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(67 votes) Published: Oct 15, 2007 5:08 p.m. In 1 Favorites Lists Viewed 232 times
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It is too often that i will go to a car show and see guys install racing suspension components but not have them tuned correctly to give any performance advantage. The reason why their "$50,000" modded up car can be beaten by some shitbox ’94 nissan sentra is simply because they were not educated in properly tuning suspension components to work together to the vehicle’s advantage. This is going to be a long egg so cook up a poptart or go take a dump if you dont think it can hold off for 15 minutes.
Suspension performance has alot to do with:
-chassis rigidity
-spring rate (coil springs, leaf springs)
-shock damper (high rate, low rate)
-alignment (+/- camber, toe-in, castor)
-vehicle width
-weight distribution between front and rear wheels
-wheelbase
-swaybars
-wheels/tires
PRELUDE:
Before even considering modifying the suspension in your car, make sure that you and the car are both ready for it. If your car is 35 years old and the chassis is feeling a little bit soft, just drive the car until it shits the bed. Understand that a car that handles well, will not be a car that rides well PERIOD! Soft suspension will feel all fine and dandy over bumps but taking a corner while accelerating can result in vehicle rollover, tiresqueals and misplaced limbs.
CHASSIS RIGIDITY: Strut tower braces, rear hatch braces, subframe braces and chassis braces will stiffen up the car alot more. If you want to see how much your chassis flexes, park your car so that 1 tire is up on a curb. Unless you already have a really advanced suspension system or a short, stiff chassis, i highly doubt that the chassis will stay straight. After parking the car like this, hop out and look at the front of the car, the suspension will be loaded at opposing corners and unloaded at the other opposing corners. however, the suspension wont be COMPLETELY loaded or unloaded so the chassis will have a bend to it. This same bend will happen around hard corners. The alignment of the wheels can go out of whack if the chassis flexes, the rear tires will want to go straight while the front inside tire will try to cut in sharp but the front outside tire will be cutting in fairly sharp. This is bad. This is why sometimes it feels like the rear tires are "swinging" around you although there is no tire squeal or loss of traction.
Strut tower brace
Chassis brace
SPRINGS:
Springs are what make your car rebound after hitting a bump. IF you put a big beanbag chair underneath a trampoline and jump on it, the beanbag chair represents a shock absorber, but the trampoline represents the spring. You jump down, the beanbag chair absorbs the shock, but then the trampoline returns you to your original position. IF you have a really stiff trampoline, than it will take more weight to get the trampoline to drop down to the beanbag chair. This represents a stiffer spring in a car. If the spring in the car is meant to spring back at a higher rate so that the steering and chassis of the car is more responsive to the road, than you will have better handling. It takes more shock in order to lose control. Lowering springs will give a performance advantage but not because of aerodynamics or "air-foil" they give the car a lower center of gravity so it feels less "topheavy".
SHOCK DAMPER:
High rate shocks: This represents a bean bag chair that doesnt have many "bean" pellets inside of it. It wont take very much in order to completely compress the shock. This means that the road will feel softer and smoother. When the vehicle hits a bump, it will take less shock and weight to get the wheel to rise higher. These shocks absorb quicker so they are more responsive to the road but they dont necessarily keep the weight of the car on the wheels so the wheels will not stay on the ground with as much stability. These are great in a cadillac, oldsmobile, kia, saturn or toyota prius but not much else.
Low rate shocks: These absorb the road at a slower rate. This represents a beanbag chair that is packed as tight as possible with as many bean pellets in it as you can possibly fit. It takes more weight to compress it, but it is alot stiffer. The shock will be stiffer and heavier duty as to keep the weight of the vehicle on the wheels for as long as possible around corners and over bumps.
Beanbag chair
WHEEL ALIGNMENT: This is extremely important. If the camber is not set for the current ride height, than the wheels could be angled in towards the car or out towards the sidewalks. This can be good or bad. Slightly negative camber is good because the outside tire has the tendency to stretch towards the inside of the vehicle and lose traction if the camber is set at 0 around corners. Having negative camber implies that the top of the tire is inside of the wheelwell while the bottom of the tire is sticking out. Positive camber is like when a truck is lifted too much, the bottom of the tire is closer in towards the center of the vehicle, the top of the tire is sticking out towards the sidewalks. It is alot like leaning into turns on a motorcycle. If you tried leaning out, than first of all, you probably wouldnt be able to take a turn whatsoever, and second, if you could take a corner, it would be very wide and unstable.
Slight negative Camber
VEHICLE WIDTH: Having a slightly wider vehicle can sometimes allow space for wider tires for better traction and better stability around corners and on the highway. Wheel spacers make the front and rear track slightly wider so that the tires are spaced further apart.
Small wheel spacer
WEIGHT DISTRIBUTION: The weight distribution between the front and rear wheels is crucial to having a car that handles well. A car with perfect 50/50 weight distribution between the front and rear wheels wont need a hell of a lot of suspension tuning and camber adjustments to perform well. Pre-1993 Volkswagen GTis and some Jettas had perfect 50/50 weight distribution. The new mazda RX-8 has perfect weight distribution because it has a rotary engine which is significantly smaller and lighter than a conventional reciprocating engine, so this gives the manufacturer the ability to place it further back in the engine bay. Just moving the engine lower a few engines and back a few inches gives the car a lower center of gravity and less weight being put directly on the front wheels.
VR6-Swapped GTi-mk2
Mazda RX-8
RX-8 Motor (far back in engine bay)
WHEELBASE: Theres not much you can do here other than buy a car with a nice short wheelbase. It is why a minicooper can take corners so much better than a schoolbus. Pretty self explanatory unless your a big fat retard.
SWAYBARS: These control the amount of difference in wheelheight between left and right wheels. They act like a big torsioning spring bar that flexes at a certain point to allow left and right wheels to control how much the body of the car leans to the outside of a turn. If this was completely removed than the front outside shock would be completely compressed around a hard corner and the front inside shock would be unloaded with the possibility of the wheel lifting off the ground. this could be catastrophic and end with the car flipping over. Removing them can reduce understeer around corners because it brings back the independance between left and right wheels. Getting a stiffer one will put less stress on the chassis and more of that flex-energy into the shock to make the shock absorb the blow. This makes the body of the car stay level around corners and keeps the chassis aligned.
WHEELS/TIRES: This can control how your car behaves all together around corners. Alot of people dont understand the markings on tires. Some people think that a P185-50-R14 tire is a tire that is 5 inches wide, 14 inches in diameter and has a 185 width of tread. That is way off. A P185 tire is meant for a rim that is 185 mm in width around the bead seal. The 50 is the percentage of the sidewall versus the width of the tread, the 14 is the diameter of the rim that the tire goes on. if a car rim is meant for a P195-60-r14 and the driver chooses to use a P205-70-r14, than the tire will have great traction for drag racing but no sidewall stiffness and rigidity for cornering. For this rim, a mechanic could stretch a p185-60-r14 or even a p175-50-r14 for better cornering but still keep the traction for drag racing. It would be alot stiffer of a ride and corners would be alot of fun.
Other things that control suspension is brakes and the lock ratio of the differential. The braking between front and rear wheels will control how a car performs around corners and this can be adjusted to allow more/less brake pressure to the front or rear of the car. This is usually done at the proportioning valve. The lock ratio of the differential controls the maximum allowed difference in wheelspeed between left and right drive wheels. A stock differential could be set to only allow a 20% difference in speed between the left and right wheels. So when the driver hits full throttle going around a corner at 15 mph, the inside tires will squeal and the outside wheels will keep traction. Adjusting the % difference to 80% will allow more power to be given to the outside wheel so that the corner can be taken faster and sharper. The extra boost of power at the outside wheels would almost plow the car into the corner sharper. This is called a poor-man’s-posi.
HAVE FUN OUT THERE, tune up those cars, get rid of the stupid Racing-R stickers and your stupid spoilers and get some real power out of your car.
Oct 15, 2007 6:20 pm - it was really long and i didnt bother reading it but if you put in that much effort i guess its good and the random batman thing i guess is good lol 5*
Oct 16, 2007 4:15 pm - unfortunately i do not have a 189,294,313,461,120 picture database in my computer, so instead i use the internet. Many of my pictures are original ones that i have taken myself but i cant always take pictures of things that i do not have or did not have a camera with me at the time. Jettas and GTis do not need hatch/chassis support bars so therefore i do not have a picture of one in my car. The front strut tower brace in my car is painted black so it is not visible against my black engine which wouldnt be much of anything to post a picture of. My car has 2 degrees of camber so therefore it isnt much to take a picture of because it shows no visible difference in wheel alignment. The object here is to teach other people things and learn new things. There is no copywriting needed because i make no direct financial benefit from these pictures and they are posted on the giant free buffet of pictures called THE INTERNET.
Oct 16, 2007 4:20 pm - i love locked differentials. In my drag jetta, i have a solid differential which is basically just a big solid hunk of aluminum that looks like a bowl. IF i turn my steering wheel further than 1/2 turn in any direction, than i will snap an axle. It allows no difference in speed between the left and right wheels. My street jetta has a poor mans posi which allows an 80% difference in wheelspeed between left and right wheels. Its awesome.
Oct 17, 2007 3:03 pm - i have to say, nissan gets quite a bit of power and reliability out of those 1.8 litre 16v motors while they are completely stock. Its just a shame that the rest of the car sucks. My friend let me drive his 2001 sentra and i was relatively impressed.
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