SlotForum banner Nissan GT-R GT3, 2022 DiSCA GT3 Spec

9334 Views 72 Replies 10 Participants Last post by  tamar.nelwan
Having finally received my long awaited Nissan(s) and posted on their appearance in stock form ...
..they may stay like that until we return from Rockingham's Tres Petit Le Mans...but def not much longer...
... as the #23 car will be raced by my team @ Suzuka in the DiSCA GT3 race of Jan 29th 2022.
So this topic will be on how we'll prep the car(s) to DISCA GT3 spec, meaning chipping it adding lights (that will be fun)
And the fabrication of some flexible lightweight components (vacformed interior & windows, laser cut rubber rear wing mounts)
Team might even have even a certain Italian guest driver. ( and no this time that's not Grunz)

Tire Land vehicle Car Vehicle Wheel

Hard Nut to crack.

This specific Italian gentleman has given me a very hard nut to crack, cause when I check the reference pictures of this exact car...
...and compare it to the car, I can only find some extremely small areas where I can possibly improve the stock car.
More than happy to extend the black on the side skirts, as reported masking on stock car not really a match to the fine finish of the rest of the car
Wheel Tire Vehicle Car Automotive tire

And there are the solid rearwing supports, these can be lasercut from rubber with some of the openings of the 1/1 wing.
Can also extend the slots for the supports further down the trunk, will give the rubber supports even more room to "Flex"
But look at the detail, Tail lights surrounds painted in correct color...even that embossed Nissan logo is represented on the car

So..make note, add red tow band and some mesh in the lower grille. Rear window seems to have a split frame underneath (decal?)
The only thing that looks a bit "off", is the back end of the roll cage...but haven't been able to score good ref pictures of it.
Wheel Car Tire Vehicle Automotive design

DiSCA GT3 rules have a more (box) standard approach , so no trick pod mounted diffuser on this car.
Stock screws already replaced with SV Workz Titanium M2.2. Side suspension will be fitted.
Not clear yet if 1,0mm Offset Evo pod will give 1,8mm Ground clearance under motor with 20,8mm ø Scaleauto Procomp wheels.
Regs require running Scaleauto Baby Sprinter motor, hope that won't piss off "Italian guest driver" too much.
But then again Pace car he will also drive will be fitted fully with stock parts...including stock traction magnets :oops:
Yep you read it right, Traction magnets, nobody is going to bump the Official Pace car off the track on the formation lap(s), as previously happend at Le Mans 😇

O201C chip obvious choice here, testing will determine if it should be mounted longitudinal or transverse (weight distribution)
Good thing about running that big GT-R is...plenty of real estate on chassis for either configuration.

Body works
Side skirts will be cut of chassis and glued to body, most likely will do the same for the front splitter to allow independent set-up of body and chassis.
4 small Body supports will be mounted in body right in front of rear wheels and behind front wheels.
4 grub screws will be added in chassis underneath to adjust ride height. Been there done that...doing it next month
Dive plates are integrally moulded with the body, pretty sturdy too...will have to see how those will withstand the challenges of Digital racing.

Stock body now at 23,7 total. Vac formed but detailed interior should save 3,5- 4,5 grams off. Not too much gain expected from vacformed windows... plastic windows are already at minimum. So estimate maybe 5 -6 gr max from total vacformed parts.
Which mean there will stil be a lot of (careful) dremeling & scraping to get the whole body down to 14-15 there's room enough for.....
Automotive lighting Product Black Motor vehicle Font

Light(s)..let there be
Estimate 3,5 gr needed for SP44 light kit to power plenty of LED's, Slot it has moulded front lights as separate parts, so these can be done off the car.
The only Jazz I might be able to add will be some pretty purple led light peeking through the front grille.
That is unless DrC and Flag Slot manage to get their "functional LED Number/ Position Display" functional in the next month.
Oh.... good finally see somewhere I can cut into the body, opening up the bumper for the bottom purple leds :)
Automotive tail & brake light Vehicle Hood Automotive lighting Car

Ok that's it for now, got my to do list for the Nissan(s) but next update will have to wait till next month... but definitely

To be continued

With kind regards
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The idea is that they do have to be "torn apart" ;-)
More seriously, Tamar and Gary have done a lot of testing when this rule set was put together.
The Procomp 3 rate of wearing on Ninco is good enough for a race of 1 to 1,5 hour.
The DiSCA GT3 Euro Series was set up such that teams have to use some strategy to with tyres.
Initially, the organisers handed out 2 sets of tyres and that was all that you got for practice, race 1 and race 2.
At the beginning of each race, the cars must have a clearance of 1.8 mm under the motor.
So you had to use both tyres over the practice session without wearing them too much otherwise you would not pass the 1.8 mm (I learned this the hard way on my first race).
I think it was (and still is) a very good race format.
Nice idea to involve tires strategy, just don’t get Binoto on your team and you’ll be safe 😉
I think in my first DiSCA race, I was Binotto (meaning I screwed up our tyre strategy)!
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Hi Tamar,
I comeback on this topic. Why have you choose sponge tyres instead of rubber ones?
Sorry for my ignorance, I though sponge tyres were commonly used on 1/24 scale but not on 1/32.
Hello Claude
No need to excuse yourself for your "ingnorance" as it has been quite a while since our "motivation" for why we picked Sponge tires for the DiSCA GT3 series was posted on SF may 2016. ;)
Here's the link to the original post

I reread the post and I still stand by all I posted more than 6 years ago.
There is one additional factor that isn't mentioned in the post and that is that with the Scaleauto "handout" wheels both organizers and racers could rely on the fact that each and every set that came out of the sealed blister wrapping would be perfectly straight and true, and perform accordingly.
A compound that required zero tyre prep during the DISCA GT3 events, just mount them and rub them in for 10 min and you were good to go.
The only thing that has changed in al those years is that now...the best option is the Scaleauto Procomp4.

With kind regards
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Tamar, in which respect the Procomp4 are the best? I know that they should be able to last longer, but then can they last long enough to have both races on a single pair of tyres?
Is there other aspects that Procompt4 are superior over the Procomp3?
They felt a lot better to me, easier to drive when new as they aren’t so grabby on the surface. Two races definitely possible.
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Hello Gio
In addition to Gary's remarks.

As GD mentioned before Sponge tires are more commonly used in 1/24, in general the perception of using sponge tires on 1/32nd cars is that they provide too much grip.
Which was why at the time we started the DiSCA GT3 formula we went for the then hardest compound available for 1/32nd scale, the Procomp3.
But immediately I started lobbying at Scaleauto to produce the hardest compound in their range, the Procomp4, for 1/32 as well.

Scaleauto Procomp4 is a harder compound than the Procomp3 (40-45 shore vs 30-35 shore). In general the harder the compound, the less the side wall of the sponge tire will be able to deform/flex and as such the less grip it will provide.
To a certain extent a harder compound will also have a lower wear rate. And from an organisers point of view... a bit less grip and bit more durability was what we were looking for.

As Gary mentioned "...the Procomp4 is easier to drive when new as they aren’t so grabby on the surface". This is a result of the harder compound deforming less when the wheels are trued.
All sponge tires deform slightly during the trueing process. The pressure applied during trueing bends the sidewalls slightly outwards which results in a minimal "convex" profile as the sidewalls bend back "up" after the trueing is finished.
Again the harder the compound the smaller the deformation, meaning that straight out of the box the Procomp4 has a less "convex" profile than the Procomp3 and will perform better with a more neutral handling.

One would expect the lesser grip of the Procomp4 to result in a higher laptime than the softer Procomp3 and over one lap, under ideal conditions, with a fine tuned set-up... this would be correct.
But not over the full duration of a DiSCA GT3 race. In general on the Procomp3 the lap times would tend to drop during the first 20 -30 minutes of the race, after which they would tend to start rising again.
This is due to decreased ground clearance caused by the tire wear which increases the magna traction and causes the car to develop more and more the extend that the car gets bogged down on the track. Requiring you to push harder and harder to maintain the same laptimes. It also increases the motor temp which results in less power.
With the harder Procomp4 you still have the same process of decrease/increase in lap times but with a lower wear rate the handling of the car will remain stable for a longer period than with the Procomp3. As a result your average laptime over the full race duration could be lower than those achievable with the Procomp3.

Procomp4, can they last long enough to run two (60 min.) races? My answer would be yes and not only because the harder compound can provide a lower wear rate but also because you have more tyre to begin with.
On DiSCA request the Procomp4 wheels are trued to a bigger diameter than the Procomp3 wheels (20.9mmø vs 20.6mmø)
This increase in tire diameter was requested to provide a bit more wriggle room for cars with stock Sideways and Black Arrow pods that (depending on set-up) could struggle to pass the 1.8 mm ground clearance on new tires...and the bigger tires look better too 😇

A last word on the durability, as I mentioned before, a harder compound will also have a lower wear a certain extent. Tire wear is mainly caused by the amount of tire spin.
For the optimum performance of a sponge tire a minimal amount of spin is required.
But with a set up that is too loose, and/or a driving style that hangs the tail out on every corner entry and might end of with just the same wear rate as a softer compound ...or worse.

With kind regards
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Thanks Tamar for the explanations! (y)
I wonder if after these years of usage, your view of the sponge tires is the same as it was originally.

Sorry to challenge you with this question, are these tires really make the differences or it just a way for the Disca association to etablish unique rules in our hobby? :unsure:

Please, note that I like the Disca regulations, I use them to setup my cars.

Anyway, by curiosity and for experimenation purpose, I've ordered a couple of set of this Scaleauto tires to see how tey work on my small wooden track.
Hello Claude
No problem mate, its always good procedure to have ones conviction challenged from time to time.
After 7 years of DiSCA GT3 racing (ok actually 5 years due to Covid19) with events run on rubber and sponge tires i.m.o. using Procomp sponge wheels is still the best option for GT3 when it comes to hand out tires.

Is it the perfect option? no, but in recent years most of its shortcomings, the High(er) costs and higher wear rate compared to rubber tires, have been attended too.
I.m.o the higher costs were never a problem, they were a small price to pay for both competitor and organizer alike to have a trued, good, equal and uniform hand out tire/wheel combination for a high level competition event.

With kind regards
A very interesting read about foam tyres.

Before I get shot down what about silicone tyres, true out of the packet and last years.
Before I get shot down what about silicone tyres, true out of the packet and last years.
No drive-by shootings here, but here goes why...

The main issue with silicones is that they only work on a track where only silicones are used. You can't mix rubber and silicones on the same track...
Can't run DiSCA GT3's with silicones and the next (or even same day) a DiSCA WEC endurance with rubber tires on that same track as the rubber tires won't have any grip left.

Also, the wear and tear of the tires is part of the race strategy and setup of your car (certainly for endurance-type events such as DiSCA WEC, where tire changes are part of the race strategy).

Also, some DiSCA events are run on permanent tracks, which would mean that all other club races should also have to be transferred to silicones.
So you want to run Group 5 cars the week after a GT3 race with silicones? Bad news, no grip whatsoever... Unless you change to silicones...
While DiSCA events are only one weekend a year on a certain track.

Too much disadvantages related to the use of silicones.
Foam tires don't have these major issues. Yes, they do "polish" the track surface to some extent, but not as much as silicones do.
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As the track is used for multiple events then the answer is obvious as you say.
Thanks Tamar, guys, for your answers.

Also, are you allowed to use oil on the sponge tires?
I saw this to be a practice to increase in the club I used to go to.
The downside is that the track became extremely gluy and durty.
Thanks Tamar, guys, for your answers.

Also, are you allowed to use oil on the sponge tires?
I saw this to be a practice to increase in the club I used to go to.
The downside is that the track became extremely gluy and durty.
Foams with goop is normal practice with the BSCRA guys with steel chassis and lightweight vacformed blobs but I'd bet oiling tyres for DiSCA would get you DQ'd
Thanks Tamar, guys, for your answers.

Also, are you allowed to use oil on the sponge tires?
I saw this to be a practice to increase in the club I used to go to.
The downside is that the track became extremely gluy and durty.
The best thing that works on the Procomp tyres (at least of the Procomp3) is the Scaleauto tyre cleaner:
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So sponge tires are cheaper than rubber ? I mean what diference makes using Scaleauto 19.5x10AS25 racing slicks or 20x11AS25 vs sponges , or is it the whole advantages (price, performance, degradation, easier to true, etc) that gives the sponge tires an edge over the rubber?

It’s a pure academic interest as nobody around here races on sponge tires and I don’t even have wheels for those tires, but I’m curious.
Scaleauto ProComp are mounted on the rim already. Makes them even easier for hand-out. And yes Kevan, treatments are prohibited.

The other factor which is slightly less relevant now we have a 63mm width, but when it was 62mm to allow Scalex bodies to be more competitive, the 9mm sponge tyre made it easier for the naturally wider cars (Sideways, Black Arrow) to “come down” to width than it would have been for a 10mm or wider tyre.

For example, NSR glued and trued tyres might have been a good hand out choice, but at 11.5mm, they’d have been too large to allow some cars (including NSRs own) to conform at 62mm.

Before anyone asks, we changed to 63mm for this year (ignoring covid delay) because there’s now a much wider (pun intended) variety of cars on the market now. When we launched, Scalextric had the most bodies available and they were generally narrower, being more true to scale. In combination, cars like the (amusingly under scale) Sideways 720s at 66.5mm look very silly with a 62mm axel width having wheels tucked well inside the body!
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From France, I can get a pair of sponge tires for a bit more than 8€, it's not cheap but they are on a wheel:

So, overall the price tires + wheels is fair, IMO.

About the wheels ''length'', why not set a limit by car model?
Like the McLaren 720S, as you said, why not take advantage of this car design?
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Because one of the things DiSCA rule sets set out to do, especially with GT3, is to facilitate as much variety as possible on the grid. Would you like to race a 62mm Porsche against a 66mm McLaren?

And the fact is that we’ve achieved that. If you look at our GT3 grids over the years the range of different cars has always been apparent. Scalextric body cars have both won races and achieved podiums and I think thats a direct result of us balancing the width around narrower cars.

Anybody that’s been racing slot cars for a long time knows that whether it’s a club race or national competition there’s always that one car that’s favourite for any given rule set. A look at the UK Analogue GT3 Nationals for example sees several years of “every car is a Corvette C7R” and has now become “every car is a Scaleauto Viper”. That sucks in my opinion. I’m not singling out this series btw, it happens everywhere.

Except DiSCA…

While it’s not quite true that every car in a twelve (plus..) car grid is unique, it’s happened on several occasions, and if there are duplicates in a field then there’s usually only two of any given car. That’s a huge win for the ruleset and one of things I’m most proud of having achieved with DiSCA as a whole.

While it’s true we could BOP every single car individually the amount of work to do that and amount of cost we would incur to test everything would be astronomical. While I wish that administering DiSCA was my full time job, it isn’t. I don’t even have regular access to a track, and Tamar, Gio and others are extremely valuable to our organisation because they do, and can test here and there.

DiSCA has a donate button on it’s website which has only been used once since 2015. And while I’m not lobbying for donations I would like to use it as an example that people don’t care what it takes to create solid rule sets and organise competitions of a high standard. They just expect it to happen. And again I’m not complaining, I’ve done this long enough to know this is just how it is. But if anyone has expectations for individual car BOP then you better get clicking that button so we can buy every car on the market, chip it, and spend 8 hours a day testing 😉
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Great post Gary (y) (y)
Hi Garry,

It make sense.
I would too encourage varity rather than monotype, so every one can pick up the model they like.

I saw that too in France that some races goes to monotypes for an equity pupose, because its easy to manage.

My two cents on donation; you don't get any income because if you don't provide an hardware or a software, no one see the value paying for a set of rules. Even you provide things peoples wants for free, you even don't get a "thank you".
IMO, you should change the approach if you wants get some income to finance your testing. I thought you were getting some income from the Disca races entry fee?

But you got me, I wanted to a donation but the Donation button send me to the Paypal homepage. So no user info for the donation and so no way to make one. Maybe that's why you don't get any.
Can you have a look?
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