GT7 Tuning Calculator - Download v3.3 all new cars added!!

[hookedonturbo]

August 2024: GT Pro Tune is now live!!
www.gtprotune.com

May 2024 Edit: The app is nearing completion, if you sign up now you will receive a discount on the app when released.

Back in March 2023
I have developed a tuning calculator for gt7, spring rate, dampers, gear ratios, dyno plotting and LSD setup are all automatically calculated. If you would like to download a copy please see bottom of this post Or in my signature.
Any questions are welcome. Please note all updates to this calculator are part of your initial purchase. Remember to sign up with your email to receive the latest updates when they are released. If we get enough supporters this will eventually migrate to an iOS and android app.

And for anyone interested in the equations: it takes into account suspension travel, force applied under load, lever ratio and without giving away too much the following formula is applied; K = Spring Rate in N/m.

1/2pi

Sqrt(K/M)

It works on a table of every car in GT7 so that when a car is selected, the drivetrain type automatically is picked up for the un sprung weight calculation.

Give the free trial a go on the website, it’s obviously only part of the full downloadable premium version but it gives you a feel for it.

www.gt7tuningcalculator.co.uk
www.gt7tuningcalculator.co.uk
www.gt7tuningcalculator.co.uk

 

[FAN_Lawless]

I remember something like this for GT6 it give you an idea of what to do and after about a month of using it, you really got the hang of tuning for what you want without using it.

i would use it as a spreadsheet.. as is..no need to be extra fancy lmao

 

[Techlet]

App or spreadsheet, something like this would be extremely useful.

 

[hookedonturbo]

I remember something like this for GT6 it give you an idea of what to do and after about a month of using it, you really got the hang of tuning for what you want without using it.

i would use it as a spreadsheet.. as is..no need to be extra fancy lmao

Yeah I used to use it lol.
I think point is in GT7 there is a real benefit in balancing the front and rear spring frequency as this then enables more control of roll bar tuning. I would keep it as a spreadsheet but want it to look extra fancy! 😂

App or spreadsheet, something like this would be extremely useful.

It is very useful, I couldn’t believe how nice each car handles when the correct balance is applied braking improves, power transfer to the road is amazing. I even tested with ABS and TC off and it was impressive!

 

[B80]

It is very useful, I couldn’t believe how nice each car handles when the correct balance is applied braking improves, power transfer to the road is amazing. I even tested with ABS and TC off and it was impressive!

100% interested. What's the eta mate, and how much is likely to cost if you make it into an app?

 

[hookedonturbo]

100% interested. What's the eta mate, and how much is likely to cost if you make it into an app?

I am working on this as much as possible along with other projects. I would think it will be ready after testing and debugging around early April possibly sooner. Price wise I’m not sure yet. Nothing too extortionate I’m sure.

 

[AyoxSavage]

I am developing a tuning spreadsheet and looking for someone to partner with in developing an app. Any tech savvy enough to incorporate a spreadsheet calculator into an app would be perfect. Any questions are welcome. View attachment 1239297

Greatly needed this or a app

 

[hookedonturbo]

What do you guys think of the layout, I have put all of the tyre options together because this then enables the selection of different tyres to front and rear (possible tyre degradation differences) however this isn’t perfect as there is nothing to suggest how much more grip one compound has over another. I’m guesstimating around 5%, hence I have left this as an adjustable parameter. The balance of front ti rear is what is important, the stiffness should be tweaked accordingly. Do you think I should keep it like this or just select the tyres you want for both f and r and that’s the spring rate you see?

 

[bread82]

You can guesstimate tyre grip from the lateral G figures in the tuning window. There will be variation due to car and setup differences (and the telemetry doesn't update with suspension tune anymore). Aero makes a difference so I would use a non-aero car and the low speed G stats as a baseline.

It should be reasonably close.
EDIT: here's some G forces I tested months ago

Tyre max G will vary depending on car and setup. On my Silvia Q’s, stock, the lateral G (40 mph slow speed) ratings from the settings menu were:

CH	0.82	SH	1.05	RH	1.25
CM	0.90	SM	1.09	RM	1.29
CS	0.99	SS	1.16	RS	1.33

 

[hookedonturbo]

You can guesstimate tyre grip from the lateral G figures in the tuning window. There will be variation due to car and setup differences (and the telemetry doesn't update with suspension tune anymore). Aero makes a difference so I would use a non-aero car and the low speed G stats as a baseline.

It should be reasonably close.

I was thinking that, I’ll have to get in game and do some testing to get this more accurate, however at the moment it’s not the end of the world to have an adjustable rate.

You can guesstimate tyre grip from the lateral G figures in the tuning window. There will be variation due to car and setup differences (and the telemetry doesn't update with suspension tune anymore). Aero makes a difference so I would use a non-aero car and the low speed G stats as a baseline.

It should be reasonably close.
EDIT: here's some G forces I tested months ago

Did you change anything else except tyres?

 

[bread82]

No, just tyres.

 

[hookedonturbo]

No, just tyres.

The results obviously differ slightly but my guesstimate of around 5% looks about right on average to me.

 

[bread82]

Yeah, your estimate was bang on. Seriously, props for doing this spreadsheet, I can't wait to try it. I've dabbled in the past with spring rate and damper calcs but one thing that has eluded me is the strength of roll bars with the generic 1-10 scale.

I was looking at camber sweet spots from the lateral g and understeer/oversteer stats.... Until PD disabled the bloody stats for tuning adjustments.

Some of the guys that did the telemetry app on here have access to game code - you mentioned motion ratio so I'm guessing you already know this.

The graphical presentation of your sheet looks really nice too 😎

 

[hookedonturbo]

Yeah, your estimate was bang on. Seriously, props for doing this spreadsheet, I can't wait to try it. I've dabbled in the past with spring rate and damper calcs but one thing that has eluded me is the strength of roll bars with the generic 1-10 scale.

I was looking at camber sweet spots from the lateral g and understeer/oversteer stats.... Until PD disabled the bloody stats for tuning adjustments.

Some of the guys that did the telemetry app on here have access to game code - you mentioned motion ratio so I'm guessing you already know this.

The graphical presentation of your sheet looks really nice too

Thanks, it’s alright for now, will probably evolve a bit by the time final version is ready to publish. Roll bars can’t be tuned accurately until the springs are within the correct balance. That and they only really come into play mid corner which most people don’t know. I think they have made the settings 1-10 because there is no actual way of quantifying a roll bars stiffness in terms of torsion with every model being slightly different. I imagine it’s based on a race type setup where there is an adjustable length of cantilever arm in some cases. 1 being the longest length (lowest torsion) and 10 the shortest length (highest torsion).

Thanks, it’s alright for now, will probably evolve a bit by the time final version is ready to publish. Roll bars can’t be tuned accurately until the springs are within the correct balance. That and they only really come into play mid corner which most people don’t know. I think they have made the settings 1-10 because there is no actual way of quantifying a roll bars stiffness in terms of torsion with every model being slightly different. I imagine it’s based on a race type setup where there is an adjustable length of cantilever arm in some cases. 1 being the longest length (lowest torsion) and 10 the shortest length (highest torsion).

To reiterate, roll bars are a tweak for mid corner handling, springs are key for all round handling.

 

[JamCar0ne]

Can't help you with the app, but definitely interested in it.

 

[hookedonturbo]

I am developing a tuning spreadsheet and looking for someone to partner with in developing an app. Any tech savvy enough to incorporate a spreadsheet calculator into an app would be perfect. Any questions are welcome. View attachment 1239297

Update on the spring calculator, I have been working on the car data and have now got every car listed with it drivetrain and type, so now all you have is a select car option and inputs for numbers.

 

[Kraljik]

This would be awesome man.

Although I do have some knowledge for a setup, sometimes is just impossible to set cars up.

This as a starting reference to play with would be the perfect thing.

Thanks for the effort!

 

[GPGamerBoy]

Also interested to hear if anyone has the need for such an app? Do you think this will be well received?

This will be really great to have. I am sure many if us would be interested in something like this.

 

[FAN_Lawless]

looking good!!!

 

[hookedonturbo]

getting there.

I am trying to incorporate damping in the calculator. Not an easy task.

 

[bread82]

I think the damper percentage in gt7 is probably damping coefficient, usually represented by the Greek letter zeta.

100% would then be critically damped, Zeta =1. In gt7 you could have eg around 35% damping for example in which case zeta would be 0.35.

Zeta = C / Ccrit

C crit = 2 * sqrt(K*M), K is wheel spring rate in N/m, M is corner mass in kg.

C = Ccrit * zeta. Units of C and Ccrit should be N/ms-1, force per velocity, the damper rate.

So it's possible to calculate what damping percent you need to get a desired C, the damper rates. You can therefore match the front and rear C, even if you have a different nat freq front and rear.

Also the damping has an effect on the suspension frequency by modifying the nat freq. Fdamp = Fnat * sqrt(1-(zeta^2)).

 

[hookedonturbo]

I think the damper percentage in gt7 is probably damping coefficient, usually represented by the Greek letter zeta.

100% would then be critically damped, Zeta =1. In gt7 you could have eg around 35% damping for example in which case zeta would be 0.35.

Zeta = C / Ccrit

C crit = 2 * sqrt(K*M), K is wheel spring rate in N/m, M is corner mass in kg.

C = Ccrit * zeta. Units of C and Ccrit should be N/ms-1, force per velocity, the damper rate.

So it's possible to calculate what damping percent you need to get a desired C, the damper rates. You can therefore match the front and rear C, even if you have a different nat freq front and rear.

Also the damping has an effect on the suspension frequency by modifying the nat freq. Fdamp = Fnat * sqrt(1-(zeta^2)).

I’ve got the equations just translating them into dynamic values that work for every car on GT7. I think I’ve managed it so far, just working through the list to check each setting.

Gearbox ratio calc in production as well!

 

[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…

 

[hookedonturbo]

I’m uploading the sheet to a website which will require a payment of £10 to digitally download it. Hopefully this is not out of reach for the majority. I think it’s a snip for what this will do for you!!!

Any queries please let me know

 

[FAN_Lawless]

Gearbox ratio calc in production as well!View attachment 1240735

sweet baby geezus I have been waiting on something like this to return as well

 

[hookedonturbo]

Just awaiting web developer to translate the code to work. The gear ratio calc is definitely a must! It’s works like a charm. Cars like the GT-R and Scooby need calculated ratios to make the most of the power band.

 

[hookedonturbo]

I am developing a tuning spreadsheet and looking for someone to partner with in developing an app. Any tech savvy enough to incorporate a spreadsheet calculator into an app would be perfect. Any questions are welcome. View attachment 1239297

Also interested to hear if anyone has the need for such an app? Do you think this will be well received?

And for anyone interested the calculations take into account suspension travel, force applied under load, lever ratio so without giving away too much the following formula is applied; K = Spring Rate in N/m. Allowance for unsprung weight. So far this works like a charm.

1/2pi

Sqrt(K/M)

Working on a table of every car so that when a car is selected, the drivetrain type is automatically selected, along with Road, GR4 or Race.
Looking forward to getting this running in an app that everyone can use easily. Obviously this will later include other parameters for roll bars, dampers and wheel geometry.

Unfortunately I didn’t check the rules about post advertisement on gtplanet so my link was removed. I will keep you posted on what happens next…

 

[hookedonturbo]

We are now back online! 😄

Download your copy.

www.gt7tuningcalculator.co.uk