Ok so my car is lowered with Sportlines and it does have larger rear tires 275/40/17's. I do not appear to have any handling problems or noticable rear side to side movement when driving, nor do the rear tires rub.

I have just installed a Hotchkis non-adjustable panhard rod and it seems to be just a touch more stable during cornering, but nothing to write home about. Is an adjustable one really nessessary? How about lower control arm relocation brackets? I intend to upgrade to aftermarket LCA's eventually.. are the relocations worth it?

I'm a weekend warrior, never seen a strip nor have I been autocrossing.. probably never will. I just hit'er hard and carve the twisty mountain roads and the occassional stoplight drag.

 

no... every one says yes but if you know anyhting about trigonometry you realize that how long the panhard bar is and how little the angle changes from lowering the car 1.5- 2 inches you can realize that it is not really needed.

 

Maybe not with the panhard bar but with the new control arms and relo brackets, yes! Seeing in how you lowered the car, the stock arms will flat'n out and once you hit the go pedal and the weight is transfered to the rear, the lca's will flatten even more giving you nasty wheel hop as there is nothing holding the wheels to the ground. I too have sportlines and ordered myself some BMR control arms with the relo brackets. It's a must on a lowered car that wants to perform. Some guys with stock ride heights do this as well, as it does help them out.

 

umm...when i droped my car with pro-kit i droped an inch in the front and about a half-inch in the back. The rear of my car also shifted a good 2-3 inches to the right...adjusted the spohn panhard i just installed and i fixed it. So it DOES move a noticeable amount. It looked stupid as hell i had to walk around the car like 2 times and kept saying something doesnt look right, sure enough looked at it from the back a lot more tire was sticking out on the driver side. Like i said the car droped about a half inch in the back i have no idea what it would do if it droped an inch+. Ill find out because im not keeping the rake i currently have with the pro-kit.

 

ok well at the moment i'm sitting on stock rims and tires and it looks damn near dead even side to side from the rear.. if anything its less then 1/4" more to the drivers side.

I'll check it again when I get the aftermarket rims and wider tires back on. Thanks for the replies.

 

You want the lower control arms to be parallel to the ground, so if they are pointing up towards the rear, then you want to get the relocation brackets. As for the panhard rod, if your rear tires aren't rubbing the fenders and it isn't off center more than 1/2-3/4" then you don't need an adjustable panhard.

 

U want the rear end centered underneath of the car period. (I will admit due to drastic build quality differences in thirdgens some are centered when lowered still and others are not.) Any yes a 1 inch drop will move it over on some cars, mine did noticeabley.

U also want the LCA angle to be correct period.

Just these two changes after the other suspension work and lowering made another large difference in the feel of the car and hookup from a stop.

later
Jeremy

 

If' you're lowered, the lca relocates are a must, lca's themselves are worth it, lowered or not. - As for the adj. panhard...if the rears not way outta whack, seat of the pants wise you won't feel a difference. - Do you have subframe connectors? If not, theres another thing you should do. These cars twist enough under normal use, none the less any performance launches/twisties.

Also, you don' t necessarily want the lca's parrallel to the ground. That is usually the best starting place, but not always the best angle. Ride height, torque arm mount point/height, torque arm length, hp, auto/manual trans, etc... all change your ideal lca angle. Draw an imaginary line straight forward from the lca and from the tq arm. Wherever those lines intersect is the point at which you're trying to "lift" the car on launch. No car is the same.

 

On the PHB adjustability is a side effect of the best PHB options. Rod ends are better for keeping the rear end in place during cornering. Believe it or not poly does deflect a fair amount.

 

Yeah, he wants it to launch well from a stoplight, but handle mountain roads well also. So in that case, for the best handling you want the lca's parallel to the ground or maybe slightly lower in the rear so that when you apply power and the rear squats the lca's will then be at a good position for handling. Set up like this with the rear of the lca slightly lower than the front will help with straight line launching also.

 

I say it depends on the ride height, that setting will determine the geometry of the suspension. You can tell by measuring your car as it sits right now. You can also tell when you get an alignment on one of those computerized racks. Is the rearend centered? Are the rear wheels centered? Are the geometry angles on the computerized rack the same? etc, etc. You dont always need adjustable parts, but in some scenarios you might want it.

 

For every action there is an oppsite and equal reaction! Remember this, it is very important! Now let's look at some basic concepts.

(1) Tires their maximum forward (acceleration) and side (g or corner) bite just before loss of traction. Note- stopping is a different situation as you will see later

(2) The more weight on a tire, the more bite it has up to loss of traction.

(3) The weight of a vehicle is constant at a given time, therefore the suspension controls the transfer of weight from front to back and/or side to side.

(4) Springs store energy in the form of weight. This stored energy can be measured by the spring rate (pounds per inch of compression). For our purposes we will use coil springs as our example. Add weight and they compress, reduce weight and they expand. Important- they do this equally in each direction. This is because the weight is stored equally through the spring.

(5) The tires see this transfer of weight as added or reduced bite

(6) When a spring compresses, the tire looses traction- Whoa- How did we get to this statement? As a spring compresses it stores energy, its length shrinks, its not pushing down on the tire. Wow what a concept- I don't want the back end of my car squatting when I accelerate! I want the front to come up and the back to raise up too. but is this possible?

(7) YES- It is controlled by the spring rates and the geometry of the suspension. The geometry of the suspension is controlled by the mounting points of the suspension. On third gen vehicles the stock rear suspension mounting points are not conducive to efficient weight transfer. an earlier reply mentions drawing lines to show where the suspension mounting points form an angle where they meet. The meeting point is called an "instant center".

(8) Instant centers indicate where a certain force is being applied. As this point sometimes falls outside of the vehicle or in ineffective part of the vehicle, the force applied is sometimes detrimental to the vehicle's handling. At this point this subject begins to get a lot more complicated so I'll stop after I kill a couple of common misconceptions.

(9) A shock's only function is to control the rate of gain or loss of energy by the spring. It does not change spring rates or effect ride height (unless you bottem it out and then its toast).

(10) Everything I said for acceleration and cornering bite is just the oppsite for braking. The less weight on a tire the better the stopping power of the tire until wheel lockup. Therefore you want the whole car to squat when you let off and hit the brakes.

Yes you need an adjustable panhard bar and adjustable lower control arms if you intend to take advantage of the best handling you car has to offer by changing mounting points.

 

...and that sums it up.
- great info too -

 

wow, thanks for all the great info guys.

 

I never looked at it like that. When a spring compresses the tire loses traction so that is why a stiffer spring is helpful. While it is not expanding it is not compressing as much either.

 

....and then you see drag cars using V6 springs (not as stiff) to get better ET's...

I'm not arguing, what you say makes sense in principal, but in reality it seems the opposite is true, a car that squats more puts more weight on the rear tires, and gets a better 60' time.

 

i know it... you olny lowerd the rear a 1/2 inch? there is no possible way that it moved 2-3 inches... the way it moves sideways is a small fraction of how far you lowered the car....

 

Lesson #2 - Remember - For every action there is a oppsite and equal reaction

Drag Racing- Front to rear weight transfer is GOOD- up to the point of the front wheels lifting off the track- then forward motion is reduced as the car climbs the ring gear - Squat is BAD - weight that is transfering to the rear is being stored in the rear springs as the springs compress - unless you don't have enough forward tire bite to take advantage of having 99.9% of the car's weight on the rear tires.

(1) The amout of weight that can be transfered from front to rear is determined by the spring rates and the mechanical leverage that the rear suspension applies to the car.

(2) Third gen cars have a built in leverage in the form of the torque arm and the lower control arms. Unfortunately the average 3G has built in problems, the rear mounting point of the LCA is usually higher than the front mounting point in relation to the ground and lowering the car makes the situation worse. The instant center for this combination falls behind the vehicle. This does nothing to help transfer weight. (BUT it does help squat if you need it )

(3) Now we will get into some theory- Theory is always right when 100% of all parameters are met! Let's not get into the complications that can result from deviating from theory

(4) Every car has a center of gravity (CG), at which it is perfectly balanced front to rear (acceleration) and side to side (cornering).

(5) When the vehicle moves the CG moves- This movement effects the handling of the vehicle. In drag racing the ideal movement is upward and rearward. Upward allows both the front and rear springs to unload energy. Rearward places more weight on the rear tires.

(6) By lowering the rear LCA mounting point the instant center can be moved to the front mounting point of the torque arm which is fairly close to the car's CG. This makes the rear suspension pivot on its IC. This creates both front and rear suspension lift.

(7) The amount of lift is determined by the spring rates and spring length.

(8) The rate of lift is determined by the shock rates for rebound in the front and rear (90/10 and 50/50 being common front and rear compression and rebound rates for drag racing)

 

Awesome info!