2010 Mazdaspeed3: Suspension Walkaround
November 11, 2009
With a new floor jack in hand, it's finally time to get back into suspension walkaround mode. And it just so happens that I brought said jack home in the back of our 2010 Mazdaspeed3.
Let's see what she looks like with the wheels off.
The Mazdaspeed's front suspension is standard fare you'll find on most front-drive compacts: A MacPherson strut (green) paired with an L-shaped lower control arm (yellow). A lot of these parts look very similar to those found within our departed 2008 Ford Focus SES.
But these components are even more similar to those found on the European Ford Focus - the one we don't get here. That's because the Euro Focus and the Mazda 3 both use Ford's C1 platform, wheras the US Focus uses the closely-related C170. Ford and Mazda may have parted ways, but this project was well along before that came to pass.
In fact it may help to switch back and forth to the 2008 Ford Focus suspension walkaround every now and then as we move along.
Struts almost always have their coil-over springs mounted at what looks like an odd angle relative to the strut body itself. Here you'll notice that the spring axis lines up with the steering axis. This spring orientation seeks to offset the side loads (and therefore the friction) that build up due to the off-axis orientation of the strut.
Here's a view of the L-shaped lower control arm from above. The orange arrow shows where the subframe terminates at the forward LCA mount, just like our Focus. Meanwhile the front stabilizer bar (yellow) loops over the top of the rack and pinion steering.
A slender stabilizer link attaches directly to the strut housng, signifying this as a direct-acting stabilzer bar.
The suspension knuckle (yellow) is cast iron. There's no aluminum in this suspension - which is what you'd expect at the Mazda 3's price point.
Tuning of all the various components is where the Mazdaspeed3 differs from the base car: spring rates, shock valving, bushings, tires and stabilizer bars. But the basic hard parts are pretty much the same.
And the Mazdaspeed3 indeed has much bigger brakes than either the standard Mazda3 or the US Focus. They're still single piston sliding calipers, but these have much higher stiffness and more thermal mass. Those rotors are bigger, too. In track testing, they haul the Mazdaspeed3 to a stop from 60 mph in 113 feet with no fade after repeated stops. A standard Mazda3 does the same job in 127 feet.
Under the hood, we see these reinforcements at the upper shock tower. The Mazdaspeed3's massive intercooler, which we will see in a moment, precludes the use of a obvious stress bar that links and stiffens the shock towers. But squint into the dim (and poorly focused) shadows above and you'll see that this stiffener does attach to a crossbar that links it to its mate on the opposite side.
But that crossmember is completely hidden by the rear hood seal.
The 2010 Mazdaspeed3 uses a potent 2.3-liter direct-injected turbo engine. The front tires must deal with every one of its 263 horsepower and, more to the point, 280 lb-ft of torque.
In my opinion that's too much, as the Mazdaspeed3 pulls this way and that in a significant display of torque steer as you accelerate. It can be tiresome if you're not in "track" mode. Case in point: yesterday's cloverleaf freeway merge in which I had to roll on the throttle while unwinding the steering and upshifting (one hand on the shifter) to get up to speed and fill a gap in a line of traffic. With the body still heeled over a little, the unequal angle of the two driveshafts exacerbated the condition.
In the previous shots we've seen no special suspension geometry to reduce the scrub radius and the Mazdaspeed3 does not have Ford's RevoKnuckle, a patented front suspension tweak they use in the European Focus RS to combat torque steer in that machine. Of course these issues never appeared in our 2008 Ford Focus SES because you have to have a lot of torque to have torque steer.
The Mazdaspeed3 does have one significant torque-steer countermeasure, and you're looking at it. The black jackshaft above exits the transmission and moves the RH inner CV joint to a point that mimics that of the LH side. This allows the LH and RH driveshafts to be the same length and run at the same angle on straight and level roads. But this jackshaft still represents a longer load path to the RH wheel, and that presents more opportunity for windup.
Here I've removed the engine undercover for a better look. Everything is so nice and clean! But what's that I see written on the factory filter?
FoMoCo = Ford Motor
Corporation Company. But you don't need to remove the undercover to change the oil in this machine. Let's put it back on and see.
The drain plug (yellow) sits just behind the undercover and the oil filter resides just inside the access hole.
This undercover is one of several airflow management panels our downmarket Focus never had.
The rear suspension is the same sort of control blade multilink suspension found on our Focus. There are slight difference here and there that reflect updates, but I suspect the European Focus has many of them, too.
The control blade (blue) is a trailing arm that locates the wheel in the fore-aft direction. The trick here is its very thin cross-section that allows it to flex a little so it won't interfere with the smooth operation three lateral locating links. The lower links (white and orange) define the toe-in of the wheel and their combined relationship to the upper link (yellow) defines the camber curve. It's a clear division of responsibilities that is very neat and tidy...and effective.
There it is again: the FoMoCo logo adorns the control blade, up near its forward pivot bushing.
Here's another look from below. The blue arrows show where Control Blade gets it's name. The upper link (yellow) is curved so that it loops under the load-bearing part of the unibody as it runs back to the rear bumper. And as we've seen many times before, the forward lower link (white) is much shorter than the rear one (orange) so that a stabilizing dose of rear roll understeer is created as the outer tire compresses in corners.
This view of the rear lower link shows why it's so beefy. There's so much going on that we might as well call it a lower control arm (LCA). From inside to outside, it's taking loads from the stabilizer bar, the coil spring, the secondary bump stop (yes, this car has two) and, of course, a variety of forces from the tires via the rear hub.
The rear stabilzer bar (yellow) may look large, but it has to be because it doesn't twist much owing to a motion ratio of only 0.4:1 relative to where it connects to the LCA via a stubby drop link (green).
I promised you a second rear bump stop, and here it is. This longer urethane stopper sits atop the shock. The use of two implies that this one contacts first, softening the blow gradually before the harder rubber stopper we saw before acts as the final travel limiter.
Of course the Mazdaspeed3 uses rear disc brakes, consisting of single-piston sliding calipers and non-vented rotors. The yellow circle identifies this as yet another FoMoCo part.
Of course all of this rides on some sticky Dunlop rubber, size P225/40R18 with a high "Y" speed rating.
They're mounted on 5-spoke 18 x 7.5-inch aluminum alloy wheels that have a 52.5 mm offset.
Mounted together, they weigh 49.5 pounds apiece -- about average these days.
A comparison of the Mazdaspeed3 to our old Ford Focus shows how far chassis tuning can take you when you start with a sound suspension design (particularly the rear, in this case) and let Mazda engineers with a Zoom-zoom mindset select the detail specifications of each variable: shocks, bushings, springs, bars, tires, brakes, etc. Our '08 Focus was a car with a good chassis whose main performance "flaw" was a suspension tuning intentionally chosen to satisfy non-entusiasts at an entry-level price point.
Such a comparison also shows the limitations of such an approach, as the installation of this most excellent engine in this front-drive chassis starts to generate unwanted and undesireable torque reactions that adversely affect steering and handling when standing on the gas. And, let's face it, standing on the gas is what the Mazdaspeed3 is all about.
The Mazdaspeed3 chassis is maxed-out in this regard. Mazdaspeed3 owners who install go-fast parts for even more power will likely make it worse, whereas rear-drive platforms such as the Hyundai Genesis Coupe and Nissan 370Z and all-wheel drive Subarus and Evos are much more tolerant of at-home tuning.
That said, all of this bodes well for the anticipated 2011 arrival of the European Ford Focus to these shores. The chassis has clear potential, and Ford holds the patent to the RevoKnuckle that promises to muzzle the torque-steer monster should they decide to bring out a powerful version such as the Mazdaspeed3 or the Focus RS.
Dan Edmunds, Director of Vehicle Testing @ 2,435 miles