Sharing suspension info


Gsx_hooptie
05-09-2005, 10:55 AM
Suspension Writeup:

Introduction:

It seems weird to me that half the people on this board could give awesome descriptions of turbo systems, and maybe two could accurately describe our suspension. I think a lot of people still run AGXs on 2g’s. The heart of this information is from a PM I sent. The purpose is to answer general questions and help each person decide what setup is best for them. I’d like to see DSMs on the auto-crossing scene with the same presence they have on the track.

Abstract:

Suspension is complicated, like turbos, but there's no one on our board who is an expert on it like Kevin and Jake know turbos. Most will agree that an Evo 16g is the best turbo for most of our daily drivers. Coming from guys like Kevin, it means something. On the other hand, fuel pressure theory and the PSI vs. flow rates stuff is still complicated. Suspension is the same way. On DSMtuners and DSMtalk there's near universal approval from Kevin-esque characters (the guy that won the SCCA SM class cup in a 2g DSM (2002)) that will tell you the best setup is Koni Yellows and Ground Controls. Better then Tein Flex or the lesser of the two JIC setups, arguably, and much better than Tein SS, Tein Basic, Nex, etc. So, like with the Evo 16g being the easy answer, the Koni's with Ground Controls are the easy answer. Like fuel flow, things are still complicated, though.

Terminology:

Picture a circle. Circles are divided between 360 degrees. Keep in mind with terminology where the zero value is for each dimension. Also keep in mind how much the degree value off is, in relation to 360. My explanations refer to front wheels. Impress the alignment guy at your local shop...

Camber:
Look at your car’s nose, headlong. Camber is the degree to which your tires bow inward or tilt outward. Measure this value via a true, vertical line. Negative camber is the tires titling outward. Positive camber is the tires bowing in.
During a turn, the vehicle rolls, and develops slight positive camber. Aligning camber to a half degree negative helps combat this roll and allows a better tire patch around turns. Too much negative camber, and you wear the inside of your tires. Way too much negative camber, and you cause stress on suspension parts.
Most camber adjustments are made with road crown in mind. Driving on public roads, you’ll notice that they lean to the right, to permit drainage. With neutral camber, your car would veer slightly to the right. With this in mind, some alignment adjusters move your left wheel to one quarter degree positive camber. If camber is unequal between your tires beyond a half degree or more, you’ll know, the car will pull to one side.
Changing ride height, throwing in new springs with different rates, or changing vehicle weight will all affect camber.

It's also worth mentioning that camber shouldn't always be adjusted to zero. Street DSMs can run 2 degrees, and turn better for it, so long as opposing tires have equal camber. Street DSMs also will usually run more front camber than rear camber. Auto-x DSMs have been known to run beyond 4 degrees of camber, on all wheels. This isn't a good idea for the average DSM.

Caster:
Look at your car from the side. Caster is the forward or rearward tilt of the steering axis. Picture your wheels farther to the front or back of your car than they should be. Measure, again, via a vertical line. Positive caster is the wheels to the back, negative caster is your wheels are forward.
Positive caster helps directional stability but will be difficult to steer. Negative caster will do the opposite. Most vehicles come with a slight amount of positive caster. Too much, and bumps are transmitted to the driver, and wheels will toe inward. If wheels do not share the same caster, unequal toe will result, and cause the car to pull to the side with less caster. Large amounts of positive caster will change the camber, and tire wear will show on the shoulders. If your caster is more positive than 2.5 degrees, that would be bad.

Toe:
Imagine looking down on your car from the top (this is a little harder to picture and describe). Toe is the is the movement of the front or rear of the wheels toward each other. The wheels “V” toward each other, and are no longer parallel. Pretend this is your car, looking down from the top, and the little lines are tires:

(Normal)
I...I

I...I

(Toe out)
I...I

/...\

(Toe in)
I...I

\.../

Toe is the distance between the front of the tires, as opposed to the distance between the rear of the tires. Positive toe is called toe-in, where the front of the tires are closer together than the rear. Negative toe is called toe-out, where the front of the tires are wider apart than those of the rear. With zero toe, the left and right tires of the front share an equal distance, they are parallel.
Tire tread is very sensitive to toe, it only needs to be a little bit off to cause big problems. Toe-in will cause wear on the outside of the tires. Toe-out will cause wear on the inside of the tires.

Toe is the real enemy in tire wear, even though camber gets the bad rap.

Final Notes:
The above were all examples using the front wheels. The same stuff applies to the rear wheels, in mostly the same way. You’ll find all these values on your car by getting an alignment. At the shop, they’ll only be able to align toe on 2g suspension. We adjust the other two creatively. Usually caster is close enough, front camber is left alone, and once we’re lowered we get a rear camber kit. Remember the importance of the alignment.

Also, these are the three basic terms of alignment. If you’d like to know more, start by looking into SAI, steering axis inclination.

How suspension works:

The two most common suspension setups are (1) MacPherson Strut and (2) Short Arm Long Arm (SALA) which is also called control arm suspension or double wishbone suspension. 2gs have SALA, and 1gs have a MacPherson setup.

SALA suspension looks like this (http://www.trademotion.com/partlocator/index.cfm?action=getLocator&siteid=840&chapter=AMP703&appSectionid=24&groupid=20090&subgroupid=60181&componentid=0&make=24&model=Eclipse&year=1991&graphicID=E703145&callout=6&catalogid=1): Looking at one corner, there’s a wheel, a strut, and two control arms. The upper control arm is shorter than the lower one in 2g's, although this is not necessarily the case with doublewishbone. Also note the superior geometry created with the near horizontal placement of the control arms. The control arms are attached with ball joints. A ball joint in a ball in a socket, allowing a wide range of motion, see (http://www.zjstech.net/~library/234/Lower%20Ball%20Joint.JPG). The suspension works by pivoting the upper and lower control arms on the ball joints. This is the suspension usually found on today's sporty cars.

MacPherson suspension looks like this (http://www.whiteheather.co.nz/newimages/coupe_suspension.jpg) This is a simplified version of SALA. There is no upper control arm. The strut is attached at its top directly to the frame, rather than the upper control arm seen above. The lower control arm (along with the shock) controls all the motion itself. The shock allows not only for bump and rebound, but acts as structural reinforcement. This is necessary. This system transmits bumps more easily, and is generally considered inferior as far as turning capabilities. On the up-side, this system is cheaper to make, and can last longer. This is increasingly common due to the proliferance of front wheel drive cars.

A conclusion to remember: 2gs have shocks, 1gs have struts.

How turning works:

Weight transfer

During a turn, during acceleration, or during braking, weight shifts in the car. The shifting weight causes an instability because traction is reduced for the one or more wheels. During braking, the car “dives,” and weight transfers to the front wheels. During acceleration, the car “squats,” and weight is moved to the rear wheels. During a turn, weight shifts to the outside wheels because of centrifugal force, and causes body roll. The idea is to keep all wheels on the ground at all times with maximum tire patch. This goal is realized by minimizing weight transfer and making the transfer fluid.

Sprung and unsprung mass

These are terms used in describing the theoretical side of suspension. Sprung mass is the weight the springs support. This is most of the mass of your car. Upsprug weight is the weight underneath the springs. This includes all of the suspension and the wheels. The stiffer the springs are, the better they combat weight transfer. The drawback is that less stiff springs are better at absorbing road irregularities. Don’t draw the conclusion that springs affect ride quality yet, though (they do, simply not to the degree that dampeners do). Springs do the job of absorbing energy, as we just discussed, with the dual roles of absorbing road irregularities and forces during turns.

I'll add more as I learn more. Including suspension geometry.

What car do you drive:

First off, the ideal car for Autox is the AWD 2g. If you don’t own one, or you don’t agree, don’t distress. 1g guys are also very successful, but less so on the national level. 2gs have the advantage of SALA suspension, a better camber curve, and power steering that doesn't cut out. Due to the sturdiness of the 1g struts, 1gs are the better car for rally racing. AWD, again, is king.

Front wheel drive cars are at a disadvantage for serious cornering. Even after mods have been made to reduce understeer, it'll be hard to compete with an equally modified AWD. Smartasses refer to “drifting” front wheel drive cars as “assdragging.” Serious autocrossers would be better off with AWD. Most of us are doing this for fun, don't worry.

If you have a sunroof, as many 2g’s do, your torsional stiffness isn't as good. For this reason, non sunroof cars will perform slightly better. The difference is small. If you have an early model 1995, you have vented disks. These are nice in classes where brake upgrades aren't allowed (IE, I think, anything below SM).

Shocks:

Shock primer

Shocks are handed the responsibility of dealing with springs. While springs are charged with absorbing energy, the energy they absorb would translate into endless (almost) oscillations. This is the washer-board effect, where the car goes up and down. Shocks dissipate the energy that springs absorb (they do this by translating the kinetic energy into heat that’s dissipated by hydraulic fluid, in case you care). The rest of the free world calls “shocks” “dampeners” for this reason. It’s also this reason that shocks are largely responsible for ride quality.

Energy from the spring is transferred to the upper mount of the shock, where a piston runs down a hydraulic tube and presses liquid through tiny holes, where resistance and friction is created. Obviously the piston can’t compress liquid very far, and since the holes (that lead to a reserve cylinder) are so small, the inertia of the piston and thus shock and thus spring is lessened to the extent that the liquid can be pressed through the holes. This is why suspension guys talk about dampeners (again, shocks) responding to velocity rather than force (speed sensitive, not force sensitive). You can test this, and thus whether or not your shock works, by taking the shock and holding it between your hands, trying to press it together. You don’t have to be He-Man to do it; it should give resistance but slowly back into itself. Now try and instantly force the shock closed. If your shock is working properly, you can’t. Another point worth mentioning is that the force required to move the shock is uniform throughout its travel, up until the end.

Here’s another bit of terminology to remember: compression and rebound. Springs move up and down, and so to be effective, so do dampeners. The same small holes setup is effective in both directions. The shock going down is called compression, and the shock moving upward is called rebound. Compression controls the weight under the dampener and spring, the unsprung weight. Rebound controls everything above the spring and shocks of the car, the sprung weight. Because the sprung weight is much larger than the unsprung weight of the car, the rebound cycle of a dampener has more resistance than the compression cycle. To remember which is which, remember that “compression” goes down, and “rebound” goes up. Associate these with unsprung as under (under-the-spring), and sprung weight above. Generally, for turning, we want to raise rebound, but not compression. I heard compression is good for dragging, I’m not sure.

Purchasing advice

This is why we buy shocks:
1) You lower your car
2) Your struts can't move as far, they lose travel
3) To compensate, the springs you buy are stiffer
4) To work with stiffer springs, you get different shocks

With dampeners, then, there are three things to adjust, ride height, compression, and rebound. Or, at least you should be able to ;) Crappy suspension setups allow you to adjust ride height, exclusively. Whatever settings they received from the factory are what you get, like it or not. Some coilovers or aftermarket dampeners also allow you to adjust compression and rebound. KYBs and Tokicos are examples. Unfortunately, they adjust compression and rebound together. This is bad, since as was addressed, we need rebound, not compression. The problem in mating the two is that there's no happy medium. Set one correctly, and the other is off. In the end, your ride sucks, or your turning does. The mating of compression and rebound adjustments is a mostly Japanese phenomonon. The only dampener on the market that allows independent rebound is Koni Yellows (also called Sports). You can’t exactly adjust compression on these, at least not the way you want to. Then again, as we said, we’re leaving compression alone for awhile. Konis are Dutch. They have been successfully run on nice cars, professionally.

What Rates do I Run:

If you don't know what the rates are to the dampeners you think you’ll be buying, find out. If you're thinking of buying a system that doesn't display what rates they're using, be concerned. The higher you go, the more likely you are to blow a shock. If you’re going beyond 350, you’re out of the range of both KYBs and Tokicos, it’s time to look into Konis. If you’re going above 500 (ha), start considering a revalve of the Konis. Whatever rates you run, they need to be compatible with the springs you’re running.

When thinking about rates, there are two numbers, a first and a second. The higher the rear number in proportion to the front number, the more your car will oversteer, or at least get closer to neutral (keep in mind that this is due to their compatibility with like spring rates, too). This isn't always a good thing. Cars have different characteristics with oversteer, especially when they weren’t intended to in the first place. You don’t want to kiss a ditch. Here are some general numbers for proven setups that will work:

A rule of thumb AutoX setup is 500/400. If rates like these are sustained, you could blow shocks, depending on what you're running.

A rule of thumb for an agressive street ride is around 400/325. Personally, I think those numbers lend a bit too much to oversteer, so don’t feel bad about running something more like 400/300. Opinons vary.

Final notes about shocks: Another job for your dampeners is to keep you off your bump stops, and maximize travel. Since shocks are usually installed with springs, it's good to make up for some of the travel you lost with the drop by having a shorter shock body.

What can I buy?

There are three major players in the aftermarket for upgraded shocks:

Koni Yellows: Expensive, independant compression/rebound rates, longer lasting, rebuildable, short body (more travel), not on car adjustable

Illuminas: Cheaper, mated compression and rebound adjustment, pretty sturdy, not rebuildable, relatively short body, on car adjustable

AGX: Cheapest, mated compression and rebound, not as sturdy, not rebuildable, long ass body that kills your travel, on car adjustable

What about coilovers?

Coilovers offer you the simple solution of a spring and a shock together. However, there's a lot of hype about coilovers being God's answer to turning. JIC offers a system that is adjustable in all ways, throughout a spectrum of values, and has an insanely short body that could provide adequate travel for a huge drop. Nex (while more affordable), doesn't do any of the above. The point here is that coilovers can be better, but aren't necessarilly so. A Koni setup can and has out performed Tein and the rest of the bunch. Coilovers should be subjected to the same criteria of aftermarket shocks: Price, adjustability, travel, durability, rebuildability (look that one up, lol), and whether or not they are on car adjustable. If they offer the best package for your budget, pick them up. If not, don't.

That having been said, coilovers do offer some advantages; the springs should work well with the shocks, they offer multiple items together (no needing to buy several different items and research if they work well together), and they should be a touch easier to install.

There are many more products on the market here, than with dampeners alone, giving you the opportunity to find just what you want and having a hard time picking a reputable piece from the bunch.

JIC Track: Very expensive, independant compression and rebound, tough stuff, rebuildable, very short body, on car adjustable

Tein Flex: Very expensive, mated compression and rebound, tough, rebuildable, somewhat short body, on car adjustable and option for in car adjustable (not recommended, cuts suspension travel)

Nex/Tein Basic/the like: Expensive, only height adjustable, easy to bust, some are rebuildable, body size varies, again only height adjustable

There are also "E-Bay" "sleeve" coils. These are springs on a threaded pearch, usually sold with an aluminum hat. Unfortunately, these suck. The springs are too short and too stiff. The springs sag over time. For the most part, these are a waste of money. There are few exceptions, and none of them are in a sub 250 price range. Ground Control is probably the favored provider of coils. Ground Controls use Eibach springs, and offer you a variety of spring rates from the factory. Different perches come for different shocks.

It's worth noting that Eibach's are only enthusiast springs, though, and Koni's are valved for H&R style springs. You could swap the springs out and keep the sleeves, which is the popular solution.

E-Bay sleeves: Cheap, shitty

Springs:

If you're thinking about springs, it's probably to lower your car. They do this, usually. Springs are what initially abosorb bumps in the road. These days, springs are coils. The rate of the spring refers to how elastic it is. The higher the rate, expressed in pounds, the rougher the road will feel. The rate is mainly determined from the material used, the thickness of the coil, and the spring's length in inches.

Springs that lower your car are shorter than stock springs. This reduces shock travel, which is bad (see a picture of how
here (http://e30m3performance.com/myths/travel/travel.htm) ). Reduced shock travel could result in spending time on your bump stops.

Bump Stops

Bump stops are bad! If you're lowering your car ;) Bump stops are designed to soften really big bumps when your suspension bottoms out. Otherwise, you'd be hitting metal. This doesn't mean that they're comfortable, as the spring rate theoretically approachs infinity. They do help in turns with stock springs, though. When approached durning a hard turn, they gradually add to the stock spring rate. This is intentional. On a lowered car, bump stops are bad.

A car that hits its bump stops is unpredictable, particularly when mated with aftermarket springs. Bump stops are designed with stock springs in mind, where the rate transition is at least kinda smooth. With aftermarket springs, the transition to the bump stops makes the car less predictable. In the rear you can lose traction. Up front the car will pull. While in a normal car, the bump stops are only felt with potholes, on a lowered car, you will become well aquainted, unless you do something about it. To help stay off of the bump stops, there are numerous solutions. One obvious solution is to cut the bump stops. They are rubber, afterall. Most dampener kits suggest this and provide instructions for how this is done. Another solution is to buy shocks with a shortened body. Konis do this. You can also get new upper mounts, providing you more room for travel. Lastly, because they are shorter, springs are predesigned with a higher rate than stock. The higher rate means shorter relative travel (of the spring). The higher rates or time spent on bump stops account for the reputation of lowered cars having a rough ride. Is it possible to lower the car and still have a decent ride? To maintain ride quality and turn well, keep your car off of the bump stops (as explained above), and mate your springs to appropriate shocks.

Rating springs

There are linear springs, progressive springs, and coilovers. Linear springs are rated by this formula: “The rate is dependent on a few things, wire diameter (d), mean coil diameter (D), number of coils (n), and material constant the spring is made of (G). The formula ends up being spring constant k=Gd^4/8nD^3. The basic spring force equation is F=kx, where (F) is the force on the spring, (k) is the constant from the equation above, and (x) is how far the spring is compressed.” –Nat of Nasioc online. In any event, the rate is expressed per inch of compression, and is additive. For example, a 500 pound spring will take 500 pounds to compress one inch, and 1000 pounds to compress two inches. Progressive springs increase their rates non-arithmatically. The first inch of compression may be 350 pounds, while the last inch is 1000 pounds by itself. Which are better? I’ve heard progressive springs are better for beginners. Sleeve coilovers (aka spring on a threaded pearch) do one more thing, they also adjust ride height. The lower you go, the more likely you’ll be on your bumpstops. Most setups don’t tell you their spring rates. That’s bad. Keep in mind that that rate is designed for a specific height. The lower the car goes, the lower the total amount of spring ability there is. For example, with a 500 pound rate, a five inch lowering spring has a total of 2500 pounds of compression available. When you dial it in to lower your car farther down, not only are you closer to the stops, your total compression has decreased. For example, the same spring now cut effectively to three inches will provide 1500 pounds of resistance. Some sleeve coilover systems, like Ground Controls, are good. Others aren’t so good.

Would you like some dampeners with that?

It's important to buy shocks with your springs. New springs have higher rates than stock springs, and will tear stock shocks apart over a period of a few weeks to no more than a few months. The quick and dirty is that springs are attached to the shocks, and when their absorbed force exceeds the ability of the shock to dissipate it, they beat the hell out of the shock until it leaks.

The best shocks will be those that mate to your springs. How do we know they mate correctly? It’s manifest in the compression and rebound of the dampener. Previously, I wrote here that I was still learning about this. I didn't know that I already knew... and unfortunately, it's because there seems to be more art in this field than science.

A 250 spring will work best with a shock tuned in at 250 pounds. That's in a perfect world, though. Both springs and shocks could be off by plus or minus 7% of the advertised rates. If it's seven percent one way with springs, and the other way with shocks, that would be bad. Still, this is better than stock shocks. To make things even more difficult, many shocks don't advertise their range of rates. Now things are murky, and the weak willed will say fuck it and buy Tein springs with stock shocks. Here's a rough guide: Illuminas or AGXs for 200ish-400ish, Konis for 200ish-500+ish. Again, these all have a range of rates, which presents the opportunity to dial things in right or wrong. Gear the shock along its adjustability to the spring rate. If you don't want to mess with it and want to deal with known setups, see below.

What to buy

You get what you pay for. Examples of good springs are Eibach, HR OE Sports, and Hypercoils. Eibachs will work well for most, the last two I just mentioned are intended for Konis. Ground control makes the best sleeve coilover for DSMs. Even better, you can swap their Eibach springs for something with more bite if you're running Konis.

Examples of possible setups:

Not-so-bright street:
Stock shocks and E-Bay coils

Mild-moderate street:
Tokicos or new-code AGXs with Eibach springs or Ground Controls

Rough street, autox:
Konis with Hypercoils

Whatever you buy, get an alignment when you're done. Remember that lowering a car is done best when shocks and mods that extend suspension travel are included.

Upper Mounts:

Still learning. This is ugly.

Swaybars:

Picture watching a car in front of you take a turn, your perspective always from the rear. As the car makes the turn, weight transfers from one side to the other, causing one side of the car to rise a little higher than the other. This is called sway, or roll. A swaybar is designed to minimize the vertical change, and in so doing preserve the camber and toe. To do this, it attaches to the lower control arms and is mounted to the frame. This also reduces understeer. Some consider this the single most important suspension modification. Some also believe that understeer can be eliminated to an even greater degree by only installing a rear swaybar. This idea sucks, since the driver is unlikely to be prepared for the massive shift toward oversteer.

Importance: Lots
Rough Cost: 250
Makers: RM Racing, Suspension Techniques, and RRE. Some of these follow the stock dimmensions, but are thicker. Some have a different geometry, and are only a little bit thicker. RM is the most popular. The RRE is the thickest. Keep in mind that geometry is as or more important than size, but size matters :)
Installation: Frustrating, but impossible to screw up given enough time. The front can be a bitch. This piece, whether or not it looks like it, favors going in on the passanger side, and swivels for the hump in the bar to straddle the transaxle. The rear bar may require lowering the exhaust. Some have fittment problems, this is rare. My bushings didn't fit their brackets. See www.plymouthlaser.com for more on installation.

Polyurethane Bushings:

Polyurethane bushings are helpful, but not easy to install. The idea is that stiffer suspension bushings will make the steering and response more precise, and help you maintain front camber during a turn. Theoretically, it also reduces understeer. Contrary to popular belief, some bushings in the 2g suspension are made soft for a better reason than driver comfort. The lower front arms pivot on multiple axels and their action is inhibited by stiffer bushings. Ideally, like with upper mounts, spherical bearings would be used. No product is yet on the market, but the controversial Dennis Grant of ATI (above mentioned for having won the 2002 SM via DSM, who also shamelessly plugs his products on dsmtuners) has commented that he would produce the product at some point. Until the day comes when SBs can be used, you’re still better off with polyurethane bushings than not. Keep in mind, while cheap and effective, these are reportedly a mother to install. Be afraid; there are over 100 pieces to burn out with a torch unless you have a 5-10 ton arbor press. To complete the job, the subframe needs to be removed to replace all the bushings. For most of us, this simply isn’t worth the time. This is a great mod to have around the house and install when the other things eventually need replacing, or for the dedicated track car or dragger with too much torque. If there is such a thing ;)

Importance: Not terribly, depending on goals
Rough Cost: 100-200
Makers: Energy Suspension and Prothane. Two different kinds are made, polyurethane and nylon. Either work. At some point in the future, spherical bearing bushings may be available, but don’t hold your breath. All are stiffer than stock. Prothane are much stiffer than ES. The rule of thumb is ES for street driving and Prothane for the dedicated track car.
Installation: Very challenging and time consuming. Like engine swaps, how fast you can swap bushings is a bragging right. This is more than a weekend job, but can be done in intervals. Requires use of a torch or access to a huge vice. Also requires removing the subframe to truly complete. Fun.

Strut Bars:

Strut bars are popular, but more complex than most people think, they do more than maintain rigidity and improve response. This doesn’t mean they’re worth buying. For most of us, front strut bars only look nice under the hood.

Rigidity: Theoretically, the bars help during a turn due to the torsioning of the strut towers. The rear strut bar is more helpful than the front because our cars are hatches, and even more so if your car has a sunroof. Don’t expect miracles, though. Attaching a bar to two points isn’t the “right” way to do things for rigidity; you need to triangulate the force, and for that you need a roll cage. Note how close and how well the front strut towers are secured to the firewall. Rigidity won’t be helped much here.

Camber:
A rule of thumb is that you won’t know the difference until you hit 245 r-compound tires. This is why, along with the front bar not doing much for rigidity, the front bar seems ricey. Preserving camber, though, is the other reason strut bars are good. The main purpose of the front bar is to reduce understeer. By locking the strut towers together, they can’t deflect (“bow out”), and the car keeps outside wheel camber during a turn. Simple, huh? Understeer is reduced by gaining front traction, rather than other mods (over inflating rear tires, adding exclusively a rear sway bar) that focus on reducing rear end traction. On an ending note, for the same reason, understeer will be subtly larger with a rear strut bar.

Quick and dirty: Rear bar for rigidity, front bar for less understeer

Importance: It depends, but not very
Rough Cost: 32-200
Makers: E-Bay, RRE, ARP, Neuspeed, many others. If you’re set on buying a bar, buy a good one. Adjustability is a place for the bar to flex, this is bad. On the other hand, it’s the only way proper fit can be assured by sellers. Most bars are aluminum, and aluminum flexes, this is bad. Some bars are steel alloy, but that stuff is heavy, and your weight distribution sucks as it is. Some front bars also secure to the firewall, this is good. The two best bars that I know of are those made by Neuspeed and RRE. The Neuspeed is discontinued. A DSM’er solution is to buy the crappy E-Bay bar I just told you not to, and weld the adjustability component once it fits. It’s still aluminum and not bolted to the firewall, though. You should realize by now that one bar is not as good as another.
Installation: Simple, and one reason why they’re so popular. Proper install, preloading, means installing the bar when the car is off the ground. Keep in mind how much it sucks to take the bar off each time you’re working under the hood. The rear bar requires removing a couple body panels. No sweat.

Camber Kits:

You lower your car, and your negative camber increases. Your tires look more like this (head-on)
/-----\
This isn’t always a bad thing, though, and camber kits aren’t necessarily a good thing. With negative camber your contact path is decreased, which is bad for drag racing. For daily drivers and light-core autocrossers, the addition of a little more negative camber is good. Hard core autocrossers use camber kits to get more negative camber. The argument for camber kits is the need to preserve tire wear. Toe is much more significant in tire wear, however. Unless you’re running a Sportline style drop, forget front camber. Rear camber still needs to be adjusted. On 2g’s, we can do this ghetto style, with Home Depot washers. A mod for this is listed on vfaq. The idea is, again, to push the top of the wheel farther out. Keep in mind, we’re doing this to preserve a good amount of front camber, and a little negative camber.

My ride is slammed, what now:

There are two ways to compensate for front camber, make your upper control arms longer, or make the shorter arms smaller. All (at this point) DSM kits use balljoints to extend the upper arm. The arm can then angle up to the knuckle and hit the fender, sometimes. As far as I’ve researched, you’re pretty much fucked if this happens. DSM suspension gurus don’t dedicate much of their time to help guys with a 4” drop. Also look into the double bushing modification. There’s a third problem, too. If you care about negative camber, and you should, then you have to push out the top of your rear wheels with so many washers that they contact the fender, which now needs to be rolled. Fun.

Importance: Most of us won’t need a front camber kit, get an alignment to check. Get the rear checked while you’re there, most of us will need a rear washer kit. Moderately important.
Rough Cost: 100 for front, couple dollars for the rear plus the cost of beer
Makers: Ingalls, Eibach, Home Depot, many others.
Installation: If you’re doing this, you’ve already changed out your springs and hopefully shocks, and this should be no sweat. The PITA is getting the alignment, coming back, and taking back off some of what you reinstalled.

Get an Alignment:

The most important and often forgotten modification. If you change anything that affects camber, toe, or caster (which is basically everything), go get an alignment.

Importance: Very
Rough Cost: Mine are free, I honestly don’t know
Makers: Everywhere
Installation: Depends on how far off your alignment is and what you’ll have to rip out :O

For your edumacation, borrowed from a Tuners stickey that nonmembers can’t read, your stock alignment numbers are as follows. Don’t let shops stray too far from these without your consent:

1G AWD Front Suspension;
Camber: +0.1 degree plus or minus 0.5 degrees
Caster: 2.3 degrees plus/minus 0.5 degree
Toe-in: zero plus/minus 3 mm

1G FWD Front Suspension;
Camber: +0.05 degree plus/minus 0.5 degree
Caster: 2.4 degrees plus/minus 0.5 degree
Toe-in: zero plus/minus 3mm

1G AWD Rear Suspension;
Camber: -1.55 degree plus/minus 0.5 degree
Toe-in: 3.6mm plus/minus 3mm

1G FWD Rear Suspension;
Camber: -.75 degree plus/minus 0.5 degree
Toe-in: zero plus/minus 3mm

2G FWD Front
Camber: -0.8° to +0.2°
Caster: 3.2° to 6.2°
Toe: -0.06” to 0.06” each side Total Toe: -0.12” to 0.12”

2G FWD Rear
Camber: -2.2° to –1.2°
Toe: 0.00” to 0.12” each side Total Toe: 0” to 0.24”

2G AWD Front
Camber: -0.58° to +0.42°
Caster: 3.17° to 6.17°
Toe: -0.06” to 0.06” each side Total Toe: -0.12” to 0.12”

2G AWD Rear
Camber: -1.83° to –0.83°
Toe: 0.00” to 0.12” each side Total Toe: 0” to 0.24”

Via: http://dsmtuners.com/forums/showthread.php?t=169442
Credit to pneumo, wret, and jehu

Limited Slip Differential:

Kevin is much more qualified to write this. Here’s the very basic idea. A differential lets the two wheels spin at different speeds, each carrying at least part of the total torque burden. This lets you turn, since the inside wheel on a turn will rotate less often than the outside wheel. Try and picture that, if you can. The farther from a pivot point you are, the faster you have to move to keep the same number of revolutions. To do this, mechanically, DSMs have spider-type differentials. See picture of an upgraded 4 spider gear unit: http://www.teamrip.com/images/4%20spider%20rig.jpg. The problem, is that more torque is delivered to the wheel with less traction. Enter the LSD (Limited Slip Differential). DSMs come with a Viscous Coupling system where the plates rotate near each other and one output can move faster than another. From what I understand, the two plates create a friction with the fluid surrounding them, causing heat, causing expansion, that locks the two plates together. These systems aren’t so good because they’re non-linear and hard to predict. One upgrade is the Kaaz, that acts as a clutch-pack. Two plates are in direct contact, without the surrounding fluid, and react to torque rather than output speed. The other popular upgrade is Quaife, a helical style LSD. This reacts to torque, too. These pseudo descriptions blow, and I acknowledge that I know next to nothing about this topic. All I can say is “Ask Kevin” ;).
What you care about: The idea is that for many, this is the limiting factor of how far your suspension setup will take you. LSDs are expensive, and the component to which many consider you should upgrade your suspension around. The benefit is better traction of both tires around a turn. If traction of one wheel is subpar, your lines will suck.

Importance: If you’re serious about AutoX’ing in a category where this is allowed, this is essential.
Rough Cost: 1000+
Makers: Kaaz and Quaife
Installation: For how much money it costs, not that much work. I would imagine removing the axle, let me know if I’m wrong.

Rims:

Like all these topics, I’m doing no justice to the depth of the material on this. Unlike other topics, I’m not going to even try! Hah! Anyway, this is here to eliminate common questions. The disclaimer is that this is a suspension take on rims, and a drag take will be different. You’ll note similarities like weight, however.

We think about rims for a few reasons. Rims should be lighter than stock, they should look good, and they should be appropriate for the tires we’re running. Because rims turn as the car moves, they represent rotational mass. This means that they are extra important as far as resistance and relative weight removal. Imagine running down the street with a twenty pound back pack. Now imagine running down the street with ten pound weights on each ankle. This example exacerbates how bad it really is, but each pound that is removed from the rims equates to two and a half to three pounds of weight removed from the body of the car. Now multiply by four wheels and you’re really getting somewhere. There are many different style stock rims, but as an example, the 17” cast rims that came on the gsx in 1997 were 25 pounds, according to http://www.superhonda.com/tech/wheel_weights.html. A good rule of thumb is that the rim measurement in inches should be at or below its weight in pounds. For example, a 17” rim should weigh 17 pounds. In this example, the rim is eight pounds lighter than stock, multiplied by four wheels, and the modifier of 2.5 for inertial mass, and we’ve saved eighty pounds. Wow, good stuff. Remember to also keep in mind that wheel weight is also dependant upon rim width and tire weight. Both are usually overlooked. For good tire weight, look into Kumho MX’s. BFG also makes some nice stuff, for much more money. Average 17-18” tires will run around the low 20lbs area. Removing weight from a car makes it quicker, more responsive in turns, and helps it stop quicker. Naturally, there’s some tradeoff between tire capabilities and weight. Rims should also look good. This is subjective, but should be limited among rims that are light. There’s a tradeoff between bling and weight. Chrome blades are heavy, yo. A popular, cheap choice, are Rotas. Lastly, how do we decide what size of rims are appropriate? Your rims have to fit your brake system, and your tires. Upgraded brake systems use larger calipers and larger rotors, usually 17” does the job, and 18” leaves plenty of clearance. Don’t take my word for it, figure out the size rotors you’ll be running. You also need to find an appropriate size to fit your tires. Another rule of thumb: the wheel should be at least 70% of the tire width (obviously has to do with tire choice, see below, but for now accept the easy answer of 8" width). For even the semiserious, you should only be considering 8” width. The 8” width will allow you room to move between 225s to 255s. Remember that in the faqs on this site Joewagon listed a few lightweight rims to think about.

Just to shoot your hopes and dreams, there’s a saying about rims: rims can be lightweight, sturdy, and cheap; choose two. There are exceptions, like the rx-7 3g rims. Cheap, tough, light, and with an 8” diameter. They don’t look bad, either. Wheels are made through different processes. Forged, spun, and cast are the three most common, in descending order of strength.

What rims will fit?

The 2gs are five lug, 114.3mm mounted. This is the most common size of rims found on cars today; good times. The largest diameter I’ve seen are 20s, and I think they look dumb. The larger you go, the lower your profile will be, and the more you’ll feel the bumps. As far as width, anything more than 8s can be adventurous. Beyond the lug’s and offset, though, whether or not rims will fit will depend on your tire choice. Offset is a little more complicated, and involves how far the rim is from the axel. That’s actually wrong, but an easier way of picturing it.

Your general rim guide can be found on vfaq here, including rim setups that have worked for others in the past: http://vfaq.com/mods/macross/2Gfitment.html. The most misunderstood aspect of rim fitment, as far as I’ve seen, is offset. An faq on that can be found here: http://vfaq.com/mods/macross/offsetFAQ.html.
I’ll be adding more later.

Importance: Yes
Rough cost: 200-2000+
Makers: Rota, Volk, Enkei, BBS, many others
Installation: Simple. Mounting and balancing merits a trip to the shop, though. Usually a cheap trip.

Tires:

(More soon)

The best thing you can do for safety and handling (other than learning to drive) is buy a good set of tires. Tirerack has professional opinions and a large database of buyer feedback. Large, as in, hundreds of millions of miles reported. You probably know as much about tires as I do. I have 712's that I bought used. If I could buy what I wanted and didn't have to depend on the used market, I'd buy Potenza Pole Position's. Things get expensive, fast. Safely, you can go 225's. Living dangerously you can try as high as 245's (possibly) without rolling the fenders. 225 is all most of us need. Something to look into if your tires are bald :eek:

Brakes:

Since you're getting suspension, look into brakes at some point. Brakes are complicated, too. More soon.

Nut Behind the Wheel:

That's you. Your car is only as fast and safe as you are. If you don’t know how to drive, the difference between a badass Koni setup and an even sweeter JIC track setup will be lost. For safety’s sake, if nothing else, take a defensive driving course. Your insurance will be lower in some states (true for Ca), and you could save your life or the car in question. If you're serious, look up local SCCA clubs and go to their track days. Talk to the guys there, figure out whether or not you're interested in the real deal. There’s usually a designated guy there to help out the newbs. “Race days” come up every once in awhile, where some professional AutoX’ers show you the ropes. This is usually an expensive, small class size exploration of racing. You can get a group rate with a local car club, if you don’t mind larger class sizes. A good example of a cheap (~200-300) driving school is Evolution, found here: http://autocross.com/evolution/. Remember, most people think they’re better drivers than most people. Think about that, lol. Click here if interested in more on the psychology: http://www.scienceservingsociety.com/ts/text/ch14.htm. There are arguments about whether it’s better to learn on soft (stock) suspension, or upgraded suspension. Hard to say, but the most impressive guys on the track are those who can drive the stock setup to the limits, seconds faster than guys with thousands of dollars invested.

Importance: Prime
Rough Cost: 200-2000
Makers: See your local http://www.scca.org/ group. Some tour, such as the above mentioned Evolution school. For a slightly more corporate approach, see this site: http://www.racingschools.com/geograph.shtml
Installation: More difficult than you think 

Events:

The flat truth is that DSMs are not competitive in more than slightly modified races. The addition of a boost controller, an early upgrade, already throws you higher than you want to play (street modified). You'll see quick M3's and Porsche's, which is bad. This isn't to say we don't have winners. The ways the rules are set, however, odds are against you. Have fun at regional events, there at least, it's more about the driver. Also remember that there are open track days, when everyone gets a shot, and you don’t have to worry about what class your current setup places you in. This will be more expensive, though. Whatever the case, bring a solid helmet. Also think about getting a harness. Hopefully you have a decent brake setup. Find out where you fit, or, if you're building your car, figure out where you want to be. The following sites will help:
http://www.moutons.org/sccasolo/
http://www.wincom.net/trog/autocross/
http://www.azsolo2.com/classes/ModificationsSpreadSheet.htm
For inspiration, see here ;) : http://www.dsmtuners.com/gallery/showgallery.php?cat=500&ppuser=28279

“In SCCA Solo racing, the 2G Turbos run in G-Stock, E-Street Prepared, C-Prepared, and E-Modified. The 2G non-turbos run in E-Stock, C-Street Prepared, E-Prepared, and D-Modified.”

Importance: Is it?
Rough cost: 30-200 (c’mon, it’s cheap)
Makers: See here: http://chasinracin.com/track-locator/viamap.shtml
Installation: N/a

Conclusion:

My favorite quote from the past month (after a question about Konis and Illuminas):

"DSM = doesn't spend money

Even when the difference is only 20% in dollars and 200% in performance.

It's something that has taken me a while to get used to on this list. My advice: Laugh it off, assume that some lurker got the point, and move on to the next "whatcha think of these 19" wheels?" thread.

- Jtoby"

:)

Edit>> More soon

gthompson97
05-09-2005, 12:55 PM
i'm thinkin sticky, anyone agree?

JoeWagon
05-09-2005, 01:37 PM
Agreed.

Now the only question is if I lower my car, if I will make it 2 hours without scraping. Maybe I'll go with Kevin's alternative of sway bars and stock suspension.

kjewer1
05-10-2005, 01:37 AM
I would just like to add that the upper mounts are good for 1 inch of added travel. I never verified that, and we all know how much I trust vendors. But before the mounts I was on the bumps stops and there was no way around the related understeer on the circle track. After the uppper mounts I was no longer on the bumstops all day, and I could actually control the car in turn 3 and 4 for once.

Kuhn
10-30-2005, 01:01 PM
This was extremely helpful. AutoX is what I'm really into... not so much the drag racing. So this is getting bookmarked! Thanks! :bigthumb:

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