Ride Height Vs. I/C

[Avenger1]

Need suspension help.

During the winter I installed another set of rear coilovers on my car. Everything was torn down...no motor, trans etc. Ofourse I did not record the original height. My question is if the ride height is different from the shocks i removed, will i need to re-scale the car again. How much does ride height affect the suspension reaction? If i wanted to lower the cars ride height, is that a mistake without rescaling.
the car has been handling like a dream...straight and hooks hard. I don't want to ruin that.

Thanks in advance

[Avenger1]

Any advice appreciated.

[s14slideways]

You wanna try not to lower it too much. Just research the factory ride height on the internet for your vehicle and measure the height its at now. That'll tell you how much your car has dropped. As for the whole performance thing goes, if you're looking for great handling, I don't think it really matters how low it's sitter if you have all your other components squared away (sway bar, front strut bar, rear strut bar, etc). They help out a lot on the track. If you're looking for a drift set-up, don't go too low. Auto-cross would be the same.

[s14slideways]

oh yeah..i would rescale with any suspension upgrade

forgot to add that in there lol

[Ed-vancedEngines]

anything that you do which changes the ht of suspension torque transfering mounting points in relation to the ground will raise or lower the IC.

Examples are, speaking of drag racing suspensions;
ladder bar or 4 link, if you put a larger or smaller diamter tire on it, the IC will change either up or down accordingly. Same thing applies if keeping the same tire diamters but you change ride ht. The IC will be changed too.

Ed

[Ed-vancedEngines]

Added to this.

any thing that results in changing ride ht. with same tire size will also be changing the bar angles, which will be changing the IC too.

Ed

[Bubstr]

Raising or lowering ride height will change several things, Intant center lines, cenrer of gravity height and roll centers. The good part of this is, when you linkage mounts raise to change intant center, you cener of gravity hieght raises also, The relationship of Instant center and center of gravity is what makes or breaks a good handeling car, but ride hieght changes the relationship slower, because both are moving in the same direction, just at a different rate. It may not be off as far as you think. Ride heigth can be a good tool to fine tune to that suspention sweet spot, because it changes the relationship at a slower curve that moving linkage points. If you know what weight differental you want in the rear, I would scale it to get that back.

[Ed-vancedEngines]

Bubster,
You are 1000% correct. I learned that little fine tuning trick way back in 1983 from Warren. I was with him during a race when I heard him to tell a crew member to drop the rear ride ht by 1/2 inch about a little problem they were having. Later I asked him why. He shared with me that it was a way to do a small fine tune that was much more precise than changing a bar adjustment or even a shock adjustment would have been. Blew my mind. I asked him about it affecting the high speed handling and he told me "not enough to make a difference that I have seen". That also surprised me.

Ed

[Avenger1]

This is somewhat the way I was thinking. The ride height shouldn't make the car drive too crazy unless I went to the other end of the spectrum. I don't think i'm off terribly, but definently not at the same height I was before. My thoughts were to try the car, look cloosely at 60 ft. and handling and tune the height from there. Ofcourse I don't want to to see any wall action.

I knew it would change the IC & COG but wasn't sure how much.
Thanks for the help and I appreciate any other advice also.

[Maximum Race Engines]

You don't want the "rake" in the suspension. However some cars do have higher ride ehights than others, but as long as you make the car as level as possible, the suspension has the ability to work better. If it has too much rake, ie: jacked up to the moon in the back, the car has way too much to overcome to get the weight transfer needed. As pointed out, ANYTIME you make an adjustment to the ride height, all the geometry gets changed. I have seen too many guys looking for traction, and throw these huge tires on thinking it will work, and then the car hooks but goes much slower, because he just changed the entire suspension geometry. Just because a car hooks, does NOT mean it is working. There IS a difference.

Ed-
We have been doing that trick for many years and still do. Once the bars are where they need to be as well as pinion angle and instant center and center of gravity, just by raising that coilover a hole or lowering it a hole is a smaller adjustment than actually lowering/raising the bars, and often does the trick for a fine adjustment. Some cars we have dealt with were built so long ago, that the 4-links or ladder bars were put in too low or at the wrong angle, and it takes alot just to get them close to hitting the tire, and have found adjusting the ride height has a complete effect on helping the suspension, so I would say yes it is important.