GT5 Quick Tune: ***VERSION 3.1***

[RevoWRX]

This seems like a great idea. I'll do some testing after work today. Thanks!
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[oppositelock]

Something else I just thought of: most car makers deliberately dial in understeer out of the factory, if they're using springs to do this, then it messes up your motion ratio calc. Not that I can suggest a way to avoid this, but just something to keep in mind...

Absolutely correct. This is one of the reasons I implemented the balance fine tune function in order to make spring rate adjustments. Unfortunately I think Rotary Junkie is correct in saying that under certain circumstances it doesn't really work as advertised. As of this moment I'm not sure why this is, but I have some theories.

 

[jenoma]

I have used this to tune some cars I have in my garage, and with lot of satisfaction I may add. One thing I consider interesting is that with the tunes provided by your sheet I've been able to do some interesting lap even online, without losing control on Nurburgring Karussell, as it always happened with extreme low ride height settings, which leads me to believe that online the car bottoming out is modelled differently than offline.

I have tuned an Enzo with 922BHP, without rear wing, and the results where optimal, the only things I had to modify where dampers settings because on Nurburgring needed to be softer (but only when using Suspension Level 4). I've used camber high values, like 4 on front and rear, and raised the balance to an 8 and been able to get consistent lap times online and offline, but most importantly the car has become easier to drive.

Any car I've tuned using this method, have become more reliable and I successfully dialled out almost any sort of oversteering and, for what it concerns my experience, I was able to drive even the most difficult cars with a DS3 and minimum aids setting (ABS1) offline and online.

So great work here and thanks for sharing

 

[oppositelock]

That's great to hear! 👍 One of my goals with this was to produce consistant, stable, easy-to-drive baseline tunes for controller jockeys like myself, and I'm happy to see it works as intended. Now I just have to figure out how to make it work equally well for those wheel guys....

I have a slightly improved version with some very, very minor revisions that I should be posting soon. After further testing I've concluded that running front toe, either positive or negative, seems to simply degrade the steering feel while providing little to no handling benifit, so I'm considering recommending zero front toe across the board. I'd like a little feedback from the hive mind before implementing this, however.

 

[jenoma]

[...] After further testing I've concluded that running front toe, either positive or negative, seems to simply degrade the steering feel while providing little to no handling benifit, so I'm considering recommending zero front toe across the board. I'd like a little feedback from the hive mind before implementing this, however.

In my opinion you're right, I always end to personalise the results and I put neutral toe-in on front and usually lower it at the back. It's just a matter of personal preferences in driving stiles I suppose.

 

[tuga703]

Thought i would post to say thank you and to BUMP this thread a bit because i find this great to find a base tune which i can then change a bit for my needs.👍

 

[BlueShift]

Personally, I don't think ride height in and of itself should be used to alter handling. Ride height should be dependent on suspension stiffness, not vice versa, and I don't see much benefit to using rake in either direction unless your spring rates are really goofy and you were able to detect the soft end bottoming out. Raising one end of the car and then then raising the spring rate to counteract that is not something I would do myself.

You're wrong.

Moment of lateral force are made different. Higher = more moment, lower, less moment.
That's why you lower the RH. But sometimes lowering it equal/equal don't remove problems.

Example : very low RH in front and very high RH in rear (adjusting SR to real RH so spring force stay the same), make the car oversteering and raise rear to front weight transfer rate without touching to anything else ie SR balance. Outside forces stay the same but the car steer better (but brake less). You absorb the greater moment by ~+1 rear comp and anti-roll and that's done. (or it's a way to remove rear comp or ar bar when set at 1/2)

It also raise rear aero by a few degrees or so.

 

[oppositelock]

You're wrong.

Moment of lateral force are made different. Higher = more moment, lower, less moment.
That's why you lower the RH. But sometimes lowering it equal/equal don't remove problems.

Example : very low RH in front and very high RH in rear (adjusting SR to real RH so spring force stay the same), make the car oversteering and raise rear to front weight transfer rate without touching to anything else ie SR balance. Outside forces stay the same but the car steer better (but brake less). You absorb the greater moment by ~+1 rear comp and anti-roll and that's done. (or it's a way to remove rear comp or ar bar when set at 1/2)

It also raise rear aero by a few degrees or so.

I didn't say it can't be used. I said it shouldn't be used. Like how you say toe shouldn't be used to fix handling problems. You think it's a poor technique. I think dialing in rake to tune handling balance is a poor technique. There's a half dozen other settings that work far better for this purpose without making your car look like a dragster.

 

[nomis3613]

It's been a while, sorry for the delay but I've been meaning to test this:

After further testing I've concluded that running front toe, either positive or negative, seems to simply degrade the steering feel while providing little to no handling benifit, so I'm considering recommending zero front toe across the board. I'd like a little feedback from the hive mind before implementing this, however.

My tests found that front toe is useful and works the same as GT4 (ie it is the balance between early and late corner front grip). For rwd cars, -ve front toe reduces exit understeer, but also reduces turn-in. +ve front toe improves turn-in, but reduces exit grip.

Since this setting is mostly about steering feel (hence driver preference), it's gonna be hard to make a formula for your spreadsheet. Perhaps just leave it at a "neutral" setting (0.0).

Hope this helps.

 

[oppositelock]

Since this setting is mostly about steering feel (hence driver preference), it's gonna be hard to make a formula for your spreadsheet. Perhaps just leave it at a "neutral" setting (0.0).

That's what I'm thinking.

Where I'm really struggling is on the rear toe formula. I wanted to post a new version a week ago but I'm still banging my head against the wall here. I'm thinking of making it horsepower or power-to-weight ratio dependent, so that faster, less stable cars get more toe-in than slower cars. But that's another parameter to enter and I'm trying to keep it as slick and minimal as possible, so we'll see.

I'm also doing extensive testing on a new set of LSD formulas. I'm hoping more initial torque and decel will help stabilize the car so I can dial back the rear toe. It's all ties together and I'm trying to find the right balance.

To be continued...

 

[nomis3613]

^ yeah I reckon for rwd you're better off running +ve rear toe for traction, then use some other setting to dial out the understeer.

 

[tuga703]

Hi oppositelock, I've made a spreadsheet for transmission to keep the engine in the powerband whenever you change gear, but i'm having problems with the limits that GT has so i was hoping you could help as you have made your formulas based on the minimum and maximum spring rates etc. and we could then have a single spreadsheet that could give a full tune with suspension and and transmission etc. in one neat package.

Thanks in Advance

 

[jenoma]

Hi oppositelock, I've made a spreadsheet for transmission to keep the engine in the powerband whenever you change gear, but i'm having problems with the limits that GT has so i was hoping you could help as you have made your formulas based on the minimum and maximum spring rates etc. and we could then have a single spreadsheet that could give a full tune with suspension and and transmission etc. in one neat package.

Thanks in Advance

That would be fantastic

 

[oppositelock]

Hi oppositelock, I've made a spreadsheet for transmission to keep the engine in the powerband whenever you change gear, but i'm having problems with the limits that GT has so i was hoping you could help as you have made your formulas based on the minimum and maximum spring rates etc. and we could then have a single spreadsheet that could give a full tune with suspension and and transmission etc. in one neat package.

Thanks in Advance

Believe it or not, I have a gear ratio spreadsheet left over from GT4! I actually have way more time and effort invested in it than in my Quick Tune sheet. I'm somewhat reluctant to share it because people had trouble using it when I first posted it in the GT4 tuning forum about a year ago. It's kind of tough to master, but if you can figure it out it's an extremely powerful tool. You can download it here:

http://www.mediafire.com/?dnnqb2txu1z

Instructions are here:

http://www.mediafire.com/?mty2jybpmu2

I'd have to add support for eight speed transmissions, but otherwise it seems to work for GT5 as well. I'd be interested in seeing what you have so far as it might give me ideas on how to streamline the whole process. 👍

 

[tuga703]

I haven't tested yours yet but I find it a bit complicated and bulky at first sight, here is mine, the problem with it is the ratios are nearly always out of the scale that GT allows
http://www.mediafire.com/?pqasc3pue8xqi5d

 

[oppositelock]

I see you made one of the same exact mistakes I did when I first started working on mine, which is having each gear be a fixed percentage of the previous gear. Seems logical, right? Well, it doesn't work for reasons I still don't quite understand. If you were to actually drive a car using a gearset created with your sheet you'd find the RPM drop actually increases in each progressive gear with little regard to your "Revs after Shift" value. If you look at the ratios in my sheet, you'll see a big percentage gap between 1st and 2nd which gets progressively smaller as you move up though the gears. Despite this, you'll usually find that the revs drop to the almost the same exact RPM range from about 3rd gear on. Mathematically this shouldn't happen, but it does. Coming up with a formula to compensate for this phenomenon took me months of trial and error. And since the fixed ratio method leads to either excessively tall lower gears or extremely low higher gears, you'll have trouble fitting your ratio set into the allowable range, just as you described.

 

[tuga703]

So what you mean is that the revs don't end up at what would be mathematically correct after a shift by the means of magic? Does that mean that it is pretty much impossible to create a calculator that keeps the revs exactly where you need?

I'm sorry if these questions are really stupid but I am confused now...

EDIT: Just tried your spreadsheet on my '91 Honda Prelude and it matched the power band near perfectly and it turned out noticeably better acceleration when it finished wheelspinning, I guess I wasted last sunday making mine lol

 

[oppositelock]

So what you mean is that the revs don't end up at what would be mathematically correct after a shift by the means of magic? Does that mean that it is pretty much impossible to create a calculator that keeps the revs exactly where you need?

I'm sorry if these questions are really stupid but I am confused now...

Not stupid at all, it really is confusing. My sole (and rather lame) theory is that at higher speeds the car decelerates slightly between shifts due to friction and drag, but even that doesn't explain the huge differences in RPM drop I've noticed. I don't think it's a GT bug either, I think it's a very real phenomenon, otherwise real car gear ratios would look more like yours instead of mine. You really have to see it for yourself, try to find a car with a very close default ratio spread that you can fit your ratios in. Frankly, I don't see any shortcuts around it. Not to say there isn't a solution, but it won't be easy.

 

[oppositelock]

EDIT: Just tried your spreadsheet on my '91 Honda Prelude and it matched the power band near perfectly and it turned out noticeably better acceleration when it finished wheelspinning, I guess I wasted last sunday making mine lol

Awesome! Well, not about wasting your time...you know what I mean.

 

[tuga703]

Well I'm off to sleep, Thank You!

 

[chuyler1]

Hi, I can safely say that your spreadsheet is better than me at tuning.

I did some runs on Trial Mountain just now in my '86 Toyota MR2. My initial tune has been all messed up after bouncing between sport soft and racing soft tires. I figured the best way to get a feel for the car would be to run sport soft tires and I did just that for this test. For the record, I use a DFGT with the bungie cord mod. I ran a minimum of 3 laps and typically lap 2 was the quickest in all cases. When I pushed things to squeeze more time out of a setup it usually resulted in a lap time 1-2 tenths slower but still within a reasonable margin of error to make these conclusions.

Setup 1 (what I had to start)
Initial time: 1:37.540 (after 6 laps to familiarize myself)
Notes: Car was very unpredictable. Had great initial turn in but quickly turned to understeer upon releasing the brake. Applying power caused more understeer. Applying too much power on exit would cause immediate oversteer and resulting spinout. Car was also unstable over bumps and curbs.

Setup 2
Spreadsheet Settings: 2 / 5 / 2.0 / 2 /3 (defaults)
New Time: 1:36.410 (after 3 laps)
Notes: This 1 second drop in time was obvious since my added confidence had increase and I could squeeze more throttle out of turn exits and turn in was more predictable making it easier to fine tune braking points. Overall the car understeered more than I liked so I typically braked a little earlier and harder to make sure I could get the nose inward enough to hit the apex of turns. Suspension felt stiffer over bumps but remained stable provided I wasn't going too fast.

Setup 3
Spreadsheet Settings: 2 / 6 / 2.0 / 2 / 3
New Time: 136:016 (after 3 laps)
Notes: The spreadsheet did as expected. Increasing the balance fine tune dialed back the understeer and I was able to brake a little less in turns and let the tires scrub some speed off for me. Increase in time was small but the car drove more to my liking.

Setup 4
Spreadsheet Settings: 2 / 7 / 2.0 / 2 / 3
New Time: 135:860 (after 3 laps)
Notes: Again the results were as expected. Understeer was dialed back even more and I was able to quickly increase my times.

Setup 5
Spreadhseet Settings: 2 / 8 / 2.0 / 2 / 3
New Time: 1:35.532 (after 4 laps)
Notes: At this point the car began to feel a little loose. I was working the steering wheel much more and as a result it took a little more effort to get a better lap time, but it only took an extra lap.

Next I went back to Setup 4 to see if I could match my lap time with Setup 5. After 10 laps I couldn't do it. The best I managed was a 1:35.610.

So the logical step was to go back to Setup 5. After 3 laps I hit a 1:35.323!

Finally, I bumped the balance fine tune up to 9 for one more round. I did a 1:35.516 after 5 laps but it felt like a perfect lap. Going up to 9 seemed to reduce my mid-corner grip. When I had it set at 8, I didn't really have to try to find the speed.

In conclusion, your spreadsheet rocks and has really helped me find some time in this car.

For reference, this was my tune before:

suspension:
-10 / -10
5.5 / 6.5
4 / 4
3 / 4
3 / 2
1.3 / 1.0
.05 / .20

lsd:
20 / 45 /30

brakes:
8 / 3

And this was my tune after using your spreadsheet with a fine-tune of 8.

suspension: (changes in bold)
+5 / +5
5.2 / 7.8
5 / 7
6 / 6
4 / 2
2.0 / 2.0
.05 / .20

lsd:
9 / 36 / 18

brakes:
8 / 2

 

[oppositelock]

Fantastic! Seeing it actually help people makes it all worthwhile. 👍

I have version 1.1 back up and running, the link is in the first post. Notable changes:

The formulas for both swaybars and damper extension were slightly tweaked. Output for suspension level 3 and 4 is the same, but level 1 and 2 results are now more consistent.

LSD formulas were revamped. There is now stronger initial torque and deceleration values across the board, and all values now increase and decrease with the adjustment.

Front and rear ride height are now separate for vehicles with different front and rear adjustment ranges.

Default torque split is now 25/75 instead of 20/80 for increased traction.

Recommended front toe is now 0.00 across the board.

Rear toe is now horsepower dependent. More powerful vehicles now get more toe than slower cars as they are more prone to instability. I don't find this a particularly elegant solution, but I'm open to any better ideas.

There may still be some bugs lurking due to mixing and matching of formulas, so if you spot one please notify me as soon as possible. Thanks!

 

[chuyler1]

How about compensating for weight changes? Overall I think the tunes I got are on the stiff side, but that is probably because my MR2 has weight reduction from stock. Could you factor in original weight vs current weight?

 

[oppositelock]

Factoring in weight would be pretty damn tough, but someone else suggested being able to use decimals in the suspension level field. For instance, if 3 was too stiff and 2 too soft, you could input 2.3 or 2.7 to get something in between. It would work fine with the ride height and spring rate, but the dampers and swaybars would tend to make sudden large changes without warning. I'd probably have to split them up with their own separate adjustment. Have you tried using a level 1 setup, or mixing level 1 and 2 settings?

 

[chuyler1]

I ran some more timed runs today with various settings. I figured out that a camber of 2.0 was making the car slick mid corner. I tried 1.0, 0.0, and finally settled on 0.5. My lap times on Trial Mountain increased by 2-3 seconds once I fixed camber. Next I played with the suspension setting. I ran several laps on racing soft tires with a setting of 2, then went back to a setting of 3. Lap times were very close, within 3/10ths so its hard to say which is faster...but when it comes to feel, it might be perfect somewhere between the two. I'll have to try a setting of 1 later since I ran out of time.

I tried your spreadsheet on a few more cars as well. A '90 RX-7 and the Ferrari 512BB. Both tuned up nicely and were well behaved. For the 512BB I had to use a suspension setting of 4 to remove extra body roll. For both I stuck with a camber setting of 0.5. In general it feels like I could squeeze more speed out of the cars by forcing some oversteer...but it will take some more time behind the wheel to dial it in any tighter than what you have provided.

 

[BarclayGT5]

FYI - the transmission spreadsheet that you posted works great for GT5. The tire factor is easy to measure on Special Stage Route 7, since it's just a long straight road. The suspension also worked great for my NASCAR. All in all, I was able to shave several seconds off my Daytona lap times using these spreadsheets. More importantly... I now have a car that is competitive against the other racers on-line.

Thanks!

 

[chuyler1]

I just wish there was a version that would work on my iPad or iPod touch since I don't usually have the laptop out when I play.

I mentioned incorporating weight into the equation before. I think weight really just becomes a factor of the suspension stiffness. For lighter cars running a lower number helps. Another item to consider is downforce. Adding a wing really helps stabilize the rear end of street cars...but it probably changes how you would dial in understeer/oversteer.

 

[Smudger92]

Good work with the spreadsheets, top quality, helped me gain 3 seconds on deep forest raceway using the suspension and transmission. If using the transmission for race setting add a few mph/kph in case you get a slipstream just so you dont redline it.

 

[Adrenaline]

I have version 1.1 back up and running, the link is in the first post. Notable changes:

The formulas for both swaybars and damper extension were slightly tweaked. Output for suspension level 3 and 4 is the same, but level 1 and 2 results are now more consistent.

There may still be some bugs lurking due to mixing and matching of formulas, so if you spot one please notify me as soon as possible. Thanks!

I'm not sure if this is a 'bug' or maybe it was designed that way, but wanted to point out, that while tuning a Corvette, the Sway Bars don't change at all for the FR column, regardless of fine tuning. They are only effected by Suspension level. I assume this is by design, but you mentioned a tweak, so it's worth bringing up.

A side note, I think it would be in your benefit to include short and simple explanations of factors not accounted for in the spreadsheet, and add them to the original post. For example, the post says "If you find the initial setting to have either extreme oversteer or understeer for your driving style please use the swaybars to correct this before trying the fine tune." but then never mention how the sway bars should be adjusted, or what the results will be.

Another aspect the spreadsheet doesn't account for, as designed, is front toe. Again, this is fine, but it'd be helpful if you added another small excerpt about the effects of positive and negative front toe. Nomis3613 mentioned the following "My tests found that front toe is useful and works the same as GT4 (ie it is the balance between early and late corner front grip). For rwd cars, -ve front toe reduces exit understeer, but also reduces turn-in. +ve front toe improves turn-in, but reduces exit grip." and if you find that to be accurate, would be all that's needed to add.

The last 2 things that falls into this category are Camber & Shocks. What are signs that camber are too high / too low? Using the default of 2.0, how do I know if I should increase or decrease it, based on how the car responds? As Rotary Junkie mentioned, adjusting shocks can be far more effective for correcting entry/exit issues. As with the others, a short and sweet explanation will go a long way.

It just helps fill in the blanks, of what the spreadsheet can't be designed to account for. Driver preference, pretty much.

On the up side, using this spreadsheet I was able to take 1.1xx off of my lap time at Trial Mountain with the Corvette, going from a stock set up, all the way to 4/10/2.0/1/4 set up. So it's clearly effective and helpful. Not only does the spreadsheet work, but it also allows people to see "Changing X in theory results in Y" For me, this was as simple as spring rates and handling results from understeer to oversteer as I increased from level 0 to 10.

The only thing that didn't work for my personal style, was the LSD settings. I found them hard to control, and ended up using much lower Acceleration Numbers, but this has been a trend regardless of who's tunes I've used. On FR cars I usually default to a 15/10/5 set up, and it seems to work for me.

Overall great design, just need to help fill in some missing bits of information, based on your target audience, myself included. Congrats and thanks for the great work, I, and I'm sure many others, are extremely appreciative of your efforts.

 

[oppositelock]

I'm not sure if this is a 'bug' or maybe it was designed that way, but wanted to point out, that while tuning a Corvette, the Sway Bars don't change at all for the FR column, regardless of fine tuning. They are only effected by Suspension level. I assume this is by design, but you mentioned a tweak, so it's worth bringing up.

Yeah, the big problem with using swaybars in conjunction the fine tune adjustment is the large increments involved. Say you went to fine tune 6 and my formula bumped up the rear sway one click and dropped the front one click, so instead of 4/4 you have 3/5. Not only is that a huge jump, pretty soon you're going to run out of adjustment range. Heck, a suspension level 4 FWD car is already at 3/7, meaning there's no remaining headroom after fine tune level 5. So I was pretty much forced to limit the use of swaybars for correcting the most obvious handling problems common to each particular drivetrain.

A side note, I think it would be in your benefit to include short and simple explanations of factors not accounted for in the spreadsheet, and add them to the original post. For example, the post says "If you find the initial setting to have either extreme oversteer or understeer for your driving style please use the swaybars to correct this before trying the fine tune." but then never mention how the sway bars should be adjusted, or what the results will be.

You're probably right, I kind of figured it was common knowledge. If understeering, soften the front and stiffen the rear. If oversteering, do the opposite.

Another aspect the spreadsheet doesn't account for, as designed, is front toe. Again, this is fine, but it'd be helpful if you added another small excerpt about the effects of positive and negative front toe. Nomis3613 mentioned the following "My tests found that front toe is useful and works the same as GT4 (ie it is the balance between early and late corner front grip). For rwd cars, -ve front toe reduces exit understeer, but also reduces turn-in. +ve front toe improves turn-in, but reduces exit grip." and if you find that to be accurate, would be all that's needed to add.

I actually don't find that description particularly accurate, so there's that. My real-world experience says that front toe-out should result in sharper turn-in, which is why it's commonly used in autocross. I haven't been able to reliably duplicate this in GT, much less come to the conclusion that it works entirely to the contrary. At this point I have no rock solid suggestions on how to utilize front toe to your advantage. The only thing I'm sure of is that zero front toe has no negative side effects, so that's my recommendation for the time being.

The last 2 things that falls into this category are Camber & Shocks. What are signs that camber are too high / too low? Using the default of 2.0, how do I know if I should increase or decrease it, based on how the car responds? As Rotary Junkie mentioned, adjusting shocks can be far more effective for correcting entry/exit issues. As with the others, a short and sweet explanation will go a long way.

Without tire pyrometer readings, camber in GT is definitely a black art. Generally speaking, I'd say low camber settings are good for braking, straight line traction, and turn-in. Higher camber settings are typically good for pure cornering grip, after the weight has transfered and the body starts to roll. The trick is finding the "sweet spot" between the two. It's really trial and error, no shortcuts here.

File damper settings under "stuff I don't understand well enough to tell other people how to use it".

It just helps fill in the blanks, of what the spreadsheet can't be designed to account for. Driver preference, pretty much.

On the up side, using this spreadsheet I was able to take 1.1xx off of my lap time at Trial Mountain with the Corvette, going from a stock set up, all the way to 4/10/2.0/1/4 set up. So it's clearly effective and helpful. Not only does the spreadsheet work, but it also allows people to see "Changing X in theory results in Y" For me, this was as simple as spring rates and handling results from understeer to oversteer as I increased from level 0 to 10.

👍

The only thing that didn't work for my personal style, was the LSD settings. I found them hard to control, and ended up using much lower Acceleration Numbers, but this has been a trend regardless of who's tunes I've used. On FR cars I usually default to a 15/10/5 set up, and it seems to work for me.

That's cool, it's all about what works for the end user. Actually, my first LSD formulas were a bit on the loose side, I only bumped them up after seeing people using much higher settings. If I get someone else saying that they're still too loose I'll know I'm in the right ballpark.

Overall great design, just need to help fill in some missing bits of information, based on your target audience, myself included. Congrats and thanks for the great work, I, and I'm sure many others, are extremely appreciative of your efforts.

My pleasure. I'm just happy this thread is still going over a month later.