42056 - Porsche 911 GT3 RS - MODs and Improvements

[Didumos69]

@Didumos : Aren't your fake brakes touching inside the rims ?

Nice mod to get an Ackermann geometry too !

Thanks! I tested whether this would fit the rims and it does. The 4x1 square flat plate would not, but that one is still in the same position.

[JunkstyleGio]

Based on this thread...is the Porsche the most flawed Technic model ever?

I've been building the real model now and with the major five easy modulations forementioned and made by various people here on eurobricks.the model is fun to build, has awesome looks and works like a charme.

Like Blakbird said a few posts earlier: it IS a very good model!

Edited July 3, 2016 by JunkstyleGio

[Pangolyn]

I wanted the gears to shift properly (90° with no flipping back a bit) but I wanted a solution I could apply without taking the model apart.

I have a ton of axle 2 notched so I put one in each red thing:

This works perfectly and can be applied without too much trouble. The inner one is a little harder to insert but it's doable with a creative use of another long axle and an axle connector.

Continuing to build to verify it will work with the body added.

Edited July 4, 2016 by Pangolyn

[Saberwing40k]

Not even close. With nothing but the Step 5 (which requires no extra parts) my model works completely fine. Most of the things in this thread are improvements to make it better. Any set could be made better, I suppose.

Rather than the most flawed, I would say it may be the furthest from the expectations of AFOLs, but that is at least as much due to high expectations as low quality.

So, what do you think would be the most flawed Technic model? I think this one comes close, given how many of the functions do not work out of the box, and how long it was supposedly in development. But, I can see your perspective, where most of the criticism is for this set being too simple, rather than bad.

[Didumos69]

It's probably a matter of personal opinion whether this set is flawed or not. It depends on what you expect from this set. I personally expect gears to rattle happily and mechanical features to work properly. This might require some finetuning to minimize friction etc., but it shouldn't be necessary to change the model.

Fact is that there are numerous reports on a badly functioning gear shifting mechanism and on severe friction in the drive train - also from Jim, Paul Boratko and Sariel.

I have taken the paddle shifter unit apart several times and every time I rebuild it, it turns out to operate differently. Sometimes it works almost perfectly, sometimes it almost aligns on 90 degree positions instead of the ideal 45 degree positions. It's a bit of a gamble actually.

I analyzed the friction in the gearbox and I can't imagine anyone who has built this set to end up with

- especially in 2nd gear - without making changes to the model. Even after applying Blakbird's step 5 fix. If anyone did encounter happy gears in the out-of-the-box build, then please report on it.

So my conclusion is that this set has two major flaws: The badly operating gear shifting mechanism causing double engaged gears and the from friction suffering drive train causing the clutch gear to slip a lot in some gears. Both can be eliminated with a few very straight forward changes that I summarized in the 'Minimal version' sections in the OP of my ultimately playable thread.

Edited July 4, 2016 by Didumos69

[skppo]

So my conclusion is that this set has two major flaws: The badly operating gear shifting mechanism and the from friction suffering drivtrain.

Considering that these are two major ( and to me the only worthwhile ) features of the model, I can't see it as anything but a failure.

Sorry if a bit off-topic

Is anyone planning to implement a rear axle steering on this thing?

[JunkstyleGio]

After 14 hour of building time and with a little help from Emmet and Gail...

Awesome model.

Gearbox and pdk working fine.

Me one happy puppy!

Is it my moneys worth?

Totally, and that is not because I got it as a gift..

(Thanks to Edwin Korstanje BTW..)

Was it worth the extra month of waiting?

Again a full YESSS

(But that might be because i had the time of building the model in LDD and got to study all of the moifications.)

[Didumos69]

Awesome model.

Gearbox and pdk working fine.

Me one happy puppy!

...

(But that might be because i had the time of building the model in LDD and got to study all of the moifications.)

Great to see that you're happy with your Porsche. In the end I am too, but that's mainly because I like fixing stuff.

Could you let us know which modifications you applied? EDIT: Never mind, you posted about that already. Thanks!

Edited July 4, 2016 by Didumos69

[Didumos69]

Nice mod to get an Ackermann geometry too !

@DayWalker, I just finished my Ackermann version and it works as a charm. When you push the model without Ackermann steering, you can feel the tyre scrub resistance in turns. You can also see the outer wheel making jumps to the side every few inches to overcome the lack of Ackermann-steering. But now that I have incorporated Ackermann steering - which roughly boils down to your geometry - the resistance in turns is completely gone! This really adds to playability. Thanks again for hinting in the right direction! I will write a full build report on my playable thread tonight.

Edited July 4, 2016 by Didumos69

[Richard Dower]

Personally, I can't justify the price tag... I will wait until it drops to €250.

Also...pity no 1×9 liftarms in Orange... I need one.

[Didumos69]

I've been building the real model now and with the major five easy modulations forementioned and made by various people here on eurobricks.the model is fun to build, has awesome looks and works like a charme.

@JunkstyleGio, I see you incorporated the 90 degree limiter. Did you also drop the 8T friction gear?

[JunkstyleGio]

I did keep the gear and only replaced the conector to a non-friction one.

Something funny:

The Slip-gear only slips in chassis-mode, not in the fully build model...

Edited July 4, 2016 by JunkstyleGio

[Didumos69]

I did keep the gear and only replaced the conector to a non-friction one.

Okay, thanks for clarifying. Good to know that you removed the intended friction.

Something funny:

The Slip-gear only slips in chassis-mode, not in the fully build model...

This does not surprise me. The chassis by itself is not very sturdy and bends under its own weight. This bending causes axle connectors to rub against liftarms and gears to be squeezed. It is mainly Box 2 that adds stiffness. I don't see this as a flaw or something, even though I tried to improve on this in my build. A self-supporting body is actually quite realistic these days.

Edited July 4, 2016 by Didumos69

[efferman]

what do you say about this frontend? i know day light and radiators are missing

Edited July 4, 2016 by efferman

[ddeklerk]

what do you say about this frontend? i know day light and radiators are missing

When comparing it to the real thing, I would not place those vertical panel pieces so far apart.

Oh, and I am not sure about orange behind the headlights. The black matches the color of the actual headlights better I think.

I do like what you did with the very tip of the nose though.

Edited July 4, 2016 by ddeklerk

[efferman]

This frontend will not be for the 911, but for my 929 so i dont want fully replicate the gt3 rs frontend

[efferman]

i have worked a little bit on it. to let it look more like a 911

[__________________________]

i have worked a little bit on it. to let it look more like a 911

What is the difference?

[efferman]

you see no difference to yesterday?

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

[Didumos69]

News on the minimally playable version (see my ultimately playable thread): A few days ago I asked Blakbird to testdrive (= review) my compilation of the most essential 'community-driven' modifications - a.k.a. minimally playable version of the Porsche. Let me quote: "After everything, the model moves REALLY smoothly." Blakbird provided me with some useful feedback that helped me narrowing down the most essential modifications even further. There were a few things that did not really prove to add to the overall smoothness, for instance the 5x7 frame on top of the gearbox. As a result I decided:

- To replace the 5x7 frame on top of the gearbox with a more simple support for the axle running from the D+N+R gearbox to the differential.

- To drop the improved support for the toggle joint in the D+N+R gearbox. It didn't really add much and required a 13L liftarm to be replaced with an 11L liftarm.

- To revert to Attika's suggestion to simply flip the changeover catches in the PDK-unit instead of replacing them with 2L (+0)-liftarms. The replacement didn't really make much difference.

This means that the overall recipe for succes now boils down to the following modifications (I also updated this list in the OP of the ultimately playable thread). In case I will be able to narrow down this compilation of modifications even further, I will of course report on that in my ultimately playable thread. But that does not withstand the fact that the current set will guarantee a smoothly moving Porsche. Btw, especially for the gear shifting MODs it is important that you apply all of them. They rely on each other:

Gear shifting MODs (link)

- Apply Paul Boratko's gear sequence fix as described in Jim's review.

- Flip the change-over-catches in paddle-shifter-unit by 180 degrees (as suggested by Attika).

- Add the simple 90° limiter to the gear selecter axle; use two of the four white silicon bands.

- Remove the 8 tooth gears used to add friction; minimize friction in the selecter axle instead.

- Use only one silicon band for each paddle shifter; wrap it around the neck of the ball joint once.

- Extend both change-over-catches in the gearbox with half a stud (more info here).

Friction reducing MODs (link)

- Replace the pinjoiner in the D+N+R-console by bushes as suggested by Blakbird, see his detailed build report.

- Avoid red gears from transferring torque on axles rotating at different speed, see eliminate friction in gearbox.

- Add an extra support for the 15L axle running from D+N+R gearbox to differential, see alternative axle scheme.

- Avoid axle connectors from rubbing against liftarms as suggested by nerdsforprez, see alternative axle scheme.

- Replace the white clutch gear with a gearless friction clutch, see alternative axle scheme and white gear replacement.

- Now you can gear up the engine: Replace the 2 16t gears with a pair of 24t-8t gears, see eliminate friction in gearbox.

I also made an updated LXF-file available that reflects these modifications in terms of groups. In each group there is a subgroup representing the old structure and the new structure. In the LXF-file all new structures are embedded in the chassis and all old structures are placed to the side of the chassis. By clicking on a subgroup you select all parts in that group. That way you can inspect the differences. Besides the 'Minimal version' modifications listed above it contains HoG steering and a 4th to 1st gear block. If you want, you can skip the HoG steering; it's not essential for a smoothly moving model.

Next step will be to provide instructions by means of an errata-sheet with references to the building steps in the original building instructions and a parts list.

Enjoy!

(Sorry for double post, but I thought this would be useful info here too.)

P.S. Here's an image showing the complete set of modifications. The original parts are in the background:

Edited July 6, 2016 by Didumos69

[TheItalianBrick]

stretched tyres, anyone? :tongue:

I did put the 42000 tyres on the Porsche rim.....amazing result!!

[stumpypete]

So got my GT3 RS yesterday and just finished box 1. I would like to offer up a BIG THANKS to everyone who has posted mods, I implemented the shifter mod (flipped catches), extended the changeover catches, the reduce friction mod (step 5), the gear sequence mod, the avoid red gear friction mod, and the 8-24 engine mod.

It runs like a dream!!

Stumpy

[Didumos69]

So got my GT3 RS yesterday and just finished box 1. I would like to offer up a BIG THANKS to everyone who has posted mods, I implemented the shifter mod (flipped catches), extended the changeover catches, the reduce friction mod (step 5), the gear sequence mod, the avoid red gear friction mod, and the 8-24 engine mod.

It runs like a dream!!

Stumpy

Good to know!

[nerdsforprez]

my copy has finally come. I have been working on it when time allows. Thanks everyone for the changes and improvements that have been made thus far. I intend to make my own "ultimate" version, with many of the changes implemented thus far by others. My hat goes off especially to @didumos69 for quoting my recommendations and also for all the changes he has recommended.

Couple of questions:

we are all aware of Blakbird's recommendation on step 5. Great stuff. Something I implemented for a better working gearbox. However, quick question is that why should we be adding bushes anyway? I understand the contact is minimal, but using two full bushes still has some contact and therefore friction:

Now, I understand that this is usually done to avoid any gears or the 5L pin to slip/move, but really I see this as a threat only in a motorized model or something under significant duress. I don't see it as a threat for this model. Wouldn't it make more sense just to brace the pin with a 1/2 bush, such as this?

Here there is no contact whatsoever. Again, I know the above contact is minimal, but as we can see in Blakbird's original recommendation, even small decreases in friction have great results in the overall effectiveness of the gearbox.

Also.... and forgive me because I have forgotten exactly where this was posted (with so many posts and attention to this model, it is easy to forget where ideas are posted for the same model), but the brake calipers have gotten some flack because they do not resemble the shape of real calipers. TLG sought to rectify this with stickers. I, as with many others don't like this solution. in fact, does not seem like a solution at all. Someone, somewhere recommended this piece

http://www.bricklink.com/v2/catalog/catalogitem.page?P=93273#T=C

and to my this seems like a good, obvious choice, but I don't think it was ever attempted or actually implemented to see if it would work inside the new wheel hub. I played with this a little, not alot, and likely there are better solutions, but using a 1x2 bracket (non-inverted- inverted will not work) this is what I came up with. Forgive the poor coloring on the bracket and 2L axle ends, I colored these in GIMP because I couldn't find these colors in my collection - although they are inexpensive and available in real life so it is something easily reproducible.

What do people think? Is this an improvement or not? I am kinda mixed..... I certainly like the shaping better, it is more realistic, but don't really like the black axle ends showing through.

[Didumos69]

we are all aware of Blakbird's recommendation on step 5. Great stuff. Something I implemented for a better working gearbox. However, quick question is that why should we be adding bushes anyway? I understand the contact is minimal, but using two full bushes still has some contact and therefore friction:

Now, I understand that this is usually done to avoid any gears or the 5L pin to slip/move, but really I see this as a threat only in a motorized model or something under significant duress. I don't see it as a threat for this model. Wouldn't it make more sense just to brace the pin with a 1/2 bush, such as this?

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 have no opinion on the calipers.

Btw, thanks for taking your hat off

Edited July 7, 2016 by Didumos69