AC GT3 @ Mugello - Sunday 17th July 2022

[Kek700]

Interesting reading your comments, the Nissan does well here, the front left just about shot on the last right hander.
Then the tyre has plenty of time to recover before T1.
I am not so sure the mid engined cars have that advantage, I am just guessing that the rear left will overheat making the car quite skittish for some of the circuit.

Just got Dmitry answer above.

You can definitely run softs on the Z4, Mercedes’ and Nissan.
If I was home instead of waiting for our tunnel crossing, I just could never be a lorry driver, ridiculous long long queues for the ferry or tunnel. I would see how the Mercedes faired here.

 

[Alfred Wayne]

On the topic of hot tires, since they seem to cool off after they get cooked, it's that just part of the racing at this track and you have to live with it? or is it possible to cool the front left of a little with set up changes?

I assume it just means that tires going to wear before the rest and I can "ignore" the extra heat

 

[demetri]

On the topic of hot tires, since they seem to cool off after they get cooked, it's that just part of the racing at this track and you have to live with it? or is it possible to cool the front left of a little with set up changes?

I assume it just means that tires going to wear before the rest and I can "ignore" the extra heat

well, my setups are usually balanced, so if the rear tires get super-hot (as they like to do in the Audi) and lose grip the car becomes an unstable oversteering mess and that would heat up them rears even more as they start sliding. This positive feedback loop eventually results in me either backing off quite a lot or spinning out and neither is good for lap times, so it's better to just use a harder compound. Same (or even better) laptimes but more confidence

 

[Kek700]

Dmitry has pretty much summed it up.

I think that because you have no choice but to go as fast as you can , any effort to counter is alway minuscule, .compared to the loading on the tyre.

I sometimes run less toe , and you can run an extra 1 psi to try and offset the speed at which the tyre heats. It may be all that you need if it is marginal..
I did this with the Porsche setup, because the extra psi did not effect lap times, and it helped to get the worst corner out of the way before tyre temperatures caused a spin.
You can also modify your damper settings, but you are now starting to effect your lap times.
But invariably it is all usually to no avail.
So it is live with it, you just cannot slow down,
Aliens can go mediums and still be competitive, but for most of us a loss of 1 second a lap and 30 laps rather spells a sad outcome for us.
You just cannot make up the 30 seconds lost. If you could miss a pit stop completely, it would make sense.

 

[demetri]

Setup adjustments only work if you need to drop a couple of degrees (Celsius it is). If you're +5C into the red zone no setup tricks are gonna save your tire if there's a next turn that will load it up again coming right at you.
As for the extra pressure, my findings were that I needed about +5 psi to offset two degrees of heat. And pumping it further would be too detrimental to the overall grip, so you'll again be losing it against a harder compound

 

[Interslice]

Cheers Brian! It was my fastest lap but definitely not the cleanest lines as you've noticed. T1 is interesting I suppose, I tried to steer it wide for T2 but that always kept me running out so I try and stick it in early. I'll have to figure out a better way through that section!

Correntiao, I completely missed the corner there to be honest, thought I had ruined the lap there haha

That last corner is also something, I tend to have a ton of understeer there so unless I let go of the throttle or add a little brake there's not much to do to get it in closer. Though that is also worth experimenting with.

Thanks for the feedback Brian!

I'm still in experimenting phase with this track. Your arriabattas.. can be huge time lost there.. and last corner are really good. Still some things up in the air for me. If you look a Demetri's line into the last corner it's a completely different v shape where he brakes late and stays high and right for longer. Maybe it's the way to go or depends on the car/setup which is faster. If you go the early turn in route a spin is also more likely late in the race. One for the data/delta app to sort out!

 

[RasmusP]

A little waffle as Ernie would call it:
In ac, 75% of the temperature part of the grip equation comes from the core temperature. So surface temp isn't that critical as long as you keep the core from overheating.
You can check the temperature table by either unpacking the car or looking into the gt3 tyres in the mod folder somewhere (not at home, sorry).

These 75% core, which are apparently not unrealistic since the tyre is working and flexing as a whole, not just the surface building the grip, mean that you would normally open the brake duct a little more for the front left to cool it down between the corners.

You can also try to run asymmetrical toe and try to reduce the mid corner toe for the front left (motec!).
Another thing that can work is to shift the aero balance towards the front (in a formula car run more front wing) to be able to steer less and therefore reducing the scrubbing of the front left.

Last but not least: reduce the abs setting (in ac, less = stricter abs, like tc) and run a lower brake bias to take some load under braking from the fronts.

 

[The Almighty Snark]

Another thing that can work is to shift the aero balance towards the front (in a formula car run more front wing) to be able to steer less and therefore reducing the scrubbing of the front left.

Though increased downforce can also increase tyre temperature at speed due to the increase of downwards pressure also increasing friction. It's a fun balancing game.

 

[Kek700]

I have always assumed small corners, average speed, long forever corners , higher speed you use more of the real estate of the corner, slower speed , less real estate of the corner.
So you go further but faster , slower but shorter. as long as you have traction, I have assumed not much in it.
.
I have always thought as Robert said more downforce, less tyre scrubbing, more downforce higher tyre loading. As it is a simulation situation again ?

ABS , worth an experiment,

I like Rasmus toe answer, never thought of that.
Worth an experiment.

 

[JamKart22]

How did you analyze this info?

1) Load Rasmus's workspace into Motec
2) Load Ernie's and my fast lap into Motec
3) Go to "5. Circuit" page
4) Do the GPS trick Rasmus mentions in the Redbull thread to get the circuit looking OK
5) Select the two fasted laps from Ernie and me
6) If you select the Ground speed window you'll see a Variance icon (F3). This will show you where your times diff. It was fairly easy to see (marked in red in the image) that I was loosing time in Arrabbitta 2 (1 not so much)

I can walk you through this over discord if it's not clear

 

[Alfred Wayne]

I'll give that all that a try, thanks

Or I just accept the tire heat and buy this add on bbq grill accessory for my spare tire

 

[The Almighty Snark]

1) Load Rasmus's workspace into Motec
2) Load Ernie's and my fast lap into Motec
3) Go to "5. Circuit" page
4) Do the GPS trick Rasmus mentions in the Redbull thread to get the circuit looking OK
5) Select the two fasted laps from Ernie and me
6) If you select the Ground speed window you'll see a Variance icon (F3). This will show you where your times diff. It was fairly easy to see (marked in red in the image) that I was loosing time in Arrabbitta 2 (1 not so much)

View attachment 582570

I can walk you through this over discord if it's not clear

Cheers, I tried to import the workspace into the latest motec version but it doesn't recognize the i2wsp-archive format. Renaming it doesn't work either. How did you guys get this to work?

 

[JamKart22]

I used the lasted 64-bit version on the motec website

MoTeC > Software > Latest Releases

Default Meta Description

www.motec.com.au

i2 Pro v1.1.5.0085

 

[demetri]

I'm still in experimenting phase with this track. Your arriabattas.. can be huge time lost there.. and last corner are really good. Still some things up in the air for me. If you look a Demetri's line into the last corner it's a completely different v shape where he brakes late and stays high and right for longer. Maybe it's the way to go or depends on the car/setup which is faster. If you go the early turn in route a spin is also more likely late in the race. One for the data/delta app to sort out!

V shape is definitely an artifact of the car/setup/driving style. This is the way I'm used to drive the Audi - go deep, rotate the car on braking, and speed out of the corner. A car with better front grip (488, 650s) could probably use a different line

 

[demetri]

A little waffle as Ernie would call it:
In ac, 75% of the temperature part of the grip equation comes from the core temperature. So surface temp isn't that critical as long as you keep the core from overheating.
You can check the temperature table by either unpacking the car or looking into the gt3 tyres in the mod folder somewhere (not at home, sorry).

These 75% core, which are apparently not unrealistic since the tyre is working and flexing as a whole, not just the surface building the grip, mean that you would normally open the brake duct a little more for the front left to cool it down between the corners.

You can also try to run asymmetrical toe and try to reduce the mid corner toe for the front left (motec!).
Another thing that can work is to shift the aero balance towards the front (in a formula car run more front wing) to be able to steer less and therefore reducing the scrubbing of the front left.

Last but not least: reduce the abs setting (in ac, less = stricter abs, like tc) and run a lower brake bias to take some load under braking from the fronts.

I'd think that asymmetrical toe on front axle does nothing, but moves your neutral steering wheel position to one side (for the rear axle it is very different and makes your car drive a bit sideways when going straight). Meaning that if you decrease left side toe by two clicks you could very much decrease both left and right by one click and have exactly the same handling (well, apart from 100% steering lock situation that you typically would never use in GT3 anyway), but the wheel centered properly on straights.

 

[The Almighty Snark]

I usd the lasted 64-bit version on the motec website

Yup I got the same one. No import options for the -archive extension and when I rename it to a normal workspace extension the application just doesn't do it. How did you import it?

EDIT: I'm a dummy, I needed to double-click the -archive file from Rasmus to install it into Motec...

 

[Aksu]

In

 

[RasmusP]

I'd think that asymmetrical toe on front axle does nothing, but moves your neutral steering wheel position to one side (for the rear axle it is very different and makes your car drive a bit sideways when going straight). Meaning that if you decrease left side toe by two clicks you could very much decrease both left and right by one click and have exactly the same handling (well, apart from 100% steering lock situation that you typically would never use in GT3 anyway), but the wheel centered properly on straights.

Makes sense, yeah.. My thinking is about the toe in relation to the camber while cornering.
Basically scrubbing the tyres on the straights to reduce "bump steer" as it's called in English afaik.
So while you're getting a non-straight steering while on the straights, you might get less toe during right hand corners.
But not sure about this at all...

EDIT: I'm a dummy, I needed to double-click the -archive file from Rasmus to install it into Motec...

Hehe yeah but to be fair I'd think that there's an import option too to import workspace archives...

 

[RasmusP]

Though increased downforce can also increase tyre temperature at speed due to the increase of downwards pressure also increasing friction. It's a fun balancing game.

I have always thought as Robert said more downforce, less tyre scrubbing, more downforce higher tyre loading.

Missed these posts, whoops!
From my experience:
Your front tyres never become hot on the straights, so the straight line load seems to be mostly irrelevant.
But as Ernie says, in the corners you're increasing the load while decreasing scrub.
But that's not completely true!

The important bit is that I'm talking about increasing downforce but not using it to go faster. Going faster should be possible in theory...
But you're only using it to scrub less.
Which means more scrubbing at the rear, I guess...
Either more slip at the rear and therefore a tighter corner without steering more or the increased load goes nowhere...

Or third possibility:
More downforce changes the very complex interaction of asphalt and warm rubber, which is a mix of adhesion and sliding, which no real time simulation can calculate.

Conclusion: it comes down to what simplified equations and look up tables AC uses and how you get the maximum out of it.
I'd say increasing front downforce is worth a try

We have no idea how rubbing more with less load vs rubbing less with more load is treated by AC...

 

[Reik Major]

What's the PW for the server please?

Edit: Got it.