Thread: Tuning Basics
View Single Post
  #1  
Old 11-17-2003, 07:55 PM
sperry sperry is offline
Registered User
 
Join Date: Nov 2003
Location: Reno, NV
Posts: 17
Tuning Basics

I thought I'd start a thread with basic tuning info, since not everyone knows a lot about vehicle setups. Comments, corrections and additions are welcome!

The goal of tuning is to set the car up to match your driving style to the surface you're racing on.

A "loose" or "oversteering" car will tend to break rear traction before front, allowing the back-end to "come around". This is good for drifting, but will also lead to more spins. A loose car usually has more traction in the front than the rear.

A "tight" or "understeering" car will tend to break front traction before rear, causing a "push" condition where the car will slide in a straight line. A tight car usually has less traction in the front than the rear. A tight car will not be as fast as a loose car in general, however it will be much easier to drive. Remember, if you're the only one not spinning, you'll dominate the race!


SPRINGS:
Red - Soft
Yellow - Med
Blue - Hard
Silver (stock) - seems to be somewhere between Red and Yellow

Harder springs will result in less body roll, faster bound/rebound, and less overall suspension travel.
+'s: The car will react to steering and power inputs quicker becoming more manuverable.
-'s: The car will "skip" over rough surfaces, and lose traction more easily.

Softer springs will result in more traction, slower bound/rebound and more overall suspension travel.
+'s: The car will have more grip, allowing higher acceleration and latteral G's.
-'s: The car will have more body roll which means longer time between telling the car to turn and when it actually turns. More travel also means a greater chance of bottoming out and rubbing body kits on the ground.

Tuning for tight or loose is a matter of running relative differences in stiffness between the front and rear. If the front is stiffer than the rear, the car will tend to be tighter. If the rear is stiffer than the front the car will tend to be looser.


TIRES:
Soft Treaded - most grip
Soft Slicks
Stock Slicks
Hard Treaded
Hard Slicks - least grip

Tires may be the single easiest way to tune the car, since tossing on a different set of tires is easy and directly effects the traction. It seems like the treaded tires will generate more grip than the slicks, which is contrary to most common tire logic. In my experience however that is the case, at least on linoleum. YMMV.

Like the springs, tuning the tires is a matter of front to rear grip differences. Harder tires in the front will be tighter, while harder in the rear will be looser.

One more thing to note, the soft tires can come off the car pretty easily if you're drifting over rough surfaces. I was able to lose my inside front tire if I slid over a crack in the concrete! If you lose a tire in a race, you'll definately be slower than if you had gone with harder tires that didn't fall off.


STEERING RODS:
**still need rod specs**

The steering rods adjust the amount of "toe-in". Toe is the angle that the tires point towards each other, like the term "pigeon toed". The more toe in, the easier the car will turn and the more stable it will be in a straight line. However, toe in will limit the top speed of the car, and potentially will wear out the front tires faster (however I have yet to wear out a set of tires...)


WEIGHT DISTRIBUTION:
Batts front
Batts middle
Batts rear (except on RSX)

There are 3 positions for the batteries (except on the RSX who's short wheelbase leaves only 2 positions). Sliding the batteries will change the amount of weight over the tires, and will greatly effect the grip at each end.

Batts rear will increase traction in the rear (tight), and decrease traction in the front. This will help prevent spins, and give RWD cars more traction under power. On RWD cars, Batts rear will help with breaking, since only the rear tires stop the car.

Batts front will increase traction up front (loose), and decrease traction in the rear. This will be especially noticable under breaking.

Batts middle is a compromise between the two.

I have found no real reason to run with the batteries anywhere but all the way rear. I tried playing around with them in other places, but I could not tune out the oversteer with other methods.


WHEELBASE:
Short (none)
Medium (RSX)
Long (Civic, Skyline, Supra)

The different bodies have different length wheelbases (the distance between the front and rear tires). There's not much you can do right now to adjust this, however as new bodies come out, this will be a tunable setting.

Longer wheelbases tend to be more stable, and harder to turn. A long wheelbase car will spin less often, but won't be able to turn as tightly as a short wheelbase car.

Shorter wheelbases tend to be more manuverable, allowing a tighter turn radius, but an easier chance to spin.


DIFFERENTIALS:
Red - Limited Slip Differential (LSD), comes with the AWD kit.
White - Open Differential

The LSDs are designed to "lock" when the rotational speeds of the wheels on either side of it gets too great. This usually occures when one tire is slipping. As the tire slips, and it's speed becomes greater than the other tire, the differential transfers power to the other tire so that it can drive the car. Open differentials on the other hand will simply spin the slipping tire and the car will flounder. The draw back to the LSD is that it can lock up when the car is going around a tight corner, causing the car to hop as the rear drive axels bind up.

For a tighter car with more straight line traction install LSDs, especially in the rear of the car. However this will increase your turn radius.

For a looser car with a better turn radius, install the open differential. This will be at the expense of overall traction, especially on slippery surfaces.


ALL WHEEL DRIVE:
The AWD kit turns the front tires into drive tires, and comes with two LSDs. AWD dramatically increases the car's overall traction, at the expense of manuverability, top speed, and battery life. On slippery surfaces, it is invaluable, as more RWD cars will simply spin out. AWD also adds 4-wheel braking, since all braking is via the motor, so the AWD kit means the car will stop more quickly.

One trick to get a very manuverable AWD car is to install the AWD kit, but to leave the stock white (open) differential in the rear of the car. You will gain the traction up front, but your turn radius will remain small because the rear won't bind up.

There are reports that the rear control arms that come with the AWD kit are somehow different than the stockers. I didn't see any difference, but if you have please let me know!


METAL BEARINGS:
The metal bearings reduce friction and compliance in the drivetrain. They should increase battery life, and top speed, at the expence of slightly slower acceleration due to weight.


MOTORS:
Drift
Drag
Road Race
Top Speed

The four motors come in two stages, 1 and 2. Stage 1 motors turn at 26k rpms, while the Stage 2 motors turn at 30k rpms. Basically Stage 2 motors are plain old faster than Stage 1, at the cost of battery life. For tuning purposes, what's important are the gear ratios the different motors have.

The gear ratios allow you to convert between torque and power. Torque is what gives you acceleration, while power is what gives you top speed.

The Drift motor is geared for torque over speed. This means it can blast off the line very quickly, and break the tires loose for drifting with a quick stab of the accelerator.

The Top Speed motor is geared for speed over torque. This means it will be far slower off the line, but will have a much higher final top speed.

The Drag motor is a compromise between Drift and Top Speed with an emphasis on torque (acceleration).

The Road Race motor is a compromise between Drift and Top Speed with an emphasis on power (speed).


****Suspension Tuning Summary****

SPRINGS:
Tighter handling: stiffen the front, or soften the rear.
Looser handling: soften the front, or stiffen the rear.

TIRES:
Tighter handling: harder tires in the front, or softer tires in the rear.
Looser handling: softer tires in the front, or harder tires in the rear.

STEERING RODS:
Add more toe-in to gain a smaller turn radius, and better straight line stability
Less toe-in to gain a higher top speed, and less tire wear

WEIGHT DISTRIBUTION:
Tighter handling: move the weight rear
Looser handling: move the weight forward

WHEELBASE:
A longer wheelbase is tighter and more stable
A shorter wheelbase is looser and more manuverable

DIFFERENTIALS:
LSD: More traction on slippery surfaces, harder to turn
Open: Smaller turn radius, less traction on slippery surfaces

ALL WHEEL DRIVE:
Install AWD for tons more traction, especially on slippery surfaces, and 4-wheel braking.
Remove AWD for higher top speed, greater manuverability, and longer battery life.

MOTORS:
Install the drift or drag motors if the course is small and accleration is important.
Install the road race or top speed motors if the course is long and high speed is important.
Reply With Quote