Handling Upgrades For S197 Mustangs With Maximum Motorsports

The Maximum Motorsports 2005–2014 Ford Mustang K-member shown above the stock k-member. Photo via car owner Michael Heintz, unless otherwise specified.

Track and autocross photos courtesy of Casey Cronin

Install photos by: Spenser Murabata

Maximum Motorsports (MM) has developed a full line of late model Ford Mustang suspension components, that in the right hands makes the S197 Mustang handle like a completely different car. These components come as a kit or can be purchased individually. The most recent part from these masters of Mustang suspension is a K-member kit for 2005-2014 Mustangs. We were recently invited to follow along with Michael Heintz and the installation of a new MM K-member kit as well as a host of other parts from the company for improving handling.If Heintz’s name sounds familiar, that’s because we’ve worked with him and his 2012 Boss 302 before. Heintz frequently races the car at autocross and track events. Even though his Boss was the best handling production Mustang ever when it was new, like all Mustangs there was plenty of room for improvement.

We spent some time talking with Chuck Schwynoch, the owner of Maximum Motorsports to get a better understanding of the “why” behind its new K-member design and to glean notes from both Schwynoch and Heintz on the install of several MM upgrades. Heintz took his car to Voss Performance in Placentia, California for this install.

MM K-Member

The MM K-member for Ford S197 chassis Mustangs.

The MM K-member for Ford S197 chassis Mustangs.

Schwynoch says, “We had heard a lot of complaints about NVH (noise, vibration, harshness) from people using aftermarket S197 K-members, so when we began our design we expended a lot of time and effort to allow the customer to retain stock motor mounts and stock control arm bushings.” According to Schwynoch, MM’s new K-member (PN Mm5KM-7), delivers better overall handling and feel. Schwynoch says stability and precision are improved and more predictable because of the increased stiffness and optimized roll center height. MM built a test fixture so its designers could load up a K-member to simulate cornering and braking loads. The design team also measured deflection of a stock K-member. Roll center height is optimized for a lowered Mustang because of the raised front control arm pick-up points, eliminating the need for using extended-length ball joints.

Getting ready to install the engine support beam.

The strut tower brace is removed in order to install the engine support beam.

Since we're removing the K-member, and thus the engine mounts, installing an engine support beam is necessary to hold the engine in position while work is performed under the car.

Beginning the prep under the car. Splash shield removed.

Beginning the preparation under the car. Splash shield removed.

Heintz says, “Before installing the Maximum Motorsports Tubular K-member and bumpsteer kit on the front of my car, the car would be very rough over bumps and shook the steering wheel violently. The bumpsteer kit cured all of the issues with the steering shaking wheel shaking violently when I went over bumps or any rough road. The tubular K-member stands out because it corrected the geometry.”

Final prep for removing the K-member. Top row: You can see the engine support straps in this image. Bottom row: The lateral support arm has to come off.


Blue threadlocking compound is applied to all of the bolts prior to installation of the new parts.

Top Row: Time to yank this baby out! Left and Center Left: Loosening the bolts securing the K-member to the frame. Center Right and Right: The old K-member is out and ready to be stripped. Bottom Row: Reassembly begins. Left and Center Left: Everything has been transferred over to the new K-member. Top Center Right and Right: K-member being slid into position under the car. Bottom Left: In place, ready to be bolted up. Bottom Right: K-member in and bolted up.

Bumpsteer Kit

Extended-length tie-rods from the Mm5TR-2 Bumpsteer kit.

Extended-length tie-rods from the Mm5TR-2 Bumpsteer kit.

Getting rid of the old tie rods to install the bumpsteer correction kit.

Getting rid of the old tie rods to install the bumpsteer correction kit.

Installing the bumpsteer kit. Left: New tie rod adjusting sleeve installed. Right: New tie rod extension installed.

Schwynoch says, “Ford always designs in a little bit of bumpsteer in a way that promotes understeer. Our bumpsteer kit allows tuning out that part of the design. There is a widespread myth on the Internet that lowering a Mustang (any model Mustang from 1979 to 2015) causes bumpsteer. Lowering a Mustang does cause the camber to change, becoming more negative. Any change in camber in turn causes the toe setting to change. After lowering, a simple alignment job restores both camber and toe to their proper settings. Lowering has almost no effect on bumpsteer, and what little effect it does have is inconsequential, so small that there is no need to adjust for it. What does effect bumpsteer are changes to suspension geometry, such as moving control arm pick-up points, extended length ball joints, or a large increase in positive caster.”

Installing the bumpsteer kit. Left: Getting the sleeve and extension to match up. Center: All matched up, ready for the lock nut. Right: Lock nuts instead of castellated nuts and cotter pins are used to secure the adjusting sleeve to the tie rod extension.

The MM K-member for the S197 chassis moves the control arm pivot points upward. This makes it so the outer tie rod end has to be moved downward to compensate for that and to eliminate the bumpsteer caused by the relocated control arm inner pivots. MM’s bumpsteer kit (PN MM5TR-2), allows for that.

Bumpsteer Gauge

MM's MMT-4 Bumpsteer Gauge. You have to have a gauge to adjust bumpsteer. Image via Maximum Motorsports website.

MM’s MMT-4 Bumpsteer Gauge. Setting bumpesteer requires a guage, and MM has one available specifically for doing this. Photo courtesy of Maximum Motorsports.

There is no way to “eyeball” tie-rod end adjustment when installing a bumpsteer kit to compensate for bumpsteer induced by tie-rod end positioning. MM’s Bumpsteer Gauge (MMT-4) is an easy to use and inexpensive way to ensure that you get it right without hours of trial and error. The Bumpsteer Gauge can be added to your cart by checking the check box on the Bumpsteer Kit page.

Engine Support Beam

The MM engine support, MMT-11si indispensable for this and other projects.

The MM engine support, MMT-11 is indispensable for this and other projects.

Prior to this little beauty, swapping out a K-member required having a cherry-picker or a universal support system of some type. Those can be hard to rent and expensive to buy, so the MM team went out and designed the MMT-11 Engine Support Beam. This easy to use crossbeam that, when coupled with two 600-pound (minimum) ratcheting straps (you supply these) eliminates the requirement for the cherry picker. Schwynoch also says it can be quite handy for owners who want to remove their oil pan to inspect engine bearings, and need to drop the k-member to do so.

Caster-Camber Plates: The Final Piece of The Alignment Puzzle

These Caster-Camber adjustment plates makes alignments a snap. Image via MM website.

These Caster-Camber adjustment plates weren’t used in this installation, but they make alignments a snap. Photo courtesy of Maximum Motorsports.

If your author may be allowed to editorialize for a brief moment, when I was turning wrenches on a daily basis for a living, my specialty was suspensions, especially alignments. I’ll tell you here and now, looking at these babies, I would have killed to have them installed on every car I worked on equipped with MacPherson struts. MM invented double-adjustable caster-camber plates in 1993. Since then they’ve had to design new plates for each succeeding generation of Mustang after it hits the market because Ford engineers change something in the strut tower, upper strut mount, or the strut.

MM’s Caster-Camber Plates, (PN MM5CC-6),  allow for quick and easy caster and camber adjustment on 2011–2014 Mustangs (except 2007–2014 GT500s which is a different part number). The design of these plates allows adjustments to caster and camber separately, instead of having to adjust both angles together. There are ways to adjust camber on these cars, but without these plates, caster is non-adjustable.

Extreme Duty Rear Lower Control Arms Mm5RLCA-53

Max Motorsports Mm5RLCA-53 lower control arms with Mm5RLCA-57 mounts.

Maximum Motorsports Mm5RLCA-53 lower control arms with Mm5RLCA-57 mounts.

Side-by-side comparison of the stock (above) and Max Motorsports (below) control arms.

Side-by-side comparison of the stock (above) and Maximum Motorsports (below) control arms.

Removing the old rear lower controls arms and mounts.

Relocation Brackets for RLCA Mm5RLCA-57

The S197 Mustang has far less anti-squat geometry than is desirable, even at the stock ride height. This is exacerbated by lowering the car. MM’s Relocation Brackets  (PN RLCA-57) correct this by moving the instant center location, greatly increasing the anti-squat percentage, aiding traction. The Mustang’s traction control is turned off when exiting hard corners in order to save the rear brakes. These relocation brackets compensate and allow for hard acceleration out of corners, whether on the street or on a road course.

When a Mustang car accelerates, the rear axle tries to rotate upward, pushing on the lower control arms and causing pinion angle to rise. All this force of launch and acceleration is then translated to the lower control arms, bushings, or spherical rod ends, the bolts, etc. In order to handle big power, the control arms need to remain stable under this extreme load, as well as the bushings and spacers that the pivot bolts pass through. If these are allowed to buckle or distort, the result can be a loss of the clamping force of these components.

Schwynoch says, “That’s why we use steel spacers rather than aluminum, and a relatively large diameter steel tube for the arm itself on MM’s Extreme Duty Rear Lower Control Arms (PN Mm5RLCA-53).” Want big power handling capability? These control arms are rated to 1, 172 lb-ft of torque with the stock 3.55 gears and are excellent for street or strip. They improve traction by eliminating the deflection of stock rubber bushings and the weak stamped steel control arm. Understeer is noticeably reduced because the offset design also greatly improves the rear suspension geometry.

Installing the new rear lower controls arms and mounts. Far Left: Bolting up the new rear control arm brackets. Center Left: Front of control arm bolted up to frame mount. Center Right: Attaching the control arm to the new heavy duty bracket. Far Right: One down, one to go.

Manual Transmission Cooler Scoop

The Mm5KB2-21 has been designed to fit the new MM k-member.

The Mm5KB2-21 has been designed to fit the new MM k-member.

On the track, keeping things cool is paramount. While many of us think of engine oil and coolant as the two critical areas, the transmission is another that needs special attention. This is especially true in the high RPM environments of road racing and auto-crossing. The 2012-13 Boss Laguna Seca came equipped with an air scoop to direct more air to the transmission from under the car. This is a common upgrade for standard Boss owners looking for lower transmission temperatures, however it’s not compatible with most aftermarket K-members.

MM developed a new air scoop, (PN Mm5KB2-21) similar in design to the OEM part on 2012–2013 Mustang Boss 302 Laguna Seca models, but has been configured to fit the new MM K-member only. It won’t fit the OEM K-member. It’s designed to fit on all 2005–2014 Mustangs, with the MM K-member. The design redirects air up toward and around the manual transmission to help reduce its temperature and increase its lifespan.

Installing the new transmission air scoop.

Heintz reports that after the installation his Boss has noticeable improved handling. There’s far less understeer, and the car rotates through corners more precisely and predictably. The front end feels more solid and put together, and the changes to the rear suspension have also eliminated the feeling of the rear of the car being disconnected or delayed in reacting to what the front wheels are doing.

Article Sources

About the author

Mike Aguilar

Mike has been wrenching on cars since the early 1970s when he worked at his dad's auto repair shop. By the age of 14 Mike had built his first performance suspension, and by 16 he had built, and was racing cars in several sanctioned events in the San Francisco bay area.
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