Modded Mustang Forums banner

1 - 20 of 450 Posts

·
Registered
Joined
·
1,598 Posts
Discussion Starter #1
Thought I would write this up so I can stop explaining it every time I come across one of these suspension questions.

The Mustang suspension was poorly designed for High Performance Driving. It was originally designed to be good but not great. The 4 Link design that was incorporated in to the rear of GT’s between 96 and 2004 is poorly created concept. It uses 2 lower control arms and 2 oddly angled upper control arms to position the axle side to side, prevent axle wind up and transfer force from the wheels to the chassis.

The frost suspension is no better. With a flimsy sheet metal K-member that weighs double what tubular parts do while offering half the rigidity and prevents easy access to just about everything. The Strut design also leaves something to be desired with caster camber needing to be carefully monitored and tweaked to optimize handling. The Modified Macpherson strut is the design of putting the spring about half of the distance from the pivot point on the K member to the ball joint at the spindles. And the Strut being placed on the spindle it self. This leads to a slow and clumsy wheel rate ( the speed the wheel reacts to changes in the road) and a poor ride. You can’t get good handling without punishing your low back.

The body is also flimsy and allows for huge chassis twist and rebound. But HOLD ON! It sounds like you are screwed but your not. In fact you are in a pretty good place. The mustang once fixed, all possible for a couple of grand, will out handle just about any car around. Including ferrari’s ( check the video at www.griggs-racing.com )

The solutions are as follows.

Chassis Rigidity: The first thing you need to fix for your safety and for any kind of racing is the Chassis rigidity. Poor chassis rigidity leads to poor weight transfer, sloppy handling and poor ride. Not to mention the inability to take advantage of any mods that affect the movement of your car… think about it, that’s everything.
Solution: Subframe connectors and/or a roll cage. A good set of subframe connectors will connect the front and rear suspension with a strong steel subframe, kind of like every other good car in the world. You can also do a cage, which will work better, but not required for your average joe. I recommend any good companies kit. Maximum Motorports, Griggs, even steeda makes a decent set. They weld to the frame underneath your car and cost less than $200. Not only does it make your car safer, it will make your car doors keep from getting out of alignment after a couple years of hard driving. It happens

The Macpherson strut. The true macpherson strut is what you would normally see on a car. The shock is inside the spring. This links the recoil and spring rate together. It also means that you can place a smaller spring a lot closer to the wheel, giving you a better wheel rate and a smoother ride, while reducing weight. A coilover, is simply a macpherson that allows you to adjust the height of the spring, allowing you to adjust the ride height of your car to the application. In the case of our cars, converting to coil overs actually means you get a better designed suspension component and adjustability. A Double Wammy! Coil overs are recommended for the front of your car and require no more modification than the parts them selves. Unless you plan to go hard core, I don’t recommend the rear coil overs, as the ride quality will suffer due to the MUCH higher spring rates. The front ones will improve ride quality to a point, depending on the stiffness of your springs.

Springs. Should you decide that coil-overs are too much of a step for you, you can purchase a good set of springs for your car. Stiffer springs improve handling. Of course there are limits, but lets assume they don’t matter. For a drag car there are many spring combinations available. Generally soft springs in front and semi soft in rear are the desirable set up. But there are better sources for exactly what spring rate you should get for drag. A good source for those rates is available at StangSuspension.com. They have a table on their web site of just about every spring out there. They are also very knowledgeable if you have any questions. Just remember with stiffer springs, comes a harsher ride. I recommend H&R, Steeda, FRPP, Eibach springs. I had the H&R Race springs. They were very stiff, and I loved them, but it was not for everyone.

Shocks, are an important part of buying your coil overs. High quality coil-overs will be customized to your shocks. There are many choices for shocks and many are specific to certain applications. Regardless, do NOT buy suspension components from an exhaust company. The shocks you get also has just as much to do with your ride quality as the springs. Your shocks are what keep the spring from bouncing after absorbing a shock. This means that you can over or under dampen your springs very easily. If you buy some amazing springs and keep your stock struts/shocks. You will hate life. The springs will overpower your shocks and you will spend all day bouncing down the road. Good companies for Shocks/Struts are harder to find. They cost more money. I will break it down for you in a few different ways. I don’t recommend adjustables unless you truly plan to adjust them a lot.

Drag Adustable – Tokico Illuminas, best adjustable drag shock out there. Its been proven many times.

Road Course Adjustable – Tokico D spec, best adjustable shock/strut out there. And not horrible expensive either.

Road Course Non Adjustable - Bilstein HD’s, and Bilstein custom valved from Maximum Motorports for Coil Overs. Also Koni Yellows are amazing shocks, but expensive and require very good springs.

Cheap Shocks: There are lots of cheap ones out there. Tokico HD’s and KYB’s are ok if you want a stock replacement. Not generally that great for high performance though.


K-Member / A arms - Your K member is the most important part of your front suspension. It is what your engine, struts, A arms and subframe connect to. Your only choice is really a tubular set up. This usually require changing to tubular A arms and Coil-Overs as well. This can be a large change all at once, But definitely worth it. There are some A arms that don’t require A new K member, but most K member require the tubular A arms since they do not allow you to keep your modified macpherson strut. The reason is that they need to add a ton of material to keep that stupid spring where it is; which leads to more weight and less access to the engine and exhaust. A new K-member will give you better suspension geometry leading to better corner loading and body roll. It also adds stiffness to the front end, as well as clearance for new motors, turbo’s, exhaust and flat convenience. It is a big mod, and takes some time, but a worth it one in the end.


And now to the Back of your car.

4 Link - Your stock mustang comes with a brilliant design called the 4 link. I explained its flaws above. The real fix is a package kind of thing. There are too many jobs that the 4 link is trying to do. The following parts work together to fix its flaws.

Lower Control Arms- Lower control arms are the Heart of your rear suspension. They hold the axle in place and transfer the majority of the energy to your car’s body. The stock ones work well, they are just weak. New ones will firm up the rear end, making for better transfer of energy to your chassis, less axle bind and less windup.

Upper Control Arms – Upper control arms are the wonder twins of your rear suspension. They are simply a couple a steel pieces that connect at a funny angle to your upper differential casing. In a normal car, they are fine, but when at the limits, they are plain dangerous. They bind under hard turning making your tire grip unpredictable, they help prevent but in no way stop axle wind up.

Panhard Bar / Watts Link – These two items are pieces designed to take over 1 job from the 4 link. They bolt to your frame and connect to your axle with either a single pivoting bar or 2 bars connected to your differential housing. They both align the axle with the middle of your car. This prevent the rear axle from ever moving out of alignment and eliminates side to side axle bind. This means you can drift or turn hard without having to worry about the rear end skipping off the road and ruining your traction. 05+ models have a factory Panhard Bar installed.

Torque Arm - A torque arm is a piece that takes away the second job of the 4 link. It bolts to the housing of your differential preventing axle wind up entirely. It also runs parallel to your driveshaft and is welded to your subframe connectors. If you install it and the panhard bar. You can remove your upper control arms. This will save you a decent chunk of weight and give you a stiffer yet freer moving suspension. This leads to better wheel rates and solid transfer of energy to the wheels and chassis. Torque arms not only increase the ability to turn and accelerate, it also moves the connection point of the rear wheels to the body, making your car actually stop faster too. Instead of causing the car to dive as much, it keeps the car more level allowing your rear tires to do more of the work than stock.


Most of this information transfer’s to other models of mustang. I’m pretty sure all of the 5.0’s use the same suspension. And the cobra’s have the same front suspension as us. The 05+’s also use the same front and rear with the addition of a panhard bar. There are some other extreme options out there. You can for instance get an unequal length double a arm set up for your front. This gets rid of the strut and cc plates in the front, and replaces them with a shock and two A-arms that make you have a fixed toe and caster with an adjustable camber angle. ( I believe I don’t have those switched) The new set up is far superior but, very expensive. $4-5 for the whole thing. But that is new K-member, coil-overs, and A arms. It’s a worth while change if your car is a track only monster, but not for just about anyone else.

If you have any questions. Feel free to post them. I know a lot more, that I’m sure I could squeeze out if I wanted to spend the time.

I also advise doing some research of your own at the following sites.

Griggs Racing ProductsMaximum Motorsports :: The Leader In Mustang Performance Suspension
www.stangsuspension.com
Tiger-Racing
 

·
Registered
Joined
·
1,598 Posts
Discussion Starter #3
Can we sticky this so people will be able to look things up here?
 

·
Priest of the Car Gods
Joined
·
17,313 Posts
A few additions.

The rear suspension was the same starting with the fox body all the way through the '04s, with the exception of the IRS used in the '99-'04 Cobras. In '05 the rear suspension went to a totally new 3-link design

If you're not going to modify your suspension all at once, the rear is much more important to modify than the front; the front may be bad, but the rear is horrible. Maximum Motorsports measured 2" of lateral axle travel with stock suspension. That's the wiggle you feel in the rear end under hard braking coming into a corner.

There are other options than the torque arm mentioned above, including but not limited to the decoupled torque arm, tri-link, and 5-link. The torque arm is the most used by road racers, but it does have it's detractions. For one, it's heavier than some of the other options, and for two it sacrifices braking stability for stability under acceleration.

Regarding adjustable shocks, I highly, highly suggest AGAINST them. Place a budget adjustable (read: anything less than about $500/corner) on a shock dyno, and you'll understand. If you can't afford to spend $2k or better on your shocks, your best bet is to talk to someone that specializes in shocks and have a set of nonadjustables (Bilsteins are my preference) custom valved for your application. Shocks should match your springs, not compensate for them.
 

·
Registered
Joined
·
1,598 Posts
Discussion Starter #5
Lowering FAQ

*With all of these answers, there are definitely exceptions, these are just the general guide lines as I have sourced from numerous suspension manufacturers.

1. Will Lowering my car Require me to buy CC (Caster/Camber) plates?
Not Always. When lowering a car up to 2" you are not REQUIRED to get the CC plates. More than 2" it will be very difficult if not impossible to get the car properly alligned. Some places can get extended bolts and such to make the alignment work, but CC plates are the preferred alternative.

2. What are CC Plates?
CC plates are Caster Camber Plates. They sit on the top of you strut tower and locate the top of your strut, allowing for the adjustment of your caster and camber. After market ones add strength and added adjustability to your car's alignment. They are required for most Coil Over conversion kits.

3. Will Lowering my car make me need new shocks?
Ideally you should always get new Shocks/Struts to match your springs. Although the budget minded modder might do otherwise. Most aftermarket springs are not a ton different in spring rate than your stock springs. Making it possible to swap them out withouth hugely affecting your shocks/springs and handling. Lower than about 2" of drop or a good 30% softer or harder spring rate and you should definitely be buying new shocks. Stock shocks will not be able to support the new limits of the suspension with that much lower suspension. Your suspension geometry will also be greately affected by that much of a drop with out several other supporting mods.

4. When do I need to get a Bumpsteer Kit?
When you want it. Bumpsteer is created by bad geometry in your suspension. The lower your car is, the worse it is. A good guage is the 2" mark. Belowe 2" you will begin to really feel the difference, above 2" it is more up to you.

5. What are the required parts for a drop greater than 2"?

CC plates
Specialized Springs or Coil Over Kit
New Shocks/Struts to match Coil-Over or Spring's spring rate.
New K-member and A arms to support the new geometry.
Bump Steer Kit
 

·
Registered
Joined
·
1,598 Posts
Discussion Starter #6
bumping this, so people will just read it instead of asking questions over and over again.
 

·
Abyssinian of AX
Joined
·
7,994 Posts
Nice post, MM97 :)

Funny, I was gonna "fill in" some info from your last paragraph on post #1, but you beat me to it ;)

I agree with the sub-frames whole-heartedly :D This was the single best upgrade of my entire suspension. I wish I knew about them when I ran around in my Fox body for over 20 years :( The Fox is said to be 25% less stiff than the SN95/New Edge and the S197 is supposed to be 75% (or 125%, I forget) stiffer than those! Think of sub-frames as Viagra® for your pre-'05 Stang :cool: Even Griggs does not do any sub-frame support on the S197, but hey do install a tubular "K" member and certainly helps. Oh, I almost forgot, nowhere on the Griggs site will you even find a strut-tower brace. So if someone wants to sell one for an S197, tell 'em to.... fugettabouttit! :D

Jazzer :)
 

·
Registered
Joined
·
69 Posts
Don't forget the Maximum Motorsports site, Maximum Motorsports :: The Leader In Mustang Performance Suspension . Their prices aren't the best :cough cough:, but the technical writeups they have citing the stock suspension issues, and what their aftermarket parts do to help remedy that are great. If you're new to suspension parts, it's a great way to learn. They've also got some great installation guides in PDF format that easily guide you through the installs.
 

·
Priest of the Car Gods
Joined
·
17,313 Posts
Oh, I almost forgot, nowhere on the Griggs site will you even find a strut-tower brace. So if someone wants to sell one for an S197, tell 'em to.... fugettabouttit! :D

Jazzer :)
I think a lot of people don't understand effect a strut tower brace has on handling. A strut tower brace stiffens the front suspension, which decreases front grip and causes the car to tend more towards understeer. As the Mustang is already predisposed to understeer*, a strut tower brace on an otherwise stock car is actually going to be detrimental.

*The oversteer that most people associate with Mustangs is not due to suspension design, but a failing of the suspension wherein the rear links start to bind.
 

·
Registered
Joined
·
11 Posts
Suspension is where I am first headed torwards, this post was informative. I was wondering which part first, if the tubular K-member can be used on a street vehicle, and if the torque arm is a good move. Many thanks.
 

·
Abyssinian of AX
Joined
·
7,994 Posts
Personally, I would go frame support first. That would frame connectors (upper and lower if you can afford it). A "K" member is just fine for street, but can get your budget to go upward as this opens door to upgrading LCA's and that leads to decision of going coil-overs or not. If you are not sure about ultimate goal, stop with frame connectors and go after that 4 link out back.

Is your goal cornering and twisties :D:D:D or to put power to the ground? Good suspension will help with both, but $$$ always comes into play at some point.

Start a new thread for this question and put a budget together for available $$$ for your mods.

Jazzer
 

·
Priest of the Car Gods
Joined
·
17,313 Posts
Suspension is where I am first headed torwards, this post was informative. I was wondering which part first, if the tubular K-member can be used on a street vehicle, and if the torque arm is a good move. Many thanks.
Just be careful with which tubular k-member you get. A lot are geared for drag racing and are only for weight reduction. If you're into cornering, make sure you get one that's designed for it, and isn't just part of a drag race setup.

And there's absolutely 0 loss of streetability with a tubular k-member, if anything it will increase your streetability, as the car will be better balanced.
 

·
Abyssinian of AX
Joined
·
7,994 Posts
^ I'm partial to Griggs myself :p
 

·
Registered
Joined
·
195 Posts
Is anyone having a problem accessing the griggs link in this post?
 

·
Priest of the Car Gods
Joined
·
17,313 Posts
Suspension is where I am first headed torwards, this post was informative. I was wondering which part first, if the tubular K-member can be used on a street vehicle, and if the torque arm is a good move. Many thanks.
Was flashing back to this on my drive in to work today - definitely do the rear first! (and a torque arm is a fantastic move)
 

·
Registered
Joined
·
210 Posts
Great post.......I bought a set of struts and coils for my 85 GT but have a set of coil overs. Should I put the coil overs on instead of the struts?
 

·
Registered
Joined
·
2,182 Posts
hey guys i bought upper and lower control arms for the my 97 cobra...they are Lakewood and i got them for 125...is that a good deal?
 
1 - 20 of 450 Posts
Top