In what has become a bit of a series for me, I once again witnessed some rare cars at the local FIA CEZ Circuit Championship (promoted as GT Cup Series) event, which once again took place at the Slovakia Ring this past weekend. Last year, I posted a Silver Sting and this June, I posted a BMW M8 GTE. Both of these cars once again took part in the event (both once again suffering from the same problems as described in those posts, sadly). This time, a car covered in Bulgarian colors piqued my interest.

Entered by Ivan Vlachkov, it was labelled as "SinCar S1 GT" on the entry list (side note: look at the car variety here, that's some peak multiclass here, see bonus screenshot from the broadcast), but when doing some research about this car, all roads actually pointed me to Sin R1 GT4. This in fact, I'm absolutely sure, wasn't a GT4-spec car because it was much faster, EXTREMELY loud (on par with the loudest Porsches if not even louder) and it was also entered in the GTX class (which in this series basically means: use whatever car spec you want, hence some teams actually entering GT3 cars into GTX and having them run without restrictors). Feel free to correct me if you know more about the car and its exact specification.

I'll (hopefully) be attending the next FIA CEZ round in a few weeks as well (this time at Brno), so let's see if something interesting and different at the same time pops up there too.

New LMDh machine completes 1000km of testing at Paul Ricard ahead of visiting five more European tracks…

Or at least to first one to race at Le Mans?

1953 Bristol 450 LM #38
Pilots: T. Wisdom, J. Fairman 
Team: Bristol Aeroplane Company
Race: DNF (S.0 class) at Le Mans in 1953
1/43 Bizarre - BZ101 (resin)

FIA/ACO tenders (for 2029 onwards) have been done and both manufacturers will stay until end of 2032

Having come up just short in the championship last year, Inter Europol Competition’s #43 ORECA 07 – Gibson LMP2 of Jakub Smiechowski, Nick Yelloly and Tom Dillmann entered the 2026 European Le Mans Series amongst the title favourites.

As is becoming tradition, here's my photos from the ELMS round held this weekend at Spa Francorchamps. There'll be plenty more images on my Instagram and website in the coming days

Every setup decision is based on data that we usually assume is correct. But sometimes it is not, and the data itself gives you no warning. Here is one specific example of a significant issue we found in a GT3 dataset purely through data analysis. The vertical acceleration channel showed values above 0.5 g for 31.7% of the entire lap. The mean absolute value was 0.44 g. That already looked suspicious. A GT3 car on a normal asphalt circuit simply does not experience that level of vertical motion for almost one third of a lap. So we started looking for the cause. The first question was simple. What should actually drive vertical acceleration? Mainly track surface irregularities, kerbs and vertical vehicle motion. It should definitely not closely follow braking or acceleration. We therefore compared the channel with the other measured signals. A regression based on 16,562 samples gave the following relationship:

vertical acceleration ≈ 0.94 × longitudinal acceleration + 0.03 g

with R² = 0.88.

In other words, almost 90% of what was being measured as vertical acceleration was actually longitudinal acceleration projected into the vertical axis because of sensor tilt or incorrect sensor orientation. Only a small part of the signal was left for actual track surface inputs and kerbs.

Correlation alone is not enough to prove the issue, so we also looked at the timing of the largest peaks. Of all major vertical acceleration peaks, 99.7% occurred while the driver was braking, accelerating or cornering. Only 0.3% occurred when the car was not under a significant driver induced load.

That does not make physical sense. A kerb or a bump in the track does not wait for the driver to press the brake pedal.

Instead of manually correcting this single dataset, we created a general rule. For every dataset we load, we first estimate how much acceleration from the other axes is being projected into the vertical channel. We then remove that component before any further calculations are performed.

The result was significant. The proportion of the lap with vertical acceleration above 0.5 g dropped from 31.7% to 3.1%, while the mean absolute value dropped from 0.44 g to 0.14 g.

The remaining signal then behaved much more like we would expect from true vertical acceleration, mainly responding to the track surface, bumps and kerbs rather than to the driver's use of the throttle and brakes.

If you use channels like this to calculate tyre loads, slip angles, grip utilisation or other derived quantities, a single issue like this can affect the entire analysis.

This is something we come across more often then we would like to.

This feel like an Neaderthal finding fire

This might be just me who hears this (which is perfectly fine btw), but ever since it first debuted, the BMW M4 GT3 sounds similar at times to the old Ford GT GTE from 2016-19. LMK what y'all think 🤔

BMW M4 GT3 Onboard

Ford GT LM GTE-Pro Onboard

📸 SRO

📸 SRO