GT7 Tuning Calculator App

[hookedonturbo]

Springs and damper calculator is 99% complete, gear ratios calc is complete. I dont think there’s any benefit from adding more parameters into this, roll bars are user preference and tuneable once springs and dampers are set correctly, camber i will leave out as this is track specific and also tyre wear specific. Toe, I don’t even play with these settings so I’ll exclude that as well.

Now this leaves LSD settings. I don’t really see these as being something you can calculate with the parameters in GT7. Correct me if I’m wrong?

 

[bread82]

My gut feeling is that you're correct that its hard to calculate LSD settings into something usable.

I usually go by a combination of feel, and using the telemetry app to look for the two driven wheels slipping. I like a little inside wheel slip since if the diff is too locked, both rears light up at the same time and its mega oversteer (for an FR car).

I suspect the LSD accel and decel are "percentage lock", which is the torque difference the diff can support before the clutches slip. So, in real life, if the total torque to both driven wheels is 100%, an 80:20 torque split generated by the LSD between the wheels would be 60% lock, 80-20=60. This is also known as torque bias ratio in real life, 80:20 is a 4:1 TBR. A welded diff has 100% lock or infinite TBR. An open diff should have 0% lock, 1:1 TBR but in practice the internal resistance of gears gives a few percent lock.

Initial torque is tricky in gt7 as in real life it's given as a straight value in Newton meters. I think in gt7 it could be a percent of driveline torque in one of the high gears, but this is a very large guess. I did have some numbers written down somewhere vs real life diff specs, and they kind of agreed.

Even assuming I'm correct on the above (which I might not be).... just considering accel lock for the moment, accelerating as you come out of a corner, is that the lock % desired would depend on the grip difference of the two driven tyres during cornering (and also driver preference). And this is probably impossible to calculate accurately.

To calculate the grip distribution of the two rear tyres, you'd need to know tyre load distribution, and the details of the PD tyre model.

To know the load on each tyre even in a 1G steady state corner requires (at least - I may have missed some): CG height which together with track width can give lateral load transfer amount. load transfer distribution (axle stiffness distribution, and our anti roll bars are in arbitrary units), roll centre height (because of geometric weight transfer through the suspension arms).

Someone with access to the game code might have access to some of these parameters. I'd be all ears if you know how to get/calculate any!

 

[hookedonturbo]

My gut feeling is that you're correct that its hard to calculate LSD settings into something usable.

I usually go by a combination of feel, and using the telemetry app to look for the two driven wheels slipping. I like a little inside wheel slip since if the diff is too locked, both rears light up at the same time and its mega oversteer (for an FR car).

I suspect the LSD accel and decel are "percentage lock", which is the torque difference the diff can support before the clutches slip. So, in real life, if the total torque to both driven wheels is 100%, an 80:20 torque split generated by the LSD between the wheels would be 60% lock, 80-20=60. This is also known as torque bias ratio in real life, 80:20 is a 4:1 TBR. A welded diff has 100% lock or infinite TBR. An open diff should have 0% lock, 1:1 TBR but in practice the internal resistance of gears gives a few percent lock.

Initial torque is tricky in gt7 as in real life it's given as a straight value in Newton meters. I think in gt7 it could be a percent of driveline torque in one of the high gears, but this is a very large guess. I did have some numbers written down somewhere vs real life diff specs, and they kind of agreed.

Even assuming I'm correct on the above (which I might not be).... just considering accel lock for the moment, accelerating as you come out of a corner, is that the lock % desired would depend on the grip difference of the two driven tyres during cornering (and also driver preference). And this is probably impossible to calculate accurately.

To calculate the grip distribution of the two rear tyres, you'd need to know tyre load distribution, and the details of the PD tyre model.

To know the load on each tyre even in a 1G steady state corner requires (at least - I may have missed some): CG height which together with track width can give lateral load transfer amount. load transfer distribution (axle stiffness distribution, and our anti roll bars are in arbitrary units), roll centre height (because of geometric weight transfer through the suspension arms).

Someone with access to the game code might have access to some of these parameters. I'd be all ears if you know how to get/calculate any!

My gut feeling is that you're correct that its hard to calculate LSD settings into something usable.

I usually go by a combination of feel, and using the telemetry app to look for the two driven wheels slipping. I like a little inside wheel slip since if the diff is too locked, both rears light up at the same time and its mega oversteer (for an FR car).

I suspect the LSD accel and decel are "percentage lock", which is the torque difference the diff can support before the clutches slip. So, in real life, if the total torque to both driven wheels is 100%, an 80:20 torque split generated by the LSD between the wheels would be 60% lock, 80-20=60. This is also known as torque bias ratio in real life, 80:20 is a 4:1 TBR. A welded diff has 100% lock or infinite TBR. An open diff should have 0% lock, 1:1 TBR but in practice the internal resistance of gears gives a few percent lock.

Initial torque is tricky in gt7 as in real life it's given as a straight value in Newton meters. I think in gt7 it could be a percent of driveline torque in one of the high gears, but this is a very large guess. I did have some numbers written down somewhere vs real life diff specs, and they kind of agreed.

Even assuming I'm correct on the above (which I might not be).... just considering accel lock for the moment, accelerating as you come out of a corner, is that the lock % desired would depend on the grip difference of the two driven tyres during cornering (and also driver preference). And this is probably impossible to calculate accurately.

To calculate the grip distribution of the two rear tyres, you'd need to know tyre load distribution, and the details of the PD tyre model.

To know the load on each tyre even in a 1G steady state corner requires (at least - I may have missed some): CG height which together with track width can give lateral load transfer amount. load transfer distribution (axle stiffness distribution, and our anti roll bars are in arbitrary units), roll centre height (because of geometric weight transfer through the suspension arms).

Someone with access to the game code might have access to some of these parameters. I'd be all ears if you know how to get/calculate any!

Yeah I think I need to get on to that telemetry app…