For a racer, exploiting every last possible area for performance improvement is a rite of passage. As the racer steps up a car’s horsepower capabilities it’s wise to start improving the suspension to match. Florida racer Brett LaSala is well-known in the Mustang community. His “Snot Rocket” twin-turbo S197 has been at the forefront of Coyote performance for many years. His transmission-building skills have served him well in the community as he’s known as one of the go-to guys for making vast performance improvements to the 6R80 transmission.
As he has stepped up the Snot Rocket’s efficiency at the track, he’s made incremental improvements to the car overall. He recently dove headfirst into updating the S197 suspension and altering the traditional three-link geometry to get a better handle on the car. With the help of Don Lamana at ProFab Performance in Hudson, Florida, LaSala mapped out a plan to change the car up for the 2021 season.
For reference, the car features a stock-displacement, Fast Forward Race Engines-built Coyote featuring Manley Performance internals, GT350 cylinder heads, custom cams, Plazmaman billet intake manifold, Plazmaman air-to-air intercooler, and twin 7675 Precision turbos in a custom turbo kit. It’s tuned by Jay Meagher at Real Street Performance (Brett’s place of employment) and runs on One Ethanol fuel.
Optimizing the S197 suspension for somewhere around 2,000 wheel horsepower on radials involved many changes. These include moving the rear shocks into an advantageous location, switching the dampers to a set of double-adjustable units at all four corners, completely replacing the front suspension, a new 9-inch rearend housing from Team Z Motorsports, and more. Let’s get into the details!
Team Z At Both Ends
One of the reasons LaSala wanted to get away from the tried-and-true 8.8 housing was to gain access to the variety of gearsets available for the 9-inch Ford housing. Long championed as the go-to choice for street-style race cars, the 9-inch in all its forms has been delivering robust strength and reliability for decades. But this 9-inch is not just any 9-inch; LaSala turned to Team Z Motorsports for one of its fabricated housings.
The housing features 3-inch 4130 chromoly tubes and a full-length rectangular back brace to prevent the tubes from flexing under the massive horsepower this car develops. Additionally, Team Z sunk one of its multi-hole upper control arm brackets into the top of the housing; this mounting location provides LaSala with the flexibility to get the instant center exactly where he wants it. Since the car is often raced in no-prep scenarios, optimizing the suspension to the track when the conditions are poor is a massive advantage over the competition.
Shock Location & S197 Suspension Specifics
Not only did he want to locate the lower control arms in a specific position, but he also needed to be able to mount the Santhuff coilover rear shocks to the backside of the mounting brackets.
By creating the clearance in the rails seen above, Lamana positioned the shocks where he wanted them and used the coilover configuration.
The main reason to move the coilovers to their current position is that running on a radial tire means that the suspension needs to extend to do its job correctly on the track; at their set position, the rear shocks have one inch of compression and seven inches of extension. This location helps them do their job correctly, but requires the factory frame to be modified, as seen in the photos.
Team Z Motorsports delivered the fabricated housing without the lower control arm mounting points; Lamana designed his own lower control arm mounting brackets to work with this specific vehicle for a couple of reasons. The upper control arm body-side bracket is from Racecraft, Inc. and offers several mounting positions, similar to the housing-side mount. Both uppers and lowers are constructed from chromoly tubing and high-quality Heim joints.
Although in factory form, the S197 suspension can be made to handle quite admirably, even at the dragstrip, when you step up to the level of LaSala’s machine, there is one critical issue — the Panhard bar.
“We removed the factory Panhard bar — it isn’t exactly good for a car with extension because the Panhard bar mounts to the frame on one side, and then it’s mounted to the diff on the other. As the car goes up and down, the diff moves side to side. With the full extension of the car, the diff would probably move almost an inch from side to side because of the Panhard bar. Its job is to keep the differential centered in the car, but the problem is it’s only centered at ride height and maybe an inch up and an inch down, relative to the center. After that, it’s actually moving over,” says LaSala.
As you might imagine, this is not good when you’re running mid-7-second elapsed times at 180-plus mph.Additionally, they mounted a TRZ Motorsports bushing-style anti-roll bar above the rearend housing to control the body roll.
At The Track
Talking about specific adjustment holes and setting the suspension up to start depends upon ride height and instant center measurements, and several other parameters which vary from car to car. Let’s talk instead about a bit of the theory Brett employs to find improvements.
To successfully hook a radial-tire car, power is applied in a way that gets the car to stand up on the suspension. Instead of squatting like a slick-equipped car, the goal is to make the rear of the chassis stand up above the crankshaft centerline and shift the weight forward to drive the nose into the track — and in the process push the rear tires down into the track surface as well.
He turned a recent track trip into a data-gathering session and learned quite a bit about what’s happening underneath the Snot Rocket.
“All of the bracketry is to give us a wide range of bar angle adjustments for the instant center. We got the car to extend about three-and-a-half inches further down the track now that we were running the upper bar becoming level again at the top of the extension. We had another adjustment hole left that we just went to that was probably going to get another inch of extension. We haven’t gone out to see how it’s going to react to that yet, but it will,” he says.
He is confident in the changes because of his data acquisition capabilities, as the car is equipped with a MoTec M150 ECU. He is past making significant changes, trying to dial it in based on what he’s learned so far.
“You can watch the shocks and everything based off of your run, overlaid on your regular datalog, so your time, like how long you’ve been on the transbrake, how much boost and RPM, you see it all together. It’s all done electronically,” he says.
“The big adjustments really show you if you’re going in the right direction or not. Small adjustments will be more in the shock; we have a shock travel sensor on there, so we can see how long it takes the shock to reach extension. We can control the amount of time it takes to get to the extension by the shock adjustment. I’d say suspension adjustments are more of a big change, and then small changes will be made in the shocks. The car at ride height is a certain height, and then a car at extension is at a certain height. The shock is going to control how long it takes to reach that point.”
Most importantly, he stresses that it’s essential to have a solid baseline to start from and says that Lamana and ProFab have been a big help to his program — but he also puts his own twist on it.
“Get the car set up by a chassis shop and make sure everything is in the correct positions and working. They’ll give you their baseline where they want it to be if they’ve worked on that chassis a lot. If you plan on racing and tuning yourself and not relying on a chassis shop every time you go to the track, there’s a lot of information on YouTube about how all this stuff works. Go out there and make a change and watch it work, and make one change at a time making sure to document it. That way, you can learn what it does and then apply your own theories,” he sums up.