[BAracer]

I thought that I would start a DiSCA GT3 themed thread in order to create a single source of knowledge on the topic where previously, individual queries or sharing of knowledge might have been spread across various locations.

My interest in the topic stems from a desire to compete in the DiSCA GT3 Race Series at some point. My interest in slot car racing was re-kindled last year after a 40 year gap, and the whole digital racing scene that has started up in the meantime has just got my juices flowing! Just to clarify, I am not an expert on the topic and am very much hoping that if nothing else, I will learn from others who have been doing this longer than me, or who are simply more technically skilled than I am at the moment. This is my current Work in Progress, a Scaleauto Porsche 991 RSR...

   


So, without further ado, lets start the thread, and what better to start with than the current DiSCA GT3 Rulebook!
   

GT3_technical_v7.pdf Size: 183.79 KB  Downloads: 235

[BAracer]

So the original press release for the 2020 races issued in November 2019 read as follows:

2020 UK DiSCA oXigen Championship: GT3 and WEC

 
We are pleased to announce the inaugural UK oXigen digital GT3 and WEC championship held by UK clubs.
 
The championship will be held over 3 weekends from July to November between Rockingham and North Staffs Slot Car Clubs. The technical rules will follow those established by the Digital Slot Car Association (DiSCA).

GT3

 
Technical ruleset as per latest DISCA GT3 rules. Available from http://www.officialdisca.com/
 
6 rounds of GT3 taking place on the Saturday of each weekend, consisting of 1 ½ -2 hour races for teams of two, with mandatory pitstop and enforced driver change.
 
Points awarded for pole position (2pts), fastest lap (2 pts) and finishing position (20, 16, 14, 12, 10, 9,8,7….)
 
Rounds 1 & 2: Rockingham Slot Car Club, Saturday July 25th
 
Rounds 3 & 4: North Staffs Slot Car Club, Saturday Oct 3rd
 
Rounds 5 & 6: Rockingham Slot Car Club, Saturday December 5th (revised date)
 
Entry to the championship is £5 per person (covers GT3 and WEC), which will cover trophies. Any surplus being used to purchase prizes for an end of championship raffle.
 
Best 4 of 6 rounds count towards championship. In the event of a tie, points scored in the other rounds will be used to determine the position of those tied.
Entry to each event will be managed by the respective clubs.  Note you will not have to enter the championship to race at each event, but priority will be given to those parties whom have entered the championship.

[BAracer]

So here is my starting point...

   

Made up of...

Scaleauto 991 chassis from the R-Series donor car
Slot.it anglewinder motor mount, 0.0mm offset
Slot.it 12/27 gears
Slot.it oXigen Type C chip
Regulation motor Scaleauto 0027b 18,000rpm "Baby Sprinter”
Regulation rear wheels & tyres, Scaleauto SC2018 ProComp-3 20.5 x 9mm 

With the intended Scaleauto 991 body, weight will be around 91g against the class minimum 85g. And I still have to fit the lighting kit, which will add a few more grams.

Some of the choices I made; 
Slot.it motor mount over the Scaleauto mount as it makes for a easier install for the digital chip
A 12/27 gear selection as this mirrors the original R-Series model. I have never raced at North Staffs or Rockingham, so have no experience to know whether this is the best choice, but I am expecting gear ratios to change over time as I get to know how the car behaves.
Slot.it oXigen Type C chip as I can set it to SSD mode so I can run the car on my home Scalextric track and try different tuning options.

There is a body with my name on on the other side of the world which, when restrictions become relaxed, will be winging it's way onto this chassis.

I would welcome any comments on preferred set ups from those of you who have raced in this series previously and have experience of the events.

[Nonfractal]

Jeremy ,

I see you haven't installed the hall sensor yet, A critical component. 
If the hall sensor is not installed working properly, you will skip laps on the counter (and every lap matters)
Get this sensor as low to the track as you can
Ensure you install the right way up.

Install a fly lead LED emitter whether you think you need it or not. It's a useful backup when the main LED gets dirty or the chip is dislodged in an incident. Install that LED with the right polarity! It's not necessarily intuitive so be sure to read the instructions.
A bad LED will impede lane change.

Read anything and everything by Tamar, then read it again...

Get the weight of the car down any way you can. Lightweight axles, wheels, screens etc. 

Ensure you have the kit to hand to lengthen the ratio. 

Get spares: chip, hall sensor, led emitter (and controller cartridge if you can )

Hope these tips are useful.
Alan

PS take that magnet out

[Tamar]

Hello Jeremy, looking forward to meeting you at one of the future DiSCA GT3 races

Nice topic and you've made some good progress with the Porsche.
A few remarks in addition to those made by Alan.

First off all some protective measures to prolong the life of your O2 chip:

1. get some small diameter heat shrink tube and isolate the bare metal legs of the ferrite man, the front leg is very close to the end bell, if your wire moves due to a crash ...short circuit = dead chip. While your at it, reroute the legs so that they will clear the rear body support tabs as the way you have them now will most likely interfere with your bodyfloat.
   
2. get a slightly bigger ø  5-8 mm long heat shrink tube that will fit over your Chip antenna, slide it down to the base of the antenna and secure with some flexible glue to the chip. Once glue has set shrink tube on top side. This will reinforce the base of your antenna and prevent it from braking off the chip.
   
3. Mount your chip flexible on your chassis this will prolong life, not only in crashes but also during regular running as it will dampen the vibrations and zillion little bumps as your car rides the track connections. My preferred mounting material : double sided foam tape and or foam pads. Avoid hot glue.
   

As for your desire to test run it on your SSD track, I'm no SSD expert but unless you have a upgraded powerbase the Scaleauto motor might be a bit too much for the system to handle.

Lat but not least, Order that lightweight vacformed interior for your Porsche and you'll be much closer to the min weight even with a light kit.

With kind regards
Tamar

[BAracer]

Thank you for the replies. It's seems its never too soon to optimize...I was just happy that all the bits went together and it ran round my track under its own steam! 

Just some initial responses.

That's no magnet. If Slot.it have made the effort to include a holder in it's motor mount, it would be rude not to fill it with something...that's one of their tungsten weights. I have lots of lead ready for when I start handling testing, but I hate to see a holder go to waste. 

I have a hall sensor, I hadn't fitted it for SSD running, but will now so I don't lose it. 

I will probably swop the motor leads round and put the FM at the chip end, as the Spanish do. 

Heat shrink wrap - I have tried different ways but have never managed to shrink any. Help! 

Remote LED - I have some of these so will have another go at fitting them...but I refer you to my problem above. Help! 

Chip position - If I fit a remote LED, I imagine it will sit immediately below the chip. Do I just lift it up on double thickness pads, or move it somewhere else?

Lightweight interior - that would involve a bit of detail painting, but I suppose I need to enter that mysterious world sooner rather than later...

[Nonfractal]

All good tips from TAMAR above  
Magnet or weight? Doesn't matter, I recommend you dump it. 
Cover the aperture with tape if the hole offends your sense of aesthetics.

Weght in analog cars ? I can put that down to personal preference.
In Oxigen cars, weight is the enemy. Tune your car by chassis & suspension adjustment etc. 
Weight and drag put load on the chip. Do anything and everything you can do reduce drag and weight. 

I guarantee that when you first do a DiSCA event, you will be aghast how much faster everyone else is using the same motors and same chips. 
There is no silver bullet. That speed comes from a  thousand cuts, every little innovation brings a little improvement in the arms race.

The best place for the flylead LED is right behind the guide, ahead of the chip. 
Drill the chassis if you have to) but never allow an LED to protrude below the chass is line. If and LED is exposed to the track and gets lens damage it will cease to work effectively. I have found that the flylead LED (in addition to the onboard chip LED) improves lane change response but I'm not sure why that would be.

Shrink wrap does take quite a lot of heat to contract it. I use a soldering iron.
Choose a wrap tube only just large enough to slip over the component you wish to protect. It does not shrink very much. 
Boxes of different size wrap tubes are available on ebay.
Be very careful when using shrink wrap close to the chip. Heat will fry it.
Dirt, vibration, short circuits, impact and heat will all mess up the chip.

If you are not going to use the hall sensor right away on oxigen, store it safely. The sensor is very fragile and does not tolerate being fitted, removed and refitted easily, especially the C-chip ribbon. You may end up changing the chassis during your tuning.

I forgot to mention, drill into the body, interior (and even windscreen if needed) to allow the antenna to protrude through. Dont bend the antenna!


Alan

[BAracer]

Ok, never let it be said that that I am not prepared to listen and learn...

Remote LED fitted [just held in with blutack at the moment, but maybe hot glue?]

Motor cable reversed to bring FM inboard and away from danger [?]

Tungsten weight removed [and to avoid leaving an empty slot, I have reverted back to the original R-Series Scaleauto pod]

So...I have got my head round getting a Lexan interior, and that relaxes the positioning options for the chip, which then negates the need for the Slot.it pod, and a part of me likes the idea of using the original motor pod. The scales would suggest the Scaleauto pod is 2.5g heavier than the Slot.it pod as the overall weight of the chassis has not changed...

   

[Tamar]

Hello Jeremy....hrrrrrrmmmm Sorry to have to say this, but you're latest update....i.m.o. one step forward, two steps back.

Yes you have eliminated the chance of shorting the ferrite man on the blank motor parts, but now your wiring interferes with both rear body support post.
Yes you have listened to Alan's advice and added a LC led on lead wires...but have not moved it that much forward from its initial position.
So no gain here, just more parts added and thus also and added possible point of failure. 
You have returned to the OEM Scaleauto pod but without the exploiting the main benefit of that configuration which i.m.o. is the central suspension at the front of the pod.

Not questioning your willingness to listen and learn.... but you have omitted the most important stage between listing and learning and that is to check what you have heard.. and verify for yourself by testing ;)

But before you continue, please do the simple mod of reinforcing the base of your antenna on the chip.
As in this stage you'll be handling the chip a lot and will bend the antenna left right and center. 
The only thing that's holding the antenna to the chip is a tiny blob of rigid soldering on the bottom of your chip.


With kind regards
Tamar

[Nonfractal]

.. and that is to check what you have heard.. and verify for yourself by testing ;)

With kind regards
Tamar

Testing DiSCA:
Testing has always been a problem for us GasMonkeys (and team KesselRun before that) 

Without access to an oxigen track in reasonable distance we've had to be creative. 
These are the steps to took:

Step1 : use a  tachometer to validate the motor. 

Step2 : hook the car up to a rolling road at 12v, pair it up to the SCP  then spin it up. 
Not as useful as for analog cars because we don't have enough baseline data.  Gearing for oxigen is completely different.

Step 3: analog track testing. 
We used an analog throttle in the club plug point and held it open on full throttle.
We then powered the SCP by a 9v battery to drive the car.
We were able to test the power, handling, lights and gearing this way on local analog tracks. 
Nasot Wood has the same Ninco track surface so is useful for wheel selection.
Wood green is scalextric/urethane but has smooth corners and has a long straight so is useful for gearing.

Step 4. : How To ? 
We have not worked out how we can test:
- the emitter LEDs for lane changing (incorrectly polarity stops it working) 
- the hall effect sensor for lap counting. (Installed upside down stops it working)
- set up an oxigen dongle to update firmware on the chip and SCP. 

Tamar, if you have any tips for step 4 , please let me know. 
Jeremy , expect DiSCA setup and testing to be an ongoing challenge 
Alan