could use a little help on a project if anyone has free time :)

[Otaliema]

What about adding body rigidity to the car or not, and what about driving aids all OFF or some ON ?.

That would exsarbate the understeer problem. I use body rigidity on MR car to settle then down. In fact it gets so much understeer into the cars I have to generally tune it like a FR after its installed.

 

[demonchilde]

I really appreciate everything everyone has tried and tested.
Although I believe the newer set ups are closer to the cars potential, I don't think he will be winning any races with it.
At 600pp, actually trying for lap times, you should be around 1.17-1.20, anything over 1.20 on that track is just not going to beat normal go-to cars for 600pp.
It's just with that kind of power.....hmm mommy
You know, we could be going about this all wrong
The initial thought that "maxed out the car still does not naturally hit 600, so Max it and tune it"
I think might be off base.
Normal go-to cars for 600pp don't have that 800+ hp, and yet get faster laps........
This car might just plain do better with less weight altogether, tuning around the front weight, and lowering the power/torque to something the chassis can handle?
Am I nuts?

Oh, and Ridox, "The lap was driven like I stole the car, hooligan exit ( some wheelspin in last portion of some corner exit but floor it and it sort itself out as long as keeping steady on the steering )" ........ you just described my drive style to a tee, lol.

 

[Ridox2JZGTE]

I really appreciate everything everyone has tried and tested.
Although I believe the newer set ups are closer to the cars potential, I don't think he will be winning any races with it.
At 600pp, actually trying for lap times, you should be around 1.17-1.20, anything over 1.20 on that track is just not going to beat normal go-to cars for 600pp.
It's just with that kind of power.....hmm mommy
You know, we could be going about this all wrong
The initial thought that "maxed out the car still does not naturally hit 600, so Max it and tune it"
I think might be off base.
Normal go-to cars for 600pp don't have that 800+ hp, and yet get faster laps........
This car might just plain do better with less weight altogether, tuning around the front weight, and lowering the power/torque to something the chassis can handle?
Am I nuts?

Oh, and Ridox, "The lap was driven like I stole the car, hooligan exit ( some wheelspin in last portion of some corner exit but floor it and it sort itself out as long as keeping steady on the steering )" ........ you just described my drive style to a tee, lol.

500 or 550PP would be a decent level for the Buick I have installed body rigidity on my car after that initial est, still drives okay it was meant to have it anyway If it does become too stable or tight, usually ARB or damper tweak will cure it ( to back like without rigidity )

 

[demonchilde]

Let me know how much you like it, if you think it's worth it, I will do the same.
You have tuned enough cars to know by now, lol, I trust you. ^^

 

[Ridox2JZGTE]

Let me know how much you like it, if you think it's worth it, I will do the same.
You have tuned enough cars to know by now, lol, I trust you. ^^

It's best if you drive the setup I posted, the car has min front and max rear ride height, and to free up the car, you can do many things, like putting stock LSD, or raising front height, or if necessary, front damper extension and rear extension changes. The changes with body rigidity is like adding extra ARB value on both axle

I setup the car within limitation of visual ride height, so it if that limitation is gone or lessened, the car will free up ( more loose / agile ), it's up to you how far you want it to go. The spring rate range can also easily alter the balance of the car, I used lowest value on both axle, increasing front only will add more stability, good for compensating less ride height difference. Play around a bit with the setup and you'll get the idea.

After you drive the setup I posted, try this for a start : rear damper extension can be lowered or increased, try lower or higher by 2, and see how the car react. Originally it has rear extension at 7 when it used CS tire.

If you like how responsive the car to changes, install body rigidity, and if you find it too tight, lower both ARB by 1 to 1/6 in this case, it should get you closer to the way it was before but still have that extra stability and less snappy To bring even more rotation, use 70 front ride height for a start. I'm sure it will turn in more

 

[MrGrado]

You want a tune with RS tires?

 

[demonchilde]

The friend of mine who asked for this tune, will be using both SS and RH tires mainly, and be competing against normal go-to cars at the 600pp level.

And Ridox, I only did Rigidity (in gt6) on 1 car that I liked the improvements on after I did it.
It was one of the audi race cars like the Playstation team one.
I tested it only a few times after that, and didn't like the outcome.
So yeah, it is the very rare car that it will make the difference, but this car sure is pretty individual if you ask me. I think I will give it a shot and try out your set-up.
I am really leaning towards thinking this car is going to work with little to no added weight, but just using less HP. Maybe not. We shall see.

 

[lBt_33]

Car : Buick Special

Weight : 1200kg ; 83 kg of ballast at 50 position

Weight distribution : 55/45
Power Limiter : 94.1%

590PP


Parts :

Install :
All Parts


The Setup :

Front, Rear

Ride Height: 96 106
Spring Rate: 8.40 9.74
Dampers (Compression): 3 6
Dampers (Extension): 6 4
Anti-Roll Bars: 5 4
Camber Angle: 1.2 1.2
Toe Angle: 0.02 -0.08



Transmission :


Set to default
Adjust final gear to 5.000
Move the max speed to 220km/h
1st. 2.400
2nd. 1.780
3rd. 1.390
4th. 1.125
5th. 0.930
6th. 0.800


Final gear. 3.300


LSD -

Initial Torque : 12
Acceleration Sensitivity: 16
Braking Sensitivity: 9


Brake Balance :

Set 4/6 or your favourite BB. All are tested without ABS and any assistances.


NOTES

 

[MrGrado]

Buick Special
589PP
807BHP
1117kg
58:42
Tuned 28 December 2015

Tyres
Racing Soft

Suspension
Full Custom Suspension
ride height: 88 120
spring rate: 9.25 4.85
bound: 2 1
rebound: 9 8
sway: 6 5
camber(-): 2.8 0.8
toe: -0.85 -0.40
Racing Brakes
brakes: 6 6

Transmission
Standard Transmission

Drive Train
Full Custom Differential
10 / 60 / 10
Triple Clutch

Power
Limiter: 100%
Engine Stage 3
Racing exhaust
Isometric Exhaust Manifold
Intake Tuning
Supercharger

Body
Ballast: 0@0
Downforce: -----
Weight Reduction stage 3
Carbon bonnet
Window weight reduction

GT Auto
Change Oil: no
Increase Rigidity: no
Fitted Parts: -----

Tuner Notes

Tuned at Bathurst. 2:01.xxx. For perspective, 1:55.xxx is a middle of the road 650PP Race car lap time. I'm not sure what times I might get with other 600pp cars here sorry.

I had a different setup with ballast but I went faster without ballast. These are extreme settings because this is an extreme car. There's not much room to adjust some of the settings to cater for harder tires, but I imagine this will go alright like this with other tires.

A lot of my tunes recently were built specifically to perform to the max at Bathurst, they may not perform as well at other tracks.

This setup will almost certainly require a slightly different approach from a racer, but it could possibly produce results if they discover how to drive it harmoniously.

 

[demonchilde]

Out of curiosity, i saw how you can achieve 51/49 with 1,300kg.
All weight reduction on, ballast at 183@+50.
I would have to start all over from the beginning though if I went that direction, so instead I am asking you guys, have any of you played with this at 51/49 while you were testing?

Anyway, I am testing the different set ups as we speak. I will probably do the chassis reinforcement after testing all of them, if i have to buy another one, I won't mind having 2 of them. I have enough cash to blow another million if needed.
I will let you guys know how i made out shortly.

 

[CBH]

Out of curiosity, i saw how you can achieve 51/49 with 1,300kg.
All weight reduction on, ballast at 183@+50.
I would have to start all over from the beginning though if I went that direction, so instead I am asking you guys, have any of you played with this at 51/49 while you were testing?

Anyway, I am testing the different set ups as we speak. I will probably do the chassis reinforcement after testing all of them, if i have to buy another one, I won't mind having 2 of them. I have enough cash to blow another million if needed.
I will let you guys know how i made out shortly.

I think this car is better with chassis reinforcement I will try it out later and see, but if I keep this car I will make it in a 550PP or a 500PP car and I think its handles better.

 

[demonchilde]

"Best of 3" lap times @ Apricot Hill while testing the posted settings;

Fordracer = 1.25.716 very fast and great pick up speed, but understeer preventing further lap time reduction.

Ridox = 1.26.356 better turn IN then Fords set up, but had issues with understeer AFTER the apex and on long turns.

Ibt_33 = 1.24.985 this set up solved a lot of handling issues, and because of that, was able to shave a little time from the laps, but that understeer on the wide and longer turns is whats killing further time reduction. ..... for all 3 set ups, not just this one.
I adjusted the brakes to 8/7, was able to pull off more with added braking ability.

MrGrado = 1.25.598 had to approach this drive very different, but after I did i got a good handle on it. It has a great ability to work out the understeer while on the gas pedal, but the second you take your foot off the pedal BAM, understeer, almost like its 2 seperate cars. The tune solved some issues.

The major 2 issues kept showing up. The understeer the car has naturally, and IMHO the bigger issue, the understeer that comes when not accelerating.
If it kicks out wide when not accelerating, that means forced braking to get the nose corrected on long gradual corners. Coasting is a massive time saving ability, as we all know, this car, on every set up i have tried, will not allow coasting without huge understeer.
That is the one thing I believe that if fixed would easily shave lap times down to the 1.22's. Maybe even lower.
Thank you for everyones input so far, everyone has achieved something so far, and i believe we are all on the right track to getting this car, well, "as perfect as it is going to get", lol.

I am going to do the chassis reinforcement.
Doesn't mean I won't be able to try anything else you guys want me to, I am just buying a second car. Just make sure you let me know which car to test whatever on.
Thank you thank you thank you thank you thank you thank you thank you all. I am very impressed with everyone's abilities, I like the thought processes I am seeing.

 

[CBH]

I tested this car at 550PP with no oil change, but with body rigidity on RH tyres and I was only just over 1 second slower than my 591PP car time of 1:24.160, I think this car is a lot better at 550PP at it handles very good with hardly any understeer in the corners, so I am keeping this Buick at 550PP. 👍

 

[demonchilde]

Yeah, as i mentioned, i had a feeling that was going to be the case.
I am exploring a few things along those lines also.

 

[demonchilde]

On the chassis reinforcement car, I have a best lap time so far of 1.22.797
Which is a little more then 2 seconds under the best lap time from the other non-reinforcement set ups.
Heres the settings i am currently at, kinda mixing everyones little fixes into one tune.
All weight reduction added
196kg @ +50 (51/49 distribution)
All power options added except Exhaust (semi just sounded better while testing lol)
Lsd = 5/20/17
Suspension;
100/80
8.50/9.50
6/8
6/8
3/6
0.0/1.0
0.20/-0.15
Brakes- 8/8
And again, i just auto set the trans to 205.
After we are all done tweaking the car, I will actually do the transmission for keeps.

Anyone wants to take it for a spin who has already done the chassis reinforcement, please do.
And feel free to tell me where I should change something, lol, i am overloaded on tweaking right now.

 

[CBH]

On the chassis reinforcement car, I have a best lap time so far of 1.22.797
Which is a little more then 2 seconds under the best lap time from the other non-reinforcement set ups.
Heres the settings i am currently at, kinda mixing everyones little fixes into one tune.
All weight reduction added
196kg @ +50 (51/49 distribution)
All power options added except Exhaust (semi just sounded better while testing lol)
Lsd = 5/20/17
Suspension;
100/80
8.50/9.50
6/8
6/8
3/6
0.0/1.0
0.20/-0.15
Brakes- 8/8
And again, i just auto set the trans to 205.
After we are all done tweaking the car, I will actually do the transmission for keeps.

Anyone wants to take it for a spin who has already done the chassis reinforcement, please do.
And feel free to tell me where I should change something, lol, i am overloaded on tweaking right now.

Will your friend like it, because everybody driving style is different and we forgot to mention that. If we make changes to suit the way you drive but will it work for you friend ?.

 

[demonchilde]

Exactly my point.
If i wasn't worried about that part, i wouldn't bother asking the opinions of all of you, lol.
I value your opinions.
Im just trying to get that lap time as close to 1.20.000 as possible, because i know if i can't there's no way he's going to beat others in that pp range. But thats me, the overall effectiveness of the car in general is priority ONE. Any speed and times will follow.
Might eventually get it down to 2 set ups, and give it to him as 2 presets that he can test for himself.
And i am not happy with the above settings. I felt that working out those issues was actually possible though, after testing it.

 

[Ridox2JZGTE]

"Best of 3" lap times @ Apricot Hill while testing the posted settings;

Fordracer = 1.25.716 very fast and great pick up speed, but understeer preventing further lap time reduction.

Ridox = 1.26.356 better turn IN then Fords set up, but had issues with understeer AFTER the apex and on long turns.

Ibt_33 = 1.24.985 this set up solved a lot of handling issues, and because of that, was able to shave a little time from the laps, but that understeer on the wide and longer turns is whats killing further time reduction. ..... for all 3 set ups, not just this one.
I adjusted the brakes to 8/7, was able to pull off more with added braking ability.

MrGrado = 1.25.598 had to approach this drive very different, but after I did i got a good handle on it. It has a great ability to work out the understeer while on the gas pedal, but the second you take your foot off the pedal BAM, understeer, almost like its 2 seperate cars. The tune solved some issues.

The major 2 issues kept showing up. The understeer the car has naturally, and IMHO the bigger issue, the understeer that comes when not accelerating.
If it kicks out wide when not accelerating, that means forced braking to get the nose corrected on long gradual corners. Coasting is a massive time saving ability, as we all know, this car, on every set up i have tried, will not allow coasting without huge understeer.
That is the one thing I believe that if fixed would easily shave lap times down to the 1.22's. Maybe even lower.
Thank you for everyones input so far, everyone has achieved something so far, and i believe we are all on the right track to getting this car, well, "as perfect as it is going to get", lol.

I am going to do the chassis reinforcement.
Doesn't mean I won't be able to try anything else you guys want me to, I am just buying a second car. Just make sure you let me know which car to test whatever on.
Thank you thank you thank you thank you thank you thank you thank you all. I am very impressed with everyone's abilities, I like the thought processes I am seeing.

The setup that I posted has front min and rear max height as well as stock weight + 59/41 weight distribution ( these alone generally means understeer ), have you tried to increase front height ( lower the height differences ), use stock LSD, full weight reduction and move distribution towards rear ? All of these would reduce understeer, and front/rear toe can also be explored as my setup has zero toe all around ( you can try toe out on both axle )

The setup with 55/120 height showed that it can still be driven and do decent lap at 1:24s with stock weight+distribution, stock gear ratio, stock clutch+driveshaft ( this should be good for about half a second improvement ), stock brakes, and medium lock LSD.

Here's something that I would do on the setup that I posted :
Install all drivetrain upgrades ( clutch + driveshaft )
Full weight reduction and add ballast ( shift weight to the rear - my setup has 1364kg, so 100kg lighter would help a lot )
Use any gear ratio that others posted here to improve over stock ratio I used.
Ride height : 70/70 or 70/90 ( I did tried 70/120 when I tested it, and it was easier to turn in and hold the line on long left sweeper at Apricot Hill than 55/120 )
Toe : -0.10 0.00 ( for a start )
Front camber set to zero
Use stock LSD or other LSD setup posted here ( mine was 20/20/5 which is pretty high and may have caused the coasting understeer ) Less initial torque will free up the car when coasting and lower accel will make long turns more manageable.

The Buick is quite responsive to little changes ( I actually have 3 different damper setup for different tires/track ) I would recommend to make the change in steps ( find improvement in every step )

 

[steve nfs]

Don't stressful yourself. When opponents is 'alien' , your friend will still at least 3 seconds slower. That's life.

 

[demonchilde]

The setup that I posted has front min and rear max height as well as stock weight + 59/41 weight distribution ( these alone generally means understeer ), have you tried to increase front height ( lower the height differences ), use stock LSD, full weight reduction and move distribution towards rear ? All of these would reduce understeer, and front/rear toe can also be explored as my setup has zero toe all around ( you can try toe out on both axle )

The setup with 55/120 height showed that it can still be driven and do decent lap at 1:24s with stock weight+distribution, stock gear ratio, stock clutch+driveshaft ( this should be good for about half a second improvement ), stock brakes, and medium lock LSD.

Here's something that I would do on the setup that I posted :
Install all drivetrain upgrades ( clutch + driveshaft )
Full weight reduction and add ballast ( shift weight to the rear - my setup has 1364kg, so 100kg lighter would help a lot )
Use any gear ratio that others posted here to improve over stock ratio I used.
Ride height : 70/70 or 70/90 ( I did tried 70/120 when I tested it, and it was easier to turn in and hold the line on long left sweeper at Apricot Hill than 55/120 )
Toe : -0.10 0.00 ( for a start )
Front camber set to zero
Use stock LSD or other LSD setup posted here ( mine was 20/20/5 which is pretty high and may have caused the coasting understeer ) Less initial torque will free up the car when coasting and lower accel will make long turns more manageable.

The Buick is quite responsive to little changes ( I actually have 3 different damper setup for different tires/track ) I would recommend to make the change in steps ( find improvement in every step )

The last set up i posted was me trying to wotk out that understeer. You will see in it, i did a bunch of things that normally do just that, including the front ride hight trick. (Which actually isnt an understeer fix, its a turn in fix, but you say potato, i say potato, lol)
I will explore some of the other things you mentioned next time i get on my ps3

 

[Ridox2JZGTE]

@demonchilde, I just did another test again, my setup but with these changes :

Installed Body Rigidity Improvement
Ride Height 70 70 ( looks funky now )
Rear Damper Comp/Ext 3 9 ( increase by 1 both comp and ext to improve rear end traction/balance )
These are the only changes to the suspension.

Install Triple Plate Clutch and Carbon Driveshaft ( quicker acceleration )
Install all body weight reduction
Ballast 143kg at position 31 for 55/45 distribution = 1260kg

The Buick has 589PP now, 9PP more and about 104kg less weight. Still use stock gear ratio which I consider adequate for Apricot Hill.
LSD still uses 20/20/5. Same power at 807HP, torque 803 ft-lb, stock brakes 7/10 BB.

1st lap, the car did 1:21.5xx lap with some slow parts, but now the car is more stable when exiting corners as well as more agile on turn in and can hold higher speed through the long left sweeper as well as on full throttle earlier ( still can be improved ). 1st sector now is low/mid 27s and last sector at 55.5s 1:20s high or 1:21s flat may be possible as some corner entry and exit were a bit slow.
Top speed reached just over 300kmh on main straight.

So, looking at it, 600PP may just break into 1:20s or 1:19s with custom gear ratio, more looser LSD, and more power, but it's very demanding car on the driver. In a race, it will be difficult for most driver to hold consistent lap times.

Replay provided can be used as ghost.

 

[demonchilde]

Sweet, cutting that time down some is always good. ^^

In hot road cars i hit the high 1.teens.000 on that track. In touring or gt300's i hit the 1.15.000 range. Now I know he would be insane to think he could take on gt300's in the buick, lol, but if we can get it around 1.20.00ish, then he has a chance against road cars depending on the driver.
I will check that out tomorrow man, thanks again as always ^^

 

[MrGrado]

Lsd = 5/20/17
Suspension;
100/80
8.50/9.50
6/8
6/8
3/6
0.0/1.0
0.20/-0.15
Brakes- 8/8

After seeing that you were testing on Apricot Hill, I realise that my first tune will be no good. Even for cars that are only a little bit front heavy and generally drive very nice, I will make big tuning changes for Apricot Hill. I will try to make the rear heavier than the front and I change rear toe by a large margin.

So for me, an absolute prerequisite for this car will be max ballast at +50 and a large amount of negative rear toe (-0.60) to start with).

The car with your setting drives alright, it just doesn't like to turn much. The first change I made was toe. I set 0.00 / -0.60. The dampers, ARB, LSD settings seem fine. The next change I made was to ride height, I tried a few things. The car seems to drive better with lower ride height, but lowering the car seems to introduce new problems also. If you get a more fast, more refined tune I would also look at camber to ensure you have maximum front grip available. Max front grip for this car is an absolute necessity and it's also especially required for any car on Apricot Hill.

Another approach I looked at was to have ride height min, spring rates max, ARB max, toe: -1.00 -1.00, etc . It might turn out to be a good starting point.

One last thing would be brake balance. The car tends to plow straight ahead occasionally with too much brakes. Higher rear brakes seems to work nicer. It's not something I usually do, but with the massive rear tires on this car it works just fine.

 

[OdeFinn]

How fast is good?
Apricot Hill RH offline grip real noABS 549pp 1:25.716, good or just for personal fun?

 

[Ridox2JZGTE]

How fast is good?
Apricot Hill RH offline grip real noABS 549pp 1:25.716, good or just for personal fun?

@demonchilde asks for 600PP tune and hoping the car would break into 1:19s at least on RH. My 589PP did 1:21s with ease, and still has many aspect that can be improved like gear ratio, LSD, power etc.

I'm interested to see what you can do Should be fun to find the power/weight/distribution as well as gear ratio that would bring it into the required lap time.

 

[OdeFinn]

@demonchilde asks for 600PP tune and hoping the car would break into 1:19s at least on RH. My 589PP did 1:21s with ease, and still has many aspect that can be improved like gear ratio, LSD, power etc.

It starts Moulinex multipurpose kitchen tool on rear if pushing to 600pp, unless you could install flat floor on to it.
550pp range and it's really enjoyable to drive, laps on R-series tires Nordschleife 6:50-7:10 when going noABS.

Maybe I'll try to push that 600 for fun.

I'm doing with Stock weight and gearbox, even springs are stock

 

[Ridox2JZGTE]

Stock spring rate is too stiff for the car IMO ( I tried all the spring rate combo available for the real car and they are lower than GT6 stock spring, turns out the lowest spring rate 400/350 is okay ) and I'm surprised the stock gear ratio is quite good even at Tsukuba.

 

[demonchilde]

Also, to clarify, it has to 'compete' at the 600pp Level.
Doesn't necessarily mean it wont be faster at 550 itself, which i think could really be the case here. That additional HP from 550 to 595 (it's max), is not helping anything but straight line speed, its hurting the agility when NOT in a straight line, and drag is not the goal.
I'm willing to bet any of us will be faster lap time wise, with less HP, simply from gaining time during the turns and agile parts of the track.
If 'the average' driver can hit around 1.20.000 consistently with whatever setting, this goal is achieved. Because from what i have tried around 600pp on that track, except RC and TC-like cars, all road cars hit between 1.18.000 and 1.21.000 depending on the car and tune.

And the track, was picked as it really really stresses your car to the limits while tuning. If you can make a consistent tune on this track, it can easily be adapted to anything else.

 

[Ridox2JZGTE]

This is wacky, I tried 550PP ( using the 589PP setup I posted above ), I simply remove all power upgrade parts, dead 550PP, and it lap in 1:24.188 on 1st lap without breaking a sweat, no drama at all, just glide and blaze on Crazy ...so much more enjoyable at 550PP, less nervous when on power and even if it does slide a bit, full throttle away...

576HP / 1260kg.

 

[Ridox2JZGTE]

Tried again with stock weight 1364kg, 59/41, 576HP, 542PP, stock gear ratio, only suspension and lsd - 1:24.394 1st lap with some sloppy over revving . Much safer with stock weight/distribution, full flat throttle exit on most corners. Even at 542PP, the car is capable of 28.4s 1st sector with ease, it shows that more power may be detrimental to track performance.

About 2 tenths slower between 542PP and 550PP and over 100kg difference.

Can provide replay for both 550 and 542 PP if requested