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DiSCA GT3 Open Testing

13489 Views 62 Replies 8 Participants Last post by  tamar.nelwan
As Gary published the first DiSCA digital GT3 Open event and regulations this weekend, the expected questions about the how and why of certain choices were posted soon after. To keep the "event" thread clean and "on topic" (posts about entries and event info) I thought it might be a good idea to open a seperate topic on the tech specs etc etc.
So lets have those here

DiSCA GT3 Open, looking for a digital set up
Some of the test for the new DiSCA GT3 Open rules we done on the 32m Suzuka shaped Ninco track of the SRC Eindhoven in Best, NL.
Besides testing the Scaleauto Baby Sprinter motor for O2 compatibility we also tested the several tyre and wheel combinations we considered for the hand outs.

Below you'll find two tables, one with data on the magnetic pull of the different motors we tested and the influence of their ride height has on the magnetic pull.
The second table list the best laptimes we did with some of the motors with the different tyres and different ride heights.
Although the 2nd table lists the best lap times these were not the goal of our tests, they were just a reference tool.
The goal was to look for a set-up for the GT3 cars that would have "... a sharp level performance and drivability".

Preparation time of the hand out tyres/wheels
The first test we needed to do was to see how much time it would take to prepare the handout tyres from hand out into RTR wheels. Tested were :

NSR ultimate grip 20 x 11 (black 5230)
NSR WEC 20 x 11 (grey 5230) N22 20 x 11,3 (PT1171N22) F22 19,5 x 10 (PT27)
Scaleauto Procomp 3 20,5 x 9 (SC-2018)

As the time for tyre preparation will be limited at the GT3 events, I had set myself a target time of max 15- 20 minutes per set (requiring 30-40 minutes for two sets). Of the "rubber" tires the F22 required the least time (slips right on the wheel but benefits from slight trueing), the N22 and NSR tyres required the most (as they needed to be glued and trued). Interesting was that while both the N22 and NSR tyres are listed as ø20,5mm, when mounted on a ø17,3mm wheel they're actually above the 21mmø to begin with. Within the target time I managed to true the N22 and NSR tyres down to 20,8 and 21,0 respectively.
Additionally I needed to true at least one side of the tyres to a width of 10mm to avoid pinion clearance issues @ the max axle width of 62mm.
The Scaleauto Procomp3 sponge wheels required no preparation at all.

Motors and their Magnetic downforce in relation to their ride height (a.k.a Ground Clearance)
As all of the current O2 ready tracks that can host larger events have metal(lic)rails, the magnetic "down" force of the motors would be part of the equation in their suitability for the GT3 formula. Here we measured two values, the magnetic pull translated in grams on a Magnet Marshal and the ground clearance under the centre of the motor measured in mm. Why? Well first of all beacuse not everybody has a Magnet Marshal at their disposal and even if you do, calibrating them would be an issue. Secondly because, as you can see in the table below, the magnetic pull of a motor and its distance to the track rails are directly related to each other....and that relation is exponential.
Obviously the lower you get the harder it starts to pull, but if you look at the far right column (NSR Baby King) you'll see that the first decrease of GC by 0,5mm in increases the magnetic pull by 5gr, the second decrease with just 0,4mm increases the downforce by 10gr

What we were looking for was a motor that would have a similar level of downforce as a DiSCA LMP1, at a ground clearence that would keep the motor far away from the undulations of the Ninco track rails (≠1,6 mm) with a margin for the expected tyre wear. (hence 1,8mm)

image courtesy of

Track test 1, May 14th
After all the measurements had been done it was time to put the different specs through some track testing, you know.... the proof of the pudding and all that....
Base reference times were set with the NSR C6R in DiSCA LM spec (Flat6 closed side down with 14x28 gearing), starting with the F22's that were still on the car since Henley (refurbished by trueing @ 19,5mmø) The track was a bit green so it took about 20 minutes before I reached a stable grip level.
After 30 minutes I had managed a best time of 9,72 on the F22's with average lap times in the high 9,80 sec. An other 15 min session with the Scaleauto Procomp3 noted a 9,46 sec best and mid 9,5's average. These times were about 3/10ths above what I'd done with both compounds in the run up to the Le Mans race, but the narrower spread between best and average laptimes on sponge was the same.

First steps of the Baby (Sprinter).
With the base line now set it was time to swap the Flat-six for the Scaleauto Baby Sprinter. I must say that from the very first steps this "Baby" made on the track its was immidiately clear that it had the legs to match the Flat-6. Which in all honesty isn't a fair match to make, considering that in order to "Flatten" the "six" had to shave quite a bit off the top and bottom of the motor magnets. `
The extra torque of the Baby Sprinter gives it better acceleration, and to my ears it sounded like it revved just as high as the Flat-6 on the Suzuka main straight. After dailing in the SCP2 controller to cope with the increased powerband I noticed that I had bettered my best laptime on F22's by 0,2 sec but my average laptimes had not. Unless you nailed your corner entry speed perfectly and got your brake and accelleration points exactly right the F22's struggled somewhat in handling the extra load of the Baby Sprinter's torque.

Looking for a bit more grip.
So off came the F22's and on went wheels with the NSR ultimate grips, a tyre reputedly well capable of handling a bit of torque.
Well to be honest...I was a bit disapointed, yes the compound felt softer, more grip on acceleration but not as smooth, a bit more grip on corner entry but not really constant trough the whole corner. Best laptime was higher than the F22's but the difference between best and average was smaller. Swapped the NSR's for the equivalent and behold, the N22 performance was in many ways the same as the NSR rubber.

To be honest again, due to the time limit I'd set to prep the tyres, the large diameter resulted in a higher ride height and thus less magnet downforce. There were also some slight rubb marks in the wheelarches. Now I'm sure there's a lot more performance to be had from both compounds by spending more time on their preparation, but this is exactly what you wont have at the GT3 events.

For statistics sake I did a last test with a set of trued and glued NSR GT3 (grey) tires that had been worn down to ø 20mm.
With the smaller diameter rubbing issues were solved and the lower rideheight gave a bit more downforce.
The C6R now had a more stable handling trough the whole corner which gives you so much more confidence in attacking them.
As a result I managed to improve on the best time set on the F22's and with a much smaller difference between the best and average lap times.

Sharp level of performance... and drivebility
Time to test the Scaleauto Procomp3 sponge with the Baby sprinter and whoa, first lap a 9,38 and within 5 minutes (dailing in the SCP2) a best time of 9,25 with the ability to run comfortably in low 9,3's average. I guess had I pushed on for an other 15 minutes those times would have dropped further, so the "Sharp level of performance" was there, but that was not all we were looking for, drivability being the other main item.
Well with the sponge tyres you can dive deeper into the corners and once the car settles, immidiately start to put a load on the tyres while in the corner and thus start to accelerate before the exit of the corner. But the best thing about this run was that the car felt very safe. Even when you would exceed the range of the Motor magnets downforce there was enough grip left to catch the car in the slide.
The strenght of the sponge tyres lays in their increased lateral grip, which will be very helpfull in perfoming a succesful lane change.

Do the sponge tire have no vices then? Off course they do! Put to much load on the tyre and the sidewall will start to compress.
The first signs of you reaching that limit will be a lift on the inner rear wheel, back off quickly or you will risk pulling the car on its side and into the kitty litter.
Going for harder springs, running more on the front wheels and moving a bit off weight towards the front off the car are some of the options you can try here.

Track Power....less is more?
It had been a long day of testing but before I could close off there were still two test I wanted to do. First I wanted to double check to see how far improving track conditions had influenced the laptimes. So I switched back to the F22's I'd started with and did another 10min. run. Improved my best laptime by 0,02 sec, but average laptimes did drop by 0,2 sec. I could now comfortably run in the low 9,6 sec which now put the F22 more or less in the same range as the N22's and the NSR tyres.

During the track testing I had done on this day I specifically made no set up changes to the C6R, it ran well as it was, actually a bit too well.
Running alone on a clear track with all that power and (sponge) grip, challenged me to push harder and harder, as all I needed to focus on own car.
But this situation is not representative of the race conditions during a GT3 event.
Here you will need to divide your focus between running your own car and the position of the other cars around you.
So it was now time for the last test of the day, doing some 10min. runs at reduced track voltage settings.

Running @ 11,5 volts
As you can see in the table above just, half a volt reduction in track power increased the laptimes on sponge by 0,25 sec and 0,10 sec on the F22's.
But what was more relevant, it made the handling of the Baby sprinter much more docile, requiring less focus to keep the car's laptimes at consistant level with a smaller spread.

Running @ 11,0 volts
Running at 11volts increased the sponge times by 0,4 sec. and the F22 times by just 0,2 sec.
But this power setting killed of all of the "sharp level of performance" I had enjoyed all day, and although circulating the track was now almost a no brainer... did not improve the drivebility.
I actually had a couple of deslots because now you had to push the car all the time to compensate for the loss of power. And the only way to do so was to dive deeper into the corners, maximise cornering speed and and try to accelerate as soon as possible.
Now the extra grip of the sponge actually became a disadvantage, with not enough power to spin the wheels it was harder to keep the refs up and the C6R felt like as it was bogged down in sticky goo.

I would by no means claim that the tests I performed are 100% accurate and exact, or even approach academic testing...
..but they were thourough enough to give a good indication on how the different motor and tyre performances compared to each other.
Based on these test we're confident that the specs and rules of the new GT3 Open formula will provide the "sharp level of performance... and drivebility" that we were looking for.

I will continue to test some of the different cars and set-ups that can be used in the GT3 events and will post updates here.
Some of them you can already read in the posts below.

with kind regards

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I'll go make a coffee and make myself comfy for an interesting read
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Hello Kevan
Hope you didn't stay up too late last night...waiting for me to post......but dashing 650 km up and down to Gaydon on Sunday...finally caught up with me on Monday

with kind regards
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I'm a patient guy
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Hello Guys
Sorry for the delayed post, thx for the patience.
As I started to write the posts on the first test results of sat. 14 may, I found some issues that required some more testing before I would be comfortable with publishing them.
So last sunday I went back to Eindhoven to do some more back to back "endurance" testing.
Still haven't been able to find the time to process the test results into a table that displays all the data in a comprehensive way, but to keep you guys happy...
.... here's a teaser vid taken last sunday.

What you are looking at is a late afternoon session with me running my (by now old, tried and tested) NSR C6R Corvette with the Scaleauto Baby Sprinter...
...and Stefan Kievit running a brand new Scalex Bentley that he assembled that afternoon.
The Conti had a very basic set-up using the Stock body & windows, a MTR lexan interior, a 3d chassis an unsprung 0,5mm offset pod and a Baby King (only had one Baby Sprinter available).

We tested a feature in the oXigen Chrono RMS using the max.power setting on the fuel page to match the performance between the two different motors.
Running both cars @ 12,1 track voltage but with the Baby sprinter @ 75% max speed setting)
Laptimes during this session were in the 9,4 - 9,5 bracket, which would put them in the same league as a good wel set up NSR GT3,
running glued and trued NSR air wheels (17mm) with Ultra Grips (19x11mm) and + 20 gr magna force.

C6R and Conti, running the same 2:1 ratio (14x28 C6R, 13x26 Bentley), weights (85gr total and 19gr body) and Scaleauto Procomp3 wheels (20,5x9mm).

Prior to the vid I had done a 60 minute session with the C6R to doubble check the wear rate of the sponge tyres.
Based on my 1/24 experience with Procomp3 sponge on wood I had estimated a wear rate of 0,3 -0,5 mm p/hr for a 1/32nd car on Ninco,
but I was happy to see the actual wear rate to be far less (in the 0,1 -0,2 mm range) I really had to measure my wheels twice to see the difference.

During the test we were not looking for outright performance or fast laptimes, we were looking at possible handling and radio interferrence issues,
and how the cars behaved when running in close proximity.
All in all I must say that the cars were reasonably matched, the C6R more fluid and a bit faster down the straights, the Bentley a bit more "chuncky" but very stable.
With the 0,5mm pod the Bentley was pulling a whopping 28gr of magna force (measured on a magnet marshall) where as the C6R managed just 13gr (similar to Flat6 open side down)
When I checked the ground clearance of the Bentley it was 1,3 - 1,4mm. (C6R at 1,9mm)
I thought that the 0,5 offset mount would be equal to the NSR pod, but apparently chassis using a motor mount will require a non offset pods (CH29 or CH61evo6)
to clear 1,8 mm Ground clearance. Have ordered a 0,0 offset and will test again on friday.

to be continued

with kind regards
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Hi Tamar
Cool stuff. I have been watching that video over and over to try to memorize the track/throttle rhythm. ;-)
About the magna traction of the conti: did you measure it with the baby king (BK) or the baby sprinter (BS) on it?
AFAIK, the baby king has more magna traction than the sprinter. So basically although the BS has 1K more RPM over the BK, the BK has more pull.
You can definitely see the vette being a bit lose when exiting a corner and the throttle is open up. While the conti is more planted. In other words the conti is behaving more like a car with magnet on it.
Both motors are a good match with different compromises for speed over traction. I would like to see the BK as one option for motors in the specs for this class...but hey I am not Gary ;-)

I am really curious to see how the conti (that has a tall and heavy body) is going to perform with a 0 offset pod and a BS on it (with less magna traction than the BK).

Also, have you noticed any radio interference or link drops? In my experience, the BK is not an issue at all whit oxigen provided that the cart is working properly.
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Hello Gio

Lunchbreak so just a few quick replies
Scalex Bentley Continental was run/ measured with NSR Baby King @ 1,35mm Ground Clearance with 20,5 mm wheels, Magnet force on Magnet Marshal 28gr
I did measurements with a Scaleauto Porsche 991 with several motors and @ 2,35mm Ground Clearance with 21,25 mm wheels, Magnet force on Magnet Marshal was:

09gr Scaleauto Baby sprinter
14gr NSR Baby King

Now the Magnet Marshall is a very handy tool to compare, but not very exact (only one digit display)
But you can say that the differences in Magnetic pull between the Baby Sprinter and the Baby King would be that the Sprinter pulls 35% less or the King 50% more.
These differences may increase at lower GC's as the increase of magnetic force is not linear to the descrease in distance.

As for the Big Bentley's performance, it may look tall and heavy, its definately the biggest GT in the class, which is why I picked it for the test.
If we can make the Bentley behave as we want the GT3 cars to do...we can make them all behave

And don't forget in DiSCA GT3 spec the RTR Scalex body tips the scales @ 20,5gr just 1,5gr above the min weight.
To the advantage of the has the longest wheelbase of 87,4mm which is about 3,5 mm longer than average.
Last sunday we ran the Conti in a very basic set-upo, no springs, to wide and untreated front wheels etc etc. There's much more performance to be found

Last but not all the hours of testing with both Baby sprinter and Baby drops

with kind regards

to be continued
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Cool. really looking forward to how the conti is going to perform on a more advanced setup.
I have a 3d printed chassis for it.
Hello Guys

I finally managed to finish my initial post on the testing we did for the GT3. I have edited my original post as this is what will pop up should some one would use the "search" function at a later stage.
So scroll up for the test report, further updates will be added to the thread.

I'm currently working on two Bentley's (Scalex and TA71) with a BA F458 (with a stock and a Olifer3D chassis) and a Mclaren ( 3Dfab chassis) waiting in line.
Would be nice if some of the other cars being build for the Manchester event find their way into this topic as well.
Pleas feel free to post pictures..and questions for the GT3 Open formula

with kind regards
Very interesting. There's no reason sponge tyres shouldn't work well, I've used them on carpet, tarmac and polished wood surfaces for decades on my R/C cars.
Glad you found the post interesting Kevan, hope it was worth the wait. It took a while to write, lot of data, lot of text...few pictures

I agree, sponge/foam tyres are common practice for RC and 1/24 slotcars and to some extend for 1/32nd cars on routed tracks.
Not seen many of them being used on Ninco tracks, but at least in the digital Open GT3...that's about to change

Ok just plucked these from DiSCA's FB page where Matt Tucker shared the firt pics of the Black Arrow F458 they will enter for the South Manchester event.

with kind regards

"Underwood and Tucker's Rockingham entry in progress, just a few little bits to do but everything works well. Looking forward to the event at S Mancs on 31st July.
The innards. Not straight forward to install the digital chip. Have added a separate lane change LED on wires and placed that just behind the front body post."
( text and images by Matt Tucker)
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thread saved for future reference

...I like the look of that Black Arrow F458
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thanks for the time you have spent for testing, collecting, and posting these results.
I assume that the C6R was with the 14/28 gearing, but was the gearing of the conti?
Also, do you have any data for the conti with the scaleauto motor?

I have never used sponge tyres: these from scaleauto are already glued to the rims? No need for truing them?
The GT3 races will be around 1h racing so the spongy will be good until the end. But for longer races, how many pairs do you rekon will be required?
Hello Gio

Yes it takes time to test...and write test reports, but its also a big part of the fun

And for a new series under a new set of rules, the more information one can provide to the competitors..the better the competition will be.

As you may have noticed in the Laptime table, I have done some more (analoge) testing with the Conti in a more "advanced" set-up (May 27th)
The Src Eindhoven had GT3 clubrace that friday, they have also started opening up their previous strictly NSR GT3 class for other makes as long as they run a Baby King and NSR tyres.
So this was a perfect oppertunity to get some race milage with the Bentley...and after the race do some more testing with the sponge tyres.

That will be my next test report...with the Baby Sprinter due time

Gear ratio
To keep the tests as comparable as possible I will run all cars with a 2:1 gear ratio. So the C6R is geared 14x28(NSR) and the Bentley 13x26 (
The reason why I picked this ratio is because:
1: This put the highest strain on the motor, a condition under which the EM interference would manifest its self the most. (But so far still no package drops.)
2: I wanted to test the top speed of the cars with the (almost) maximum allowed gearing. (Sharp performance level and drivebility)
3: The 2:1 ratio can be run with all of the current Stock pinions and AW spur gears. (test consitancy)

It is not the ideal ratio for the Suzuka track...but close enough.

Tyre trueing
The Scaleauto Procomp wheels have their tyres glued and trued and the ones I've used in the test came straight out of the bag.
For routed tracks with a lot of grip it does help to true the outer edges of the tyres.
Scaleauto wheels are produced in large batches and trued on a sanding drum. As they are pressed (slightly) against the drum, the side walls of the sponge bend (slightly) outwards.
When they're taken off the drum the sidewalls return to their original form and thus the running surface will be (slightly) higher at the edges than in the centre.
A (slight) touch up with some emmery paper round the edges will solve this in a does running a couple of laps on Ninco

Wear rate
As I reported in my May 24th post, so far we've measured a wear rate of 0,1 to 0,2mm p/hr with more or less equal wear for left and right.
The latter will vary per track and how balanced the set up of your car is.

For the GT3 events the teams will recieve two sets of Procomp3 wheels with which they will have to run not only 2 x 60min of race time but also 90min of practice.
As you can see in the Laptime table, a fresh set of ø20,5 mm wheels will give you a GC of 1.95 mm.
With the wear rate of 0,1-0,2 mm p/hr you could still pass 1,8mm GC at tech for the start of the race....but it makes more sence to swap sets half way the practice session.
That way both of your sets will be trued and rubbed in, ready to run and with plenty room to pass Tech.

Endurance Wear rate
As for longer endurances the amount of sets needed will depend a lot on the type of track and the rules governing required Ground clearance.
On routed tracks the wear rate will be bigger at the start of the endurance but will slowly diminish as the race progresses and the track gets rubbered in more and more.
On a Ninco track, in a race like for example the DiSCA oXigen Le Mans 24hrs, if you were to start with the same 1,8mm GC it would take 2,5 - 4 hrs before your Motor would start to hit the high parts of the Ninco track ( @ ≠ 1,4 mm CG)
Wear rate would most likely be higher for GT's and LMP2's ( higher CG and less downforce) than an LMP1, but I guess you could do 24hrs with 8 sets of tyres on the Procomp3 compound.

The Procomp3 (≠30 shore) is currently the hardest sponge compound availble from Scaleauto for 1/32, but its not the hardest compound in the Scaleauto range.
That would be the Procomp4 (≠40 shore) of which they are prepraring some test samples for DiSCA to evaluate. In general, the harder the compound, the lower the wear rate.

with kind regards
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DiSCA GT3 Open, Lights and O201b1 chip installation...some tips
Here's an update on one of the DiSCA test hacks, the Scalextric Bentley Continental GT3 with a 3Dfab chassis and a 0,0mm offset Evo 6 pod
Chipped with the O201b1 digital chip I have now been able to fit the car with functional front (as required by the rules) and brakelights...
...without the use of an extra light set. Which in the case of the Bentley (not the lightest lad in the group) helps to keep the weight down (and costs as well). has copied most of the Scalex chassis features on its 3DP chassis including the mounting brackets for the front and rear PCB boards with the SMD lights.
All you need to do is to transplant the stock Scalex pcb boards form the Original chassis to the 3DP chassis and connect the wires to the O201b1 chip light socket.
You can do this by using one of the SP 34 lighting kit connectors.

Connect the + red wire of the front led board to the + red wire of the connector. Connect the + red wire of the rear led board to the yellow/orange wire of the connector.
Connect all - black wires voila....You've got working front lights and brake lights.

Just make sure that your guide wires clear the LED board..with the guide turning

Now the stock wires are a bit big and the connectors are not the most user friendly if you want to mount and dismount them frequently.
So I've swapped the wires for some smaller guage (modeltrain) wires and used PCB pin headers and sockets for the connectors.
For the lights I've used the smaller connectors (max 1amp CS 1,27 mm pin spacing) and soldered a socket directly to the chip at a 90˚ angle.
+ red is to the right pin, - black to the left pin + brake yellow/orange is on the middle pin.

O2 Chip and Hall Senor installation with a connector, easy to swap between analoge and digital testing
Most of you will be building and testing your cars on analoge tracks, so here's a tip that will allow you to switch easilly between them.
As you can see in the picture above right, I've mounted a PCB connector between the O2 chip and the Motor.
Here I used a bigger connector (max 3,5amp CS 2 mm pin spacing) as you don't want any loss of power.

Make a second set of lead wires and you can now easilly swap between an analoge and digital running.
Add some wheight to compensate for the chip and the hall sensor and your set up testing will remain consistent.

Note: If you do this conversion it is wise to solder the ferrite man on to the chip connector.
You need the little ferrite man for digital running but is been know to blow if left in place during analoge use.
Also if you use these type of connectors, mark the correct mounting position. You would not be the first to leave the startline...backwards

Here's a usefull link to Conrad.UK for such connectors.

Hall sensor placement, make you laps count!
If on an analoge track you pass the start/finish line but the RMS does not count your lap most of you will address the Race direction.
Cause clearly something must be wrong with the lapcounter

In digital racing this is not always the competitor shares resposibility to make all laps installing the Hall sensor correctly.
Make sure its mounted with the beveled side facing downwards, mount it at least @ 20mm offset to the slot and keep the cables clear from your motor and light cables.
Last but not least, check the height of your Hall sensor above the track.
On a run of the mill chassis this will not be an issue, but with some of the chassis in the Open GT3 class it can be (NSR and some 3DP chassis) as they have thicker chassis.
In the case of the 3DP chassis for the Bentley (and most likely the same will apply for the McLaren and F458) I've milled a small recess in the chassis to get the hall sensor closer to the track.
There's a small bulkhead on the Bentley chassis right behind the front wheels, I've cut a hole here that I can push the Hall sensor through.
Its a tight fit, so I don't need to glue the sensor down. Again this makes it easier to swapp between analog and digital.

with kind regards

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Excellent set up, Tamar.
I am almost done with mine. Much more basic than yours.
On each side of the chassis I have put two slabs of lead (I have to check what is the max weight allowed).
So my Hall sensor at the moment is facing backward on the left side of the chassis.
But given I was not able to put a bit of lead under the rear axle, I will move my side lead backwards to give more weight on the rear tyres.
This will free some space up front for replicating your sensor placement.

I think for the lights I will be taking the power from the pickups as I do not like that the rear lights come up only when braking.
Would be cool if the oxigen chip would dim the back lights when the throttle is pressed and give full power when braking.

By the way,is that the correct front-axle set-up? I can see that the top grab screw on the right side is a bit more outside than the left.
Ok, I have done a bit of testing on my track with my conti.
The body is still in its original trim and weighs 21gr.
As I said, I like to have some lead on the side of chassis: with body and chip total weight is 101.45 gr.
I had some N22 on the rear that I might have treated at some point but in the far past: they looked quite dry.
My chassis is the one with the DPR option and LMP guide. I have put in DPR hatch from one of my scaley cars and put a hole into it to let the LED shine through.
The chassis is not really flat...interestingly enough the left front side is a but taller than the right one. So the left grab screw has to be screwed deeper (similar to Tamar's pic).

Anyway, the car is really stable and fast.
At 11V with the NSR porsches on standard gearing 31/13 (2.38), air system, and no lead you can really push them down to high 6.9x
The conti today managed a 6.93 with 27/11 (2.45) gearing. I found out that I have also a 26 crown which would give me on a 11 pinion a 2.36 ratio.
Let's see if I have time later to try. But next I have to order the 12 and 13 pinions.

I will add some pics later on.
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I did a bit of testing with the 26/11 gearing. I could push the car a bit more but I could not gain enough speed on the straights. Best lap time I managed was 6.98.
I have two straights of almost 5 meters and I keep the throttle fully pressed for a couple of secs on each straight. I think that with the 2.45 ratio the car is not at its full speed yet but is more responsive especially in exiting the corners. I might need to play more with the controller settings.

Anyway, my car at the moment is not legal: missing the side mirrors and I do not have a cockpit. The original cockpit does not fit with the AW set up.
Is it allowed to cut the original one to make it fit?
Really excellent post Tamar. There's great benefit from the hints and tips you've shared so thank you for doing so!

Hi Gio, good to see you building and testing too. It's good feedback the pace is already equivalent with NSR as it suggests the formula works

The regulations don't allow you to cut the interior, only to replace it with polycarbonate (lexan) with a clearly defined drivers head, bust, seat back and steering wheel. Interiors must be painted. If you don't have anything specifically for the Bentley, I would suppose anything for a larger GT car could be adapted. The DTM lexan interiors by or Sloting Plus might work ok.
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Hello Gio
Thanks for your post and testing,nice to see the GT3 open formula has made it all the way to New Zeeland.
A few remarks on your tests

On each side of the chassis I have put two slabs of lead (I have to check what is the max weight allowed).
No max weight in the DiSCA rules

So my Hall sensor at the moment is facing backward on the left side of the chassis.
@ DiSCA events there are finish line magnets on both sides of the slot, so no problem here.
I usually place my hall sensor on the right to keep the wires a far away from motor and light wires.

Placing your Hall sensor more to the rear can cause problems if you cross the finish line with a big slide.
The only problem you could experience (if only theoraticly) is in a dead heat with an other car, your noses might cross the line at the same time...
...but as your hall sensor is further'll still lose

But given I was not able to put a bit of lead under the rear axle, I will move my side lead backwards to give more weight on the rear tyres.
If you use the pod you can mount balast under the rear axle. has the nicely preshaped Tungsten balast (SP23) thatb will clip right in.

image courtesey of

I think for the lights I will be taking the power from the pickups as I do not like that the rear lights come up only when braking.
Would be cool if the oxigen chip would dim the back lights when the throttle is pressed and give full power when braking.

If you feed the lights from the O2 chip you can have both brake and running rear lights.
You'll need to add an extra resistor and possibly a diode in the plus wire to dimm the running lights. I just posted the most simple version.
(I'll see if I can post that light set-up at a later stage)

By the way,is that the correct front-axle set-up? I can see that the top grab screw on the right side is a bit more outside than the left.
I'm running ø20,1 mm front wheels (to fill those big wheelarches) so I've build up some extra material on top of the axlemounts with superglue and mineral bubbles Now the grubscrews have a bit more flesh to hold onto even in the highests position. Might be that I've added a bit more to the left than right..and chassis not yet straightned as well

As I said, I like to have some lead on the side of chassis: with body and chip total weight is 101.45 gr.
I did a bit of testing with the 26/11 gearing. I could push the car a bit more but I could not gain enough speed on the straights. Best lap time I managed was 6.98.
I have two straights of almost 5 meters and I keep the throttle fully pressed for a couple of secs on each straight. I think that with the 2.45 ratio the car is not at its full speed yet but is more responsive especially in exiting the corners. I might need to play more with the controller settings.

With your Bentley @ 101.45 gr you will loose some acceleration, Specially when compared to the NSR Porsches with no lead.
I've got my Scalex Conti down to 89,8 gram, did the glass roof chopp, she's still a bit top heavy so will put her on an even more strict diet.

But looks like you've got some 8 gr of ballast on your side pods, that seems to me a bit much.
Although balast on the chassis does lower your centre of gravity... it also makes the car heavier. Besides less acceleration and brake this extra load also pulls heavier on the magnetic downforce in the corners.

with kind regards
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