IRS How to - Page 3 - Suspension and Brake Forum

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Re: IRS How to
Tuesday, August 09, 2005 10:09 PM
am I missing something or have you all just lost your minds - yea IRS is a cool conversion but unless your'e off roading you don't want body roll right? well then why would you want to go from a solid trailing axle where the entire axle acts like a big sway bar keeping the car from excessive roll to the IRS which serves no purpose in drag racing or autocrossing - its not like were driving over two foot tall boulders and need the independent travel - besides the cars are front wheel drive - not rear i.e. non-drive - dont need traction to go only to follow - also from the pics I fear the welds on that car - they do not look like someone who had enough practice before trying to weld a very critical structural part - don't get me wrong I don't want to insult anyone but I guess i'm just missing the point - unless this was done just to be different - if so COOL - Good Job, (check those welds - i'd hate to see you damage your car cause it looks nice)

Re: IRS How to
Tuesday, August 09, 2005 11:00 PM
as for off roading comment... have you ever looked at any other race car, scca or otherwise? IRS are stock on most all of those cars....

"IRS serves no purpose in autoX....."

please tell me you are drunk or joking....


IRS is very beneficial in autoX and road race simply because no track is perfect. hence it has imperfections and each wheel can take them independently without affecting the overall handling, especially on the opposite side... try taking a twist beam on a test track like nurburgring or laguna seca vs an IRS car.... nite and day.

the suspension we have is old and outdated, however cheap to make, hence part the reason it still exists on our cars....


body roll isnt just a factor of the suspension design... in most irs or ifs setups the sides with em have stiffer spring rates.... less body roll and pretty much the same as a car with a older beam setup.




look at most all sports cars....IRS
most used autoX cars......IRS

might wanna do more research before you say something is useless.

to start....

http://www.stangnet.com/specs/cobra2000drive.html

Quote:

IRS deploys a 26 mm stabilizer bar, and in front a 28 mm bar is used. [bold]IRS permitted higher spring rates and a stiffer car, so while the stabilizer bars changed their sizes compared to a solid rear axle '98 Cobra, equivalent roll stiffness was retained.[/bold]

[bold]Important ride and handling benefits are derived from IRS and the modified MacPherson strut front suspension. Steering response and on-center feel are improved over a solid rear axle car including a reduction of the turning circle to 38 feet[/bold] for the Cobra.

[bold]The IRS system also made the rear track wider by 1.2 inches, increased suspension travel, and gave the Cobra better weight distribution. Thanks to IRS, handling is especially refined on uneven or bumpy road surfaces and rear-end lift under hard braking is reduced.[/bold]



http://www.autozine.org/technical_school/suspension/tech_suspension2.htm

read up on the DOUBLE WISHBONE SUSPENSION....


if you need more i got plenty of books and sites i can give from.



Re: IRS How to
Wednesday, August 10, 2005 8:15 AM
Erdody: What were you thinking when you posed that? You need some serious education in modern suspension technology. I highly recommend you start with Chassis Engineering.

As for the welding: I can safely assume you have never welded. And we can ignore everything you said about his welds. Because they look very strong, especially if they were MIG or TIG welded. Even Arc stick comes in a wild variety of strengths, hardnesses, brittleness, etc.

Don't hate on people's projects just because you don't understand them.


Re: IRS How to
Wednesday, August 10, 2005 1:04 PM
our twist beam , what ever happens to 1 wheel gets transfered to the other wheel in some way


independant , 1 happend to 1 wheel doesnt get transfered to the other wheel


plus the irs rides better on uneven or unequal surfaces







Re: IRS How to
Wednesday, August 10, 2005 3:49 PM
C.T.S wrote:

Don't hate on people's projects just because you don't understand them.


seriously...



Re: IRS How to
Thursday, August 11, 2005 2:57 PM
Guys I'm not "hating" I understand the principles behind IRS but stop and think for a minute - once you add a sway bar essentially your bring the car back towards being a solid trailing beam setup since when one wheel compresses the sway bar transfers the force back to the other wheel causing it to want to compress - obviously not as much as the stock suspension but having a sway bar on IRS is like taking a short step backwards after taking such a leap forward and P.S. I have Tig, Mig, and Oxy/acetylene welded for over ten years and those welds looked like they may have not had enough penetration and I just don't want anything bad to happen to another j-body fan who obviously put a lot of hard work into that - so stop bitchen and re-read what I had ask it was intended to be a polite question
Re: IRS How to
Thursday, August 11, 2005 3:22 PM
Hey mikey, stop for one minute and evaluate all that you've said before you choke on your foot, first of all if I.R.S were so bad, why do indy cars use it along with sway bars? why do most race cars have a form of sway bar? why do monster trucks run sway bars? to prevent body roll, the sway bar is not meant to compress the wheels, its meant to keep the body parallel to the suspension, exerting more force on the wheel to which the body is rolling causing the car to plant itself that much harder into a corner, think of it in terms of a pry bar, the body twists, the bar is mounted to the body, the body now pushes that direction forcing the bar down.

as for I.R.S being offroad only, yes in extreme travel it is great for rock crawling and mud trucks, but look how well hondas can be made to handle...guess what they have...I.R.S look at high end cars all of them have I.R.S why? because it can be tuned very nicely to stick to the road, if you do not run a sway bar on I.R.S you will DIE so it becomes a matter of saftey.

as for those welds, they look just fine, looks to be penetration all the way thru the weld and there isnt a big bubble gum weld on top. what exactly makes you nervous about them? a proper weld will start with both surfaces being ground to form a v shape, then the v is slowly filled with welding rod penetrating thru the back then bridging the v to the top and then laying a finish pass on top to seal the edges up nicely. now had it been me i would of also boxed the back side of those brackets with some 1/4 inch strap just as an extra measure....but his welds are just fine, especially if hes been driving it since april .

J~
Re: IRS How to
Thursday, August 11, 2005 3:38 PM
Michael Erdody wrote:

Guys I'm not "hating" I understand the principles behind IRS but stop and think for a minute - once you add a sway bar essentially your bring the car back towards being a solid trailing beam setup since when one wheel compresses the sway bar transfers the force back to the other wheel causing it to want to compress - obviously not as much as the stock suspension but having a sway bar on IRS is like taking a short step backwards after taking such a leap forward and P.S. I have Tig, Mig, and Oxy/acetylene welded for over ten years and those welds looked like they may have not had enough penetration and I just don't want anything bad to happen to another j-body fan who obviously put a lot of hard work into that - so stop bitchen and re-read what I had ask it was intended to be a polite question


you obviously have no clue as to what double wishbone or multi link suspensions are.... do you?

when you made the statement
Quote:

the IRS which serves no purpose in drag racing or autocrossing


that pretty much showed your ignorance, and you prob didnt even read the links that have been posted thus far....

you;re talking about going over 2 foot tall bumps, where as most all race cars, especially purpose made non street legal race cars are multilink, or IRS as well as IFS cars....

race cars, million dollar sports cars, etc.... any of those never came across you mind before you made that statement?


seriously... i wanna know.



Re: IRS How to
Thursday, August 11, 2005 5:18 PM
Event - whats good for the goose is not necessarily good for the gander ie just because PURPOSE built race cars have IRS does not mean that it will work the same on a street driven car - "ignorance" as you stated is ASSuming it would ( p.s. to assume is to make an ASS out of U and ME ) see how that word spells - again I applaud mcmoney for his work I think the idea is cool but think about it if you can get off your high horse of assuming you know everything about suspension design - when he enters a hard turn now the car is naturally going to want to shift its weight to the opposite rear corner of the car causing the front inside tire to want to lift - to avoid this you need to do one of or both of two things put on a VERY stiff rear spring rate and or apply a sway bar - again a sway bar transfers force from one side of the vehicle to the other JUST LIKE THE STOCK TRAILING ARM SETUP that;s why the car does not come factory with a rear sway bar because the trailing arm setup is designed to act as one - the only reason to add another sway bar is to stiffen up the rear anti roll effect more than it is already built in from the factory - which IF YOU READ THE OTHER POSTS "you" already recommended in your "suspension how -to" - if your going to try to insult me get your facts straight - besides I am an ASE certified tech with 4 years of schooling in automotive repair and design I do have a very good idea of what I'm talking about, also on any race track or any parking lot auto cross event you will most likely never see an indifference big enough to see ANY benefit from IRS in a CAVALIER it will naturally have way to much Body flex as there is no solid chassis under our cars - welding in a heavy roll cage may help but only mildly to moderately as this car was not designed as a race car

P.S. J~ thank you for the polite and intelligent counter opinion you offered although I still disagree with you on exactly how a sway bar works you seem to understand what I am saying and as I'm sure we are both not "experts" on the subject I do have a large amount of knowledge on the subject and better yet schooling on the subject and on-hand experience which is where my opinion comes from - I just want people to stop and think about the benefits vs consequences of this conversion vs how much more they would benefit from a good "stock" suspension setup and If money and/or skill permit an LSD - besides more people are likely to cause serious mis-alignment issues and or permanent damage to there cars trying this sort of conversion which is most likely above most avid tuners skill level
Re: IRS How to
Thursday, August 11, 2005 5:28 PM
Michael Erdody wrote:

Event - whats good for the goose is not necessarily good for the gander ie just because PURPOSE built race cars have IRS does not mean that it will work the same on a street driven car - "ignorance" as you stated is ASSuming it would ( p.s. to assume is to make an ASS out of U and ME ) see how that word spells - again I applaud mcmoney for his work I think the idea is cool but think about it if you can get off your high horse of assuming you know everything about suspension design - when he enters a hard turn now the car is naturally going to want to shift its weight to the opposite rear corner of the car causing the front inside tire to want to lift - to avoid this you need to do one of or both of two things put on a VERY stiff rear spring rate and or apply a sway bar - again a sway bar transfers force from one side of the vehicle to the other JUST LIKE THE STOCK TRAILING ARM SETUP that;s why the car does not come factory with a rear sway bar because the trailing arm setup is designed to act as one - the only reason to add another sway bar is to stiffen up the rear anti roll effect more than it is already built in from the factory - which IF YOU READ THE OTHER POSTS "you" already recommended in your "suspension how -to" - if your going to try to insult me get your facts straight - besides I am an ASE certified tech with 4 years of schooling in automotive repair and design I do have a very good idea of what I'm talking about, also on any race track or any parking lot auto cross event you will most likely never see an indifference big enough to see ANY benefit from IRS in a CAVALIER it will naturally have way to much Body flex as there is no solid chassis under our cars - welding in a heavy roll cage may help but only mildly to moderately as this car was not designed as a race car

P.S. J~ thank you for the polite and intelligent counter opinion you offered although I still disagree with you on exactly how a sway bar works you seem to understand what I am saying and as I'm sure we are both not "experts" on the subject I do have a large amount of knowledge on the subject and better yet schooling on the subject and on-hand experience which is where my opinion comes from - I just want people to stop and think about the benefits vs consequences of this conversion vs how much more they would benefit from a good "stock" suspension setup and If money and/or skill permit an LSD - besides more people are likely to cause serious mis-alignment issues and or permanent damage to there cars trying this sort of conversion which is most likely above most avid tuners skill level


Before you read the following, you should know that I rarely flame people on this board. I usually save it for those special kind of idiots that think they know something when they don't.

Please stop spreading your idiocy around our board. Just because you are an ASE certified mechanic doesn't mean anything. I have met plenty of ASE certified mechanics that never get $#@^ right on my car.

IRS > Twist beam axle. End of discussion.



Re: IRS How to
Thursday, August 11, 2005 6:06 PM
firstly drop the BS about "oh you think you know everything" if you dont have anything realistic to say besides extraneous BS filler, then simply dont post.

secondly, the front inside tire will not lift granting you have your rear suspension setup to where the compression of the strut isnt at a high speed, nor the spring rate isnt too soft and you are running a positive rake angle and not some "lower in the rear cause i wanna get rid of my wheel gap springs"


if you are an ASE certified tech, then you wouldnt have made the statements you did.....

not all the cars i have mentioned are purpose built race cars....pretty much all cars these days come with it...

if you knew anything basic, mr ASE certified tech, which really doesnt prove much besides you know how to study and regurgitate what you learned and pass a test these days.....

you would know that IRS setups use stiffer springs, to basically achieve the same setup/handling as a semi independant rear.


along with the advantages of IRS are no input from any other source which allows each corner to deal with the road....

not deal with the road and be affected by the other side of the suspension. this is where precision of handling comes into play.



but now you wanna trade quotes...

your statement of "IRS serves no purpose in autoX"

assumptions only make an ass out of yourself realistically.... but more appropriately... assumptions are the mother of all F ups... and by making that statement, you def F-ed up. theres far more factors of the suspension that you probably convieniently left out.

whats the first and foremost thing about a race car, or a street car used for a race car?

adjustability.

running IRS allows for FAR more adjustability and CONSISTENCY than a semi independant setup...


its pretty pathetic that after 4 years of ASE certified techician stuff under your belt, you dont know about advantages of IRS, and why most cars street and race cars use em and offer more advantages over the setup we have on our cars....

whoever taught you, did a piss poor job on this subject. nothing personal, but if you would take a simple look around at how cars over the years have changed suspension designs, or may sat down and googled why cars even now are finally changing to IRS setups, unless you are just thick headed like the rootbeer commercials, you would know a bit about IRS besides thinking its just for rock climbing....or going over 2 foot tall obstacles...


so you dont miss this part, mr ASE assumption man....

Quote:

also on any race track or any parking lot auto cross event you will most likely never see an indifference big enough to see ANY benefit from IRS in a CAVALIER it will naturally have way to much Body flex as there is no solid chassis under our cars


so are imports and the many other domestics that have IRS... no rail chassied cars, basically unibodies, and they do quite well at the track with the ability to adjust and their handling is superb.

but wait... one thing.... not many people...actually about 3 or 4 have actually done this... one car at sema, another guy from about a year ago, and mcmoney....

so really you havent even seen the results of what can come of it, yet you already say it most likely will NEVER benefit a cavalier?????

yea....way to assume.



few books i reccomend you read, and not skim over cause your knowledge is def lacking. you might be great with the cars you work on... i dont know, but like others have pointed out... howstuffworks.com and a few other links above.... you def need more input johnny 5....

http://www.amazon.com/exec/obidos/tg/detail/-/0837601428/ref=sib_rdr_dp/103-7607218-8874267?%5Fencoding=UTF8&no=283155&me=ATVPDKIKX0DER&st=books

http://www.amazon.com/exec/obidos/tg/detail/-/1859606628/ref=pd_bxgy_img_2/103-7607218-8874267?v=glance&s=books&n=283155

http://www.amazon.com/exec/obidos/tg/detail/-/1557883661/qid=1123807112/sr=1-5/ref=sr_1_5/103-7607218-8874267?v=glance&s=books

and DEF these... MAINLY THESE

http://www.amazon.com/exec/obidos/tg/detail/-/0912656468/ref=pd_sim_b_4/103-7607218-8874267?%5Fencoding=UTF8&v=glance

http://www.amazon.com/exec/obidos/tg/detail/-/1557880557/ref=pd_sim_b_1/103-7607218-8874267?%5Fencoding=UTF8&v=glance

http://www.amazon.com/exec/obidos/tg/detail/-/185960644X/ref=pd_sim_b_1/103-7607218-8874267?%5Fencoding=UTF8&v=glance



the last three will set you straight.... the first few will give you more real live examples including aerodynamics.


if you think IRS is the main factor in body roll, when you didnt even factor in the length of the arm used, which will partially determine the amount of suspension travel to begin with....(think leverage arms or a see saw setup)

and then you said nothing about slip angles, camber adjustments, or factors of springs and struts, the consistency of camber during hard turns, and of course making the rear shocks and struts take the bumps rather than transfering up to 40% of the energy one side takes to the opposite side causing the arse end to slide out under hard cornering. thats a definate disadvantage of semi idenpendent rears.

heres a small hint to get you started...

ebay coilovers...most are designed for hondas and cars with IRS.... double wishbone, etc... fully independent all the way around...

coilovers designed for our cars from decent companies, especially in the rear are usually between 225 and 275.....

coilovers from IRS cars are usually in the range of 350 to 375....reason the stiffer spring rate offsets the semi independant rear factor...


and on matters of SCCA.... why do miatas and BMWS handle so great... and usually abundant similar to how the 240SX is in drifting....

their suspension designs are the reason.

if you wanna talk suspension, we can talk, but you sitting there saying "oh were not looking for two feet of travel" and some of the other clueless stuff you posted, you really arent looking at the whole picture of IRS.

theres a reason cars have gone from leaf springs, to semi independant, to full independant suspension over the years.

theres simply more advantages in tuning em.


as for body flex, there really isnt as much as you wanna make it seem.... if you are really that worried, stitch weld any spot welds and maybe add in a cage, but thats def not needed.



you were the one who came on here saying this and that will most likely not work, saying IRS is for taking 2 foot tall obstacles, etc...

if anyone was acting like you think you know everything, it def was yourself.


like the song says.... "they say i;m cocky, and i say what, it aint braggin mutha -F if you back it up....

so far i;ve posted at least 8 links backing up anything that was directed to you....you can take it personally if you want, doesnt matter, you made an ignorant statement and poor assumptions, and someone called you on it.




Re: IRS How to
Friday, August 12, 2005 10:09 AM
How do you determine how far for/aft to mount the C-channels?


<img src=http://hometown.aol.com/yogiandbooboo7/images/french.jpg>
Re: IRS How to
Friday, August 12, 2005 10:13 AM
Tape Measure + Good Guessing

Drill the holes in the C-Channel for the sub frame after[/] they are welded on.

I'm still getting all the parts together for this swap, but when I do it I'll take a million pictures and write up a detailed how-to.


Re: IRS How to
Friday, August 12, 2005 10:35 AM
damn.......

{insert best owned pick here}




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Re: IRS How to
Friday, August 12, 2005 10:50 AM
After reading only half of this thread, and knowing probably half of what some people know about suspension, i think that you guys have missed one of the greatest things about IRS (although i don't know what type of IRS the alero is, so this might be wrong).

With our axle as the suspension is compressed, the camber is not affected. As the body rolls, and the car becomes angled relative to the ground, this reduces the contact patch, which affects traction (yes, for tires, surface area does affect friction, trust me, i've done a lot of research). In an IRS suspension, (or at least a multi-link IRS), camber is adjusted as the suspension is compressed, keeping the tire "flatter" on the road, enhancing the contact patch, increasing grip. I'd have to say that's worth it alone.
Re: IRS How to
Friday, August 12, 2005 11:54 AM
The Alero suspension wasn't designed to do much camber adjustment. It does lean into corners a touch better than the stock torsion axle does though. Double wishbone would be much more effective, but this is a "swap".


Re: IRS How to
Friday, August 12, 2005 12:54 PM
Good point. I guess that was more directed to the guy who said "IRS (in general) isn't necessary"

also, as a not, people have been ragging on the mustange because it still doesn't have IRS. If IRS were so un-necessary, i wouldn't think people would want it on a mustang... hmmm
Re: IRS How to
Friday, August 12, 2005 9:22 PM
IRS is good for handling. IRS is not good for power to the wheels (not necessarily bad, but harder to get it right). Solid axle is the best for getting the engine power straight to the ground. So mustang's always have, and still do have a solid rear axle.

Of domestic production cars the corvette has always (for many years anyway) been the best, and had IRS for a while now. The modern vette suspension has 5 links. This alero suspension has 3 + a strut (which kind of makes 4). If you have no idea what I'm talking about, go read the book I mentioned about 10 posts up, it will provide more detail than you really wanted to know.


Re: IRS How to
Thursday, October 06, 2005 6:51 PM
Ok, I have a question...



How did you come to the 9" measurement?

I swear it's 10 inches on the N-car.. when I line mine up (on the upside-down half-car in my garage ) to 10 inches, the spacers required would be tiny (only two, and both exactly 1 inch), and it doesn't appear to need any modifications to the bar lengths...

I'm far from completed tho... so maybe I'm missing something... I'm going to try and find an 04 Alero to measure again... or maybe I'll try aleromod and see if someone can measure theirs for me LOL





Re: IRS How to
Friday, October 07, 2005 8:59 AM
9" Centers the wheel front to back in the well.



Re: IRS How to
Friday, October 07, 2005 9:00 AM
Ohh. Also, because you have to cut the link bars to skinny the setup, the trailing arm will need to be cut (or it'd be too wide still), and that will push the setup forward to 9".




Re: IRS How to
Friday, October 07, 2005 9:17 AM
Ok... work with me here

The wheel well is 29" wide. The metal crossmember/support bar (that big honkin' piece that everything attaches to) is 9" wide (roughly). That leaves 20 inches, so 10 on each side.

Assuming you didn't have to skinny the setup... which I'm not planning on doing (my rear wheels are about 1 inch inside of the fender as it is... I was looking forward to the wider stance this mod would give).... then you don't have to shorten the bars... then you don't have to shorten the trailing arm....

Then in theory... it's more bolt-up than custom....

I'm going to the wrecking yard to confirm my measurements... but I'm certain that's supposed to be 10" (if you don't have to account for any shortened bars).





Re: IRS How to
Friday, October 07, 2005 10:25 AM
Chris wrote:

After reading only half of this thread, and knowing probably half of what some people know about suspension, i think that you guys have missed one of the greatest things about IRS (although i don't know what type of IRS the alero is, so this might be wrong).

With our axle as the suspension is compressed, the camber is not affected. As the body rolls, and the car becomes angled relative to the ground, this reduces the contact patch, which affects traction (yes, for tires, surface area does affect friction, trust me, i've done a lot of research). In an IRS suspension, (or at least a multi-link IRS), camber is adjusted as the suspension is compressed, keeping the tire "flatter" on the road, enhancing the contact patch, increasing grip. I'd have to say that's worth it alone.


you get my vote, beat me to it

IRS assists all 4 tires in maintaining maximum tread to road contact, thus maximizing grip and increasing the amount of speed possible while taking a turn.

All cars can benefit from an IRS.

As event said, the rear torsien beam in our cars is there because it's cheap and inexpensive.

However there is the fact that by allowing more adjustability in the IRS it does take more time to tune it, thus a decently tuned rear torsien beam car will be comparable to a poorly tuned IRS car.


-Chris

Re: IRS How to
Friday, October 07, 2005 10:26 AM
BTW I highly reccomend "How to make your car handle" excellent book!


-Chris

Re: IRS How to
Friday, October 07, 2005 11:05 AM
Lenko, John Lenko wrote:

Ok... work with me here

Assuming you didn't have to skinny the setup... which I'm not planning on doing (my rear wheels are about 1 inch inside of the fender as it is... I was looking forward to the wider stance this mod would give).... then you don't have to shorten the bars... then you don't have to shorten the trailing arm....



If you don't cut the lateral arm you gonna have like 15 or 20 degree of negative camber
and If you don't cut the trailing arm the tire will hit the rear bumper

I know that because i tried both of them before i cut everything



Location: Montreal, Quebec
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