I thought I would start a thread for the guys getting ready to lower. Hopefully there will be many additions to the

"IDIOTS GUIDE TO LOWERING THIRD GEN'S"

I have lately been reading about the LCA re-locating piece........I am curious just how these work, where they attach, and who sells them. I am sure others will also be glad to know. How much traction do I stand to gain with these?

Here is a list of what I know you should do when you lower.

Get some good shocks and struts while you are at it, they make a huge difference in handling too.

Adjustable Panhard bar.

Remember it will be necessary to have alignment done, you will be changing the ride height.

Sounds like a good idea to add these LCA re-location devices, should look into these if you are planning on retaining optimum traction.

Please add any problems you might encounter when lowering your car, or tips you used to your advantage in the process or afterward.

 

Well the reasoning behind the relocation brackets is to try help bring the cars geometry back to spec. When you change the ride height you are changing the cars geometry (which also includes the front alignment like you mentioned) and this affects the cars handling/traction characteristics. The relocation brackets modify the mounting point to level the LCA's back out after lowering the car. I'm not really sure how much it would help, all depends on how much the car is lowered versus the corrected angle. I would say if its lower than 2" its probably a good idea to consider. But always remember that you can lower the car first and address the issue of wheelhop after the fact (if you even have wheelhop). Dont let those brackets affect your choice as far as ride height.

 

Do it right the first time. DONT CUT YOUR SPRINGS!!!! I did and it has been working for right now but i know im gonna have to get actual lowering springs soon. If im correct the springs lose there spring rate after doing this????

 

No, if you want to do it right don't heat your springs. Cutting them is okay, just keep the spring cool with a water soaked rag.

 

Actually, cutting springs will INCREASE the spring rate. By making the spring effectively shorter, you shorten the overall length of the spring and since the coil rate stays the same, it's effectively stiffer.

I know this isn't exactly correct but let's approach it this way:

600 lbs/24 inches= 25 lbs/in

600 lbs/22 inches= 27.27 lbs/in


See what I mean? Maybe some real engineer can explain it right but that's basically the concept.


Ed

 

Thanks for clearing that up fo me Ed. :hail: I've gotten mixed reviews on this suject. When i lowered my car back in like feb. a few people were like WTF are you doing! After lowering it, the ride was 10 times better!
If there is gonna be a book called "IDIOTS GUIDE TO LOWERING THIRD GEN'S" then maybe my face should be on the cover!!

 

You really only need

An Adjustable panhard rod
LCA relocation brackets.
Front end allignment


You can get away without thse two but your rear will not be centered and you will most likely have wheel hop. Shocks and struts are not necessary but you will destroy your stockers after awhile. I went about a year on my stockers until they peaced out.

 

My Iroc has the Pro Kit on it and I don't have LCA Relo brackets and no wheel hop. I don't race the car at all and if you do, definitely install the relo brackets. For a street car, the brackets are not a must-do mod. I have a set and will install them when I go to a 3.27 rear in the near future.

Ed

 

to really do it and correct all the geometry, you would need an adjustable torque arm, to correct the pinion angle. Also, the way the front roll center takes a dive when you lower a thirdgen, a PHB relocation kit would be a good thing to do. That doesn't even touch the a-arm angle, and camber curve up front, or the front roll height, tie-rod geometry, etc.

you can get out of control trying to re-do everything after lowering. People take some of these things to extremes, and are not really 'needed' I would guess there is enough variance in PHB lenghts from the factory, coupled with the extremely long PHB on our cars, to guess that lowering will actualy center some rears better, some will be worse, etc. with the lenght of our PHB, and 1" drop yeilds a very small amount of lateral movement. Also remeber, that with the relocation brackets, if you get the LCA angle to extreme (say droping the mount 2", lowering the car 1") you get roll oversteer. There are SO many things that each of these diffrent points effect, what you really need to do, is look at how all those changes interact with each other. And look at the uses of the car. I would bet that for most people who are just looking to lower the car, it is for looks, and they never drive the car hard enough to notice a 1/16" diffrence in the rear lateral location.

Anyway, its a slow day here at work, but I will stop rambling. I just wanted to point out, that there are MANY things that do change when you lower, but some of them are not as major as people think, and they make a big deal about them, and other major changes that people overlook.

 

A-Arm angle change alone will change roll center height dramatically, increase bumpsteer with overall suspension travel ranges if travel is not decrease dramatically. The parallel length of the arm shrotens from swing causing increasing toe-out of the wheels when the wheel travels upward from a bump. You do gain better neg camber angles though. If you lower a car, spring rates need to be increased and suspension travel limited as a result. That result will produce greater spring frequencies that will cause the NEED for a much higher damper force strut- Hence why I always suggest Koni Yellows for handling at the very least to help control unwanted movement of the high frequency springs.

Lower a car with only a slight increase in spring rate and a slight increase in strut force and the car will ride comfortable but will wander all over when road imperfections are hit. I choose control over comfort. If you want comfort, stay at stock ride height or be prepared to invest alot of money to lower the car properly any and every adj provisions to help "try" and minimise the effects from the geometry change from stock.

 

Every single peramiter of the suspension should have a force angle parallel to the direction of that force at AVERAGE suspension travel height. "Average" meaning: the angles if suject to a range of travel above and below that parallel force should be adjusted to where the midpoint is parallel in the travel range- most often favoring standard ride height.

I'll give an example;

Lets say a rear LCA rear mount point has a maximum used travel of 5" (Max meaning thats as far as it will go under the harshest bump) but the average range may be 4" that is incountered in 99% everyday use. I would then set the outer mount point aprox 1 1/2" down form parallel at stagnant ride height so the average upswing is 2 1/2" above parallel and 3 1/2" max up.

Why 1 1/2" down and 2 1/2" up- thats not even? In fact it is in most cases indeed an aprox even because the LCA will also drop out at times to 2 1/2" down when that tire incounters a dip, and rarely go to 3 1/2" down in a max travel condition.


Now these are netral setting and a good starting point for all suspension adjustments. At this point, any single or combination of angles can be altered to help the front of back (or even one side) of the car to balance better for handling characteristics.

But you need every adjustent availiable to you when you buy aftrmarket suspension parts.

 

Very good post for questions about LCA relocation.........

https://www.thirdgen.org/techbb2/sho...arm+relocation

 

This is going exactly as planned. I am glad to see so many replies. I was thinking that the reason for LCA relo's wasn't for wheel hop as much as it is to keep the angles correct for better force direction......like adjusting your four link on a real 4 link setup. Can anybody confirm or deny this????
Thanks guys, I think this will really help when somebody is getting ready to lower their car.

 

You have confirmation That is correct. The more you angle the LCA for traction on acceleration, the more you unload ( or chance of wheelhop) on braking

 

That is not correct. Assuming you don't heat the coil when you cut it, the spring rate stays the same. For example:

Lets say you have a spring with 300lbs/in spring rate.
Lets say the weight of the car is 3500 lbs, with a 55/45 weight distribution (55% on front wheels, 45% on back wheels).
That results in 1925 lbs of weight on the front wheels.

Now, figuring 2 springs with the aforementioned spring rate, the effective rate for the pair is doubled (600 lbs/in).

Take 1925 lbs divided by 600 (spring rate). When the car is parked, the weight of the car compresses the spring 3.2 inches.

Whether the spring is 24, 22, or 20 inches does not affect the spring rate, but it will affect the final ride height.

Your assessment may have been based in the observation that "sport" or other stiffer springs are often times shorter. This is because a stiffer spring does not have to be compressed as far to support the chassis weight. In effect, if the stiffer springs were the same height as stock springs, when installed in the car, the car would ride higher.

EDIT: disregard my blathering...i erred in my math and figured this incorrectly

 

I had springs installed and my car and nothing else. I don't race, I don't fly around corners...I just got them for looks...and that's the only purpose for mine. So...I really have no need to buy all the extra's...even though I will be changing my shocks/struts next summer probably

 

Cutting the springs does increase the rate. A larger force is required to deflect a shorter spring than a long one, and hence the more this spring is deflected, the stiffer it becomes. The basic relationship for spring constants is k=F/y where F is the force, and y is the deflection of the spring due to the force. F stays constant and as y gets smaller k gets bigger.

 

nevermind...i was mistaken

 

my apologies...I dug out the ole physics book and reworked my calculations, and you are in fact correct. If my math is correct, the spring rate should increase in proportion to the original uncompressed length relative to the newly shortened uncompressed length. e.g. a spring cut in half would be twice as stiff.

 

You got it man Old text books are a great tool

 

It just seemed counterintuitive until I thought deep enough into it.

Old textbooks are cool, but old service manuals are cooler

Unfortunately, my text books are just barely old enough that I'll have to buy new ones when I go back to school

 

i have a question for u wizards..
Im planning on getting the Eibach Pro-Kit (1" lower stance than stock). I plan on getting the adjustable panhardrod, adjustable torque arm, and new shocks and struts(do they have to be adjustable or will stock replacement work fine? I know nothing about lowering as u can see) but since i am only going down an inch, is it necessary to replace all the mounting hardware with adjustable pieces? I dont road race, i will just be going to the track a couple of times a year and then it will be a street machine otherwise. If it matters, im gonna have 3.73's out back by spring.
If not all of the adjustable pieces are necessary, but some are, could u please tell me what i should get?

Thanx for the info and the help!

Rabbitt