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So, We've been having a little discussion over on CubRSX regarding Lower control arm angles and such, and I figured the guys and gals interested in making their car handle better would benifit from that discussion.


1st things 1st... There is VERY much a thing as too low of a ride height, especially when it comes to cars equiped with MacPherson struts, For two main reasons.

1. Suspension travel. This is a problem on MacPherson strut suspensions, as there isnt much suspension travel to begin with. Why is it so important? Well, if you happen to bottom out your suspension mid turn (front or rear) then not only are you risking damaging your suspension, but which ever end does bottom out will momentairly have what could be considered an Infinint spring rate on that end of the car... Meaning, Bottom out the front and the car will instantly understeer, bottom out the rear and the car will instantly oversteer. On this car bottoming out the front is much more probable then bottoming out the rear. There are a couple ways to deal with this lack of suspension travle. one would be to simply not lower the car too much, or you could shorten the length of the struts you are using ala Koni modification, you could buy a "coilover" that allows for adjusting ride height and suspension travel seperatly or you could simply increase the spring rates and or anti-roll bar effectiveness on that end of the car (which brings its own set of pros and cons).

2. Camber Gain (or loss). Its been said many times on this board..."The front doesnt need a camber kit"... as you lower the car, because a MacPerson strut doenst gain negitive camber as you compress it... Well this isnt true. As a MacPherson strut compresses it gains negitive camber as long as the angle between the Strut and the Lower control arm is Less then 90 Deg. Go past that point, where the angle between the strut and the LCA is greater then 90 Deg, and the strut begins to gain Positive camber. This is why those people who have really "slamed" their cars say that the front struts dont need camber adjusters. Because they have passed that point where the strut gains negitive camber and gone in to where the strut Loses negitive camber. Why is this important?... :P Well, Simply put, Gaining negitive camber as the suspension compressis is a very good thing when it comes to handling (helps to keep the tires contact patch flat on the road). Gaining Positive camber as the suspension compressis is VERY bad for handling. So, for this suspension the Best ride height would be the one where at Full compression in a turn (where all the weight thats going to transfer has) the angle between the Strut and the LCA is at 90 Deg or slightly less then 90 Deg. How high that is depends on your spring rates and anti-roll bar effectiveness... but remember that increasing spring rates decrease mechanical grip, and increasing the effectiveness of your anti-roll bars decreases the amount of grip that end of the car can make...


So, watch your control arm angles when tuning for handling.

 
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Finally. Thank you for posting this.
If you think lowering your car will make it handle better because you have a lower center of gravity, think again. Lowing the CG of your car 3" will NOT have a noticable difference on the handling of the car. However, with stiffer springs (all lowering springs are stiffer than stock) - your car will have less body roll, giving the perception that it is handling better.

The idea of your cars suspension is to absorb impact energy from stuff you are driving on. To maximise car control and ultimate grip, the wheels would be on the ground all the time. If your car is lowered severly, and you have limited uptravel (say you have 1" of wheel travel before you hit bump stop), then if you hit any object larger than one inch, that wheel will leaver the ground momentarily, loosing traction. Your car has more body roll than you think, so that 1" is also trying to cope with your body roll, meaning high grip corner = NO available wheel travel.

As above, the front suspension is a macphersion strut, which is an easy, reliable system. Most (if not all) rally cars use struts because you get large wheel travel numbers in a small package. On stock struts, our civics are capable of approximatley 8" of front wheel travel.

The rear is the killer. With short upper arms, there are radical camber changes going on, and the wheel travel is ultimatley limited. Because of this, most people will complain about civics pushing (understeer) even with exotic shocks/springs. Reason being, you gain rear camber with wheel travel way more than the front gains camber.

Say you have 1deg camber front and rear at ride height(car on level ground). Going around a corner at speed, just the body roll (assuming perfectly flat track) will mean that your loaded tires (outside) now have way different camber numbers. Just as an example, it would probably be around 3deg negative rear, and around 1-1.5deg neg front. Meaning? - rear tires have flat contact patch w/ road surface, fronts are rolling over. So, front has less traction = understeer.

Sorry - I had to rant. If you want a summary, best way to get your civic to handle well is keep it close to stock height, set rear camber at 0 ride height, front at 1-2deg negative at ride height. Best mod I ever did was raise my car.

 
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The above post was not directed at anyone (especially Zzyzx) - just informational. By the way, did you get your handle (Zzyzx) from the old school mountain bike fork?