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Thread: the end all suspension thread

  1. #1

    the end all suspension thread

    ok i don't know how long it's gonna take me to finish this but ****... i guess i'm doing it cuz... i don't even know why i'm doing it.

    before i say anything it is by far best to first search all of evom's resources before you ask any question about suspension. the reason this faq is being made is simply for the fact that too many questions have been asked repeatedly too many times.

    here are some preliminary references for interested buyers and enthusiasts to read:

    http://www.chris-longhurst.com/carbi...ion_bible.html
    http://www.club4ag.com/faq%20and%20t...mendations.htm
    http://www.reference.com/browse/wiki/Car_handling (similar but more permanent)


    WHAT DO YOU WANT?

    when it comes to suspension there are many choices to be made and you can't make any of them until you decide what you want. even that is a question. so first, what do you want? once you've decided what you want then you can proceed on with the endless sleepless nights of debating and recanting and more debating about what you're gonna get.

    i'll start with the most casual applications and then move on to full dedicated race setups. in the end the philosophy is always the same. get what you need to get the job done, only do more if you have money to waste.

    if you are a show car stud and just want a 'drop' then there are several questions you want to ask yourself.

    how low?
    do i want a comfortable ride?
    do i want to compromise handling?
    do i drive that often?
    do i still want to drive it like it's an evo?

    some of these questions are redundant but i put them there to emphasize the point.

    if you don't drive your car and it just sits in show rooms and occasionally moves to a car show then you really don't need top of the line coilovers unless that too is a part of the show. and if the latter is the case then it doesn't matter how you have it setup or what kind or weight springs you use.
    consider any spring or coilover, consider even cutting springs or worm gear clamping them. since your suspension doesn't matter too much as it's not very much used. if you must bling it then consider the jdm hottness coilovers.

    if you are a 'euro' style baller then you have to ask yourself:

    do i just cruise around in my car?
    do i slow down to dangerously low speeds to go over bumps, gravel, driveways etc?
    do i swerve on the highway to avoid potholes
    do i basically drive to cater to my overly lowered, ready to bottom out car?

    if you do drive your car low and you want ONLY a comfortable ride. this can be done by getting a set of coilovers, lowering to the desired height and then tuning the suspension to full soft. but if you do this DO NOT drive like you have s performance vehicle... you will end up bottoming out, losing traction, looking like an idiot and possibly hurting other people. man up and act the way you paid to, if you didn't get racing suspension, don't race!
    consider any coilover as the quality doesn't matter too much when you just want a cushy ride. you can determine how much longevity you want personally and go from there. companies like tein, tanabe, jic, buddyclub etc ad nauseum make suspension for people JUST LIKE YOU. their backwards spring rates and horrid damping will not give you a balanced performance handling machine, but a lowered, cool cruise, pimp ride.

    if you don't want to go coilovers you must ask yourself

    do i want to compromise the life of my dampers?
    which springs are best match to my dampers?
    am i ok with the drop?

    if you want a lowered ride and you're on a budget. then you must look into springs that match the factory dampers. such springs will give you a better feel overall and the 'drop' that you may seek. keep in mind that the mr and the gsr have different dampers and thus require different springs.
    consider espelir gt, works, swift.

    if you're a track hound but you're only a beginner or don't have lofty aspirations to become the next time attack king, then ask yourself

    who should i have tune my suspension?
    how much am i willing to spend to have some fun?
    how much life do i want out of these coilovers?

    if you want a track ONLY ENTHUsiast's suspension. you only use your car on the track, you don't drive bumpy streets, your car is a trailor queen but you're not quite experienced enough to do your own knob fiddling. then you may only consider coilovers. the fact is that most coilovers will be just fine for a track application. you don't have to have the best. you may want someone VERY experienced to set them up, but as long as they can set them up in one good very generalized configuration then you're good to go. this means go to a well known winningest guru and have them take something off the shelf and "make it work" it's not their custom shiznat but it'll do the job.

    if you're an obsessive compulsive track hound that loves to drive on, embarass big hp cars in your awd sedan, roll off, and then roll home on your r compound tires, then consider this to yourself...

    who do i like best out of all the suspension tuners?
    who's most accessible to me?
    who's driving philosophy do i most match up with?
    who is modifying the suspensions that i'm looking for?
    what kind of competition do i forsee myself in?
    how many adjustments do i need?
    do i know how to use those adjustments?
    how much can i learn?
    there's many more that i don't feel like putting in tonight.

    if you must have the best of both street and track then you must only consider the custom tuned suspension packages from well known suspension tuners. there are no ifs ands or maybes, if this is your desire then you must fork out the money and humble yourself, otherwise just change your preference to include the crappy ride that other less holy suspension setups will provide you.
    going to a well known suspension tuner means that the product you receive is well tested, the damping is well matched to the custom spring rates. you don't have to sit track side and scratch your ass wondering how many different springs you should go home and order cuz the ones that are best are already under your wheel wells. your time is then better spent making FINE small knob twists as you check your stopwatch, gps timer and motec logging and discussing with your favorite suspension guru how big of a hoosier you can fit without pulling your fenders too much.

    consider: john mueller's - ohlins, motons, dms, jic, buddyclubs and almost any other suspension that is worth customizing.

    paul gerrard's - ohlins.

    robi's - dms, kw.

    other high end suspensions you may consider: jrz, ok someone help me out here... i'm blanking.

    if you're a suspension guru and you race in the upper echelons of competition... stop reading this and mocking my grassroots upcoming.


    NOW MORE BASICS

    there's more to suspension than brand names and lingo but here's a start.

    in the basics of chassis dynamics, stiffer always means faster loading. seam welded chassis, faster chassis communication (intra chassis loading). stiffer springs, faster tire loading. stiffer sway bars, faster tire loading. stiffer strut towers, faster suspension communication which translates into faster tire loading. remember... too stiff is bad, hopping is bad, loading tires too quickly gives LESS traction. and the last and first thing about chassis tuning is it's all about the tires... you're doing it for the tires, to not overheat them, to give them more traction, to give them more travel to give them less deflection, all about tires. if there's anything else it's about... it's about you... what makes you feel good.

    SPRING RATE

    spring rate is the most basic part of suspension. it's what your car sits on. the spring absorbs the bumps and sways that the chassis encounters. the stiffer the spring the harsher the ride. the damper makes it so you don't oscillate forever. the stiffer the spring the stronger the damping needed. so of course the weaker the spring the less damping force needed. springs used in adjustable perch coilovers can be adjusted to stiffer settings by tightening the perch and giving the spring more preload. the opposite can also be achieved by reducing the spring preload.

    DAMPING

    it's the single most important factor of coilover suspensions, simply because this is the only factor that largely differs between manufacturers. a spring is a spring is a spring, and the mounting knuckles and all that crap doesn't get too fancy. what can get very fancy is the way that a manufacturer chooses to damp their spings.

    in short, damping is achieved by moving a plunger through oil. the plunger has holes in it and as the oil goes through the holes the viscocity slows everything down.

    there's 4 types of damping, high speed and low speed, compression and rebound. there's 4 combinations begot from these 4 types of damping. high speed compression, low speed compression, high speed rebound, low speed rebound.

    high speed is when you hit a bump, wheel goes up fast and comes down fast.

    low speed is when you make a turn in, wheel compresses slow and when things stable it comes back out slow.

    special case! overdamping. overdamping is the when the damper goes hydraulic (solid) because the orifaces of the piston are too small and don't allow the oil through fast enough. this creates a suspension that feels like a solid rod. many cars such as civics and corollas come overdamped and this is apparent when those porcellein bobble heads start chipping their necks and shoulders cuz the ride is so harsh. overdamping is usually a case of high speed damping.

    SUSPENSION TRAVEL

    proper suspension travel is very important in all cars, not just race cars. not having enough travel in your suspension results in "bottoming out" or hitting the bump stops of your suspension. this is a bad thing as the suspension at that point CEASES to operate. this is the equivalent of going hydraulic in your dampers. no more movement means your car gets a sharp jolt and likely a big hop in the air which is no good for handling or safety.

    COUPLING BARS

    also known as sway bars, anti-sway bars, anti-roll bars. these bars are shaped like a U or a C depending on how you look at them. they basically couple the front wheels to each other and the rear wheels to each other. sway bars are not necessary but are present in most all modern vehicles.

    the sway bar makes the wheels on the two sides of the car less independant of each other. when one tries to move up... the other will too, this keeps the one that's trying to lift, from actually doing so.

    the way this happens is that the bar resists the twisting and this resistance to twist creates a spring like force. sway bars can be adjustable. the FURTHER OUT the link is the SOFTER the setting. the CLOSER the link is the STIFFER the setting.

    sway bars increase the overall spring rate but ONLY under cornering conditions. under normal conditions where the load on both transaxle wheels are the same, there is no spring force created as the assembly moves up and down as one, not torqueing the bar. this means that the bars only contribute to the wheel rate under corning.

    coupling bars have the advantage of increasing spring rate only in active conditions, this also allows for a lot of suspension travel as the spring is allowed to move and does not have to be too stiff in order to create the proper cornering reaction forces. this is advantageous for street cars as full suspension travel and a liveable ride become more possible.

    WHEEL RATE

    wheel rate is the final spring rate experienced by the wheel, this total rate factors in sway bars, springs, damping rate and maybe even tire pressure to create an overall amount of resistance to body rolling. body roll is a direct characteristic of wheel rate, the higher the wheel rate the less body roll. this is why when you add coupling bars your body roll is lessened. this is why when you up your spring rate the body roll is likewise lessened. trying to tune out body roll with a damper is not a good idea unless you're only trying to tune out the low speed body roll for turn in characteristics.

    SPRUNG AND UNSPRUNG WEIGHT

    sprung weight is all the weight of the car that is held up by the springs. you may have thought that all the weight is held up by the springs but this would be incorrect to assume. basically everything that is below the top part of the damper is not held up by the spring. this includes lower control arms, the bottom half of the damper, the wheel, the hub, the axle, brakes, etc etc.

    everything else that is held directly or indirectly by the monocoque or subframes connected to the top part of the suspesion is sprung weight.

    ALIGNMENT and TIRE PRESSURE

    the alignment and tire pressure are two things that you always want to keep in very specific settings. alignment should be addressed after any change to suspension geometry. tire pressure should be adjusted according to heat, wear, contact patch and other such tire conditions. read further for alignment details.

    CAMBER

    camber is the way your wheels sit with relation to the verticle axis of the car. basically if you're behind your car looking at both wheels /? ?\ this is known as negative camber and \? ?/ and this is known as positve camber.

    negative camber increases lateral grip to an extent because as you apply lateral loads to the tire it will deflect to INCREASE its contact patch instead of sliding onto the shoulder, decreasing the contact patch.

    TOE-IN and TOE-OUT

    toe is the direction that your tires are facing relative to the horizontal plane of the car. so if you're looking from above the car and your wheels look like /? ?\ then you are toe-in, if it looks like \? ?/ then that's toe-out.

    VARIOUS CENTERS and AXIS

    the most common phrase used chassis tuning is the center of gravity. the center of gravity is the point which all the forces that act on the car act through. the roll center is the verticle moment of the car, or the place where the center of gravity torques about/around. the polar moment of the car is the value that dictates how easily the car spins/torques about the center of mass. you can affect all these values through lowering, track width, wheel base and various other manipulations of suspension geometry.

    CHASSIS BRACING

    chassis bracing is used to stiffen the chassis. stiffening the car's monocoque will quicken response and provide more accurate feedback to the driver. bracing can include full weld-in or bolt-in cages, strut tower bars, lower control arm braces, various bars gussets and other such items placed throughout a car's critical structural areas. one common misconception is that strut tower bars keep the towers from leaning towards each other. in actuallity they keep the towers from pulling AWAY from each other.

    MONOTUBE vs. TWIN TUBE

    this is about as deep as i'm going to get into coilovers. any more and you can reference the advanced section for the ultimate suspension discussion and reference material. monotube is better than twin tube. twin tube is cheaper that's why it's used. monotubes can come with resevoirs. resevoirs are great because they give you all the air you need without taking up VERTICLE space in your wheel well, PLUS you can have the cute adjustment knobs placed there for easy access and convenient adjusting from an engineering standpoint.

    some very good information would come from all the "making it stick" articles in sports compact car magazine.

    known suspension gurus include: john mueller (road race chassis/engineering), paul gerrard ([forum-restricted] tuning), robert 'robi' fuller (robispec). i'm sure there are others that i've left out but these are the ones i talk with most.

    here are some useful links from evom:

    http://forums.evolutionm.net/showthr...ight=robi+paul

    http://forums.evolutionm.net/showthr...ight=robi+paul

    http://forums.evolutionm.net/showthr...ight=robi+paul

  2. #2

    Re: the end all suspension thread

    Nice write up O0

  3. #3

    Re: the end all suspension thread

    bump all the way

  4. #4

    Re: the end all suspension thread

    this is very informative thanks
    [size=1pt]Mitsumaster Techs<br />2003 Evolution VIII<br />Mods:<br />My car is DRUNK 24/7 :)<br />^ 1200cc of Alcohol Injection<br />Dr. Gray Tune!<br />Custom 3&amp;quot; DP with QTP cut out<br />Invidia O2 Housing<br />HKS RS Intake with K&amp;amp;N filter<br />Perrin MBC<br />HKS 272 i/e Cams<br />Stiffy Torque Dampener<br />TRE Stage 2 Tranny with cryo, shot peen, gearing<br />RC Engineering 750cc Injectors<br />Whineburro 255 lph fuel pump<br />ARP Headstuds<br />Race Ported Head<br />Polished Combustion Chambers<br />Port Matched Intake Manifold<br />Ported Exhaust Manifold<br />GReddy Counter weight shift knob<br />JDM C-West Full Body Kit- gone<br />Stock evo VIII front bumper<br />CF Canards<br />APR Splitter<br />JDM IX Rear Bumper<br />Seibon OEM-Style Carbon Fiber Hood<br />Stage One Weight Reduction<br />Project Mu B-Force Brake Pads<br />1st Gen DSM BOV Recirculating<br />Dejon Tool UPIC<br />Speed Source Shifter Bushings<br />B&amp;amp;M Short Shifter<br />ACT HD SS Clutch[/size]

  5. #5

    Re: the end all suspension thread

    perhaps you can add an install thread as well? Thanks!
    Back from the dead...where is Everybody???? Baby Jesus cries everytime an Evo owner buys Rotas, V i s h NU,HKS, KW Variant 3, Cusco, Stoptech, Work Emotion, DEFI, Kenwood, Dynaudio, Xtant, JBL, www.tuningtechnologies.com, www.500whp.com

  6. #6

    Re: the end all suspension thread

    wow!!! good job

  7. #7
    Not So Newbie
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    Re: the end all suspension thread

    awesome info!!! Â* O0 O0 O0 O0

  8. #8
    Evo Specialist jamesinger's Avatar
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    Re: the end all suspension thread

    This thread is always worth the yearly necro bump for sure!!

  9. #9

    Re: the end all suspension thread

    umm.... yearly???

  10. #10
    Experienced
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    Re: the end all suspension thread

    Now the is the BEST write up and no drama NICE
    Turning Technologies
    West Coast Auto Sales

  11. #11

    Re: the end all suspension thread

    really helpful

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