5.0 Mustang & Super Fords
Autocross Suspension Upgrades - Crossing The Line
Learn the Basics of Suspension Modification
Credit Ricardo Topete of GTR Performance for the idea. A longtime dealer of Maximum Motorsports suspension parts, Ricardo, along with his brother-in-business Gonzalo, asked us if we'd be interested in doing a bolt-on suspension story. Instead of the usual step-by-step documentation, why not skip the installation and concentrate instead on what the parts do for you?
A great idea that gets right to the heart of what the average guy can expect from suspension modifications. To keep things in the real world we agreed to attend a local autocross where the Topete brothers could bolt-on a series of popular suspension parts from handling specialist Maximum Motorsports and Eibach. Items tested were alignment settings, Maximum's lowering springs, Panhard bar, an Eibach rear sway bar and shock settings. On hand, but not tested because a day is only so long were the matching Eibach front sway bar and Maximum rear lower control arms.
Just as real-world as running out of time is the test car, Ricardo's '01 Mustang GT daily driver. Before the test Ricardo re-installed his stock springs and set the car to stock alignment so it would represent the typical project car starting point. Under the hood the internally stock 4.6 was augmented by its long-installed Novi 1000 supercharger plus a smattering of performance knick-knacks, none of which materially affected our handling exercise. More to the point, the stock five-speed gearbox and 3.27 gearing remained intact and '00 Mustang Cobra R brakes by Brembo tabled any stopping concerns.
To speed the test, Ricardo pre-installed the Maximum Motorsports adjustable Panhard bar, then removed the bar itself. That allowed fitting the bar to the car in just a few minutes at the track. Alignment settings were pre-checked, and the car was already equipped with Maximum Motorsports caster/camber plates and adjustable Tokico shocks, so those adjustments were easy to do trackside as well. As for the lowering springs, the SN-95 and New Edge use non-concentric spring/shock package, making spring changes relatively easy, especially for Ricardo who has popped more than his share of coils in and out of Mustangs.
Suspension testing requires the maximum available grip from the tires. Old or low-traction tires will slip and slide no matter what suspension they are bolted to. Good traction is a must for suspension improvements to show, so we turned to Nitto for a set of NT01s, and that was the end of any traction questions. After years of happy experience with NT01s, we can reliably report these street-legal road racing tires are great for track-driven Mustangs thanks to excellent grip, a linear breakaway at the limit, and a reasonably durable wear rate.
So, how did the pieces do? In a word, great. On a slalom course that took most cars present about 1:42 seconds to lap we opened in the 1:41 to 1:42 range and finished the day with consistent low 1:39s. That's a big jump, not to mention the tremendous gain in responsiveness and overall stability.
From a seat-of-the-Levi's perspective, the two items making the big differences were the lowering springs and the rear sway bar. The springs gave the Mustang a solidity and responsiveness that could be felt driving in the paddock. On track they transformed the car from a somewhat sloppy street car into a reasonably taut performer that could be driven both more precisely and with more aggression.
The rear sway bar did wonders for reducing understeer. By increasing rear roll stiffness, the rear bar transferred some of the cornering loads from the front to the rear tires, allowing the front tires to bite harder and better balance the Mustang's inherent nose-heaviness. To a lesser extent, dialing in more negative camber using the caster/camber plates reduced understeer as well. Also keep in mind the lowering springs also gained us a much-needed degree of negative camber, so simply stiffer spring rates and a lower ride height weren't all of the lowering springs advantages.
Steering precision and reduced lateral body motions over bumps were the main gain from the Panhard bar and stiffening the shocks. This is more difficult to feel or single out in your mind compared to the springs or rear sway bar, but are important in reducing lap times or building driver enjoyment on the street. Furthermore, our experience with the Panhard bar may have been a fluke of our test; Maximum Motorsports says they almost always detect an immediate sense of confidence and fewer mid-corner corrections from fitting the Panhard bar and we certainly felt it was an important part of the suspension on our now-retired '96 open-track car.
Shock tuning is always a subtle thing, and we opted to set the Tokicos on their softest settings until late in the day. With all the hardware we were going to get on the car installed we turned the front shocks from full soft to full hard (from 1 to 5) and that helped calm the front end a little bit, gaining our fastest time of day. Turning the rear shocks from soft to hard in the same fashion was our final test, and it was the only one that didn't return better feel or a faster lap time. Both the feel and lap times were nearly identical to the previous setting, and we'd have to say such a small difference is within our margin of error, both in feel and driving consistency. Likely the shock settings would vary from track to track depending on how bumpy they are. Previously on the street we've found the Tokicos best at medium to soft settings.
We felt badly about not getting to the front sway bar and especially the rear lower control arms. Previous experience and talking with Maximum Motorsports indicates the front sway bar would have increased understeer at the autocross, and thus slowed us down. But on the street where it's impossible to corner as aggressively, the larger front bar would sharpen steering turn-in, which feels great. The rear lower control arms aid precision and would likely show up mainly as steadier mid-cornering action. Our previous experience indicates the lower control arms are beneficial for any handling duty while a larger front sway bar is usually too much roll stiffness.
At the end of our autocrossing day we were certainly smarter about how suspension parts interact. A simple test, it reinforced our belief that far too many enthusiasts concentrate on underhood improvements when there are just as great gains to be had in the wheelwells. 5.0
Horse Sense: While changing springs Ricardo pointed out that the Tokico shocks we were looking at were the exact same set that we photographed for a suspension story on this car back in 2001. Can a decade really go by that fast?
Leveling UpMaximum Motorsports has always done a great job of bundling its various suspension bits into sensible kits or boxes as they call them. The most popular of these is the Road & Track; pretty much what we tested in this story. The Road & Track box is a spring, sway bar, and shock group, along with some chassis stiffeners. It re-tunes the stock Mustang suspension design for more responsive handling and is both affordable and effective as our results show. To fit Ricardo's New Edge the R&T box lists for $2,446.72 and we recommend it for anyone looking for a nice gain in daily driving street handling or light open track duty.
But there is another step up from re-tuning the stock suspension and that's Maximum Motorsports' Maximum Grip box which is more of a suspension replacement. Here the main player is a torque arm rear suspension that replaces the '04 and earlier Mustangs schizophrenic four-link rear suspension, plus a geometry-restoring K-member for the front suspension. Much more involved than the R&T box, the Maximum Grip box lists for $4,664.84 and must be strongly considered by anyone serious about handling either on the street, strip or especially a road course. It will transform your Mustang.
The PartsThe following parts were tested at the autocross. Note that Maximum Motorsports sells the Eibach sway bars, so they are available from either company. Also, most of these parts are available separately or as parts of kits. Because suspension parts have interlinking functions, we recommend buying kits—the more encompassing the better.
|Lower Springs||Maximum Motorsports||422HO||$247.00|
|Panhard Bar||Maximum Motorsports||MMPB99A||$359.95|
|Rear Sway Bar||Eibach||3510.312||$172.43|
We have to say it was tasty to get on an autocross course after years of road racing and open-track driving. Autocrossing is much less expensive than those other two corner-intensive disciplines and is the best way for an enthusiast to introduce himself to the corner-bending business. Like grudge-night drag racing, autocrossing is an affordable motorsport.
If nothing else, there is essentially no chance of either car-to-car and minimal chance of car-to-wall contact, plus brakes and tires last far longer because they just don't get worked as long as on a road course. On the plus side, the quick timing and technical nature of the course layouts is superb driver training. Ride-along passengers are a regular part of autocrossing, so the all-important coaching from an experienced driver is easy to get.
Our autocrossing test session was sanctioned by Speed Ventures, a Southern California-based organizer of autocross, open-track, and training events. We've driven in Speed Venture open-tracks before and found them well-organized, and held at a variety of interesting tracks. Typical of autocrosses, the only gear required was a daily driver Mustang and a helmet, and we drove 31 laps between 9 a.m. and 4 p.m. using about half a tank of gas. We can't imagine not giving it a try.