Are we allowed to go past the homologated car downforce limit for our racing trims?
Edit: Where are we supposed to be getting our down force number from anyway? Is it the downforce at max speed in the aero screen, or is it the downforce stat displayed on the test track tab?
No, I clarified this in the rules now.
From the test track tab, I clarified this in the rules now.
For which? Production version or race car? Quality for the race car goes into the category “anything not mentioned here is forbidden to be changed from the homologated car”
EDIT: added much more severe ET/PU limits (dependent on Group now) to prevent quality spam.
To improve readability and to better fit the flow of building a car for the challenge, I have re-structured the rules (see Google spreadsheet below). How do you like this new structure? A few rule fixes included - I think this is the first release candidate. Let’s see if new issues arise.
are sami slick allowed for the race car? (say blocked in homologation, available to change in race)
Yes, Semi Slicks are allowed. I explicitely state that now in the rules.
does the " car body family year" mean the year the body unlocks in the game? i have quite a few 50’s and 60’s cars build on johndoe’s 50’s body that unlocks quite early in 1947
Yes, exactly - any car body with an unlock date before 1955 won’t be available, sorry.
is tire compound implied in this section?
Are we allowed to change rim offset between trims?
Yes, I forgot that. Tire compound is influencing tire wear of course. Sports last roughly double the time than Semi Slicks, but I’ll have to check again and sum it up when the challenge opens.
@Der_Bayer - Can you remove the rear seats in the race car, as long as the minimum weight is still observed?
That is only allowed in Group 2 and 4. But I am open to turn away from reality here to make bigger bodies a bit more viable. Poll started (24 hours for voting):
In addition to that, Car Number selection is now open for early birds: Google Spreadsheet
Fine for Group 2 and Group 4, as already in the rules.
Now that we can have numbers, there was a way of designating the cars class in racing here in Australia. Letters were used as a suffix to the numbers themselves, eg: 64E… anything like that applying here, or did that never happen internationally?
Nope, no letters in European racing as far as I am aware of.
IIRC, at least in rallying, they labelled capacity classes like this: 4/4 means Group 4, over 2000cc, 3/3 means Group 3, 1600-2000cc, 2/2 means Group 2, 1300-1600, and 1/1 means Group 1, under 1300. Obviously with class system we’re using, that doesn’t work, but some variation of it could?
Yeah I thought of something similar to visualize the group classifications during the races. Nothing set in stone/implemented yet though 
Spreadsheet says - << all from left or:
Shouldn’t that be - << all from left and?
The track has been released!
Does it really matter? You have to score well in one out of the demographics from the left side or/and from the group column. What could you understand wrongly if the “or” is kept? Maybe my English is too bad to see your point.
Poll about interior weight removal in Group 1/3
The results of the poll have been pretty clear: almost 80% in favor for keeping the rules as they are - no interior weight reduction in Group 1 and 3. Poll closed.
EDIT:
To make sure I’m reading the excel correctly - the Group 1/3 cars can have one spoiler and in group 2/4 cars you can either keep that spoiler or exchange it for a ridiculous table-like monstrosity held on by scaffolding i.e. a wing?
I think the engine reliability information is still to come but in case I just can’t find it can someone please point me in the right direction.
I am relearning the fun of teaching manners to mid/rear engined cars. All ye gods of suspension tuning, don’t fail me now.
In general cars must keep the aero fixtures from the homologation car. No exchanging a spoiler for a wing for the race, no addition of lips. If you want a wing, it must already be on the homologation car.
I will clarify later that you can increase downforce up to Group 2/4 limits when coming from Group 1/3 using the aero sliders. Does that answer your question?
Regarding engine reliability: No recommendation. The more, the better. It can always hit you, regardless of reliability. I won’t tell any failure chances, as I still need to balance the model for a 24h race. That won’t happen within the next few days.
No car will retire completely because of any failure - every car can be brought back to the pits and be repaired. But it might take a looong time if you had major issues. So, the recommendation is again: as much reliability as possible.
Edit: I’m away for the weekend and won’t be able to provide homologation confirmations to the very early birds during those days.