99 suspension mods
Record Breaker
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RE: 99 suspension mods
Yup. Sounded like a good idea at the time. The thought was to make for a better launch at the dragstrip. But on an autocross course or even spirited driving on the street, you can really feel the difference between front and back. Stick with one or the other - Highs for family car, X-Highs for personal fun car. People have used the High rates on stock based struts (KYB GR-2's) and seem to like them, but they don't really autocross or push their car all that hard... Koni's are definitely required if you want the struts to last with X-Highs, and I'd recommend them for the Highs as well.
Best of luck!
Best of luck!
Record Breaker
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RE: 99 suspension mods
Way, way back in the day, folks used to put the Eiback Pro's on the Koni struts. Then the Mopar springs came out... Eibachs are a progressive rate spring and shorter than the Mopars. So:
- the strut bottoms out more often because it is shorter (reduced strut life)
- the starting rate is softer than stock springs, and finishes just below High Rates, so:
--- they do not perform as well as High Rates (more body roll)
--- they are overdamped for 90% of their travel, making the ride bouncy
--- mismatched struts and springs make for shorter strut life.
In short, no one makes struts for the Eibachs. You put them on whatever you want, and replace them when they blow. Both KYB and Koni have lifetime warranties, but using the Eibach Sportlines will void that warranty (too much drop) for both.
So, you're planning on mixing and matching Eibach's and High Rates? Which ones in front/back, and why?
Off the starting line, the weight is going to be transferred from front to back. That takes weight off the front wheels (drive wheels for us). Traction is determined by weight (above the wheel) and friction (between the wheel and the road). So it should be obvious to keep as much weight as possible over the front wheels, since we can't change the amount of friction with springs...
Spring rates don't affect the amount of weight transferred, they control how the car responds to the weight transfer. If two identical cars (with the exception of springs) launch the same, the one with the softer springs will have more squat in back and more lift in front, but the amount of weight transfered is identical, and the amount of traction available is identical. Having less squat/lift means less deflection in the suspension, so less effect on toe, camber and caster (to some degree). So stiff springs are important, but they aren't going to do anything for traction.
A lower center of gravity will reduce the amount of weight transferred. 1.5" (Mopar) is a decent amount. The 1.75-2" or so from the Eibach Pro's isn't all that much more, and they don't have the stiffness to reduce squat/lift. The Eibach Sports have plenty of drop, but they are too short for any strut (and also not very stiff)... Then there are the true coilover setups, which are ideal. You can get 3-4" of drop all around, so less weight transfer, so maximum traction (for that tire/surface); and you get tons of stiffness, so less effect on suspension geometry.
- the strut bottoms out more often because it is shorter (reduced strut life)
- the starting rate is softer than stock springs, and finishes just below High Rates, so:
--- they do not perform as well as High Rates (more body roll)
--- they are overdamped for 90% of their travel, making the ride bouncy
--- mismatched struts and springs make for shorter strut life.
In short, no one makes struts for the Eibachs. You put them on whatever you want, and replace them when they blow. Both KYB and Koni have lifetime warranties, but using the Eibach Sportlines will void that warranty (too much drop) for both.
So, you're planning on mixing and matching Eibach's and High Rates? Which ones in front/back, and why?
Off the starting line, the weight is going to be transferred from front to back. That takes weight off the front wheels (drive wheels for us). Traction is determined by weight (above the wheel) and friction (between the wheel and the road). So it should be obvious to keep as much weight as possible over the front wheels, since we can't change the amount of friction with springs...
Spring rates don't affect the amount of weight transferred, they control how the car responds to the weight transfer. If two identical cars (with the exception of springs) launch the same, the one with the softer springs will have more squat in back and more lift in front, but the amount of weight transfered is identical, and the amount of traction available is identical. Having less squat/lift means less deflection in the suspension, so less effect on toe, camber and caster (to some degree). So stiff springs are important, but they aren't going to do anything for traction.
A lower center of gravity will reduce the amount of weight transferred. 1.5" (Mopar) is a decent amount. The 1.75-2" or so from the Eibach Pro's isn't all that much more, and they don't have the stiffness to reduce squat/lift. The Eibach Sports have plenty of drop, but they are too short for any strut (and also not very stiff)... Then there are the true coilover setups, which are ideal. You can get 3-4" of drop all around, so less weight transfer, so maximum traction (for that tire/surface); and you get tons of stiffness, so less effect on suspension geometry.
Record Breaker
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RE: 99 suspension mods
Absolutely not. That was one of the more expensive mistakes I've already had the pleasure of making for you... The ride and performance was worse than stock. If you don't have the money, leave the suspension alone...
There's a really cheap option out there, by the way (no kidding), if you're just looking to lower the car. Parts stores sell "spring helpers" for about $15 a set (you'll need 2 sets). You'll have to pull the strut assemblies off and use a spring compressor (rent for free at Autozone) so you can join 2 coils together(2 helpers per spring placed opposite each other), which is good for a 1-2" drop, depending on placement. While you're in there looking, make damn sure the bump stops are still there, and replace them if they aren't (you'll need to take the spring off for this). Because with 2" of lowering with no bump stop, it's going to hurt your butt almost as much as the strut on hard bumps. If you can get the "inverted christmas tree" style (meant for the ACR fronts), even better.
There's a really cheap option out there, by the way (no kidding), if you're just looking to lower the car. Parts stores sell "spring helpers" for about $15 a set (you'll need 2 sets). You'll have to pull the strut assemblies off and use a spring compressor (rent for free at Autozone) so you can join 2 coils together(2 helpers per spring placed opposite each other), which is good for a 1-2" drop, depending on placement. While you're in there looking, make damn sure the bump stops are still there, and replace them if they aren't (you'll need to take the spring off for this). Because with 2" of lowering with no bump stop, it's going to hurt your butt almost as much as the strut on hard bumps. If you can get the "inverted christmas tree" style (meant for the ACR fronts), even better.
