Night rider327

iTrader: (13)

I know the benifits of aftermarket LCA's and the LCA mounting point lowering brackets, but don't quite understand the idea and point of adjusting the LCA's lenght.

Anybody care to clue me in alittle.

Thanks

91formulaSS

All an adjustable lower control arm is good for is moving the axle fore/aft, that's it. Basically to position your wheel in the wheel well. There are reasons why this is benefitial in dialing in your suspension. There are others on this board that can explain it better than I. Let's hope they chime in.

MrDude_1

honestly?

there isnt one.. they make them because someone will buy them.

vjo90RS8

iTrader: (1)

if i knew then what i know now i would have just bought non adjustables.

vsixtoy

When you really learn how adjustments can benefit an optimum setup on your car, you will be glad you have them.

1) to dail in a 0* thrust angle.
2) to shorten the geometry throw to help induce roll understeer as much as the driveshaft length will allow.
3) to allow for any future ride height adjustment and relocation positioning that will change when a car is later lowered. Without adjustment provisions, you will misalign the springs in the cans and not be able to reposition the axle back forward after the corrected pinion angle rotates it upward and back in the wheelwell.

If you do not have adjustable LCA's then you will not be able to fully utilize relocation brackets and their diferent mount positions to accurately maintain the desired wheelbase will finding the best setting your car needs for handling based on what combined other things it has had modified *or* will have modified in the near future.

Cars are always changing. I will give an example. When I first set everything on this car and ran it ion a skidpad about 1 1/2 years ago, things were new. With those exact same componants, the car is now set differently slightly to maintain that same proformance level as it did when it was new. Things age, wear, soften, harden, and loosen at different rates. Adjustments allow the provision to keep things at the optimum point as the cars attitude changes from fatigue.

91formulaSS

I thought that this was not necessary due to the fact that all the mounting holes on the LCARB (spohn design at least) are located on the arc path of the original mounting hole related to the front mount and swung down.

vsixtoy

That is only true if you weld the relocation brackets in place and then never change the ride height or pinion angle. That is verutally imposible because maost every car changes over time with different springs, diferent shocks (gas charged will raise the risde hieght alittle over a conventional shock- ex. KYB's). It is just cheap insurance to have the provisions if you intend on keeping the car- you never know what the future brings in modifications and needs. If you don't plan on keeping the car for long, then my opinion is you should not even bother wasting your money buying anything like this for it in the first place. In that case, even non-adj LCA/s is a waste of money- You will NOT recoupe your investment if you ever plan on selling the car someday. I NEVER put a dime into a car performance wise if I were to ever plan on selling it- the cars I built I am keeping for life so money is not the issue, having the correct performance options is.

91formulaSS

agreed 100%. BTW. When i do up the rear end this winter I plan on getting LCA's with one rod end for the axle mount to eliminate bind, adjustability is just a side effect.

CaysE

The simple answer:

If you have an adjustable torque arm, you need adjustable LCAs. Otherwise they're not necessary, but can be handy if used to experiment with different suspension setups and parts.

MrDude_1

ok. you said it.

now answer this:

WHY, and what are you adjusting for?

and if you're going to say "to re center the wheel in the wheel well, so it looks right" i might as well save my self the trouble and shoot myself in the head now.

KagA152

iTrader: (5)

you dont just center them so it doesnt look goofy, but if theyre misaligned from each other, the car will dog track. with my spohn ones set right where they came (factory length) my axle was a little bit out of alignment. running a pro kit and spohn adjustable torque arm played a factor is this im assuming, but it was fixed and is straight as an arrow. i made sure to mention spohn, cause i know how much you love his stuff

DJP87Z28

Anything with the word "Adjustable" just means more money for the part. All the Pro for adjustable are from people who would adjust anything that had a nut on it. For the rest, once installed thats it.

vsixtoy

Don't bother with what is being thrown at you right now. You are in fact 100% correct with this statement and I 100% 2nd what you said. Some people will just never have an understanding of mathimatics and how the basis of suspension geometry ties into real math. In alot of cases, they didn't get it in school and they are not going to get it now.

vsixtoy

I will give one final answer in this post and then I am finsihed here with this going nowhere topic.

If you my friend were to replace everything adjustable in MY car with NON-adjustable componants in their place, It my friend would completely through off all the balance I have manipulated into my cars' handling and it would probalby then drive as bad as yours.

If you rode in my car and then got back into yours- you would be awakened to the reality of how well a 3rd gen can truely handle. I will boldly say that statement goes to about 98% of the members here. Most have never experienced what they are missing so they truely can not understand.

You need to realise that by my being here is merely me offering help to others. If you choose not to listen and learn, then so be it. therr are enough that do for me to enjoy coming into this forum to help.

RaGe

I bought the damn non-adjustables... Where were you then Dean?

I'll eventually sell my non adjustables and go to the adjustables when I get an adjustable torque arm. For now I'm happy. Except they seem to bind more (poly both ends).

I'm a hipochondriac though so the binding part may be b/s.

DJP87Z28

A reply from someone who is a "Adjustable Nut" who think nothing is perfect unless it can be adjusted. And who thinks everything isn't right until it can be adjusted. Why , why can't I become a adjustable Nut also??? But I don't care if it can be adjusted.

CaysE

If you're willing to challenge me with the BS smiley, I'm willing to deliver... normally with a touch of smack-down, but I have respect for you, MrDude. So here's the whole scoop, sans attitude:


The whole start of this mess is pinion angle. When you launch your car, you want the driveshaft and pinion gear to be on the same plane (straight). The problem is, when power is applied, the driveshaft and pinion gear are not level with each other, so you have to compensate by setting a pinion angle when the car is at rest. In the pictures below, the "pinion gear" is technically the yoke that connects to it, but it illustrates the angle that the pinion gear is at.


The only way to adjust the pinion angle on our cars is with an adjustable torque arm, like so (the black brackets on the right are LCA relocation brackets, which are bolted or welded to the rear end housing):


Since those relocation brackets are moving about now that we're adjusting the pinion angle, the LCAs aren't going to hold the rear end in the correct position:


So, we compensate with adjustable LCAs:


And here's the result:



Now why would anyone want to adjust the pinion angle, you ask? Because as you upgrade and make more power out of your engine, it takes more of an at-rest pinion angle to make sure the pinion gear and driveshaft are straight when launching. Also, if you have adjustable springs, shocks and/or struts (or air bags, or whatever you use), the strength of the suspension also determines how much pinion angle you need to make sure it is straight when launching. If you turn your Konis or Tokicos all the way up for auto-x, you don't need as much pinion angle, because the stronger suspension is keeping the rear end in place. When you turn them all the way down for street use, you need more pinion angle. Get it?

With as much detail as I went into, this is still pretty simplified, and the pictures above are exaggerated. While an incorrect geometry in the rear won't necessarily throw your passenger rear wheel into the back seat and the driver rear wheel into the rear bumper, there will be indiscrepencies that cause undesireable responses from the car.

KagA152

iTrader: (5)

i smell the begining of a tech article, or atleast a sticky

ME Leigh

Nice work, and nice drawings.

Some people (not me) can't picture things in their head worth a **** (low IQ) and pictures really help them.

vsixtoy

CayeE is somewhat on the right track, but I feel a neded to clarify things a bit better than what he has. This is in relation to lowering the car and maintaining stock geometry angles via relocation bracket adjustments and the availiabilty of an adjustable TQarm. Without an adjustable TQarm you would NOT be able to correct the pinon angle as I describe below nor would you be able to correct the wheelbase of the car without adjustable LCA's, NOR would you be able to correct the LCA angle without relocation brackets. You need adjustable componants to maintain the designed geometry of the car.

note: Purple is the driveshaft. Look at the relation it has to the pinion angle. The stock height shows it at -1* and the finished lowered car thus shows it at -1*.

vsixtoy

Go back to school and try to correct that "F" you recieved in math class. You now can really for once see where your thoughtless minded education can really be applied in the real world if you had paid attention in the first place.

I swear to christ the idiots that come into this board and offer such unfactual information.

Night rider327

iTrader: (13)

Thanks guys!!!. Now I understand what they do and why you would do it.

I'm kinda new to these suspensions. I'm use to the leaf springs of the 60's and 70's, or the coil overs, ladder bars or 4 link suspensions of drag cars

Night rider327

iTrader: (13)

I have 1 more question.

Would an adjustable LCA that has the adjuster in the center be weaker, or flex more than a solid arm or one with the adjuster at the end?

I was looking at Spohn's LCA's and his poly/poly adjustable ones are 'cut' in half with a double male bolt in the center holding them together.

It just looks like too much load would be placed on that bolt, and could bent the bolt on a hard launch or something

Am I think crazy or what?

DJP87Z28

Went to school longer then you KID. And I stopped trying to improve every little thing by Adjusting it. Some people just don't need those kind of items. Also:lala: :lala: :lala: to your HIGH & MIGHTY attitude about how great you are and everyone else is a idiot that does not agree with you.

MrDude_1

i understand pinion angle... and, like dean pointed out below your post, modifying the pinion angle causes the axle location to rotate around the LCA mounting point..... aka moving it in the wheel well, like i said earlier.

what i dont see is, where the heck do you get the axle going crooked? look at your pic you drew... you'll see its impossible to draw without making the LCA shorter.

the entire axle does shift to the side, (and can be corrected by a adjustible panhard) but it never twists to turn the car like that.... atleast as far as i can see..

in anycase, unless you want the axle turning the car over bumps, you need the LCAs to both be a equal length. so the whole "fixing doglegging down the road" argument is moot too...

other then keeping a absolute fixed wheelbase, somthing nowhere near critical on a street car, or keeping induced suspension steer to a min, somthing that only applys to the extreme case of autoX, and also doesnt directly translate to a street car, then whats the point?



and dean:
we might not be getting along right this second, so this probly falls on deaf ears, but remember, not all of us are capable of building, or even want a car as extermely tweeked as yours.. thoes of us who know you, listen and respect your opinion, but when someone disagrees with ya, you dont have to argue with them... just give them a knowing "whatever kid" smirk and let the be on their way.

CaysE

Anyone breaking the rules with blatant namecalling, straying off-topic, or arguing needlessly will not be tolerated. I don't care who it is, so everyone relax and play nice.

MrDude, the reason I drew the rear crooked is because when you adjust the pinion angle, the LCA mounting points on the axle move slightly towards or away from the LCA mounting points on the frame of the car. The difference between vsixtoy's and my drawings are that he changed the LCA mounting point on the axle by applying the relocation bracket after lowering, while I assumed the brackets were there the whole time and I changed the LCA angle. If you were to unbolt the LCA from the LCARB, adjust the pinion angle, and then reattach the LCA to the same mounting hole on the relocation bracket, only one LCA would be able to attach to the axle if you do not adjust their length. This would put the rear at an angle while having one LCA unattached.

The error I made was drawing it crooked the wrong way. My drawing shows one LCA not able to reach the bracket, when in fact it would be too long and extend beyond the bracket. I also assumed that relocation brackets were used with the lowest mounting point at all times. vsixtoy's drawing is more accurate because he maintains the correct LCA angle. Mine would simply have started out lower in the stock ride height drawing.

I agree that these things aren't really meant for street cars, as there are much more variables with bumpy, uneven, pothole-filled roads for any of this to be really advantageous.

vsixtoy

This I have to now say is 100% opposite from reality. I guess my attempts here are just falling on deaf ears with everyone.

Street use on an altered car is the MOST valueable time an adjustable part can come into play. Geometry angle throguh the entire suspension swing are the broadest on a street car because it hits larger road defects causing greater compression and extention than any race car. At those furtherst archs of suspension travel is were the problems are greatest. Adjustments allow the suspension to be tailored so the swing can be centered on parallel at mid travel.

My car is no more exotic than an parts that can be bought on these boards- its just how the parts are set AND the combination or marraige of parts is what makes the difference. My car is designed for 100% street use daily.

vsixtoy

If you are my age or even older, then you should really be embarassed at your lack of education.

I have a suggestion for you if you care to save face- Try and post your opinions and BACK THEM WITH FACTS to support them. You make silly claims an have no facts to give them credibility. Then you continue to pick a fight with me. I took the time even to give you personally a detailled example of how three different adjustable parts WILL correct geometry of a lowered car.

CaysE

Sorry, I should've clarified... adjusting pinion angle and lowering a car isn't advantageous on a street car, because you're not trying to sqeeze every last drop of traction out of the car while accelerating from a stop, and there are too many variables on bumpy, rough, pothole-filled streets for lowering to make a better performing street car. It was just my own opinion thrown in at the end, not stating a fact.

vsixtoy

I give up.

Dewey316

I don't blame you Dean.

I cannot beleive there is this much discusion about a topic like this. it is not a debatable topic. Geometry is geometry, physics laws apply, and do not change. The way the angles interact, are FACT. What is this discussion even about?

ohhh, thats right. A couple of people who can't grasp concepts that I learned in Jr. High math, trying to argue with people who have built and maintane racecars.

MrDude_1

visualize this.

the car has no trans... the TQ arm is on.. the stock LCAs are on.. the car is sitting level on ramps.

i reach under the car, and pull the TQ arm down.
the following happens:

1. the rear of the car goes up. this is because the spring mounts, behind the axle, go up.

2. the LCA mounts, being levers on the bottom of the axle, rotate back. this has the effect of pulling the axle forward


at no point in time does the axle become crooked to the side.

if you're really curious, i can ask to barrow a digital camera.... my car currently has no trans or engine, but the rear suspension is all together..

my point is this:

adjusting the pinion angle rotates the rear end housing. this effectively moves the LCA mounting points on the axle.
however, it does NOT **** the axle, and the axle still moves in the same LCA arch that it did before... granted slightly for or aft, but it would be identical on both sides. the mounting points are symetrical for this reason.


now, its important that the LCAs are NOT diffrent lengths. heres why.

lets say you have it like the pic above.. the left is shorter then the right.... but assume the mounting points did allow the axle to be straight.

the right one follows a large arch, and moves back towards the front of the car very little as it goes thru its suspension arch.

the shorter left one follows a smaller arch.. the axle comes closer compared to the right one, as it goes thru the arch.
so driving down the road, you hit a flat square bump head on... for example, new road paving has the new surface 3" higher then the old one.

the axle goes up, but as it does so, the left side goes in farther then the right... the rear of the car is very sensitive to steering input (ever drive fast backwards? you know what i mean.) that unequal arch causes the axle to point to the right.. effectively turning the car left on the bump.

thats why its important to have equal length control arms in the rear of these cars.

Dewey316

and you don't think that tuning the length, and angle of the control arm doesn't effect roll steer.

MrDude_1

i dont get it either.

its simple geometry. if you know how the rear suspension works and is layed out, you would realise that the only advantage would be to relocate the rear in relation to the wheel well....
granted, you could make them longer, so the wheelbase doesnt change as much under compression
or shorter so it changes more.

or on a roundy round race car, make them unequal so the car gets a little more turn in on the bump coming off corner 3....


but on a street car, thats not all that important.... somthing that doesnt build up grit in the threads, and cant vibrate loose, and cost $40 less and weighs less, is...

MrDude_1

a daily driven street car isnt accurate enough to define roll steer... and the only situation that occurs is when you're pulling into your parking space too fast, or trying to flip a bitch in the middle of the road.

daily driver != autocross car.


for anything short of a car being tweeked to that degree, the adjustibles have no benifit.

MrDude_1

btw, as dean has accuratly stated SEVERAL times.

he appears to be the ONLY one on this board to have his car tweeked to that degree..


and of everyone here, theres probly less then 10 people that would be able to feel what the hell hes talking about when driving the car..

the subject is on the extreme bleeding edge of somthing that most people are nowhere near seeing the edge of.

Dewey316

What are you talking about. Roll steer is going to effect a driver much more than a racecar. The softer springs run on daily drivers, make the problem worse. with 200lbs + springs in the rear of prepped cars, the ammount of travel is small. Not the case on a street car.

CaysE

If none of you think I know what I'm talking about, so be it. I know I'm on the same page as you guys, the difference being that I don't think any of this should apply to a street car. Leave the geometry stock and reinforce the stamped steel crap. Opinion only.

And who the heck paid attention in geometry class anyway?

Dewey316

People with fast cars (this is a light hearted comment, becuase of the tone this thread has taken, I'm pointing that out.)

vsixtoy

Dude, Let me clarify something CaysE did and try to at least help him clear up what he ment. This is why I stepped in in the first place and did the second drawing after his.

He has the correct info posted- it is just misleading and hard to interpet what he ment, I'll explain-

CaysE showed the car lowered from the TOP VEIW. He showed how if you disconnected the LCAs from the rearend, then try to push the axle forward to factory distance from the trans after the alteration, you would be able to connect one side of the LCA and not the other. The side you connect would set that wheel farther back and the other side would be farther forward than factory wheelbase WITH THE CENTER OF THE AXLE (the diff) remaining factory center distance for and aft. You would note be able to connect the other LCA unless you had adjustment provisons on the LCA's to shorten both of them.

My gripe with CaysE in not this, I merely helped clarify this.

My gripe with him is the statement he made that street cars do not need adjustable parts- this is untrue unless you leave your car entirely stock and at exact factory rideheight (this means not even adding gas shocks- they will raise the car slightly) If you want your car to handle the very best it is intended to handle.

Everyone ever wonder why a car doesn't feel as good as it did "new" after a few years of wear. Bushings wear, springs sag, and angles change. If you are into performance at all (that means do you drive a sportscar of any type? Are you a car enthusiest?) then you are into how a car performs. Everyone here wanting to alter there car and upgrade anything should learn what I am trying to instill so you yourself can make your own car handle to its very best when you want to drive it spirited.


In conclusion- CaysE, I am not trying to embarass you by any means, What I think the problem here is is simple misintrerpetation as to what you mean by "streetcar". I think you interpet "streetcar" as a car that is totally stock. I interpet "streetcar" as a car driven on the street no matter how built it is. I get the impression that most here, including yourself, think that a few modifications to a cars suspension makes it a "racecar" catagory- nothing is farther from the truth. My car probably yes indeed is the most tweaked here (for a streetcar) but mine is far from being designated a "racecar suspension" I think you would be awakened if you saw how much different I would have built this car if it were a "Racecar" It is so complex I am not going to get into the changes (all just say it would be locked up so much more tight that the suspension joints would bust driving it on the street and/or wear very quickly from the bumps dips and driveways that twist the chassis and you go over them- you don't get that on a racecourse. The only time a car sees anything remote to this is getting it onto and off of the trailer- you can not doulbe duty a competition racecar for some street use- it will not be competitive or it will break on street use). My Camaro is a prue breed 100% streetcar that I take out and screw around very rarely on a race course. It does very respectable on a course, however, compared to what I would do to it if it were race specific- it would turn circles on how it handles currently. It would be night and day difference and pull about 1.4g's instead of the 1.07 it has done on street tires and alignment.

If you alter any car and want it to perform, you need adjustments period. The simple word "alter" states that the car is being altered or modified for factory specs so common sense would tell someone right there that the factory length parts are not going to work optimumly. If you take a factory part and weld it in permanantly and never change anything else, then it will work. But then change something else and you may most always be screwed.

vsixtoy

So much for this thought. It sounded good at the time- I just found the importance and patience to come back and preach this importance.

Its why I hang out around here- I love to try and teach others that don't know better. I wasn't born with it- I learn it myself form others and trial & error. Just passing on knowledge.

CaysE

miscommunication fixed.

contactpatch

Is there torque on the torque arm,
when the car is at rest?

vsixtoy

Yes there is. It is not very much, but it does have constant pressure upward on the front mount when the back wheels are on the ground unless the car is "moving and under braking". The springs and angles on the rearend want to rotate the pinion upward and the diff cover downward when the car is just sitting stagnant at ride height. All cars will have different varying pressures on this based on many factors but mainly spring rate.