Mustang FAQs and Shop Talk
Choosing the right damper
While Bilstein, Tokico, Koni, Eibach, and H&R provide a wide variety of quality dampers that meet the needs of Mustang owners, we found that many of our customers have special requirements. For those situations, MM engineers worked closely with Bilstein to create new high performance valving. Our efforts have resulted in the creation of several new series of MM-valved dampers: the MM Sport dampers, and two different series of MM Race dampers, for both solid-axle and IRS equipped Mustangs.
The MM Sport series and Race series struts have our own proprietary housings. These strut housings feature much stronger mounting ears to prevent the failures associated with other strut mounting ear designs. This makes the MM Sport and Race series dampers ideal for aggressively driven track cars fitted with wide R-compound tires and racing brake pads.
The MM Sport series perfectly complements the existing Bilstein HD series. The MM Sport dampers are designed for coil-over spring rates that are too high for the HD series to control, yet softer than the spring rates used with the MM Race series. As the MM Sport dampers were also designed to provide good ride quality, they are the perfect choice for a dual-purpose Mustang that sees aggressive street driving and occasional open tracking.
The MM Race series are available with two different valving configurations, to match different ranges of spring rates. The MM strut housings for the Race series were designed to provide an increase in bump travel over standard strut designs. This is a significant benefit for the extreme amount of lowering typical of road race Mustangs. The MM Race series dampers are not recommended for street use, as their valving was designed solely for optimum performance with high spring rates.
All suspension parts on any track-driven Mustang, including struts, should be regularly inspected. If you are interested in upgrading your previously purchased MM-valved struts, or Bilstein HD struts, to the proprietary Maximum Motorsports strut housing with its reinforced mounting ears, please contact an MM Tech Associate.
How does all of this development and testing help you? It provides you with choices. You can now choose exactly the spring rates you need for your application, and be assured that there is a suitable damper to match.
What is a damper?
"Damper" is a term that describes the primary function of a shock or strut. Both are intended to control spring oscillation. They do this by damping the spring's natural tendency to oscillate by using hydraulic fluid. An un-damped spring will vibrate for quite some time after its initial compression or extension. Dampers (struts or shocks) usually reduce the duration of the spring's oscillation to one complete cycle.
Shocks usually have few other functions than to act as a damper. They are sometimes also used to limit suspension droop travel, and to limit suspension jounce (bump) travel.
1979 to present Mustangs all were designed with a strut front suspension and shocks in the rear suspension.
Introduction to FSD techology for cars
As a leading manufacturer of high performance shock absorbers KONI develops the technical features of its front & rear dampers by following a simple principle: to meet the diverse demands on its products with sophisticated mechanical solutions.
The everlasting problems with vehicle damping
Vehicle damping has always been a compromise between comfort and road-holding. An obvious example is a Formula 1 racing car which offers the best possible road-holding but with minimal comfort. In a personal of sport car one expects to experience the ultimate in comfort, combined with safe road-holding. Minimum damping is required for your comfort whilst strong damping is needed for safe and stable driving. This conflict of goals can not be solved with conventional front & rear dampers. Other damper systems, which are currently available in the market do not offer an adequate solution:
- Position-dependent shock absorbers will give you extra comfort, as they allow more movement of your car, but as a result the road-holding is inferior. Sudden bumps in the road will still be very unpleasant.
- Pneumatic and electronic adjustable shock absorbers may improve road-holding in the future. The disadvantage of such complex systems is that they are very expensive and time consuming to set up correctly.
KONl shock absorbers with Frequency Selective Damping (FSD) technology, have been specifically designed for personal and sport cars and they combine the ultimate in comfort and road-holding. The purely mechanical solution and thus the independence of electronic control components are the basis for the the first choice of KONl FSD High Performance Damper if you have to solve the familiar everlasting problem.
Comfort and handling can be split in two different frequency areas:
- For comfort, with the suspension moving in a high frequency area (Â± 10 Hz), asking for low damping forces.
- For handling, with the suspension moving in a low frequency area (Â± 1 Hz), asking for high damping forces.
If you are able to change the damping force level in relation to the frequency of the movement, you create the possibility to solve the conflict in terms of comfort and handling ever present in conventional dampers.
The KONI FSD technology does just that!
How does it work?
In standard shock absorbers the main damping characteristic is defined by the oil flow (I) going through the piston assembly.
Combining it with the FSD feature, KONl added a special valve which is able to control a parallel oil flow next to the one going through the piston. This parallel oil flow (II) is closed by the FSD feature, giving a rise in damping force almost linear to the time that the piston is moving in one direction.
Put simply: the FSD feature is a hydraulic amplifier that delays the build up of pressure. One could say that an extra tuning option has been created in order to get the best possible combination of handling and comfort. Since it is an integrated part of the hydraulic valve system inside the damper, no additional cables, sensors or any other electronic devices are needed to operate an FSD damper.
FSD is the simplest and most economic way to significantly improve the ride and driving characteristics of every car. Certainly in comparison with costly systems which work on the basis of computer technology, complex electronics and sensors.
MM Roll Bar Photos, 2005+ Mustang Hardtop
Maximum Motorsports Torque-Arm FAQs
Don't forget to read this list of questions that must be answered before purchasing a torque-arm. Most of the ordering related questions are also discussed in these FAQs below.
How do I get more traction?
Install a Maximum Motorsports torque-arm. It is the key to maximizing rear grip for a solid-axle equipped Mustang.
What will the MM torque-arm do for me?
- It will increase straight-line traction.
- It will provide more rear grip during cornering.
- It will improve corner-exit acceleration.
- It will provide superb control and predictability.
- It will increase wet weather traction.
- It will improve ride quality.
What is a torque-arm?
It is a long suspension arm that attaches between the rear axle housing and the chassis.
Is a torque-arm okay for street driving, or is it just for drag racing or road racing?
The MM torque-arm is great for all three situations. Increased rear grip helps in every type of driving; would you ever complain about having too much traction?
What's wrong with the stock Mustang rear suspension?
- All 1979-2004 solid-axle equipped Mustangs have the same 4-link rear suspension first designed for the 1978 Ford Fairmont. It has significant limitations in performance applications.
- The Mustang's rear suspension design forces the upper control arms to perform two jobs at once. They control the side-to-side position of the axle housing, while also preventing axle-housing rotation during acceleration and braking.
- The Mustang upper control arm design fails to perform either job well. This design causes binding of the rear suspension that not only leads to poor handling and traction problems, but also damages the upper control arm mounts on the chassis.
How does the MM torque-arm improve traction and handling?
- The complete MM torque-arm Suspension System replaces the troublesome upper control arms with the MM torque-arm and panhard bar. This separates the two functions once performed by the upper arms. The Torque Arm controls axle housing rotation during acceleration and braking, and the panhard bar controls the side-to-side position of the axle housing. With each part dedicated to a specific job, each can perform its function without compromise, greatly improving the performance of your Mustang.
- The MM torque-arm plants the rear tires much better during acceleration than the stock four-link design, and the panhard bar locates the axle much more precisely. Your Mustang's overall performance will be greatly improved, with much better acceleration out of corners, along with improved handling, stability, better straight-line launching ability, and increased predictability.
Which torque-arm is right for me?
- There are two versions of the MM torque-arm: Standard-Duty, and Heavy-Duty. Both provide the same performance improvements for your Mustang, but each is rated for a different level of engine torque.
- Which torque-arm your Mustang needs depends on the transmission's first gear ratio, the rear gear ratio, the amount of rear wheel torque, and how you drive it. Keep reading to see how to choose between the two torque-arms.
How are the torque-arms rated?
We determined the limits of each torque-arm by destructively testing them. Each torque-arm was then rated for the most difficult scenario possible: a high-revving-sidestep-and-dump-the-clutch launch, with no clutch slippage, on sticky drag tires that grip the pavement instead of burning rubber. That's the type of launch that will send the front tires skyward. If you don't mount up sticky drag tires and drive your Mustang like that, then the maximum rear wheel torque ratings listed may be disregarded for your situation.
How do I choose between the two torque-arms?
- Find your transmission's first gear ratio (or your transmission model) in the heading of one of the three torque-arm Rating Tables below. The first gear ratio determines which table applies to your Mustang.
- Find your car's rear gear ratio in the far left column of that table.
- On the row with your rear gear ratio, look to the right. The next two columns have the rear wheel torque ratings for each torque-arm. The first is the maximum rear wheel torque rating for the Standard-Duty torque-arm. The second is the maximum rear wheel torque rating for the Heavy-Duty torque-arm. These torque ratings refer to the peak rear wheel torque as measured on a Dynojet chassis dyno.
- Select the torque-arm that has a rear wheel torque rating that is higher than the peak rear wheel torque that your Mustang produces, as measured on a Dynojet chassis dyno.
- Note: Take into consideration any future power increases you may make to your Mustang.
|First Gear Ratio
OEM T5, T45, TR-3650, TR-3550
|Rear Gear Ratio||Standard TA||Heavy Duty TA|
|Max. Dynojet Torque
|Max. Dynojet Torque
|First Gear Ratio
Close Ratio T5, TR-500, TR-600
aftermarket T-56, 4R70W
|Rear Gear Ratio||Standard TA||Heavy Duty TA|
|Max. Dynojet Torque
|Max. Dynojet Torque
|First Gear Ratio
C4, C5, C6, AOD, AODE
|Rear Gear Ratio||Standard TA||Heavy Duty TA|
|Max. Dynojet Torque
|Max. Dynojet Torque
What if my car exceeds the listed engine torque rating?
The MM Heavy-Duty torque-arm has been used without problems on cars with over 1,000 ft-lb of engine torque. Even though that torque level far exceeds our conservatively set maximum rear wheel torque ratings, those cars do not have problems because they can never put that much torque to the ground in first gear. If they try to do so, the tires simply go up in smoke. The torque-arm has a lower load placed on it once the transmission is shifted into the higher gears because there is less multiplication of engine torque. In the higher gears the full amount of engine torque can be applied to the tires without spinning them, and without overloading the torque-arm.
Do I need subframe connectors?
Yes. Your Mustang must have suitable (welded-in) subframe connectors installed before installing an MM torque-arm. The MM torque-arm's front crossmember attaches to the subframe connectors. While Maximum Motorsports Full-length Subframe Connectors are suggested for best performance, they are not mandatory. See the table below for the minimum size requirements for subframe connectors.
|Subframe Connectors - Minimum Required Dimensions|
|Shape: height X width||The tube wall thickness must be at least:|
|Rectangular: 1" X 2"||.120" wall|
|Rectangular: 1-1/4" X 2"||.083" wall|
|Rectangular: 1-1/2" X 1-1/2"||.083" wall|
|Round: 1-1/2" diameter||.120" wall|
Do I need a panhard bar?
Yes. An MM torque-arm installation requires that a suitable panhard bar be installed first. The geometry of the Maximum Motorsports panhard bar compliments the MM torque-arm, and provides the best performance for your Mustang. If another company's panhard bar or Watts Link is installed, the roll center may not be at the optimum height to work well with the MM torque-arm.
Should I change my springs?
Yes, but only the rear springs... To take full advantage of the improved rear grip provided by the MM torque-arm Suspension System, the rear spring rate should be increased from what is typical with a 4-link suspension. This will help optimize the handling balance so your Mustang will have the best performance possible. There is no need to change your front springs solely because of a torque-arm installation.MM designed stock-location rear springs specifically for use with a torque-arm. The table below matches the appropriate rear spring for use with a torque-arm to various front springs.
|Front Spring Rate
|Use This Rear Spring|
|490-575||H&R 51650 or 51651|
|Coil-over 175-250||H&R 51650.99 or MM 42TA5|
|Coil-over 350 & up||Requires coil-overs|
Do I need to change my rear lower control arms?
The rubber bushings of the stock rear lower control arms allow far too much fore and aft deflection for proper axle control. For the best performance from the MM torque-arm Suspension System, also install bind free MM Rear Lower Control Arms.
Will my exhaust system need to be modified?
Maybe, it depends.
- The MM Standard-Duty torque-arm clears most stock H-pipes, and many aftermarket H-pipes and X-pipes. If any exhaust clearance problems are encountered, they usually require only minor exhaust alterations.
- The MM Heavy-Duty torque-arm does require specific modifications to the exhaust system. Any competent muffler shop can easily perform these simple changes. See the MM torque-arm installation instructions for more details.
Can I read the instructions before I purchase?
Do I have to remove my upper control arms after installing a torque-arm?
- Yes, the upper control arms must be removed.
- The torque-arm is not an add-on traction device. It is a fundamental change in the rear suspension design.
- A torque-arm suspension is a variation of a 3-link suspension. Plus a panhard bar.
- Leaving the upper control arms in place would cause massive suspension binding because you would have both a 4-link and a 3-link suspension on the same car, with both systems trying to cause their own particular rear suspension motion.
MM Mustang Panhard Bar Tech
The root of the problem
Solid-axle-equipped Mustangs were manufactured with a four-link rear suspension design that requires the rear upper control arms to do two jobs. One job is to locate the axle laterally. Unfortunately, compromises in the design of the Mustang four-link prevent the rear axle from being precisely located. The axle will shift from side-to-side by up to 2 inches. This inconsistent movement of the rear axle causes a rear-steer effect.
Rear-steer means that the rear of the car is steering itself, without any steering input from the driver. This rear-steer behavior makes the Mustang unstable, and requires corrective action by the driver. This can make the driver feel very uncomfortable, as they do not have complete control of the rear of the car. While that four-link design might be suitable for a commuter car, it cannot provide the handling prowess expected of a high performance vehicle.
The MM panhard bar solution
The MM panhard bar adds an aluminum rod as a lateral suspension link between the rear axle and the Mustang chassis. This simple design precisely controls the side-to-side location of the axle to eliminate rear steer. The unstable and unpredictable feeling typically associated with the Mustang four-link suspension is gone, making your car safer and easier to drive!
Why choose a MM panhard bar, and not a Watts Link?
There are two good methods of controlling the side-to-side location of a rear axle, a panhard bar or a Watts Link. MM's Engineering Team chose the panhard bar because it allows a much lower roll center than a typical Watts Link design. A lower roll center reduces the tendency for the inside rear tire to lift and unload during cornering. As a welcome bonus, a panhard bar is far less complex, less expensive, lighter, and allows for the use of tail pipes!
Upper control arm bushings
Whether or not your Mustang is equipped with a MM panhard bar, it is very important that the rubber upper control arm bushings be retained. This is one application where the compliance of a rubber bushing is a benefit. Retaining the rubber upper control arm bushings is a necessary compromise to achieve acceptable handling. See the Rear Lower Control Arm section here for more information about control arm bushings.
How it works: The complex interactions of a four-link rear suspension plus a panhard bar
As the suspension moves, the rigid panhard bar causes the Mustang's rear axle to move through a different, and better path than the stock four-link design. This requires the upper arms to physically change length as the suspension moves. Obviously, the metal control arm cannot change length. But its effective length, the distance between the control arm's two pivot points, can change because of the inherent compliance of a rubber bushing. If the ability of the upper control arms to change their effective length is hindered by a noncompliant bushing material, the suspension will bind up, and not move freely. The resulting restriction in the ability of the rear suspension to freely articulate will cause poor handling; the car will have a tendency to oversteer, and it may do so in a sudden and unpredictable manner.
Unique features of the Maximum Motorsports Mustang panhard bar:
- MM's Panhard rod is the longest possible at 38" between pivot points. This minimizes the amount of the rear axle's lateral movement due to the arc of the rod's travel. The longer the rod, the larger the radius of the arc. The larger the radius, the smaller the sideways movement during bump and droop travel.
- A single slot on the MM chassis mount allows for vertical height adjustment to keep the Panhard rod level at different vehicle ride heights. A level bar minimizes lateral motion over the range of suspension travel.
- Large 3/4" rod-ends are mounted in double shear at both ends.
- The unique design and quality materials of the MM axle and chassis mounts ensure they are strong enough to not break, and stiff enough to not flex, even when cornering loads exceed well over 1 G.
- Maximum Motorsports' boxed panhard bar axle mount bracket encloses the rod-end for a rigid, non-flexing mount.
- The MM chassis bracket mounts to the rear frame rails of the car, not the flimsy trunk floor or spare tire well.
- MM's exclusive frame panhard bar frame inserts fit inside the rear frame rails. These provide a structurally sound attachment point for the MM panhard bar chassis mount.
- The MM panhard bar is designed to clear the factory tailpipe routing. Aftermarket tailpipes that follow the factory routing, such as Flowmaster and DynoMax will clear the MM panhard bar without modifications.
- The MM Panhard rod is mounted as low as possible to lower the Mustang rear roll center height (which is essentially at the same height as the rod). A low roll center reduces the tendency for the inside rear tire to lift and unload during cornering. The roll center height of the MM panhard bar is considerably lower than what can be achieved with a Watts Link.
- The Panhard rod itself is a lightweight aluminum tube. It is available in either natural finish or polished. The identical item is used on NASCAR stock cars.
- While a properly installed MM panhard bar is compatible with the standard T/A differential cover, we do recommend the new low-profile T/A cover to ensure there is no interference.
The next logical step after the installation of the MM panhard bar is the installation of a MM torque-arm. Upon installation of the MM torque-arm the rear upper control arms are be completely removed. This solves the bushing deflection problem, and finally removes the last source of binding in the rear suspension. Maximum Motorsports also has complete MM torque-arm Suspension System packages.
Note: If you have a Baer brake system with PBR calipers on the rear of your 1994-04 Mustang, you will need the MM Caliper Relocation Brackets.
MM Mustang Steering Shaft Tech
Maximum Motorsports has reinvented the steering shaft assembly!
And you didn't even know there was a problem...
Improving performance over the stock steering shaft
The stock Mustang steering shaft has a rubber rag joint that flexes, giving the steering wheel a vague and imprecise feeling. As if the inherent deflection of the rubber wasn't bad enough, it is also prone to softening from the heat of aftermarket headers, especially on the 1994-2004 Mustangs. On many cars the flexing of the rubber joint causes enough play that the steering wheel can be moved an uncomfortable amount before causing the tires to change direction. Replacing the rubber rag-joint with a race-quality needle-bearing U-joint sharpens steering response. The car will respond much more quickly, and precisely, to the driver's steering inputs.
Aftermarket steering shafts: The problems
Traditionally, the U-joints of aftermarket steering shaft assemblies were secured to the steering shaft with small setscrews. These setscrews protrude out from the U-joints, and are closer to the header tubes than the upper U-joint of the stock steering shaft. It is not unusual for the end of a setscrew to hit a tube of an aftermarket header. These setscrews also come loose over time, which causes sloppy and unsafe steering. Even when a thread-locking compound is used, the heat from the exhaust will cook it out, and the setscrews will eventually loosen.
MM has long recommended aftermarket steering shafts because they improve the car's steering response. We have endured their drawbacks in order to enjoy the sharper steering response they provide. We have suffered through not only the problem of setscrews hitting the header tube, but also the continued loosening of those setscrews. This is simply the wrong place to use setscrews.
MM's new design
The MM Engineering Team designed a new steering shaft assembly that does not use setscrews. That's right, no setscrews! Instead, we secure the U-joints by welding them to the shafts. We attach the steering shaft assembly to the steering rack with a pinch-bolt, just like Ford did with the stock steering shaft assembly. An added bonus with the MM Steering Shaft is the addition of a telescoping center portion to the assembly. This collapsible section eases installation and improves safety in the event of an accident.
- From the Bottom Up --The MM Steering Shaft
- The lower needle-bearing U-joint is secured to the input shaft of the steering rack with a pinch-bolt clamp, just like the stock steering shaft is attached. This is a much more secure attachment than a setscrew can provide.
- The center section of the shaft assembly is made of two telescoping pieces, with one sliding inside of the other. This allows collapsing the shaft to ease installation. The shaft can also be lengthened, up to 1.1? longer than a stock shaft, to allow repositioning of the steering rack. The unique design of the MM collapsible center section prevents the two halves from pulling apart.
- All U-joints are secured by welding. No setscrews to loosen!
- The top adaptor stub is secured to the stock steering column just like the original shaft, making installation a breeze.
Upgrading a Fox Mustang to an SN95 steering rack
New! MM now has a Hybrid Steering Shaft Assembly that allows the installation of an SN95 (1994-2004) power steering rack into a Fox (1979-93) chassis Mustang. The SN95 steering racks are a good upgrade for a Fox Mustang because they provide improved steering feel, with slightly higher effort and more linearity than the Fox steering rack.
With the new MM Hybrid Steering Shaft Assembly the SN95 steering racks can now be easily installed in a Fox chassis Mustang. The MM hybrid shaft assembly has the correct lower U-joint to connect to the unique triangular-shaped input shaft of the SN95 steering racks. This MM hybrid assembly also features a splined joint to allow correcting the orientation of the steering wheel. This feature is required to properly center the steering wheel with the SN95 steering rack. Without this unique MM shaft the steering wheel would be rotated nearly 90 degrees from center, which is far too much to be corrected by adjustment of the tie-rods. The stock steering wheel and airbag (if so equipped) are not disturbed.
The MM Hybrid Steering Shaft Assembly is constructed with all of the great features listed above for our other high performance steering shaft assemblies. No setscrews!
Tech tip: Other required parts
Other items are needed to install an SN95 steering rack into a Fox chassis Mustang. Fox chassis tie-rods are required because the SN95 tie-rods are too long for the Fox chassis front control arms. The correct length tie-rods can be easily swapped into place because the inner threaded connection, where the tie-rod attaches to the steering rack, is the same. Note that the threads on the tie-rods, for attaching the outer tie-rod ends, are different between the SN95 tie-rods and the Fox tie-rods. This will dictate which outer tie-rod ends must be used.
For those using the longer SN95 front control arms on their Fox Mustang, and who will be using an adjustable outer tie-rod end bumpsteer kit, there are two options to choose among for tie-rods and outer tie-rod ends. The longer SN95 tie-rods can be used, which will require an SN95 adjustable outer tie-rod end kit. Or the shorter Fox tie-rods can be used, along with our MMTR-6 tie-rod end kit. This kit has a longer aluminum adapter sleeve that effectively lengthens the Fox tie-rod to match the longer SN95 front control arms.
MM's steering rack mounting bushings are also an excellent way to tighten up your steering response.
Installation of Lowering Springs | Tech Notes
Installing aftermarket springs involves more than just the spring installation itself. To get the full benefit from your spring purchase, there are several related factors to consider:
Lowering a Mustang will change the front alignment. The relative lack of adjustment features can sometimes make it difficult to restore the vehicle to Ford camber specifications without using an aftermarket solution. MM Caster Camber Plates greatly extend the range of camber and caster adjustment, allowing alignment to factory specs.
Ford installed rubber isolators on both ends of the springs to reduce NVH (Noise, Vibration, and Harshness). The original rubber isolators deteriorate with age, and compress enough over time to noticeably lower your Mustang. Whenever installing springs, it's the best practice to install new spring isolators. Urethane isolators are more durable than rubber, and do not compress appreciably over time.
Struts and shocks
Ford matched the valving in the original struts and shocks to the original stock spring rates. Most aftermarket springs are stiffer than the stock springs--enough to cause an underdamped situation, meaning that the struts and shocks (the dampers) can't control the springs. That makes the car feel floaty, disconnected from the road, and harder to control. The solution is to install dampers matched to the new, higher spring rates. MM offers a wide variety of quality high performance dampers. If you'd like help choosing the most appropriate damper for your Mustang, please contact us.
"What's that?" you ask. Ford installed a rubber block above the pinion bearing of the rear end of 8.8" solid axle equipped 1986-2004 Mustangs. The pinion snubber limited how high the front of the differential could climb as the rear axle rotated during hard acceleration. When hitting large bumps, the axle will typically hit the pinion snubber before it hit the bumpstops. MM created a pinion snubber which is slightly shorter, and has a progressive increase in stiffness, to improve ride quality. With the MM pinion snubber the axle hits it less frequently, and when it does, the impact is much less harsh than with the stock snubber. MM includes this pinion snubber with each set of 4 H&R springs.
Big Brake Caliper and Wheel Clearance
Most 13" big brake kits require 17" or larger wheels, with at least 50mm of clearance to the back of the spokes: see the drawing below. The Konig Villain rim (17x9) provides adequate caliper clearance for 13" big brake kits from StopTech, Brembo, and Wilwood.
Big brake kits with 14" rotors require 18" or larger wheels.
For the most accurate information about the clearance requirements of big brake kits, always check the manufacturers own website for drawings and templates. See below for links to StopTech.
If you are using a wheel that does not provide adequate spoke clearance, sometimes wheel spacers can be used to increase the distance between the back of the wheel spokes and the caliper.
Stoptech has downloadable caliper clearance templatesthat you can print out. They offer vehicle specific templates and instructions for how to use them on their site at the above link, as well as direct links to the Mustang templates below.
Modifications required to fit Big Brake Kits to a Fox chassis Mustang
- To install one of these big brake kits on a 1979-93 Mustang, the spindles from an SN95 Mustang must also be installed. The choice of which spindle (1994-95 or 1996-2004) to install depends on whether the car has a stock K-member or a MM K-member. See theFront Suspension topics from the MM FAQs & Tech Tips page for how to choose the correct spindle for your application, and more information about everything involved with upgrading to SN95 spindles.
- You must also install the correct brake hoses, or adapter fitting, to fit the SN95 front big brake kits to a Fox chassis Mustang, because the hoses included with the big brake kits are designed to fit the SN95 chassis, not the Fox chassis
- A front big brake kit should only be installed when the rear drum brakes have also been upgraded to discs.
- For best braking performance, all of the 13" front big brake kits should be installed on Mustangs that are also equipped with the 11.65" Cobra (or larger) rear rotor. This will maintain the brake balance that these front brake kits were designed to provide.
- If these kits are installed along with the 10.5" diameter rear brake rotor that was standard on all 1994-2004 non-Cobra Mustang models, the car will have about 10% less rear brake torque than with the Cobra rear rotor. Such an installation will cause less rear brake bias, and result in the front brakes being overworked in extreme conditions. To achieve proper brake performance, an upgrade to the larger (11.65") Cobra rear rotors is needed.
Multiple disc clutch systems tech
There are two reasons why Mustang owners switch from the stock single disc clutch design to a multiple disc clutch. The most popularreason is for an increase in torque-holding capacity. The most important reason is to reduce the clutch assembly's moment of inertia (MOI). Lowering the MOI provides several benefits:
- Quicker acceleration out of each corner on the track, resulting in lower lap times.
- Quicker engine deceleration when the throttle is lifted. That improves braking at corner entry, often allowing more rear brake bias, leading to shorter stopping distances.
- Quicker shifting because the transmission synchronizers will more easily match the speeds of the transmission gears during shifting. This also reduces wear of transmission parts.
While there are several ways to increase the torque-holding capacity of a single disc clutch, they all have limits.
- Increasing the disc diameter: This is usually impossible due to packaging constraints.
- Increasing the pressure plate's clamp force: Anything more than a small amount is impractical because the pedal effort will become too great.
- Increasing the disc material's coefficient of friction: This also has practical limits, as undesirable side effects such as poor modulation and chatter can result.
To increase capacity with the least compromise: Increase the number of discs.
Simply put, with all else being equal, two discs have twice the holding capacity of one disc. The more complete explanation: The torque-holding capacity of a clutch is proportional to the mean diameter of the friction disc material, multiplied by the clamping force of the pressure plate, multiplied by the coefficient of friction of the friction material, multiplied by the number of friction discs.
Adding a second, and even a third disc, is the most effective way to increase torque-holding capacity. By increasing the number of discs, the torque-holding capacity can be raised without causing significant increases in pedal effort or in the clutch system's moment of inertia.
Torque-holding capacity: The math
The torque-holding capacity can be quantified by this equation:
Torque-holding capacity = (mean diameter of friction material) x (pressure plate clamp force) x (coefficient of friction) x (number of friction disc faces)
MOI: That's what really counts
The term "moment of inertia" (abbreviated as MOI) refers to the rotational inertia of a rotating mass. When it comes to clutches and flywheels, the moment of inertia is a measure of the work required to accelerate and decelerate the rotation of the clutch and flywheel assembly. The higher the MOI of the clutch, the more power required to accelerate its rotation. The lower the MOI, the less power it takes to accelerate its rotation. For a given amount of power, a clutch and flywheel assembly with a lower MOI will accelerate up to speed more quickly, and decelerate more quickly once power is no longer applied. The MOI is sometimes referred to by the unscientific term, "the flywheel effect."
MOI: The math
The MOI is proportional to the overall mass of the object multiplied by the square of the distance the mass is located from the center of rotation. In mathematical terms, this is expressed as:
The distance (r) has a squared effect on MOI, while the mass (m) has a linear effect on MOI. This means that small changes in the distance of the mass from the center of rotation will have a large effect on the MOI. It is possible for two different clutch and flywheel assemblies to weigh the same, but have very different moments of inertia. For two flywheels of the same weight, and evenly distributed mass, the one with a smaller diameter will have a lower MOI.
The bottom line: A lower MOI is better
A clutch and flywheel assembly with a lower MOI will help a car accelerate more quickly, both on the road course and at the dragstrip. To create a very low MOI clutch, manufacturers must go to a smaller diameter clutch design. While designing a clutch with a smaller diameter will reduce its MOI, the friction material diameter will also be reduced, and therefore the torque-holding capacity will be less. That is why, to create a clutch with a very low MOI, it is necessary to have multiple discs. Increasing the number of discs, while also making the discs smaller in diameter, will increase the torque-holding capacity of the clutch, without much change in the MOI. The number of discs needed is determined by the amount of torque-holding capacity desired.
The Details of Multiple Disc Clutches
Multiple disc clutch systems are exactly what they sound like. The most common clutch design, the one that most Mustangs came off the assembly line with, has one clutch disc sandwiched between the flywheel and the pressure plate. Multiple disc clutches have two or more discs sandwiched between the flywheel and the pressure plate.
The main components are the flywheel, pressure plate, clutch cover, clutch discs, and floater(s). The flywheel, pressure plate, and clutch cover are very similar to single disc systems in their operation, while the discs can vary quite dramatically in both size and friction material. Between each pair of discs is a floater. The floater serves as a friction surface between the discs. Floaters are connected to the pressure plate/flywheel assembly, and therefore spin at the same speed as the flywheel and pressure plate. There are two basic designs for driving the floaters. Clutches intended for use on street-driven cars usually have straps connecting the floaters to the clutch cover. The second design has the floaters captured by pins located between the flywheel and clutch cover. While this design is stronger, it generates some noise when the clutch is disengaged, and is therefore less suitable for street-driven cars.
FAQs: Manual Brakes
Q: Why would I convert from my power brakes to manual brakes?
A: There are several situations where vacuum-assisted power brakes may cause a problem that can be solved by converting to manual brakes.
- Mustangs with low vacuum due to a big camshaft may lose power assist at the worst possible time, greatly lengthening the stopping distance.
- Some engine conversions, such as a 4.6L swap, may not allow enough room for the vacuum booster.
- Pedal feel when road racing or open-tracking may be very inconsistent due to the vacuum level fluctuating from extended periods of wide-open throttle. Brake modulation and control can be improved by converting to manual brakes.
- Turbocharged and supercharged engines may not have enough vacuum available for consistent braking with vacuum-assisted brakes.
In all of those situations, converting to manual brakes may be the best solution.
Q: Besides the Manual Brake Conversion Kit to mount the master cylinder, is there anything else I should do to my brake system when I convert to manual brakes?
A: Yes. You should improve the rest of your brake system as much as your circumstances allow. Without power-assist, everything else in the brake system needs to work as well as possible. Among the things to consider:
- High performance brake pads, matched to how you use your car, should be installed. A street-driven Mustang needs pads with a high coefficient of friction when cold. Road-raced Mustangs need friction material suited for the temperatures encountered on the track.
- Any axle endplay will contribute to increased rear pad knockback. That will cause an intermittent low pedal that is much more noticeable with manual brakes than with power brakes. The stock Traction-Lock differential should have the clutches shimmed tightly to minimize axle endplay.
- Stainless steel braided brake hoses will reduce hose expansion, and provide a firmer pedal feel. The soft pedal feel from hose expansion is more noticeable with manual brakes than with power brakes.
- Swapping to larger front discs will greatly improve the stopping ability. For example, swapping GT rotors to larger diameter 13" Cobra-sized front brake rotors will provide a significant reduction in stopping distance.
- An adjustable brake-proportioning valve will allow adjusting the rear brake pressure for the best front to rear bias on your particular Mustang.
- Properly sizing the front and rear rotors, as well as the front and rear caliper piston areas, to be close to a front/rear bias of 70%/30% will provide the best braking performance.
- In the end, braking ability is determined by tire grip. Sticky tires have more grip, and will provide more stopping ability.
- Optimize your combination. For example, a drag race car with big sticky rear tires and skinnies up front will need a brake system with a rear brake bias much higher than 30%. Designing the brake system to have more rear bias will avoid prematurely locking the skinny front tires, and take advantage of the greater amount of rear grip.
- Choose a master cylinder size that properly matches up to the front and rear brakes on your Mustang.
Q: Why is the Maximum Motorsports manual brake conversion kit the best?
A: It is the best because each component was carefully designed to do the task required. The MM Engineering Team does not take shortcuts; others lack the attention to detail required to create a safe design.
The MM aluminum firewall adapter block
- Locates the master cylinder at the correct angle to properly align with the pushrod. Excessive angularity between the pushrod and the master cylinder will cause premature master cyclinder seal failure from increased piston side loading.
- The vertical position of the master cylinder is placed to match a pedal having the proper leverage ratio for manual brakes.
- The aluminum block is machined from thick billet instead of cut from thin plate. The block reinforces the firewall, reducing flex when braking.
- The aluminum is anodized for best appearance and corrosion resistance.
The MM pedal arm
- Rather than reusing the power brake pedal, or requiring you to modify your power brake pedal arm to correct the mechanical leverage ratio, MM designed a pedal arm with the proper ratio for manual brakes. This is the key to avoiding excessive pedal effort.
- The MM arm is much stiffer than the OEM Ford pedal arms. Having less flex in the pedal arm provides a firmer pedal feel, and easier modulation when threshold braking.
- The pedal pad is separate from the pedal arm. The bolt-on attachment allows adjusting the pedal pad location to suit your needs.
- The pedal arm is designed for a pushrod with a spherical rod end attachment rather than a stock pushrod. This design eliminates excessive play, as described below.
The MM pushrod
- Mounts to the pedal arm with a spherical rod end. That eliminates the excessive pedal play allowed by the stock pushrod, a unique Ford design used for brake switch activation. Less play in the system means quicker brake response and improved modulation.
- Stiffer than OEM Ford pushrods to prevent flexing under the higher pedal loads typically encountered with manual brakes.
- Is adjustable in length to accommodate variances in master cylinders, and allow fine-tuning the pedal pad height (distance from the firewall).
The MM brake light switch
- A new switch replaces the stock switch because the MM pushrod design (to reduce slack in the system) is not compatible with the stock switch's method of activation.
- Mounts to an included laser-cut bracket that bolts to the Mustang pedal box.
The MM pedal stop
- Included is an adjustable upper pedal stop.
- This pedal stop is used along with the adjustable pushrod to fine tune the pedal pad height.
Q: How hard is it to install the MM manual conversion kit?
A: While it takes a bit of time, it is within the skill set of most Mustang DIY's.
- We include illustrated instructions: MMBAK-10, and MMBAK-13
- For easier installation, we also offer installation kits of prebent hardlines to connect the most popular Mustang master cylinders to your Mustang.
- New hardlines for the master cylinder are required because a manual brake conversion relocates the master cylinder about 6.5" closer to the firewall, beyond the reach of the stock power brake hardlines.
Q: What is the mechanical pedal ratio of the MM manual brake conversion kit?
A: The SN95 Mustang ratio is different from the Fox chassis ratio because of differences in the unibody chassis.
- The MMBAK-10 kit for 1979-93 Mustangs has a ratio of 6.15:1.
- The MMBAK-13 kit for 1994-95 Mustangs has a ratio of 5.32:1.
- These are the ratios when the MM pedal pad is in the stock position on the pedal arm. The ratio can be increased or decreased slightly by changing the pedal's position on the arm.
Q: Should I use an aftermarket master cylinder instead of a direct replacement Mustang unit?
A: While some aftermarket master cylinders will work, we recommend using one of the several Mustang master cylinders because:
- Direct replacement Mustang master cylinders are readily available at most auto parts stores. In the event of a failure, a replacement master cylinder can be located without much difficulty.
- Aftermarket master cylinders all have the outlet ports on the opposite side from the stock master cylinder. That makes bending the brake lines to fit to the ports much more difficult, as there is very little room between the master cylinder and the chassis.
- MM makes installation kits that greatly simplify installing a stock Mustang master cylinder. We do not make such kits for aftermarket master cylinders; you will be on your own to create lines with the proper tube nuts.
Steering Rack Bushing Tech
Maximum Motorsports has reinvented the steering rack bushing!
Exchanging the stock rubber steering rack bushings for solid aluminum bushings has long been known to be a fundamental step towards improved steering response. Rubber bushings, and to a lesser extent urethane bushings, allow the rack to move sideways, relative to the K-member, before any steering input begins to move the tires. This results in slower steering response than is desired for a performance car. Solidly mounting the rack with aluminum bushings eliminates rack movement relative to the K-member, and improves steering response. Along with improved turn-in, the car will maintain a more precise line through a corner, and require fewer steering corrections.
In some instances, along with the improvement in steering response, comes an unwanted side effect-steering chatter at low speeds. Chatter can be caused if the steel steering rack binds up inside of the cast aluminum steering rack housing. This binding (binding means a resistance to moving freely) can happen if the rack housing is twisted when the rack was solidly attached to the K-member through solid aluminum bushings. Twisting can occur if there are irregularities in the steering rack housing, or in the two rack mounting surfaces of the K-member.
Stock K-members are made from stamped steel, and always have some irregularities in the two rack mounting surfaces. The two rack mounting surfaces are never flat, nor even in the same plane. This may be acceptable when soft rack bushings are used, but with rigid aluminum bushings it can cause the aluminum rack housing to twist, resulting in steering chatter. For those experiencing steering chatter, the only solution until now was to swap the aluminum rack bushings for softer rubber or urethane bushings. Unfortunately, this also meant a step backwards in performance. While urethane rack bushings allow only one half of the movement that rubber rack bushings allow, they are obviously not as rigid as aluminum.
MM has designed a new steering rack bushing that retains the benefits of a solidly mounted steering rack, but also prevents the twisting that can cause chatter. The MM Engineering Team's new design uses a spherical washer to accommodate the irregularities in the K-member surface, while still providing a solid mounting for the steering rack.
These new steering rack bushings are available as a complete kit for new installations, and as an upgrade kit for previously installed MM aluminum rack bushings.
- For 1985-2004 12mm rack mounting bolts only. (N803736-S436)
- These aluminum steering rack bushings are available as center-drilled only-these are not offset rack bushings.
MM K-members have large flat areas where the steering rack mounts, so there are no surface irregularities. However, there may be irregularities in the steering rack housing itself, and the result can be binding of the rack motion, and steering chatter. Because MM K-members have a crush sleeve welded in place, we developed a completely different steering rack bushing than what we designed for the stock k-member.
This all-new bushing design allowed us to provide features that are not possible for a bushing that would be used on a stock k-member. These bushings for the MM K-member let the steering rack be installed in any one of five possible vertical locations. The center position places the steering rack in the stock location. Two different offset positions are possible: 1/4" offset and 3/8" offset. The offset positions can be used to either raise the steering rack, reducing the height of bumpsteer spacers used at the steering arms; or to lower the rack, providing clearance for oversized oil pans.
These new steering rack bushings are available as a complete kit for new installations.
Why offset rack bushings are a bad idea for stock K-members
Although sold by many as a supposed cure for bumpsteer, installing offset steering rack bushings on a stock K-member make an acceptable situation far worse than if you had done nothing at all. How do we know this? Because we did testing. We measured the bumpsteer, both with and without offset rack bushings. Our test results were first published in the July 1993 issue of Super Ford. Find more information about bumpsteer and available kits.