said:

@DayWalker Just implemented yur gear-indicator in a dummy-test-chassis (excerpt) and it works like a charm - but i'm wondering how you have mounted the driver seat - because the 12th tan bevel gear (which drives the 20th gear which in turn drives the gear rack) colides with the standard mounting point of the drives seat (a LBG 2x4 Liftarm thick)... could you please post a pic how yoz changed the driver seat mounting? Thanks a lot!

The fixation of both seats has been changed to allow an easy remove of the body. In fact, I fixed them on the body directly, as shown on this photo (in the background, we also see the inside door handle ^ ^):

[Kumbbl]

ah, i'm a fool - i have already applied the body-removal MOD so i could find this solution for myself if i would have switch on my brain ;-)

Thanks for your fast reply!

Another question: cause of the driving axle for the gear rack now the DBG part of the CV-joint (which connects to the paddleshifting unit) can not be mounted anymore ... Have you replaced the two CV-joints by two U-joints?

[DayWalker]

44 minutes ago, Kumbbl said:

ah, i'm a fool - i have already applied the body-removal MOD so i could find this solution for myself if i would have switch on my brain ;-)

Thanks for your fast reply!

Another question: cause of the driving axle for the gear rack now the DBG part of the CV-joint (which connects to the paddleshifting unit) can not be mounted anymore ... Have you replaced the two CV-joints by two U-joints?

In fact, I have put a U-joint connected on the 5.5L axle present on the chassis. On the other side, I use a 4L axle, connected on the CV joint connected on the paddle system side. So 1 CV joint and 1 U joint ^ ^

[Kumbbl]

@DayWalkerKudos to you and both your MODs: The gear indicator and the prevention from having 4 reverse gears. I have now both integrated in my Porsche (built the wonderful package "Pimp up your Porsche" by @jb70 - which i have already praised some posts above) - both your MODs can be very easily integrated in jb70's Porsche implementation! The few needed changes are very obvious and easy to manage.But one remark: Especially the gear-indicator MOD can not be build in the already built model - for this mode you have to go to the beginning because the mode-gearbox has to be dismantled and has to be mounted differently to the LBG bottom frame.

Both MODs are so well integrated into the mid console so they are invisible after applying the black curved panels:

(I will replace the 4 yellow half bushes of the paddles with blue ones so indicator and paddle have the same color - unfortunatelly the exist no yellow 1x2 liftarms thin).

Side of the gear-Indicator - only the black 20th bevel gear is visible (and of course the blue indicator at the dashboard ;-):

Side of the prevents from having 4 reverse gears-MOD:

A remark to this MOD: Overall i prefer DayWalkers's solution to that one from Appie because (a) it is more realistic (because it prevents from engaging reverse or normal mode if another gear than 1st one is engaged - which is as in the real cars) - with Appies solution you can engage reverse/normal-mode regardless of the current engaged gear. And (b) DayWalkers solution can be combined with his gear-indicator-MOD (Appies solution can not be combined with DayWalkers gear-indicator-MOD!) which is IMHO quite essential for a sequential gearbox: the driver (and of course also the HoG-driver ;-)  of a car should/must always know which gear is currently engaged - and in case of a sequential gearbox this is quite impossible without a proper gear-indicator - and this feature-lack is eliminated in quite an optimal manner by DayWalkers's solution - Kudos to you, DayWalker, works like a charm and is a very clean and robust implementation.

Summary: The gear-indicator MOD is IMHO a Must-have-MOD and the preventing-from-having-4-reverse-gears MOD adds really realism value to the model and is also very well implemented - both can be combined very well and can also be integrated very easily into jb70's Porsche-package --> Strong recommendation!

@DayWalker i have made just very few and slight changes compared to your implementation - the most prominent one is the bearing and mounting of the vertical gear-indicator-axle - see following pics:

You see i have used a 3x5 liftarm (which is also used as bearing for the reverse-gear-slider) and some pins-with-pinhole instead of your triangle-solution. Reason: with the triangle-solution the black Liftarm 1 x 2 Thick with Pin Hole and Axle Hole (mounted at the front of the gearrack) can slightly (very slightly) collide in 4th gear with the triangles (even when using the modern version) which in turn could result in some stress for the indexer-module of Didumos69. With my solution this is impossible and works in all gears without any collision and stress.

Edited May 27, 2017 by Kumbbl

[DayWalker]

6 hours ago, Kumbbl said:

@DayWalkerKudos to you and both your MODs: The gear indicator and the prevention from having 4 reverse gears. [...]

 

 

Thanks for your comments ^ ^

And your changes are very interesting since it greatly simplifies the building and makes independant the needed changes to had a HOG and the theses two mods of the gearbox. It is also more compact, even if the vertical 5L axis is only guided by a single fixation.

Edited May 27, 2017 by DayWalker

[Kumbbl]

6 hours ago, DayWalker said:

It is also more compact, even if the vertical 5L axis is only guided by a single fixation.

well, normaly i always ensure that an axle is beared at least by two pinholes... but in this case

- the complete axle (two axles and 1 u-joint) is guided by two pinholes

- there is in fact zero torque to be transmitted

- the axle spins very slowly

- pins with pinhole stick very firmly in a pinhole

so alltogether the solution is exactly as robust as it has to be here... well, if you would like to change gears by turning the blue indicator we would need a much more secured and beared solution - but we don't want this ;-)

Edited May 28, 2017 by Kumbbl

[Didumos69]

@Kumbbl, @DayWalker, @jb70, I think something very interesing is going on here. I think @Kumbbl's build is the ultimate pimp-up version! It would be nice if somehow full instruction would be made available for this version too. Just a thought. The only thing I miss is my improved paddle shifter unit with shorter shifts and a more natural steering wheel position. For ease of building the white rubber bands could stay on top and replace the red rubber bands I used inside the unit. I could make a photo sequence if anyone would want to build that unit.

 

[DayWalker]

1 hour ago, Didumos69 said:

The only thing I miss is my improved paddle shifter unit with shorter shifts and a more natural steering wheel position. For ease of building the white rubber bands could stay on top and replace the red rubber bands I used inside the unit. I could make a photo sequence if anyone would want to build that unit.

 

I agree, it is better that the white rubbers stay inside ! In my deviation, they are still outside. However, I have changed a little bit the influence of the black 2M dampers to reduce strains in the paddle system. By comparison, it seems to be better than reversing the red change over catches (a single white rubber in the 90° locking system is then enough to control the gearbox). If somebody want to test it, it would be usefull to get a feedback ^ ^

I also have a different steering wheel position with a lot of place to manipulate the gear box commands : as you can see, it is very compact ! And it is compatible with the position of the inside handles for the doors (if any is interested, here is the LXF file)

 

 

Edited May 28, 2017 by DayWalker

[Kumbbl]

58 minutes ago, Didumos69 said:

@Kumbbl, @DayWalker, @jb70, I think something very interesing is going on here. I think @Kumbbl's build is the ultimate pimp-up version! It would be nice if somehow full instruction would be made available for this version too. Just a thought. The only thing I miss is my improved paddle shifter unit with shorter shifts and a more natural steering wheel position. For ease of building the white rubber bands could stay on top and replace the red rubber bands I used inside the unit. I could make a photo sequence if anyone would want to build that unit.

 

 

Didumos69, i would be very interested in this photo-sequence - thanks a lot in advance!

[Kumbbl]

another small enhancement, now related to @jb70"Pimp up my Porsche"-package: In this version the fron yellow calipers are mounted at the rear side of the front-axle - and because at this side there is also the gearrack with Ackerman-geometry mounted the calipers have to be mounted half a stud more below - but now the calipers rub quite strong at the front-rims so the car does not roll freely when you push it... my solution: just mount the calipers on the other side, ie. at the front-side of the front-axle - there is a free mounting point on the hub so the calipers can be build and mounted just as in the retail BI of the retail Porsche - two pics of the modified (compared to the BI of jb70!) calipers and the modified gearrack-hub-mounting:

new caliper mounting at the front-axle:

Mounting of the gearrack to the hub:

Both changes are quite obvious but i thought i report them here so the ultimate pimped porsche comes closer ;-)

With this changes now nothing prevents anymore the Porsche from rolling absolute freely when pushed by hand with a strong impetus - even in 1st gear - kudos to Didumos69 and his pimped drivetrain of his errata (contained in jb70 BI-package)

Edited May 28, 2017 by Kumbbl

[DayWalker]

13 minutes ago, Kumbbl said:

 

Why not using a thin 2L arm ?

Edited May 28, 2017 by DayWalker

[Kumbbl]

for which purpose? ah, i see, you mean for the mounting of the gearrack to the hub, right? Well, i was not sure if there are axle-towballs... and i wanted to use as much as possible of the parts of 42056... but of course you are right: with a thin 1x2 liftarm and an axle towball you can mount the calipers also on the rear side of the front-axle - but does this really matter? AFAIK one side is as good as the other, isn't it? ;-)

Edited May 28, 2017 by Kumbbl

[DayWalker]

So that breaks/calipers are on the same side as the real GT3 RS ^ ^

 

(sorry, I have added a photo on the previous post)

Edited May 28, 2017 by DayWalker

[Appie]

In the real car they are mounted at the rear of the front wheels. (edit: woops just noticed another page to this topic with DayWalker's reply) 

@Kumbbl Also, from your images of the gear indicator mod I see nothing of my reverse mod that wouldn't be compatible. Your choice to use it or not obviously, but I see nothing that would stop the 2 from co-existing.

Perhaps the 4x2 liftarms behind the console would be in the way, but I question their necessity in general for this mod. Though it's probably just to keep the chassis rigid without the body. I personally don't care for that feature, because current cars also have the feature that they get their strength from the body as well. 

Edited May 28, 2017 by Appie

[Kumbbl]

@Appie: they are incompatible! Reason: for the gear indicator the mounting of the LBG vertical thin liftarms of the mode gearbox to the LBG baseframe has to be changed: the left perpendicular connectors (see pic below) have to be moved to the middle pinhole of the frame to make place for the gearrack. So the middle pinhole of the frame is blocked by a black 2L pin - and this is the pinhole where your MOD routes the new axle which passes the gearbox.... see the following pic:

And i see no easy and robust way to reserve this middle pinhole for your MOD if the gear indicator of DayWalker should be applied...of course one can combine your MOD and this gear-ndicator but this would require a complete redesign of the mode-gearbox-module and its mounting to the chassis - at least IMHO...

9 hours ago, Appie said:

Perhaps the 4x2 liftarms behind the console would be in the way, but I question their necessity in general for this mod. Though it's probably just to keep the chassis rigid without the body. I personally don't care for that feature, because current cars also have the feature that they get their strength from the body as well. 

In general and in real life i would agree with you but not for the Lego Porsche model: because the body hides completely all mechanics you can only demonstrate the features without body (therefore the removable body MOD). And therefore especially THIS chassis has to be as rigid as possible also without body... and - at least IMHO - it is good supercar buildingstyle to design a Lego chassis with best possible rigidity for itself: most Lego bodys i saw until now are way to fragile - or if not fragile then at least far away from being stiff enough (especially the very important A-frame of the windscreen is really without any stiffness in the bodies of lego supercars) to serve as a serious rigidity-factor for the complete car...

Edited May 29, 2017 by Kumbbl

[Didumos69]

16 hours ago, DayWalker said:

I also have a different steering wheel position with a lot of place to manipulate the gear box commands : as you can see, it is very compact ! And it is compatible with the position of the inside handles for the doors (if any is interested, here is the LXF file)

Also a nice solution, but the only problem I have is that in your approach the steering wheel is tilted too much. In sports cars the steering wheel orientation is usually almost horizontal.

16 hours ago, Kumbbl said:

Didumos69, i would be very interested in this photo-sequence - thanks a lot in advance!

Okay, I plan to do that next Wednesday.