How to tune GT

Discussion in 'CCC' started by THE_KART96, Jan 1, 2011.

  1. THE_KART96

    THE_KART96 TPRA Staff

    CREW CHIEF'S CORNER presents "ADDING PERFORMANCE PARTS
    AND HOW TO USE THEM".
    Hi everyone and welcome to CCC's help section. Here I will try to explain what parts to add, why you should add them, and how to use them. Some of the parts are a no brainner and might sound basic to some, but for the rookies, I hope to shed some light on this black magic.
    The LSD: This part can be a nightmare to set up. But by adding this you can fine tune how the car enters, turns and leaves a turn. Cost is 7500cr so it is something to look at. It has 3 settings:


    Initial Torque: This refers to how fast the LSD will lock up. A high setting will lock up the LSD faster. This will make the car faster out of the turns BUT it will increase understear (push). A lower setting will help the under stear, and the car will be slower out of the turn. To tune this you should start at a lower setting and work your way up to find the setting that works for you.


    Braking Torque: This refers to how the LSD works under braking. A high setting will help keep the car stable while braking and will let you brake latter, BUT the car will understear. So as before you should start at a lower setting and go up from there.

    Locking Factor: This one means that a 0 setting will let your wheels turn independently of each other. A setting of 100 will lock them at 1 to 1. The inside wheel will turn the same rotation as the out side wheel. Testing will let ypu find a setting that is right for you.
    :welcomeCCC:
     
    Last edited: Jan 3, 2011
  2. THE_KART96

    THE_KART96 TPRA Staff

    Re: CCC work page

    THE DRIVETRAIN
    Here we will look at clutches, flywheels, drive shafts and trannies.


    Clutch: Spare no expence and purchase the twin plate clutch. This will help to change gears faster and help your lap times.


    Flywheel: Again grab the semi race as it is lighter and will allow your engine to rev up faster.


    Drive Shaft: If you can, grab it. The more weight you can shed here only helps you car accelerate.

    Transmisons: I always put the Full adjustable tranny in, but if funds are short the Close 6 speed is a good choice. On long tracks you might run out of gear and you can't adjust any gears, but it is a good way to save cr. Untill you reach level 40, you can only adjust the final drive. By adjusting it you will change you shift points and thus finding a setting that you like.


    LSD: This was covered before. And a word of advise is that new tuners might want to leave this alone untill they have the car handling right. This way you will not be chasing ghosts to make it turn.
     
  3. THE_KART96

    THE_KART96 TPRA Staff

    Re: CCC work page

    Suspension
    Ride Height/Spring Rate
    Ride height can help or hurt your set up. The lower the setting, the lower the center of gravity= less pitching during acceleration and deceleration, also roll during corners thereby improving overall performance. But on a rough track, you can bottom out and send the car off line. A fine balance can help you set up.

    Spring rate has a big effect on handling. A myth is that a stiffer spring setting, the better. This is not always true. Too stiff of a setting and the tires can lose contact with the road. It can also have bad effect on pitch,yaw and roll. So the springs need to be carefully adjusted. As a basic guidline. To much of a soft front and a hard rear setting will cause over stear. And to much of a hard front and a soft rear setting will cause under stear.

    Damping Force
    The shocks control the springs. Without them, the car would bounce all over the place. Again, too stiff of a setting is bad. The car will become unstable over the bumps and a real handfull. So lets take a look at how they can be used to help the handling. On a rough track a low compression, high extension F/R will help to keep the tires on the road. They can also be used to help correct over/under stear. A high front setting with a low rear setting will cause understear. So a low front, high rear setting will cause overstear. With this knowlage you can adjust out over/understear. The damping can also help FW cars by keeping the wheels on the road. As you know, as you accelerate, the weight transfers from the front to the rear. A soft compresion, hard extension on the front will slow this down. Now if you add a hard compresion, soft extension setting on the rear will transfer weight faster to the front when braking. A rule of thumb. The compresion setting should be set before the extension. This might save you some work.
     
    Last edited: Jan 3, 2011
  4. THE_KART96

    THE_KART96 TPRA Staff

    Re: CCC work page

    How should you get ready for a race?
    Well time to look at a different part of tuning. Getting ready for the race. First off, READ THE RULES! Check the weight and hp cap, find a car that will fit, and DO NOT do a oil change. With the hp cap, a oil change can put you at the edge off the cap, but as you run your engine will gain hp as it breaks in. With the oil change you have no way to tune back the hp.

    So what to do. First..... get all the info that you can. What is the tire rule? What is the kg cap? HP cap? Once you have this info you can begin. First off, get the best. You can make some fast cash in A-spec so price is not a problem. If the tire rule is race tires, get the soft ones. I have not found a advantage by using a harder compound. The harder tire will scrub more so the tire wears out at about the same rate. I put on race suspension, tranny, semi race flywheel and dual clutch, LDS and carbon drive shaft. This will let me adjust the cars handling, lets the engine rev up faster and shifts quicker. Now to deal with the kg. Save the hood and window replacement for last. Start at the stage one reduction (if it stays above the min kg) and put it on. Now look at stage 2. It will show you what the result will be before you do the reduction. If it falls with in the rules, do it. If your car becomes to light, stop. Now lets say that after the reduction you are 5kg over. The hood change is 5kg and the window change is 10kg.


    Now on to hp. You want to use bolt on parts ONLY! Start at the exhaust. Sport first. Still under the hp? BUY IT! Now look at the next step up. Still under? BUY IT! Now the race exhaust. Still under? You know what to do. If the first 2 are way off the hp cap, you can save credits and just Pu the race exhaust. Now on to the air filters. I Pu both of them as this will let you fine tune your hp if you gain some after a race. Now look at the ECU. If it fits the hp cap, buy it. Now you might be asking yourself, Why spend so much? This way you can get as close or on the hp cap by putting on some parts and changing others. I'll use the MINI as a example. I started with the sport exhaust. hp was 177, right on the max. After one race my car gained 2 hp. Now I'm over for the next race. So I removed the sport exhaust and put on the race air filter. Hp is now at 177. After race 2 I again gained hp. Remove the race air filter and install the sport air filter. Hp is now at 177. You don't have to buy a new car and have it on your favorites as a back up. The higher hp events will let you look at turbos and blowers. With the extra parts, you can get to almost any hp you need.


    To practice, go to your lobby. Set up the room to the race rules and run there. This way you will be tuning in the race environment. Tire wear will be on so you will be ready for the race. Stay out of the practice section as it will give you a false sense on the tune. You can also ask at the forum to see if antone has a room up. This way you can get some help with the set up. (If others there will share). As for me, I buy all the exhaust parts, all the intake parts and ECU. You never know what the next hp cap will be for this car down the road. And if it fits into the kg cap, you have a car ready to go. Now if you are in a bind and just do not have the cash to get the best, pm me and we will see what can be done. I hope this helps.

    KART:sHa_thumb2:
     
    Last edited: Jan 13, 2011
  5. THE_KART96

    THE_KART96 TPRA Staff

    Re: CCC work page

    OK, lets say you want to change a car on a practice night, but it has no tune yet. Well, with the GT5 updates we have been getting, this has become a lot easier. As most of you know you can now purchase almost everything you need while in the race lobby. Chassis lightening is not a option, but most everthing eles is. So now you have changed the car and added parts to meet the rules, now what. Well over the last while, I have been talking and working with other drivers to tune cars, and have found a system that will get you close and allow you to run a race to see what is needed to be changed. First, make sure you set the suspension to "Default", ride height can be left as is for the first time out, (but, if you have a setting you like to start with, use it now) Adjust the springs 2.0 stiffer f/r. Just leave the original gap. EG: 7.8/6.5 change to 9.8/8.5. I like to leave the dampners at default for the first time out. See how it feels and adjust as needed. 1.0 f/r at a time.(stiffer) Same for roll bars. Camber I start at 1.4/ 0.7 and if there is a free run, I will head out to see how the tires wear and adjust as needed. A 0.2 adjustment is all you need to see a difference in tire wear. if it gets better, you are going the right way, if not, head the other direction. I always start with a +0.01/0.00 toe and most of the time this setting stays the same. Tranny trick it for gears, adjust for draft etc. Not sure how to do tranny trick? Here you go: Move the final gear all the way right. Now adjust the LOWER SPEED setting all the way left. Now adjust the final so that your UPPER SPEED is at the mph/kph you wanted. There you go, a quick way to get a tune on your car and it should be close to the ball park.:sHa_thumb2:
     
    Last edited: Aug 10, 2011
  6. THE_KART96

    THE_KART96 TPRA Staff

    Re: CCC work page

    CAMBER and TIRE LIFE
    It has been awhile scince my last post here and PD has changed a few things on us with some updates. And the change to the tires is the biggest change that we all can see. Because of this change, I have had to look hard and long at the tune to try to get the most out of the tires as the Racing Softs will fall off within 3 laps if the tune is wrong. So here we go.
    I had to sit back and do some thinking on what to do to get thing working right and got close a few times but it just was not there yet. So, after getting the springs, dampers and roll bar to the way I liked it my focus went to the camber. Camber can make or break your tune as it sets the amount of contact between the tire and the road. Too little and the straight line traction will be great but go to turn and the tires will glow red. So we know that we need to adjust camber, but how much? To find out, I asked others the amount the are running. And it seemed that most kept things under 2.0 and had more camber on the front than the rear. And hearing how much everyone was having problems with tire life I started to try some things. So I started to try higher camber #'s and found that the car handled better and I was getting more laps out of a set of tires. Nice.
    With the tire wear gauge as basic as it is, how can you tell if you are going in the right way?
    The best way that I have found is to listen to the tires. As you get closer to the proper camber for each car, the tire noise will reduce. Telling you that there is less tire scuffing and more grip = less wear and better lap times. And if you go too far, the tire noise will get louder and tire life will fall off. Adjust back untill things are quiet again. Now you will noy be able to remove all the tire noise, but you can tell the difference between a proper camber and one that is off by a bit.
    So be brave and try some higher settings. You just might get a nice surprise.
     
    Last edited: Mar 29, 2012
  7. THE_KART96

    THE_KART96 TPRA Staff

    Re: CCC work page

    Added prt 3
     
  8. BlackMark7LSC-SE

    BlackMark7LSC-SE Licensed Racer

    Re: CCC work page

    Thx for the Info Racer96....I never was good at tuning ..for whatever reason..all this years of racing the GT Series..Just when i thought i had a great tune ..Here comes the same ride..with almost the same toys on them...and kicking my butt out the corners...Thx for a more detailed tuning understanding.
     
  9. rallyfanboy

    rallyfanboy Licensed Racer

    Re: CCC work page

    thanks for the info . but it's all explained in GT when you click on the question mark in tuning sections.
     
  10. THE_KART96

    THE_KART96 TPRA Staff

    Re: CCC work page

    Updated post 4.
     
  11. DarkLegions

    DarkLegions Licensed Racer

    So this has me really confused. Under initial torque: What do you mean the LSD locks up, what does that mean?

    Under braking: How does the braking LSD setting let you brake later? what does it do for that to happen, and why does it have an effect on understeer if its a braking setting?

    Locking factor: The explanation seems to override both other settings by the description doesnt it? In the other settings you talk about locking the LSD and this one sets that.

    I never really understood LSD and locking, hence my rather blunt questions, and why offroad want a locking diff. (i think i heard that b4)
     
  12. clacksman

    clacksman Licensed Racer

    Locking rate of the diff means the 2 wheels on that axle are tied together more closely on speed. Power always takes the easiest route.
    Offroad you want a fully locked diff because otherwise all the power would go to the wheel in the air.
    On road you don't want quite that much diff lock because there's some traction to be had, a locked diff resists turning as the 2 wheels would be trying to go the same speed.

    The adjustable LSD can help you dial the car in by tying the wheels toghether more or less as you want.

    Inside drive wheel spinning while accelerating? Increase the Accel setting on the LSD.
    Car won't trun in? Reduce the Decel setting on the LSD.
    Car turns in so well it's scary or is unstable while braking? Increase the Decel setting on the LSD.
     
  13. DarkLegions

    DarkLegions Licensed Racer

    Ah thats some key information i was misunderstanding. Thanks.
    But still kinda confused how the LSD is separated into 3 parts, right now i'm thinking theres one setting (the last one) that controls the LSD. Dont understand where the other initial torque and braking torque come into the LSD.
     
  14. clacksman

    clacksman Licensed Racer

    "braking torque" is how much effort it does to keep the 2 wheels the same speed under deceleration, it doesn't affect acceleration
    "accel torque" is the same as ^ except while accelerating not decelerating
    "initial torque" is something I haven't quite figured out to my satisfaction yet
     
  15. THE_KART96

    THE_KART96 TPRA Staff

    It can be a head scratcher. But there are 3 factors to the LSD. To understand it, you can play a game with it. If you have a high hp RWD car you can do this to see the effects of initial toque. Set the setting to the lowest, now do a burn out. You will see 1 then the other tire turn red. Now change the setting to the highest. Do a burn out, now both will turn red at the same time. Braking torque works in the same way but under different factors. What you are setting is the point that the wheels will be released so that they can turn separately. By delaying this the axel will stay locked and helps tp keep the car in a strait line under hard braking. But if it is still locked when you want to turn, it will resist and cause a push. The final part is how fast it locks up. A NHRA car wants it to lock ASAP. A road race car needs a slower setting so that you can accelerat sooner out of a turn.If it locks too soon, the car will push to the outside and you can run off track.
     
  16. DarkLegions

    DarkLegions Licensed Racer

    Ok its becoming much clearer, thanks for the replies.
     
  17. Forgetful

    Forgetful Licensed Racer

    http://tunerspit.com/forum/showthread.php?434-Trying-to-understand-how-to-tune-a-LSD
     
  18. Forgetful

    Forgetful Licensed Racer

    The diff will lock when one wheel starts to move faster than the other. Turn up the inital, and this happens sooner. Turn it way down, and it will let one wheel go more easily.

    Braking diff lock can happen any time the car is decelerating. That's braking or coasting, but mostly during braking, since that's when the tire's are carrying more load. If the diff locks during decel, it's going to try not to let the outside wheel go any faster than the inside wheel. That will start to pull the outside rear, and cause understeer. Allowed to spin freely, that outside wheel won't resist the turning force.

    Accel lock should happen when (or just before) one wheel starts to spin, but set too high and it will keep the outside wheel from spinning faster than the inside, which will resist turning and cause understeer.

    I usually start setting my LSD with 10, 20, 5 and go from there depending on wheelspin. Still no wheelspin? Go down on accel. Still none? Go down on initial. In low powered cars that can't spin the wheels, open'er right up. I rarely use anything but 5 on decel. I can usually cure an unstable braking car with suspension and brake balance.

    So really, you want as low a setting as possible on all three numbers, to allow the free-est rotation from outside wheel to inside. Locking the diff stops the outside wheel from going as fast as it should. Think of it like draging a brake on the outside rear. That will hurt turning.
     
  19. witrucker79

    witrucker79 Licensed Racer

    Thanks everyone you all rock! always helpful people here!
     
  20. Gar529

    Gar529 Licensed Racer

    Re: CCC work page

    YOU'RE WRONG! This is the only way to tune the suspension of a car!

    "Lets take a look at the Vette ZR1 (C6) 09 Race Modded car:

    It's default suspension is:

    RH: 0/0
    Spring 12.3/12.6
    Damp. Ext: 5/5
    Damp. Comp. 5/5
    ARB: 4/4

    Camber: 0.0/0.0
    Toe Angle: 0.00/0.20

    Now, since this is a FR car, the weight is more in the front. For this, lets say 60/40 (MR/RR do the opposite which is 40/60 and AWD do 50/50)
    Still with me?
    ok..

    Add the spring rates together..
    12.3+12.6= 24.9
    Divide that by 4 (there are 4 tires)
    24.9/4 = 6.225

    Take 6.225 and Multiply that by 0.60 for the front and 0.40 for the rear
    you should get 3.735 (rounded down since the 3 is lower then 5 you get 3.7) and 2.49 (rounded up since 9 is closer to 10 then 0 you get 2.5)

    add 3.7 to the front springs and 2.5 to the rear.
    Your new spring settings should now be 16.0 and 15.1

    Ok, now to find out the Damp. Ext...
    First, lets do the front.
    Take your spring value of 16.0 and divide it by 2 (You have to front damp). You get 8. Next, take 8 and multiply it by 0.60. You should get 4.8.
    Round up the 4.8 and you get 5.
    5 is the Damp. Ext value for the front.

    Now, for the rear.
    Take 15.1 and divide it by 2. You should get 7.55. Multiply that by 0.40 and you get 3.
    3 is the rear damp. ext value.

    Now to find out the Damp. comp.
    For the front, take 5 (The front ext value) and multiply that by 0.60. you get 3.
    3 is the front Damp. Comp. value.

    To find out the rear, take 3 and multiply that by 0.40. You should get 1.2. Rounded down, is 1.
    1 is the rear damp. comp. value.

    Now, to find out the front and rear ARB.

    Add the front Damp. Ext and Comp values. (5 and 3)
    5+3=8
    take 8 and multiply that by 0.60. You should get 4.8. Rounded up, is 5.
    5 is the front ARB value.

    Now for the rear.
    3+1=4. 4 times 0.40= 1.6. Rounded up is 2.

    2 is the rear ARB value.

    Now to find out the Camber and toe angles.
    Take the front ARB, which is 5 and multiply that by 0.60. You get 3.
    So set the front camber to 3.

    Now take the rear ARB, which is 2 and multiply that by 0.40. You get 0.8.
    Set the rear camber to 0.8

    Now for the toe..
    Take the front caber angle (3) and multiply that by 0.60. You should get 1.8. Next, divide that by 2 and you get 0.9.
    Set the front toe angle to +0.09

    Now take the rear camber angle (0.8) and multiply that by 0.40. You get 0.32. Divide that by 2 and you get 0.16.
    Set the rear toe to +0.16

    Your new suspension settings should now be:

    RH: 0/0
    Spring: 16.0/15.1
    Damp. Ext. 5/3
    Damp. Comp. 3/1
    ARB: 5/3
    Camber: 3/0.8
    Toe: +0.09/+0.16"
    :sHa_hehe:
     

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