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2005-2009 Mustang GT. Independent Rear Suspension?

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Old 09-26-2009, 01:17 PM
  #21  
ski
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The alignment specs are the same for the GT and the V6.
Here's the spec sheet.
Attached Thumbnails 2005-2009 Mustang GT. Independent Rear Suspension?-alignment-specs.jpg  
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Old 09-26-2009, 03:57 PM
  #22  
157dB
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The Rear solid axle in S197s dont have caster or camber adjustments.
Aftermarket LCAs require the rear end to be 'centered' and pointing straight.
But stock LCAs dont have 'adjustments' nor does the single stock UCA.
You cant bend axle tubes to create camber and the axle only moves
up and down in an arc so there is no caster.
Caster is only used on the front end to improve steering geometry.
Someone is castering your oil and bending you over at the same time.
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Old 09-26-2009, 04:49 PM
  #23  
Blacksmoke
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Originally Posted by 157db
The Rear solid axle in S197s dont have caster or camber adjustments.
Aftermarket LCAs require the rear end to be 'centered' and pointing straight.
But stock LCAs dont have 'adjustments' nor does the single stock UCA.
You cant bend axle tubes to create camber and the axle only moves
up and down in an arc so there is no caster.
Caster is only used on the front end to improve steering geometry.
Someone is castering your oil and bending you over at the same time.
So what exactly are you saying happened?

They said they did the alignment according to the specs for the 2006 Mustang Coupe. How can you not be able to adjust the alignment in these cars without buying aftermarket parts?

They said basiclly they aligned the front with the rear.. The front must have casters then right?
So I assume if they used the specs for the 2006 Mustang Couple then they aligned the front with the back using the front cambers, casters,etc.?
Is that the correct way to do it on these cars?

They did not say they aligned the rear... they said they aligned the front with the rear basiclly.

Are you saying they did something wrong?


I don't think I'm following you on this.

Last edited by Blacksmoke; 09-26-2009 at 04:54 PM.
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Old 09-26-2009, 09:36 PM
  #24  
dominant1
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Topic related article very interesting:

Tech: Does The Mustang Need An Independent Rear Suspension?

Story by Sam Haymart

We take a look at the long raging debate between new and old tech.


05-02-08: Having just spent some time driving the new Shelby GT-500KR which is arguably the highest performance Mustang Ford has ever offered with a warranty, the question still lingers. Should the Mustang have a modern independent rear suspension (IRS)? For many, it’s hard to imagine that in 2008 we have a Mustang with an MSRP of $80,000 that still has a live rear axle.

I had the chance to meet with some acquaintances for dinner recently some of whom engineer cars, others who write about them. We discussed this issue at length and what was most striking is that everyone has a different opinion on the matter. More illuminating is that everyone has solid reasoning behind their perspective.

People who have a broad-based enthusiasm for cars, that is to say those who appreciate many brands and models tend to be incredulous that Ford continues to use a live axle in their halo performance car. This is especially acute when you consider the price tag and horsepower of the top Mustang models today. Drag-racers and some Mustang purists are adamant that IRS is the devil and that changing over from a live axle will be the end of the world for Mustang. Engineers say it's a huge compromise to consider because IRS is heavy, expensive and not as durable.

They are all right in their own way. It made me think it was time to expand on this a bit and explore each angle of this because the question rages on. The debate about IRS in the Mustang has been floating around since the late 1980’s. Each successive generation of Mustang has been rumored to have an IRS but has shown up to market without it.





In 1999 SVT answered this desire in the Cobra Mustang. Because the SVT engineers could not alter the floor pan sheet-metal, the IRS system installed in the Cobra was a “bolt-in” assembly that used the same mounting points as the standard live axle. This made for an easier production installation but compromised the design because the length, geometry, and tuning of the suspension was dependent on the confines of a sub-frame cage that was not flexible in design.

Drag racers hated it because of unrecoverable axle-hop. Road racers liked it when the bearings weren’t coming apart or the bushings weren‘t wearing thin. Daily drivers found their bliss in a great ride and superior handling dynamics on real world roads which unlike race tracks, have bumps, potholes, and pavement seams. The triad of users are still with us today and are still the lobbyists of the argument for and against IRS.



The 2005 (S197) Mustang had been expected by many to have IRS since it was derived from the DEW98 chassis which underpinned the Ford Thunderbird, Lincoln LS, and Jaguar S-Type. The world class chassis had both a superior short/long-arm (SLA) front suspension and an fully independent rear suspension. But as time went on, the new Mustang chassis evolved to a unique hybrid of the DEW98 that not only had a live rear axle but a McPherson strut front suspension.

The reasoning given for the de-contenting was all about keeping Mustang at an affordable price-point. At the time Ford said that IRS would have cost an additional $500 per car. Because the Mustang is meant to be a mass-market leader with a sub-$20,000 entry point that’s the choice that was made. But given the many benefits of a modern chassis, wouldn’t most people pay an extra $500? On the average car loan that translates to about $8-9 per month in payment increase. Let’s have a look at the argument for and against and you can decide.

The Argument For IRS:

• Marketing: It’s the modern and mainstream format for all other rear-wheel drive sports cars and sedans - and now the Camaro and Challenger. Today the Mustang is widely beaten down by the motoring press and consumer publications for being “old fashioned“. Lack of an IRS could be hurting Mustang’s mass appeal regardless of whether or not it would actually improve the car.

• Handling & Safety: Independent rear suspension allows each wheel to react individually to bumps, undulations, and traction variations without affecting the other. Because one wheel is not affecting the geometry or stability of the other, rear axle skate and mambo dance on washboard surfaces is eliminated. This translates into increased stability, increased refinement, and better overall traction in day to day driving.

• Less Un-Sprung Weight: Without the weight of a live axle and differential assembly directly on the wheels, suspension tuners can concentrate on traction, road feel, and cornering poise. With a live axle they have to compromise those settings to also control the dead weight of the axle. Less un-sprung weight always translates to better predictability, less harshness, and better traction on rough surfaces.

• Better Front/Rear Balance: An IRS system almost always weighs significantly more than a live axle, but it’s “sprung weight“. While the extra pounds are a bummer there is an upshot. That increased weight is at the rear of the car which can help bring a balance to the traditionally nose-heavy Mustang. By changing the front/rear weight balance from the current 55/45 to perhaps 50/50 would move the center of rotational gravity to the middle of the car which can vastly improve handling balance. 50/50 is a lofty goal, but wouldn’t that be nice in a Mustang?

The Argument For Live Axle:

• Simplicity: The live axle is the least expensive and easiest format to manufacture. It has the fewest parts and requires little research and development going forward.

• Durability: They don’t break. For high power applications those thick axles and stout housings can take all the power. IRS systems typically have more complexity and more delicate parts like multiple CV joints, bushings, and bearings that can be failure or wear points.

• Racing Bliss: Drag racers and road racers alike favor the live axle because it gives them tried and true traction. On the 1/4 mile straights, the stick is easy to tune for maximum launch and is not prone to wheel hop with today‘s set-ups. For road racers, its simplicity allows for easier tuning. Panhard bars and Watts linkages both arrest lateral motions and offer track specific tuning opportunities at the twist of one nut or bolt.

• Easily Modified: For the racer or the mod-artist there are thousands of off-the-shelf parts on the market that allow easy gear changes, strength build ups, and suspension tuning. A new IRS would mean a long lead time for aftermarket parts to become available.

The Question:

The struggle is simply this. Live axle be-damned the Mustang still sells even at $80,000+ for high-end Shelbys and Saleens like the S281E. So why spend the money and add the weight if it still sells? On the other side of that is the mass market appeal. Why not improve the breed to make the car more appealing to the non-Mustang faithful?

There is a new crop of buyers entering the market who idolize technically complex import cars like the Nissan GT-R, Lexus IS, Subaru Imprezza WRX, Mitsubishi Eclipse and so on. For many it’s the technological prowess of these cars that make them exciting to buyers. Why not bring the Mustang’s technology inline with these modern contemporaries so these buyers would be more likely to add it to their shopping lists, thereby increasing market share?

But in my recent bullring conversation when the last sentiment was offered one well known Mustang auto writer vehemently countered, “The Mustang is not a (BMW) M3! It’s not meant to be!” And while I tend to think that when a Mustang costs $80,000 perhaps it should be, I thought he had a point. So on we go. Ford has been struggling with this for some time now and most Ford engineers I talk to would rather change the subject. They have been down this road before and will continue on it for time to come.
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Old 09-26-2009, 10:00 PM
  #25  
volcomchester18
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I dont mind the live rear axle, however; on turns with bumps does not feel very trusty lol. Other than that, I love it.
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Old 09-26-2009, 11:32 PM
  #26  
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Originally Posted by volcomchester18
I dont mind the live rear axle, however; on turns with bumps does not feel very trusty lol. Other than that, I love it.

I'm involved in a possible Cobra IRS getting mated with an S197 chassis in the near term. We're going to do it the same way Ford did it for the 03/04 Cobra's. I don't know that is will fit perfectly but we're going to see in the next few months.
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Old 09-27-2009, 09:05 AM
  #27  
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Dude,
Nothing personal but you need an education.

1) For your Mustang an alignment does not require parts unless a suspension component is bad etc.

2) The words are caster and camber, not casters and cambers. These are not parts they are alignment settings.

3) You keep asking people to answer questions on a subject that you don't know enough about to ask proper questions.

Go to this website for an explanation of basic frontend alignment.
http://www.familycar.com/Alignment.htm
If you still have questions then come back and ask.
Al
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Old 09-29-2009, 10:03 AM
  #28  
Norm Peterson
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Originally Posted by dominant1
The Argument For IRS:

• Handling & Safety: Independent rear suspension allows each wheel to react individually to bumps, undulations, and traction variations without affecting the other. Because one wheel is not affecting the geometry or stability of the other, rear axle skate and mambo dance on washboard surfaces is eliminated. This translates into increased stability, increased refinement, and better overall traction in day to day driving.

• Better Front/Rear Balance: An IRS system almost always weighs significantly more than a live axle, but it’s “sprung weight“. While the extra pounds are a bummer there is an upshot. That increased weight is at the rear of the car which can help bring a balance to the traditionally nose-heavy Mustang. By changing the front/rear weight balance from the current 55/45 to perhaps 50/50 would move the center of rotational gravity to the middle of the car which can vastly improve handling balance. 50/50 is a lofty goal, but wouldn’t that be nice in a Mustang?
Let's look at just these two items that *nominally* favor IRS.

The first is true once the pavement has deteriorated beyond some point, but it's not necessarily the case otherwise. The point is that a well done stick axle is more predictable to drive than an indifferently done (read: done to a relatively inexpensive price point) IRS. A suspension that the driver has more confidence in is one that he will be more comfortable driving hard. It's worse than pointless to make a big deal over any theoretical performance advantages of IRS in general if the specific IRS in question discourages you from driving it very hard. At that point, it simply rides better. I hate to trot out "magazine tech", but the various handling comparisons are not favoring the IRS-equipped ponycars at this point.

You aren't going to get a 5% shift in weight distribution by swapping out the 8.8 axle for IRS. Even if the IRS and all of its additional structure weighs 200 lb more than the live axle and it all sits right over the rear wheels, that only buys you about a 3% change (to 52/48, using 55/45 as a starting point). Of course, now your 3500 lb car weighs 3700 lb with a relatively higher polar moment of inertia . . . and don't forget that you're still working with the same motor and wheel/tire sizes.

It's not that I'm specifically against IRS (I'm not, and I'd like to see Chip's project turn out well). But unless IRS is going to really provide better performance AND be neither clumsier (think "2010 Camaro/Challenger" here) nor trickier to drive up toward those limits (a little rear end "twitch" due to rear wheel compliance toe at only 0.7 lateral g will definitely get your attention, and not in a good way), it isn't buying you any headway.


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Old 09-30-2009, 05:08 AM
  #29  
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Ok so since the alignment settings are the same for the GT and V6, and they used the specifications for the 2006 Mustang Coupe (what it was listed as on their computer), then it does not matter if it was the GT or V6 since they are the same.

Thus, they aligned the car correctly.

Right?
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Old 09-30-2009, 10:42 AM
  #30  
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Bingo, correct alignment specs.
A correct alignment job is as rare as seeing BigFoot.
They fiddle around then take your money, basically.
Unless your frame is bent, an alignment should not be needed...
Mostly wasted $$ right there.
Your tires and time will tell the whole story...

Last edited by 157dB; 09-30-2009 at 11:03 AM.
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