Suspension Theory/Chat Thread

[Sirbelch]

have fun

[Highrev1]

Thought I would bring this back up top and start a new discussion...

We are going to discuss why lowering a car acutally increases body roll...and can allow for worse camber curves than stock... Why does the body roll more? Well you are lowering the Center of gravity, but also to roll center. You in theory want to be reducing how much weight gets transfered to the outside tires. Rember the most traction your car can make is when it is sitting in a flat parking spot. As weight is added to a tire traction is increased at a decelerating rate. The more you can balance that weight between tires the more traction can be made.
What you are in effect doing when you lower the car is acutally lengthing the distance between the Center of gravity and the roll center on the car.

So unless you compensate for that with stiffer springs your car will have more body roll. Also if you go too low, under compression you can acutally go into a positve camber situation Bad for a MacStrut Car.Stolen from here

We will work on figuring out wheel rates for our cars next

[LucasBlack]

so then the lowering springs offered, which in general up the spring rates (to some degree), sorta/kinda/maybe begin compensating the lengthened CG/roll center distance?
..along with attempting to help the car from bottoming out...

[Highrev1]

Originally Posted by LucasBlack

so then the lowering springs offered, which in general up the spring rates (to some degree), sorta/kinda/maybe begin compensating the lengthened CG/roll center distance?
..along with attempting to help the car from bottoming out...

Any of the ones that are more than say 1.5" are probably worse for handling. For example, Most don't up the rates enough to acutally compensate for the distance, nor do any really attempt to compensate for bottoming out. Anyone on here run aftermarket dampers? No so they are changing the stroke range of the stock dampers limiting travel allowing for easier bottoming out.

[Sirbelch]

Thanks to Revy, I now have one more point to add to my "its too low" statements. Roll center has got to be one of the biggest influances on handling. In a more general statement, Suspension Geomerty is the biggest. You could spend a billion dollars on suspension parts and it won't do shi@ for you if the suspension geromerty sucks.

Do you all see anyone but us in this thread? We need to get more word out.

[Highrev1]

LOL...THey dont care But you dont really change the geometry when you lower it...kinda.

[Highrev1]

"It's just that we have moved our static condition to a different point on the original factory bump steer and camber gain curves. We may not longer be on the "optimum" point on the curves therefore. This is an often misunderstood distinction."

[Highrev1]

.....

[LucasBlack]

Originally Posted by Sirbelch

Do you all see anyone but us in this thread? We need to get more word out.

...or do we need to get OUT more...?

[LucasBlack]

Originally Posted by Highrev1

LOL...THey dont care

haha, ain't THAT the truth!

[LucasBlack]

Originally Posted by Highrev1

Any of the ones that are more than say 1.5" are probably worse for handling. For example, Most don't up the rates enough to acutally compensate for the distance, nor do any really attempt to compensate for bottoming out. Anyone on here run aftermarket dampers? No so they are changing the stroke range of the stock dampers limiting travel allowing for easier bottoming out.

indeed and amen to all that.
as far as springs offered, i think i generally favored(*read that word loosely for i am not condoning just spring swaps) the progress springs. i think they claim just over an inch drop and their rates seemed to be one of the more uprated ones of the bunch as well as being linear instead of progressive....that's right...progress makes non-progressive rate springs. do you wonder if they thought about that when deciding on what type of springs they were going to manufacture? purposely being paradoxical?

[aki]

Increased body roll from lowering can be compensated for in a couple ways. You could also put on anti-sway bars to balance out the body roll. Stiffer dampening reduces weight transfer. As for camber, that is why you can have more negative camber and still come out with relatively even tire wear.

As for stroke range, that is why you're advised to chop some of the bumpstop off, which gives you a stroke that's pretty close to stock.

[midnightex]

WOW... I just read the whole thread and I feel like my IQ has dropped (not meant as an insult, I was speaking comparatively).

You guys really know your stuff.

So here's my question:

What would make the progress springs' linear rate be more beneficial than a progressive rate spring like the ones in an Eibach Pro-kit?

[aki]

Originally Posted by midnightex

What would make the progress springs' linear rate be more beneficial than a progressive rate spring like the ones in an Eibach Pro-kit?

I'm personally a fan of progressive-rate springs. If it's good enough for a stock C6 vette it's good enough for me. Heck, the older Integra Type R used progressive, so I don't think progressive is "bad." A linear spring is beneficial in that it's more predictable under quick weight transfer. On a progressive spring, if the switchover from the soft rate to spring rate is abrupt, it can be jarring, leading to slower laps. Since this is my daily driver I value ride quality, hence I prefer progressive. I have Eibach pro's sitting in my closet, planning on putting em on in a month or two.

[midnightex]

So it's basically the same as with most suspension mods. The linear rate springs offer the predictability to drive the car to known limits with more confidence since there's no switch-over.

Are you planning on isntalling any other suspension mods to go with the Pro-kit?

I put a Pro-kit on my '01 Civic with upgraded tires and nothing else. About a year later my car bounced so much that I would make people buy tickets to ride in it.

I really like the idea of the whole Pro System that Eibach has but I don't know if it would be overkill or not. Plus I don't think they have an application for our cars yet, but I'm a patient man.

[aki]

I'm getting camber kit front and rear (and increase the front camber a fair amount). After that I'm not sure. When the dampers eventually go I'd want to replace em with Koni yellows, but that's way in the future. Plan on keeping this car for awhile, so takin' my sweet time w/ mods =)

[blue1]

Originally Posted by Highrev1

Any of the ones that are more than say 1.5" are probably worse for handling. For example, Most don't up the rates enough to acutally compensate for the distance, nor do any really attempt to compensate for bottoming out. Anyone on here run aftermarket dampers? No so they are changing the stroke range of the stock dampers limiting travel allowing for easier bottoming out.

Greg...Have you seen the Buddy Club Race Spec Dampers? I helped a guy install a set of these and they seem promising (although a bit expensive). The rears have sleeves for the spring and another sleeve on the damper itself.

[Sirbelch]

Originally Posted by blueroadster

Greg...Have you seen the Buddy Club Race Spec Dampers? I helped a guy install a set of these and they seem promising (although a bit expensive). The rears have sleeves for the spring and another sleeve on the damper itself.

It is going to be a compromise for all people. Those coilovers, as well as any other of the shelf coilovers, are ment to meet the needs of the many, not the needs of the few, or the one, the one. So, they might be good for one person, but suck for another. Having the ability to adjust pre load sparate from ride height really doesn't do any thing. The spring has a liner rate, so no matter how much pre load you put on the spring, it is still going to compress at the same rate. However, the more pre load you put on the spring, the less suspension travel you will have under compression (bump). Also, you have no idea what those 15 levels of adjustment do. Does it increase bump damping, rebound damping, both at once, at what rate does it do those adjustments and where in the shock dyno curve does it change the rates? It would be ok for some street and fun at the track, but, for me, not knowing what its doing does not make it a good choice.

[LucasBlack]

Originally Posted by aki

As for stroke range, that is why you're advised to chop some of the bumpstop off, which gives you a stroke that's pretty close to stock.

the thing with that is that you're still operating in a different range.
your usable extremes of compression/expansion are at different points than stock. with lowering, your shocks are, at idle, under a greater load of compression than they would be, at idle, with stock springs.

[LucasBlack]

Originally Posted by aki

I'm personally a fan of progressive-rate springs. If it's good enough for a stock C6 vette it's good enough for me. Heck, the older Integra Type R used progressive, so I don't think progressive is "bad." A linear spring is beneficial in that it's more predictable under quick weight transfer. On a progressive spring, if the switchover from the soft rate to spring rate is abrupt, it can be jarring, leading to slower laps. Since this is my daily driver I value ride quality, hence I prefer progressive. I have Eibach pro's sitting in my closet, planning on putting em on in a month or two.

refer back to how shocks and springs should be paired accordingly for "best" performance.
example:
linear spring rate - 600lb/in.
progressive spring rate - 240 - 600lb/in.

with the linear rate, you know exactly what to work with at all levels of shock movement.
with the progressive springs, you don't.
- prog. springs are meant to equate softer rates for casual driving, etc. and then higher rates for when you are at the ends of the susp. travel stroke.
overall, valving a shock for prog. springs is more difficult - for at what rate do you valve match? max rate? middle? more near the minimum? either way, there will a point where the shocks are not appropriately valved in comparison to the spring rate being applied.