First Suspension Modifications FAQ

Discussion in 'Tech, Tips, Newb Info' started by shane86, May 4, 2007.

  1. Shane86
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    Shane86 Well-Known Member

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    Well, since readymix took the liberty of writing such a nice horsepower step by step write up, thought i'd do one for the suspension.

    How can i make my car handle better?
    Well, i'm glad you asked that little billy!
    why are you calling me little billy?
    Shut up. i'm the one talking here. if i say your name is billy, it's billy.

    Well, theres a lot that you can do to make your car handle much better, and here's my list of things to do in what order to make the most effective handling car for the fewest bux.

    1) Alignment.
    Your alignment is the most important thing to maximizing your current handling capabilities. You might think that right off the bat, your car is aligned properly. oh how wrong you are. subaru has a very wide gap of whats considered acceptable alignment specs, and that range is oriented to minimize tire wear, not optimal handling.

    The best thing you can do with your stock setup, is to have your front wheels set to the most negative camber they can yeild evenly. typically, on a stock WRX, this is 1-1.5* negative. it's not enough to wear out your tires alot faster, but it will be noticeable in turn in and grip. Subaru's have a strong tendency to understeer, so increasing front grip will yeild a comparitively looser rear end. for daily drivers or inexperienced drivers, i suggest setting the toe at all four wheels to zero. this will make a car that tracks very nicely down the freeway and minimize tire wear. if your gutsy, try feeding in some toe out. that will yeild a much looser rear end. the rear camber is not adjustable, but if you do get some camber bolts, i would suggest keeping it at around -.7-1.0. too much rear camber will yeild excessive rear grip, and bring that understeer issue up again.

    2) Tires
    Tires tires TIRES! DON'T CHEAP OUT HERE! tires are the MOST IMPORTANT thing when it comes to your car's handling. everything you do with the car from accelerating and braking to turning all depends on the small contact area where your tire meets the ground. you can only make this area so much bigger, so you wanna make sure that said area is full of the stickiest thing you can get. also, make sure your getting the correct size. if you purchase a tire that is noticeably taller than the stock size, your acceleration will be noticeably slower, but on the other hand, if you go to small, your gas mileage will go down, because the engine will have to maintain higher RPMs at the same speeds.

    Good summer tires are not that expensive when you see what kind of benefits they yield. the primary choice for performance oriented drivers are the Falken RT-615s, The Hankook RS2 z212s, the Kumoh Ecsta MX, the Yokohama ADVAN AD-07s, and the Bridgestone RE-01Rs. the Falkens and the Hankooks are the cheapest, and pretty much the best option for most people.

    and you don't need to get new wheels to get the benefits of better tires, adding a set of these tires to your stock wheels will not only cost less than new, bigger wheels and their tires, but will also yield a similar level of grip.

    3) Sway Bars
    Swaybars are designed to handle body roll, and maximize tire contact with the ground through a turn. their relatively cheap, and rather easy to install. there's just a few things to keep in mind when choosing your sway bar.
    Bigger isn't always better. getting a swaybar too large for your current spring/strut setup can cause unwanted wheel lift during cornering, and cause unwanted snap oversteer. a condition that's hard to control, hard to correct, and dangerous should it happen on the street 20-22mm solid bars apear to be the sweet spot for a stock dampened/springed or lightly modified wrx. going larger can be benificial depending on the situation, such as when you begin using a heavy spring rate or very stiff coil over setup, but that's up to you to decide.

    In combination with upgrading your sway bars, you should upgrade your end links at the same time. Subaru decided to cheap out on the WRX endlinks, and use PLASTIC pecies. these can break under hard cornering with the stock bar, so it's pretty much enevitible failure. upgraded endlinks start at around $75-100 and go from there for added features such as speherical bushings, and preload adjustability. in older subarus (pre 04) it's also not a bad idea to upgrade the swaybar mount. these also have been known to fail under extreme use with aftermarket bars.

    Don't just upgrade the Rear! the front is important too! by increasing roll stiffness in the front, you increase the tire grip at the chosen camber level, and thus can increase your smooth, controlable oversteer. the best kind of oversteer!

    4) Struts

    Work in progress guys.... i'll keep working on this later.
     
  2. ShortytheFirefighter
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    ShortytheFirefighter Pokemans. I has none. Staff Member

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    I'll be doing a supplement to the suspension, as there is a bunch of stuff concerning what hats/struts/springs will fit together, especially from the 02-03 to the 04+ model years...I just need to get it typed up. I'll also be doing a wagon specific one, as we have a few different factors to consider when we want to do wider wheels/tires or different struts.
     
  3. ShortytheFirefighter
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    ShortytheFirefighter Pokemans. I has none. Staff Member

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    Alright. Here is the short and sweet answer to that famous question:

    "What struts work with what strut tops?"

    For those of you who didn't know because you've been doing hard time, you've been off of the planet or just didn't hear about it, Subaru changed the strut tops for the Imprezas in the rear for the 2004 model year. The front tops stayed the same. The rear coils are a different diameter between the 02-03 and the 04+, and they're not interchangeable.

    Also, just to throw an extra wrench in the works Subaru changed the threaded portion at the top of the strut shaft on the 04+ vehicles. Some struts are 02-03 specific at this point (Tokico D Specs are the only ones that come to mind right now. According to Zak KYB has an 04 specific AGX, and Koni inserts have an 04 specific application), so to run those struts you either have to get 02-03 strut tops, or you have to perform the "Washer Mod" to ensure the strut top and the threaded portion mate up correctly. There is also a spacer premade for the purpose, known as the "Scooby 921" spacer. Turninconcepts.com is the main vendor for those.

    What does this mean for you? You're going to have to pay attention when you're buying struts, springs and tops to make sure that your setup will fit together properly. Otherwise, you'll have really fancy looking paperweights (much like Rays car).

    There is a wider range of spring options for the 2004+ onward vehicles, so if you're the owner of a 2002-03 Impreza it's something to keep in mind. I'm not going to get into which spring is best at this point, I think my own personal views on the subject are fairly well known throughout the board.

    So, here's the breakdown:

    02-03 springs will work with 02-03 struts/02-03 hats
    04 springs will work with 02 struts/04 hats/Scooby921 spacers
    04 springs will work with 04 struts/04 hats
    02-03 springs will not work with 04 hats
    04 springs will not work with 02-03 hats

    Those are the only combinations I can think right now. Hopefully this will help clear up some of the "what spring will work on my car" questions. It wasn't short, but a good suspension writeup usually isn't. Next up: wagon stuff :)
     
  4. mlgez
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    mlgez Well-Known Member

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    And to add to the above confusion the 05+ STi's are different in the front because of the new larger bearings. My understanding is this is why they also changed the wheel bolt pattern to 5x114.3. As for the struts, the knuckle is thicker and the two strut bolts center-to-center spacing is different. So that means, as far as I know, the rears are the same as the WRX but the fronts are not.
     
  5. FuJi K
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    FuJi K Well-Known Member

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    just thought I'd throw this out because it helped me a lot.

    www.turnfast.com "Handling" article. Very tchnical, good read.
     
  6. Korsch_RS
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    Korsch_RS New Member

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    You should add that the most important thing to handling is learning to drive.
    If you haven't attended a driving/racing school, I don't believe you can drive well until you have gone.

    I have attended one Skip Barber school, and I still suck behind the wheel, but that one driving school was worth 10x more than all of my suspension upgrades combined.
     

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