# MMCARSIM Tuning Guide

### Intro:

The reason you're reading this is probably to understand how to tune an add-on vehicle for Midtown Madness: Chicago Edition. I know it's hard to tune this stuff so this tutorial should help you understand some of the parameters. Most of the info in this tutorial were taken from 5tephen's tuning tutorial (He took it off the web and he dissappered somewhere. Luckly, I printed the stuff out) and some info are from asking the experts (Cuda, Xacto, etc.). And this is for the MMCARSIM file, so it won't tell you how to make the car work as a cop car and it won't tell you how to set up the selection screen and it's directed towards 4-wheeled vehicles.

### Engine and Physics:

 ```mmCarSim :09316c78 { Mass 1800 InertiaBox 3 2.5 4 BodyCG 0 -0.03 -0.01 Drag 0 Downforce 0.3 BoundFriction 0.3 BoundElasticity 0.3 DriftTorque 2.5 DrivetrainType 0 CarFrictionHandling 1 MaxDamage 500000 MedDamage 250000 RedistHeight 1 RedistLongRatio 0.5 SlipPercentThresh 0.05 Engine mmEngine :093182f8 { MaxHorsePower 600 OptRPM 5800 MaxRPM 9400 GCL 0.25 ```
This section tells you how to modify your car. It tells how much power the motor should produce, where the center of gravity should be, how much friction it has, how heavy it is, what drivetrain to use, and how durable it is.

***Remember, if it's not listed, then don't mess with it!***

Mass 1800
This is how heavy the vehicle is. It's suppose to be in kilograms, but sometimes it isn't right. If you have the weight measurements of the vehicle in KG, then use that as a base and adjust it higher or lower until you're satisfied. If you have the weight measurements in pounds, then divide the number in half and use that as a base and adjust it higher or lower.
BodyCG 0 -0.03 -0.01
This adjusts the body's center of gravity. Think of it as a pivot for the car's movement. The first number moves it left or right. Best to leave it at 0. The second number raises it higher or lower. The more you raise the CG, the more likely it'll tip in a turn and accelerating/braking. The third number moves the CG to the front or back of the vehicle. This is an important value since sometimes the car is front heavy and it'll nosedive off a jump or if it's back heavy, it'll swing too much in turns. Also, remember that this is guess and check. You need to guess a number and then try it in-game. I know it's time consuming, but it's worth it in the end.
Drag 0
It's the amount of air resistance on the car (the amount of force pushing on the car at high speeds). The more drag you have, the less acceleration you can acheive. Most people keep it at 0, but if you want to adjust it, keep it under 0.3 or it'll screw stuff up.
Downforce 0.3
It's the amount of force the car experiences pulling itself to the ground. Higher downforce = more stablility. That means it handles like a sports car. It won't tip up on two wheels when rounding a corner and it'll have more grip.
DrivetrainType 0
0 = Rear wheel drive. 1 = Front wheel drive.
MaxDamage 500000
MedDamage 250000
These values determine the damage for the vehicle. MaxDamage is how much damage the vehicle can take before dying. MedDamage is how much damage the vehicle can take before having white smoke appear. These values work together with Mass, so it's hard to have a good estimate. Adjust in ten-thousand increments.
SlipPercentThresh 0.05
This changes the grip on the tires. It's best if you leave this setting alone. Increasing the number will cause less grip and makes it harder to drive. This setting is very sensitive and some of the slightest changes could cause your car to drive as if it's on ice.
MaxHorsePower 600
This is the amount of horsepower the vehicle has. This value is screwed up compared to real life. If you put the real life value in there, it's actually slower in-game. I've heard that 7 real HP = 10 MM horsepowers.

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### Transmission:

 ``` Trans mmTransmission :09318374 { NumGears 8 UpshiftThreshold 6000 DownshiftThreshold 2800 GearRatios [ -10 0 14 10 8 6 4 2.5 ] UpshiftRPM [ 6000 7500 7700 7600 7500 7500 7500 6000 ] DownshiftRPM [ 3000 3000 2500 2500 2500 2500 2000 2000 ] ManualNumGears 8 ManualGearRatios [ -10 0 14 10 8 6 4 2.5 ] DownshiftBias 1.85 ```
That will certainly confuse you. What will confuse and irritate you is that these numbers work with Horsepower and Mass which means more guess and check. So you have to try each number in the game to see if it's ok. Sure, it'll drive you crazy, but it's worth it. The first set of NumGears, GearRatios, and Upshift/DownshiftRPM are for the automatic transmission and the second set is for the manual transmission.

***Remember, if it's not listed, then don't mess with it!***

NumGears 8
ManualNumGears 8
These values determine the number of gears your transmission has including reverse and neutral. The first value is for the automatic transmission and the second one is for the manual (like the name says). If the car has 4 speed transmission, then add 2 and you get 6. That's the number you should use for this value.
GearRatios
ManualGearRatios
Like I said, this is that hard part. It involves guess and check which means that you ould spend a good deal of time doing this. The first number is for reverse. It's negative because it's going negative direction. The next number is 0. That's for neutral/park. Don't mess with it. The next few numbers are the forward gears. The lower the number, the higher the speed for that gear. Try to keep these numbers pretty close together since they could cause poor acceleration and crappy high speeds. Try to keep the numbers between 3 and 20 for the average vehicle. The lower the number, the more speed you get, but lower acceleration. The higher the number, the more acceration, but lower speed. Remember, try the numbers in-game and tweak to your liking.
UpshiftRPM
DownshiftRPM
Best not to mess with these. Sometimes they cause a werid side-effect of not having fluctuation RPMs and not getting into gear. Upshifts are the highest RPMs before the tranny shifts into a higher gear. Downshifts are the lowest RPMs before the tranny goes into a lower gear. Don't mess with these too much. Adjust by the hundreds.

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### Suspension and Handling:

 ``` FrontLeft mmWheel :093175c0 { Spring 63300 Damping 6200 SteeringRatio 0.37 SuspensionBlend 0.5 BrakeRatio 1 StaticFriction 2 SuspensionLimit 0.15 RenderableSuspensionLimit 0.1 RubberSpring 60000 RubberDamp 4000 OptimumSlipPercent 0.05 StaticFric 1.5 SlidingFric 1.1 RubberSpringLat 60000 RubberDampLat 8000 } BackLeft mmWheel :09317a90 { Spring 63300 Damping 6200 SteeringRatio 0.05 SuspensionBlend 0.5 BrakeRatio 1 StaticFriction 1 SuspensionLimit 0.15 RenderableSuspensionLimit 0.1 RubberSpring 60000 RubberDamp 4000 OptimumSlipPercent 0.05 StaticFric 1.5 SlidingFric 1.1 RubberSpringLat 60000 RubberDampLat 8000 } ```
This is the suspension. It determines how much bodyroll and rebound the vehicle can have. This can cause some fun stuff to happen. There are two sections. Front wheels and back wheels. All of the parameters are the same, so they stay to same for both wheels. Some of the parameters are special and they need to be different for both wheels.

***Remember, if it's not listed, then don't mess with it!***
***The values below might not be listed in order***

Spring 63300
This is rebound. It's how much bounce the vehicle has when it goes off a sidewalk (if you've ever driven in the section of One-Way streets next to the Field museum, then you know what I'm talking about). Increasing the number makes it more bouncy and decreasing the number makes it more stiff.
Damping 6200
RubberSpring 60000
RubberDamp 4000
RubberSpringLat 60000
These values affect the shock absorbers. Decreasing these numbers will cause the vehicle to absorb the impact after a jump. For example, a monster truck landing after a jump. Increasing the numbers will cause the vehicle to have a stiff bounce. It acts as if the suspension was tightened. The greater the number, the more the springs are tightened (for sports cars). The less the number, the bouncier the springs (like an average '80s car). Remember, these values are guess and check so you need to experiment with them.
SteeringRatio 0.37
SteeringRatio 0.05
These are how well the vehicle turns. You should only modify the values for the front wheels since most vehicles turn using the front wheels. Increasing the number means tighter turns while decreasing it means a larger turning radius. Keep this number small since too large of a number means a spin-out in turns and too low of a number causes it to understeer or not turn at all!
BrakeRatio 1
This value affects the brakes. This parameter works with speed and mass in order to work. For example, a large semi takes forever to stop while a compact car could stop on a dime. Increasing this value means increasing the time it takes to stop the vehicle. Decreasing the value decreases the time it takes to stop.
StaticFric 1.5
This sensitive setting controls the handling of the vehicle. This affects the amount of grip the tires have on the road. Increasing the value will give the wheels more grip and decreasing it will have less grip. It works with SlidingFric so it's another guess and check value.
SlidingFric 1.1
This sensitive setting controls the handling of the vehicle. This works with StaticFric when going into corners. Decreasing this value will lower the grip the wheels have when going into a corner. This could cause understeer in some cases. Since it works with StaticFric, this is another guess and check value.
RubberDampLat 8000
This value determines how far the vehicle leans over when taking a turn at certain speeds. Increasing the value will cause the vehicle to lean over more. For example, the '68 Mustang Fastback leans over quite a ways and even gets up on two wheels! Decreasing the value will cause the vehicle to stay stable in turns. For example, the Cadillac Eldorado remains stable in turns like most modern cars. Becareful when tuning because it the vehicle leans over too far, it could hit a curb in turns and flip you vehicle or stopping it in it's tracks.

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### Smoke Offset and Weather:

 ``` DamageSmokeOffset 0 0.78 -1.9 AsphaltRule asBirthRule :09318640 { Position -470.7 0.3408 350.2 PositionVar 0.1 0.1 0.1 Velocity 0 1 0 VelocityVar 0.4 0.2 0.4 Life 2.5 LifeVar 0.2 Mass 0.1 MassVar 0 Radius 0.3 RadiusVar 0.1 Drag 0 DragVar 0 DRadius 0.048 DRadiusVar 0 DAlpha -9 DAlphaVar 1 DRotation 0 DRotationVar 3 InitialBlast 0 SpewRate 0 SpewTimeLimit 0 Gravity 0 TexFrameStart 1 TexFrameEnd 1 BirthFlags 0 } ```
This will help you set where the damage smoke comes out and it'll help set your vehicle to handle the different weather conditions. Not much is known about the weather condition settings, but if you're brave enough, you can experiment with them. There are 5 sections with different headings (Asphalt, Off-Road, Snow, Slush, and Smoke), but they have the same parameters. The values are different for certain parameters. I will not be going over these since not much is know about it. It's fine to leave it alone. The only important thing is the smoke offset which will put the smoke in the right place when damaged.

***Remember, if it's not listed, then don't mess with it!***

DamageSmokeOffset 0 0.5 -2.02
It's best to try to position the smoke over the engine and/or radiator. The first value moves it left to right. The second value moves it up and down. The third value moves it front to back.

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### Various:

 ``` DriftThreshold 0.4 SpinThreshold 0.9 BrakeFrontFricMultiplier 0.4 BrakeBackFricMultiplier 0.3 SteerMultiplier 1 SpinStart 0.9 SpinStop 1.2 SpinStartTime 0.15 SpinEndTime 0.3 SpinFromMax 0.4 SpinFromMin 0 SpinToMin 0.6 SpinToMax 1 FrontDriftFricMultiplier 1 BackDriftFricMultiplier 0.65 FrontSpinFricMultiplier 1 BackSpinFricMultiplier 0.35 LongSlideMultiplier 1 DashCamHeadlightOffset 0 -0.2 0 POVCamHeadlightOffset 0 -0.2 0 } ```
These are at the end of the tuning file. They do not need to be modified, but some might make the tuning better. Most of these parameters have not been experimented with yet, but if you're brave, you can try them to see what they do. If they have three numbers, then the first number moves it left to right, second number moves it up or down, and third number moves it front to back. All these values are guess and check.

***Remember, if it's not listed, then don't mess with it!***

FrontDriftFricMultiplier 1
BackDriftFricMultiplier 0.65
Decreasing the values decreases the amount of friction or grip the vehicle has when going around a corner. This will cause the vehicle to drift around the corner and provide some nice powerslides if you can control the vehicle. Increasing the values will give the vehicle more grip. This makes it predictable when turning in the corner.
FrontSpinFricMultiplier 1
BackSpinFricMultiplier 0.35
These values determines the amount of grip the wheels have when spinning. When the value is decreased, there is less grip which results in large amounts of smoke. It's fun to see all that smoke, but don't lower it too much or there won't be enough grip to take off!

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