Hi there,

I am working on an Aston North reversed setup for FOX currently. The race set is quite good, very consistent and can deliver the pace too.


But I kinda can't get it work in qualification mode. The grip level boost from switching from R2's to R1's just isn't there. I tried to change tyre pressures, and camber too, but it didn't seem to improve the ultimate one–flying-lap pace.

Few areas I'll try to focus on and will appreciate any feedback:

• car balance, the uneven distribution of aero and weight (about 55 % at the rear end) could mean that raising the grip level on both front and rear end equally does translate to more rear-happy car as the lighter front end's ability to corner gets relatively a tad better than rear end's
  
• body roll, camber, bigger forces could cause more massive body roll and live camber change, maybe it would make sense to stiffen the car a bit?
  
• tyre pressures, softer tyres give bigger rolling resistance, heat up quicker and grip more
  what is the implication on car setup tho'? Especially considering the one-lap quality expected from an qualifying setup. Should I increase the pressures to regain some speed at straights and rely on the bigger grip and faster heat-up?
  Is there a certain tyre pressure for optimal grip anyway, or does it depend more on the tyre temperatures?
  
• downforce, boost in grip could allow me to run slightly less downforce, on R2's it is best at it is already, but who knows what happens with softer tyres
  

Then, there's a thing I came across in testing and which quite puzzled me. I'd be so glad if anyone could explain:

• optimizing inner/outer tyre pressures, to be clear, I consider right tyres on a clockwise circuit to be the inner tyres
  
  contrary to what I do normally (run with the inner tyres deflated a bit to increase effect of the heat gain to keep inner/outer temperatures as similar as I can get them), I did my first calibration runs on R2's with pressures from the non-reversed AS7 version of the setup
  
  well I had to keep the setting at it is, it is worth about a tenth or two to have the inner tyre pressures about 0.15 bar front tyre and 0.10 bar rear tyre higher relative to the outer tyres
  
  it makes the car turn better around right-hand corners, but couldn't the same effect be archieved by altering the balance of the car?
  

Well that's about everything for now. And again, I'll appreciate any feedback and discussion on this!

• car balance, if the raceset is good. just rebalance via ARBs
  
• body roll, camber, race camber needs to focus on keeping each tire's inner-center-outer temps decent to keep the wear in check. qual camber is only about maximum cornering grip. not through optimal temp but through equal inner-center-outside tire loads while cornering.
  
• tyre pressures, in single seaters, I've always seen maximum pressure in R1 Q sets. Gives best response with less roll resistance. This probably outweighs the extra grip you get with lower pressures. No need to focus on temperatures...as long as they don't go extremely hot. Just heat up to the proper temp in your outlap.
  
• downforce, Usually ARBs can rebalance the car fine. I could see AS7R might need some DF work since it is a bunch of very fast corners and another bunch of very slow corners.
  

• optimizing inner/outer tyre pressures, I think low pressure just costs too much in rolling resistance, we are just forced to go that way to keep the tires warm at the end of their life. But for outright pace, I tend to go high pressures.
  

Focus less on temps for Q. The temp/grip graph is a 2nd degree polynomial and you need to go pretty far hot or far cold to see a big change in grip.

Quote from PhilS13 :

• car balance, if the raceset is good. just rebalance via ARBs
  
• body roll, camber, race camber needs to focus on keeping each tire's inner-center-outer temps decent to keep the wear in check. qual camber is only about maximum cornering grip. not through optimal temp but through equal inner-center-outside tire loads while cornering.
  
• tyre pressures, in single seaters, I've always seen maximum pressure in R1 Q sets. Gives best response with less roll resistance. This probably outweighs the extra grip you get with lower pressures. No need to focus on temperatures...as long as they don't go extremely hot. Just heat up to the proper temp in your outlap.
  
• downforce, Usually ARBs can rebalance the car fine. I could see AS7R might need some DF work since it is a bunch of very fast corners and another bunch of very slow corners.
  

• optimizing inner/outer tyre pressures, I think low pressure just costs too much in rolling resistance, we are just forced to go that way to keep the tires warm at the end of their life. But for outright pace, I tend to go high pressures.
  

Focus less on temps for Q. The temp/grip graph is a 2nd degree polynomial and you need to go pretty far hot or far cold to see a big change in grip.

thanks a lot for the input, I was able to gain few tenths

now I am losing only in the slow stuff, according to the telemetry when comparing to WR lap

now it will be driving technique mostly, but is there any way to increase the low speed and low DF grip?

Quote from windmouse :

thanks a lot for the input, I was able to gain few tenths

now I am losing only in the slow stuff, according to the telemetry when comparing to WR lap

now it will be driving technique mostly, but is there any way to increase the low speed and low DF grip?

Not really. AS7R being what it is it'll be hard to have a perfect car both in the hairpins and the fast parts.

WR probably goes into the slow corners in usual WR way. A lot sideways then catching it at the perfect time & place to go back hard on throttle. Pretty unrealistic and very hard to nail every single time. You can lap close to WR using a cleaner entry but if you really wanna get near WR...sideways in is pretty much the only way to do it.

You are right, it is around 16 degrees of drift angle in the hairpins, fronts may get smaller slip angle due to counter-steering.


But isn't it absolutely ridiculous? Slicks shouldn't work at all at these extreme slip angles.

My drift angle is at aprox. constant 4-6 degrees around all corners, which should be roughly the optimum grip range. I thought anything beyond that means less grip, at least it works like that in the iRacing (which is not at all a perfect sim, nor has very good tyre simulation, but I think that at least they got the slip angle/grip curves quite right)