Hello,
after the last BoP Update myself together with a team mate did some tests regarding acceleration and fuel consumption with the GTE cars. In order to help improve the BoP, I share the findings in this post. This mainly concerns long distance races like done in VEC, P1LMS and other leagues with several hours of race length.
How did we carry the tests out? (skip if you just want to see the results)
The results:
View attachment 34324
Observations:
So, let's start with the positives:
After the last BoP update the
Aston Martin, BMW and Porsche are very well matched to each other.
The acceleration is pretty much identical. Short shifting or changing engine mapping have pretty similar consequences on acceleration and fuel usage.
Fuel tank is identical at 100 litres so refueling time is identical aswell.
I don't see anything that needs to be done to these 3 cars relative to each other!
Now let's look at
Ferrari and
Corvette:
Both are approx. 0,075 seconds faster than the other cars on the said 500 metres.
For the best acceleration you don't rev out the Ferrari completly, but short shift significantly (see cells marked red). In doing so, the Ferrari is not only faster than the other cars, but also has a lot better fuel range.
About 4% better than AM, BMW, Porsche, that are already slower, and about 5% better than the Corvette, that is equally fast.
On an average track (1:30 min to 2:00 min length in lap time), this means, the Ferrari can extend the stint length by 1 or 2 laps (while being quicker on the straights).
Additionally you can increase the fuel saving a lot (Race lean + shifting at 85% of max. rpm) and still be on par in straight line performance with the other cars (except Corvette).
This can save you easily a pit stop in a long distance race, which equates to 0,75 lap to 1 lap (that is a lot).
Another view to look at it: If the Ferrari is going as fast as it can and you want to reach the same range as the Ferrari you will lose 1,1 to 1,4 tenths in the 500 metre straight (see last 2 columns and cells marked yellow). I gather you have approx. 3 or 4 of these kind of accelerations zones in a lap. This means one loses about 5 tenths per lap with fuel saving compared to the Ferrari (that is a lot aswell).
What about the Corvette? Well, it is basically somewhere between the Ferrari and the other 3 cars. It is as fast as the Ferrari in a straight line while using 5% more fuel. Fuel saving can be done quite well (not as well as with Ferrari, but better than the others).
Due to the smaller fuel tank the Ferrari saves 3 seconds each stop and Corvette 1,5 seconds compared to the other cars.
Conclusion:
As already said, Aston Martin, BMW and Porsche are very well matched. There are slight differences, but I don't think any adjustments are necessary.
The Ferrari has a huge advantage, because of the fuel consumption. It doesn't matter which way you put it, but the longer the race, the greater the advantage the Ferrari has and it is significant. I would expect a further BoP update regarding this issue in the near future. (my advise would be somewhere around +6% with 90l fuel tank)
I think the Corvette should be adjusted in a similar manner, but the changes necessary are smaller compared to the Ferrari. (maybe around 4% with 95l fuel tank. Bit difficult to say as Corvette doesn't use less fuel, but it is faster on the straight and pretty easy to fuel save - maybe better to rob 5 hp or so)
General advise: (this has nothing to do with the rF2 GTE cars in specific)
As far as I know, the formula rFactor uses for calculating the fuel consumption is:
engine speed X filtered throttle position X car-dependent factor
The data suggests this assumption aswell (or at least it is not far off).
The reason Ferrari and Corvette can save fuel that well, lies probably in this formula in combination with a very torquey power curve (lots of power already in the low/middle rev range). You can short shift these cars, which will save you a lot of fuel, while not losing a lot of straight line speed.
In my eyes a better and maybe even simpler way to calculate fuel consumption would be using
engine power output X car-dependent factor
Fuel consumption in kg/h basically is proportional to the power output. The only influencing factor is the engine efficiency, which is dependent on a number of factors, but for a race car, which is mostly driven with full throttle and in a quite narrow engine speed range a simple car-dependent factor is a near enough approximation in my view.
Short shifting the Ferrari or Corvette would then mean, that you still wouldn't lose a lot of straight line speed, but you also wouldn't save as much fuel as is the case at the moment.
Finally a real virutal world example from VEC: There was a Ferrari team doing 38 laps on one stint of fuel at the preseason race at Imola. This was probably done with quite a bit of fuel saving. But several other Ferraris did 37 laps. We ran the Porsche and already had to do a bit of fuel saving to reach 35 laps, which were necessary for not having to do a second fuel stop in the 2h race. The fastest GTE of all in the 3 divisions was a Corvette doing 37 laps with one fuel tank.
(can't upload .xlsx-file to the forum, if developers are interested in the raw data, I can supply the file however. But basically the screenshot shows the important bits anyways)
Hope this post helps in finetuning the GTE class, which since the last update already is on quite a high level regarding BoP in my view - with the exception of the fuel consumption of these 2 cars.
Cheers
Seb
