Introduction To Tuning

Here’s a short introduction, This is the way I do my tunes:

First of all think about the track the car will be made for (short, mid or long track)
That has a big influence on the needed parts:

• Short - Needs parts that mainly increase the torque and decrease weight
• Medium - (Most of the tracks) needs parts that increase torque and top speed and possibly decrease weight.
• Long - (Le Mans, Nordschleife, Sedona, and Sunset Peninsula) needs parts to reach a high top speed.


Good parts to increase torque are:
A turbo, exhaust, air filter, cam shaft (eats a lot of PI points), spark plugs and engine size.

Good parts to increase top speed are:
Engine size, exhaust, air filter, valves, pistons and the fuel pump

NEVER use the cooler parts for the turbo (only the race version if needed and PI points need to be used) and the “liquid parts” in my German game version called Oil and Water. Those parts are useless, they just increase the weight rather than giving increased performance


Always start with the handling parts (I build the car in this order):

Aero (The Forza parts decrease the PI on most cars and gives a lot of better handling), tyres, brakes, differential, suspension, anti roll bars (on those parts I use always the race parts)
Gearbox (I mostly use the racing gearbox. Some say waste of PI, but it gives you the opportunity to adjust every single gear and the final drive)
Clutch is useless when using manual with clutch, however if you drive with automatic or manual without clutch ALWAYS use the race clutch.
Weight reduction
Rollcage (Always use it when you have chosen race weight reduce to increase stability of your car)

Now put in the turbo and motor parts as written above. Mostly you end up 2 PI too low or 1 too high. A good way to get the maximum PI in the wanted class is to change the rims. By doing this you can reach the max allowed PI (Often the rims decrease weight allowing you to put in better rods or flywheels.)


Now the tuning section:

Before starting here are some explanations of the effects of all the adjustments:

Tyre pressure:
High pressure = Higher top speed, less grip
Low pressure = Less top speed, better grip
Advised is a tyre pressure between 1.90 bar/27,55 psi and 2.19 bar/31,77 psi

Alignment:
Camber: This effects the tyre temperature and the handling. If you stand in front of the tires they will look like this: I I more negative: / \ more positive: \ / For normal circuits we usually need a negative camber to increase the tyre temperature and pressure on the inside of the tyre.
For oval tracks with steep turns the camber is used to compensate the oblique position of the car in the turns too and can be positive or look like this: / / or \ \
Advised settings: - 0,6 to – 1,1 on normal race tracks
Toe:
Toe is the distance the leading edges of the tires are closer than the trailing edges.
.Advised adjustments: front: between 0.0 and 0.2 rear: between 0.0 and -0.2
Caster:
Adjusting allows a better steering into and out of the corners.
Higher angle: better turn out – worse turn in Lower angle: better turn in – worse turn out

Gear settings:
Allow you to set the final drive (overall ratio) and the single gears.
Higher setting of the final drive: better acceleration – less top speed
Single gears: higher setting shortens the gear and gives better acceleration but forces to shift earlier lower setting increase the time till reaching rev’s end in this gear but decrease acceleration.
Those settings of the single gears work very well from F to S- class cars:
1st 2,89, 2nd 1,90, 3rd 1,41, 4th 1,12, 5th 0,93, 6th 0,80

Suspension (springs, dampers, anti roll bars):
Springs: affect how deep the body of the car caves in at the front and rear end of the car. Too low settings let the body swing too much and can take the effect that the car bottoms out on the track. Adjusted too hard the car will be taken out of the corner.
Ride height: lower = better contact pressure but bottoms out on the track earlier (needs a harder set up of the springs), higher = less contact pressure but more ground clearance.
Anti roll bars: By adjusting the anti roll bars you can define the bias of front and rear sides by going into or out of a corner. Set too “stiff”, the car can’t turn into a corner. Set too soft the car totally oversteers or becomes instable.
Dampers: affect how fast or slow (milliseconds) and how much every single spring will be compressed or stretched. The settings define the ability of going over curbs and to fine adjust cornering.
The mix of these 3 adjustment components has a very big influence how your car behaves. Every single change can have large consequences for the behavior, the handling and the tendency of over-/ understeering.

Brakes: speaking for itself

Wings: affect the contact pressure, the handling, the acceleration and the top speed of a car.
Adjusted higher = more grip, more contact pressure, better acceleration, less top speed.
Start always with max settings of the wings to have a maximum of grip. It is easier and better to set acceleration / top speed by adjusting transmission settings.
Only on tracks with long straights like Le Mans and Nordschleife you perhaps have to lower the wings to reach straight’s end without hitting the rev’s end. By lowering the wings you will notice that the car will understeer or overstreer. This means a new adjustment of suspension parts too.


There are some tuning calculators available in the internet for Forza 3 and 4.
I am not a friend of those calculators; I only use them for the alignments. Those settings work fine for me; all others (especially the suspension settings) are the greatest crap. They make the car feel like a swing boat.

After the journey through all those setting possibilities and their impacts we finally enter the test track:

First the settings you can do blindly without testing:

Set alignments taken from the calculator, seldom you have to refine them.

Max out the aero, set springs height to the lowest possible position (one step higher than the bar becomes invisible). Sometimes the rear springs are lower than the front springs after doing that. Adjust the rear springs as high or one step higher than the front springs in this case. that gives you a better contact pressure of the car.

Adjust the single gears as follows (works on all f to s class cars!!!)
1st 2,89, 2nd 1,90, 3rd 1,41, 4th 1,12, 5th 0,93, 6th 0,80

Now go to the upgrade test settings section and enter your chosen track (here we stay for a while now) Test the car after EVERY single adjustment you make!!!

Adjust the spring hardness until you have a good feeling (lower = softer, higher = harder) I prefer harder springs but that’s your personal like… The ratio between front and rear hardness has a big influence on the steering of the car.

After finding a suitable setting of the springs you’ll notice that the car still understeers or oversteers. If the car is understeering decrease the front anti-roll bars and/or increase rear anti-roll bars, in the case of oversteering vice versa. But adjust the settings slightly, 2 tenth by 2 tenth. Now you should notice that you can go into corners faster and more precise and can corner out without losing the rear or the break out of the front.
Sometimes you won’t be satisfied with the steering, so go back to the springs and adjust the ratio of them tenth by tenth. Decreasing and increasing has the same effect than the one of the anti roll bars.

To fine adjust those settings and to avoid to get excavated on curbs we enter the dampers section now. Mostly standard settings work proper when you’ve adjusted springs and anti roll bars well but you can fine adjust them. Front rebound to front bump stiffness should always have a ratio of 50% - 75%. Rear also.
The higher the curbs the softer you should set the dampers, (Necessary only at Sebring, Maple Leaf and Mugello).
The dampers allow you also to define the cornering. Harder = better corner out, softer = better corner in
But as said I only use them to fine adjust the cornering.

The brakes:
Balance: notice the weight ratio of your car ( e.g. 53%, that means more weight is at the front of the car, so we have to set the braking force a bit more to the rear end). The ratio here I choose is 2/3 of the difference away from 50%. In the example 3/66% = 2. 50 – 2= 48 So I set the braking force to 48%. Example for more weight on rear end: 44% = 6 away from 50. 6/3*2= 4 Braking force = 50 + 4 = 54
Race along the straights and brake now like you usually do. Increase braking force power as long as you feel the car is becoming unstable by braking.

Final drive: Race around the track and notice the highest top speed you reach. Go to the gearbox settings now: In the right corner is a diagram where you find 3 numbers.
e.g. 0 – 150 – 250 mp/h and five little boxes inside the diagram.
Now adjust the final drive bar to the right (usually) and you notice the graph in the diagram decreases. Take the difference between the 2nd and 3rd number and divide it with 5. In our example 250 – 150 =100/ 5= 20. That means, beginning at the diagram’s end, per each little box top speed decrease by 20.
Set the bar now nearly to the maximum top speed you noticed on the track plus a reserve of maybe 7 or 8 miles. (That’s because air drag of the aero parts won’t be considered)
To fine adjust go back to the track now and adjust the final drive as long as you notice the rev’s end is nearly hit in last gear (usually there lit up a yellow or red line on the track similar to the race line when you reach rev’s end) Adjust it the way that the line doesn’t show up.

Tyre pressure:
start the test drive again on a medium track. I use Mugello for the upcoming procedure. By pushing the analog pad up button you open the telemetry. With the right button switch to tyre temperature. Now do 2 laps and watch the temperature. It should reach at maximum 100° C and at least 85° C. Decrease the bars (but slightly) until you reach the temperature. You maybe notice that the inside temperature is slightly higher than the outside temperature of a tyre. That is the way it should be.
If not you have to adjust the alignment camber a little bit more negative to set the tyres a bit more like this: / \
The camber setting and the right temperature are increasing grip.
A higher pressure means higher top speed but less grip and acceleration and a lower pressure means more grip but less top speed (but both is marginal, maybe 2 or 3 mph)
But as said the alignment settings of the calculator I use works fine in my case.


Here is a link to the calculator:

http://forums.forzamotorsport.net/forums/thread/4859908.aspx

By reading these lines you might think that tuning is as difficult to understand as rocket science. But believe me, the more often you do tunes you will get a better feeling for the adjustments and how to squeeze the very last out of your car.

Tuning is a complex thing and depends on likes or driving style. I don't have the aspiration of being the one who found the philosopher’s stone, but for me it works pretty well like described.

Ask ten people how to tune a car and you'll get eleven different opinions...

Now the short description is done and me too.


I hope it is explained in an understandable way and it helps you a little bit to get into tuning’s stuff.