Understanding & Upgrading your Mustangs Suspension R E A D

Dalamar

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This thread is to help you better understand the basics on your mustangs suspension, and what to look at when upgrading.
there is a lot you can do to improve your car's traction and handleing. there is an enduring flaw in the mustangs 4 link suspension
design that should be addressed. you can do a little or a lot, this thread is to help you understand what I think works well, and what doesn't, based on my experience.

What is the stock suspension?
Let me tell you from firsthand experience that the mustang's suspension is not a simple as you may think.
Good explanation of components and function LOOK HERE > http://www.miracerros.com/mustang/t_suspension.htm

Problems:
The stock mustang suffers from soft bushings, and poor rear control arm geometry. Wheel hop, axle deflection, body flex and a tall ride height.
Can you say mediocure handling?


Front Suspension Definition:
The 1979-2004 Mustang front suspension consists of modified MacPherson struts with lower control arms (A-arms).

This suspension is compact, cheap to build and easy to service, but it is often criticized because (a) its geometry produces camber changes during vertical suspension movement and body roll that adversely affect handling and (b) the strut towers prevent designers from lowering the car's profile. The performance of the front suspension can be improved by installing stiffer springs and struts and by replacing rubber bushings in several locations with less compliant urethane bushings.

Rear Suspension Definition:
the 1979-2004 Mustang's 4-link rear suspension consists of a live rear axle held in position by upper and lower control arms, coil springs, and gas-filled shock absorbers. It includes an 8.8" traction lock rear, quad shocks (shocks & dampers), and a rear sway bar.

When the car leans (rolls) in a turn, one side of the chassis moves upward relative to the rear axle, the other side moves downward, and these non-parallel control arms must twist and change length axially to allow the axle to articulate. This causes the control arm bushings to bind. If this bind becomes excessive, it can raise the rear wheel rate and produce sudden, undesireable changes in handling

Ford minimizes this suspension bind by using compliant rubber bushings in both the upper and lower control arms. These relatively "soft" bushings acommodate the necessary motion of the control arms during body roll. However, they also permit wheel hop on hard launches and horizontal axle deflection in aggressive turns.
[IRS equipped cobras are obviously different]


you can do a little or a lot to improve your car's ride and handling.
I've done and redone my car's entire suspension. and learned a lot along the way.
I currently have all MM parts because I found them to be well made and provide me with the performance and peace of mind that I want.
I have tried Steeda, Grannitelli and QA1.

Major differences on my ride vs the standard lowerd mustang is that I run coil-overs and 3-link rear (Torque arm) with a panhard rod.
The handling is so far superior to the car as it was. it's stable, predictable and corners so solid. launches are straight and rear traction is vastly improved. you have to feel it to believe it.


WHERE TO START!
Most mustang owners start with lowering their car, for appearance and handeling, and upgrade or replace their worn out LCA's.

You'd be surprised how much better your car feels lowered, with wider/better tires!!



Checking out parts:
I've seen a lot of threads and hype about parts over the years.
I'd offer this advice:

1 - there is a big difference between forum opinion or regurgitation of information and someone who has actually done the upgrade.

2 - just because someone has done a suspension upgrade and tells you "it's great" or "it's fine" doesn't necessarily mean that's
true, or mean that's the right part for your car. GET FEEDBACK. I learned the hard way on this one...

3 - I recommend you check with Maximum Motorsports or Griggs. they engineer, build and test their parts, and explain why it works better. I appreciate that.
MM has been super helpful on the phone with me, and their site has great info. They've even helped me with questions about other manufacturers parts!

4 - Cheaper parts, are just that, Cheap - poor quality, little or no design work, crappy assembly.
DON"T BELIEVE ALL THE SALES HYPE out there!!



Is your car an 4 x 4 in disguise?
Lowering springs!! Check our lowering spring picture database : http://www.sn95forums.com/forum/index.php?topic=7175.0


Caster Camber plates:
also look into caster camber plates because with a decent drop your camber will be out and the stock adjustments arn't enough.
I suggest Maximum Motorsports CC plates. If your running coilovers, all the front weight of the car is sitting on the plates! so they are my only choice for coil over applications!


Control Arms
you may need A arms, lower or upper rear control arms.

I highly suggest you find out why you do not want solid or adjustable upper control arms on your STREET driven car!
Torque box reinforcements? if you need to reinforce the torque box of your car, there's something wrong there....
Your suspension should not bind up and warp the floor pan of your car! Solid uppers are better suited for drag racing vehicles.


I offer this bit of information from Maximum Motorsports web site to explain why: - rear suspension - lower control arms.
Most aftermarket rear control arms use hard 2-piece urethane bushings, Delrin bushings, or steel bushings. Those types of bushings do not allow the angularity needed for the Mustang̢۪s suspension to articulate freely. The resulting suspension bind causes the rear tires to break loose very easily. Suspension bind not only causes poor handling and poor traction, but it also causes damage to the torque-boxes. As the attachment points on the chassis for the rear control arms, the torque-boxes can suffer greatly from the abuse of poorly designed control arm bushings. After all, the torque boxes are only made of folded sheet metal.....

AND

....In the Mustangs rear suspension design, whether it is still the stock 4-link suspension design, or has been modified to a Torque-arm or three-link design, the control arms do not simply pivot. The arms also move sideways, with an angular motion (relative to the pivot axis). If that angular motion is restricted because of a poor bushing design, the suspension will bind. While some aftermarket control arms may seem to improve performance because of reduced bushing compliance, it is only improved to a level slightly higher than the stock control arms. Once the car is pushed past that level, the increased wheel rate from the suspension bind will cause unpredictable handling– not to mention damage to the torque boxes.

What this says for me is: For street driven applications, it will bind up and restrict the movement of your supsension as defined above.
IMO it's rediculous if you want any serious kind of street or cornering performance, good corner exit, and predicitability while accerating on an uneven road...


Beyond that you may want to look at updating the cars rear suspension with a panhard rod, watts link, and Torque arm.
My torque arm is my second favorite of all the mods I've done to my car!! Hellion turbo being #1.


Update: There is more information for DRAG RACING suspension setup below in post 14, and more detail for further combinations below that! Thanks to TRUUBLE and R3dn3ck for their input!



The mustang suspension has been around for a long time - and can be seriously improved.
Good modding to all! :wav:
 

SRT Handz

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Re: Mustang Suspension understanding and upgrades

i was accually in middle of typing the exact same thing.....Good work and happy modding to all
 

r3dn3ck

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Re: Mustang Suspension understanding and upgrades

That's a good start and all accurate. I've been through pretty much every suspension option you can do to a mustang and I have to say without a doubt I'll only ever use Maximum Motorsports and Griggs parts. It's just not worth it to me to have any lesser grade product when they already make something that's perfect.

After doing all the lowering springs and bushings and braces and IRS conversions and gobbledy goop I eventually found out that MM and Griggs are right. A properly setup solid axle car on a torque arm and panhard bar setup from either MM or Griggs is about as fine handling a car as you can get out of a mustang. Coil over conversions from either company are worth their weight in handling and comfort gold and they make it SOOOOO easy to adjust and further modify things that you'd be kinda silly to use just old lowering springs and new shocks.

If you're signed up on Mustangboards.com you can check out my tutorial on suspension selection for the practical mustang driver in the Suspension forum under the General Tech section. I'll cross post it here as soon as I have a bit of time unless one of you wants to grab it for me. It's a sticky.
 

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Re: Mustang Suspension understanding and upgrades

That is all excellent information that is easy to understand. This should be a sticky (unless it already is).
 

justinschmidt1

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Re: Mustang Suspension understanding and upgrades

My car handles a thousand times better going from the stock 4x4 springs to sportlines with cc plates...
 

r3dn3ck

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Re: Mustang Suspension understanding and upgrades

Now consider this, after coil over, PHB & TA and tubular everything my car handles far far far better than it did with just springs/cc plates/shocks. It handled a 10x better with just the spring/plate/shock upgrade than it did stock. Dalamar and I are in hog heaven on suspension. w00t
 
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Dalamar

Dalamar

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Re: Mustang Suspension understanding and upgrades

my buddy in AZ has a roush, with springs, subs and panhard.

after driving my car, he's going coils and probably TA on his ride. :p




Hey Redneck - did you upgrade that IRS any? I'm putting an IRS in my 67... I know you can replace all or some of the busings.
what you think?
 

SRT Handz

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Re: Mustang Suspension understanding and upgrades

i have yet to experience a TA with myself behind the wheel but i figure that the entire rear will fell difference than a 4 link
 

r3dn3ck

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Re: Mustang Suspension understanding and upgrades

Dalamar said:
Hey Redneck - did you upgrade that IRS any? I'm putting an IRS in my 67... I know you can replace all or some of the busings.
what you think?

Yep...full MM kit. Bushings all around, braces and coil overs. The rear mounting block is the key to holding it together. Use delrin for every bushing you can. I'd also replace the aluminum 3rd member with an iron case from a T-Bird super coupe. That will take care of the front ears breaking off the case with the aluminum ones. Watch the front diff bushing setup. DO NOT USE METAL OR DELRIN there. Use only poly or rubber for the snout of the diff.

I dislike the IRS for its fragility but it is the most comfortable and streetable of the options out there. I wouldn't track it much unless you're ready for a teardown after each event to find what broke this time.

SRT: If you've ever driven a (cough) camaro you know about how a torque arm rides. It's a little stiffer ride than a 4-link but it has vastly more grip at the same time so you get this sense of handling confidence and the ability to launch without blowing the tires off.
 

mich_666

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Re: Mustang Suspension understanding and upgrades

AaRoN said:
That is all excellent information that is easy to understand. This should be a sticky (unless it already is).

x2
 
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Dalamar

Dalamar

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Re: Mustang Suspension understanding and upgrades

THanks guys, I tried to make it as easy to understand as I could.

Sticky it is. :afro:
 

stang94X

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Re: Mustang Suspension understanding and upgrades

Dalamar said:
THanks guys, I tried to make it as easy to understand as I could.

Sticky it is. :afro:

just an opinion, i think it would be a good idea to also explain the different springs, struts, shock and other stuff for a more drag race application cause not everyone sets there car up to just have a lower stance and/or for street racing/cornering, i think it would be good for people that are like me that dont care about how well the car can take a turn and just want to go in a straight line, like i have steeda drag springs that dont lower the car and that they give excellent weight tranfer when launching, but there are many other companies that make drag springs like: ford racing drag race kit, eibach drag launch kit, competition engineering drag springs, and explain the difference in the front and rear spring rates that are for drag racing and the purpose and benefits of having the air bag in the rear spring, and other stuff like adjustable struts and shocks and just plain set ones that are like the 90/10 ratio and explain the diffence in struts that are 90/10, 80/20, 70/30 and so on and rear shocks that are 50/50 ratio and why that ratio among other ratios are good for drag racing, so if you or anyone else could do it i just think it would make a good write up to have, if i knew more about suspension i would do it but i wouldnt want to write something that might not be totally correct
 
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Dalamar

Dalamar

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Re: Mustang Suspension understanding and upgrades

Great idea! I'll get working on that. :thumb:
 

TRUUBLE

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Re: Mustang Suspension understanding and upgrades

stang94X said:
just an opinion, i think it would be a good idea to also explain the different springs, struts, shock and other stuff for a more drag race application cause not everyone sets there car up to just have a lower stance and/or for street racing/cornering, i think it would be good for people that are like me that dont care about how well the car can take a turn and just want to go in a straight line, like i have steeda drag springs that dont lower the car and that they give excellent weight tranfer when launching, but there are many other companies that make drag springs like: ford racing drag race kit, eibach drag launch kit, competition engineering drag springs, and explain the difference in the front and rear spring rates that are for drag racing and the purpose and benefits of having the air bag in the rear spring, and other stuff like adjustable struts and shocks and just plain set ones that are like the 90/10 ratio and explain the diffence in struts that are 90/10, 80/20, 70/30 and so on and rear shocks that are 50/50 ratio and why that ratio among other ratios are good for drag racing, so if you or anyone else could do it i just think it would make a good write up to have, if i knew more about suspension i would do it but i wouldnt want to write something that might not be totally correct


Dalamar asked me to do a write up on this subject. Although I don't pretend to know all the science and physics of weight transfer and combining shocks and struts to acheive a desired result, I do know what works for our cars as far as a drag race suspension is concerned.

The setup I have goes 1.34 60 foot and the car only traps 136 for a 9.81 ET. These numbers are very comparable to what Super Stock cars are running with similar ETs, which tells me that my chassis is working very efficiently. What's more, with the exception of the antiroll bar, I am driving on the same suspension that I drove on the street . . and it was very streetable.

Not a lot of rocket science in my setup:

Front:

Lakewood 90/10 drag struts
UPR Coilover kit with 14" 175# springs
UPR tubular A-Arms
UPR tubular K-Member
Maximum Motorsports Caster Camber plates

Rear

Steeda Drag Springs
Strange 10 way adjustable shocks
Maximum Motorsports adjustable LCAs
UPR Pro series double adjustable UCAs
Competition Engineering Antiroll Bar

Now, our cars have a tendency to launch a little crooked, with the driver's side rising faster and farther than the passenger side. Thus, we need to be able to adjust (add) preload to the passenger side of the rear suspension. This is why adjustable lowers, adjustable shocks, and an adjustable antiroll bar are important. The proper preload in all of these items will get the car launching straight and "square up" the rear end. There is no magic formula for acheiving this, you just have to play with the preload until the car goes straight. The straighter it goes, the better your 60 foot will be (theoretically).

That said, here is a video of the car launcing crooked and cutting a 1.34:

http://www.youtube.com/v/Ve3qWKG8vM8&rel=1

There is a lot of debate about spring weight in the front of our cars. All I can say is that I have had the best results with 14" 175# springs. Some will say that is too much . . but they don't usually 60 foot as well as I do.

I'm hoping that Craig chimes in here and offers some of his knowledge. He knows a lot more than I do.

Hope this helps.
 

r3dn3ck

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Re: Mustang Suspension understanding and upgrades

That seems to be about the best all around setup for a good street/strip car. 14" front springs on coil over cars will help keep the strut extending quickly as the front end lifts and keep the spring from unloading completely. Shorter 10" and 12" springs are fine on corner carvers whose wheels stay on the ground but they tend to unload completely as the wheel drops toward its lowest point and with lighter springs they don't offer enough jounce distance before they get near coil bind. With short springs that can't stay loaded, when the front wheels finally land the strut gets hit really hard for a couple inches then the spring takes over... leading to more wear and tear on the struts and really high shock loading on the entire front end.

Truuble, that's a killer ride and it cuts sick short times. Thanks for sharing the info.
 

r3dn3ck

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What to know before you ask what part to buy: Post1

The following is from my sticky over at Mustangboards.com:

Before asking questions about which part you should get do yourself and us a favor and decide exactly how you're going to want to use the car. Also, don't forget to tell us what mods you've done to your suspension already, if you're using non-stock rims, axles, etc... and what kind of money you're prepared to spend.

In large part, there are a few basic stages of spring and shock (struts will be called shocks too right now) which correlate to performance potential as well as ride quality. When you up the handling potential you usually decrease ride quality to a similar degree. Some of the more expensive setups get largely around that but nobody escapes it entirely.

Stage 1: Often called "sport" when referring to springs and almost never properly described when talking shocks. This is what you'd use if you're a street driver, sensitive to ride quality, live in areas with really nasty roads or just don't need to bump it up to the next level. Be honest with yourself if this is the level you NEED. Wanting higher rated parts doesn't make them right for your car and is almost always a bad idea. Common front spring rates in this class for standard lowering springs are 450-550 lb/in.

Stage 2: Often called super sport or something close to it. Spring rates in this class are much higher than in stage 1 and shocks need to be a little hotter valved to dampen these properly. This kind of suspension will ride notably rougher than stock and will not be super pleasant over rough roads. It will offer you the capacity to make faster corners on a SMOOTH track than stage 1 but isn't really appropriate for about half the people that use such a setup. If you are a super aggressive driver, this may be the ticket for you but you'll have to come to grips with the ride. Common front spring rates in this class for standard lowering springs are 550-675 lb/in.

Stage 3: This is race level. Race parts are no good on the street for the most part. Race tracks don't have potholes and so they're great places to drive really stiffly suspended stangs but the street isn't usually as good an idea. If you have a race suspension in place then you need really stoutly valved shocks and must live somewhere with reasonably smooth roads or like being beaten around the inside of your car. Don't use race parts unless you know you need them. Common front spring rates in this class for standard lowering springs are 650-850+ lb/in.

Rear spring rates vary depending on lots of other things. Generally whatever set of springs you buy has correct rear rate springs to go with the fronts, sometimes you'll need to spec out 2 different parts, front and back, to balance it properly.

For shocks, you can use this as a rough guide to what's what:

Stage 1: Tokico HP/Blue, Tokico Illumina, Eibach, Strange, qa1, Bilstein HD (MM HD spec), 03 cobra stock

Stage 2: Koni Yellow, Tokico Illumina, Bilstein HD & Sport (MM spec)

Stage 3: Koni DA, Bilstein Race & Sport (MM specs), tokico d-spec

There are others in each category and some of those above belong in more than one category but that's the system I use and it's generally correct enough for common use.

Above all else, if you don't know then call Maximum Motorsports and ask. Those guys are always ready to tell you what parts will work best for you and they'll build you a shopping list that's going to work for you.

Now you just have to learn to be honest with yourself about how and where you drive.
 

r3dn3ck

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What to know before you ask what part to buy: Post2

Part 2:

Shock choice and why it's important.

Shocks and struts are not there to absorb impacts so much as they are there to dampen the spring response. If you've ever seen a car go over a bump and then bounce on the suspension several times you've seen what happens when a shock is not there (or really well worn out/blown). Shocks and struts dampen in 2 directions and they're valved to absorb a specific range of forces.

Stock dampers (what shocks are actually referred to as in technical terms) are not bad but they're made to handle the stock spring rates with unwavering reliability. They're not a performance damper by most measures. They're also designed (in SN95 cars) for a car that sits pretty high and has a long wheel travel for a sports coupe. That makes them less than perfect for using when you lower the car. You end up with the struts and shocks at the bottom half of their travel range and it wears on them. The increased spring rates associated with lowering also do their best to shred the innards of your dampers and soon they're just flat toasted.

Since shocks dampen spring response in two directions attention must be payed to proper selection or you'll get things like the bumpy road jitterbug where the car will dance over rough roads because the wheel is over or under dampened. You can also make the suspension less effective by over damping the spring which makes your whole car lift when you hit a bump instead of the suspension absorbing the hit and passing minimal signal back to the passengers. Both of these occurrances reduce traction and in the worst case can lead to you wrecking your ride because you didn't have the traction you thought you did when you needed it most.

When choosing a strut and shock package, don't go and buy the neatest name brand D-spec super heavy duty just because it's the hottest, get what you actually need based on your spring rates. You'll have a better handling car for your trouble.

For most cars with sport to super-sport level springs, the more popular dampers out right now will do just fine: A set of 03 cobra spec Bilstein struts is perfect for just about any street oriented spring (up to about 650lb/in) but the rear shocks are best left on an IRS. Tokico Illumina's in the rear are also a good unit for just about any street application on a solid axle. If you're a racer then you'll need to get more heavily into the research and ask people that know about race grade parts.

Also, a little tidbit. For you SN95 guys (94-04), when you lower your car, getting fox body struts will give you back about 1/2" of bump travel that you lose with the SN95 spec struts and will keep you off the bumpstops a little better. Bottoming a strut sucks (hurts da' butt). This is a standard practice at most hardcore suspension houses including MM.

Get the damper you need and you'll outhandle cars with much more expensive and less well chosen components.
 

r3dn3ck

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What to know before you ask what part to buy: Post3

Caster Camber plates:

Most street stangs will have trouble finding a really nice driving and tire friendly alignment with the stock plates in place primarily because they weren't intended for a car that sits that low and they're not adjustable. For the 200 bucks it'll cost you to get a set of Maximum Motorsports CC plates you'll really appreciate the savings in tire cost and the ease of adjusting the settings later on (like setting 0 camber for a trip to the drag strip for less rolling friction).

I don't advocate ever lowering an SN95 mustang without CC plates and I usually don't advocate it on Foxbody cars. It's just too cheap to really do a top shelf job to blow it off on being cheap. If you have to wait 2 months to lower your car, cool. It's worth it to do it right.

It's not to say that some cars won't get a tire friendly and straight tracking alignment without plates... some do, just not enough to make it better to go without.

Lowering done right is a beautiful thing. Done wrong or just half-assed it's anywhere from annoying and expensive to flat out dangerous.

The only CC plate I'd recommend for 94-04 is Maximum Motorsports. That's the only plate that I've seen be reliable enough and strong enough. Plus, when you tire of just lowered and want even more handling potential, you can go to a coil over conversion and the MM plates are the only plates you should use with a coil over kit period.
 

r3dn3ck

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What to know before you ask what part to buy: Post4

Common Spring Rates:

This is largely very accurate however, check your facts before treating it as gospel

abe166e7.jpg
 

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