Tom Wilson
May 31, 2012

All parts manufacturers build project cars for the same reason--to get their company and its products noticed--but they go about it in different ways. Quite often project cars are over-the-top, look-at-me efforts that dazzle for a month or two, then quickly fade. Others are refreshingly realistic, such as the handsome Eibach (www.eibach.com) demonstrator we examine here.

Sure, there's a bit of 20-inch-tire swagger here, and the project sponsors are duly stickered onto the '11 Mustang GT flanks, but everything that's been bolted on has a real-world purpose. So much so that we took the car to the toughest testing ground we know, the road-racing circuit. We wanted to push this car hard--to find its weaknesses and enjoy its strengths. That's not something we do with many project cars, because frankly, few project cars can survive what a road-race circuit has in store for them. So, as we critically review Eibach's car, take our comments as an honest assessment of a winner.

From a nuts-and-bolts standpoint, Eibach's 2011 demonstrator is a bit of a mix. The aftermarket bolt-ons favor handling and performance, while the Mustang underneath it all carries an automatic transmission. There's nothing inherently wrong with an automatic in a street car, but most handling fans prefer the interaction and efficiency of a manual. That and Ford's automatic--while apparently robust, reasonably quick, smooth shifting, and featuring no less than six ratios--unfortunately does not offer comprehensive manual control. The console shifter provides detents for 1, 2, 3, and D, but there are no paddle overrides as in the Taurus SHO, and no way of holding the transmission in Fourth or Fifth gear.

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So on the road course we had to adapt a bit. Of course, on the street we didn't have to bother with all that shifting in traffic, and the blast away from stop lights was gratifyingly immediate. And should dragstrip performance be desired, the automatic is right at home. Really, the auto is a big plus for many enthusiasts who daily drive their Mustangs in heavy traffic along with hitting the autocross, open track, and dragstrip on the weekends. In that case, the auto helps on the street; works at the autocross, where it's possible to manually shift the lower gears; is a plus on the strip; and still gets around the road-race circuit. We find it ironic that Ford gives the Taurus SHO paddle shifters as something of an executive perk that we're sure doesn't get used all that often, while the more youthful Mustang goes without.

Eibach chose to add its R1-based spring, bar, and shock package. The Multi-Pro-R1 contains single-adjustable shocks with spherical upper bushing mounts and coilover springs. Advantages are numerous, starting with the ability to use any of Eibach's many coilover springs to fine-tune the ride for vehicle weight and driver aggression level. The springs are height-adjustable without much effort; so a choice of in-the-weeds profiling; low-ride height track setup; or high-water street settings for dealing with potholes, curbs, and steep approaches is possible. Corner weights are also adjustable to offset stereo or passenger loads, fine-tune the launch at the strip, or adjust for a certain track.

The gear is all made in the U.S. with quality hardware, Teflon inner and stainless-steel-braid outer hoses, and a one-year warranty. Retail on the Multi-Pro-R1 coilover kit is $2,395. The front and rear sway bar packages are available separately, and retail for $549 or $669 depending on if you want adjustability in the rear sway bar or not (we'd get it even if it's a bit pricey). In either case, the front sway bar is adjustable and tubular to save weight. Our test car had the adjustable rear bar. Finally, Eibach fitted its adjustable aluminum Panhard bar to help tame lateral rear-body motion. This is a $201 part.

If three grand seems a bit rich for suspension mods while you're making payments on that new Coyote-powered Mustang, Eibach also offers its Pro System Plus kit with standard shock mounts, non-adjustable shocks, standard replacement non-coilover springs, and without the Panhard rod, but with the same adjustable sway bars front and rear, for $1,482. This is a fine kit for real-world Mustangs and will certainly entertain most drivers nicely. Its only real drawback is the lack of adjustability for those who want to tinker with their chassis on track days.

At the other end of the scale, Eibach has its R2 double-adjustable, remote- reservoir coilover shocks at $2,895, plus the sway and Panhard bars.

Just as important to the project car's impressive track performance was Brembo's six-piston front brake package. This is world-class braking, with the massive, even squeeze of the huge calipers taken by just as impressively large, 14-inch, two-piece, cross-drilled, and ventilated iron rotors. No one seemed to know exactly which brake pad was installed, but we guessed a performance street pad as cold-stopping was good, the noise level was dead quiet, and dust was surprisingly light. Rear braking was stock, but likely with upgraded pads. Interestingly, the Brembo front brake package has a street price of $3,500 or a touch more, so they are more expensive than the suspension.

As if a stock 412hp Coyote 5.0-liter wasn't enough, Eibach bolted on a Roushcharger 2.3-liter TVS. This definitely required custom tuning from modular tuning ace Adam Montague at ST Motorsports, as Roush specifies its kit is for manual-trans cars only. Adam's main thrust was driveability, and he did a good job in a limited time with the car, although with more time he could smooth the off-idle transitions a bit more. There was no boost gauge, but clearly it was a street tune for 91-octane pump gas, so the power had to be hovering in the 550-rwhp range or less. But not much less, as this is one strong Coyote.

Also on board was K&N filtration and a Magnaflow exhaust system. It gave the expected Magnaflow civilized rumble at idle and a meaningful bellow when processing the wide-open-throttle supercharged air mass, but the vast majority of the time it was drowned by the annoying howl coming off the worn set of tires.

Put all these parts together and you have one fun Mustang. On the street, everyone enjoyed the flat cornering, minimal brake dive, and general overall competence of the new Mustang. The steering is especially nice--no doubt aided by the tauter suspension--and it was singled out by several drivers for its precision and feel. We noted a firmer-than-stock, but by-no-means-harsh ride.

We began with the shocks adjusted to their softest settings, which was pretty cush around town and when cruising, the minimal trade-off being a slight under-damped feel over big heaves or when beginning to hustle over bumpy roads (which we now have plenty of in California). Considering the short sidewall rolling stock, we thought the ride was great for a lowered, stiffer car. The suspension was quiet, with no knocks or squeaks.

Later we sampled the shocks on their mid-settings on the street and liked it best. Ride harshness was barely elevated, but the odd under-dampened pitch was mainly gone. We also got a rude surprise when positively hammering on the throttle on a back road. With the shocks at their softest, we hit a big hummock in a fast corner and the front end bottomed and took a quick heart-in-the-throat step outward. That was a lesson to keep things sane when the shocks are adjusted softly.

Did we mention this thing has a ton of power? The combination of auto trans and blower torque made little squirts of power nearly irresistible and super-easy.

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Our track day was a modern classic. The ease with which a car such as this can transform into a track-friendly bruiser is a real mind-blower to anyone who lived through the old days. We eyeballed everything on the Speed Ventures self-certified tech sheet, checked the oil and coolant levels, put a torque wrench on the lug nuts, filled the tank with 91 octane, put on a helmet, and rolled onto the roval at California Speedway in Fontana, California.

This is an infield road course and about half of a super speedway oval, and in the long front straight and heavily banked turn there is plenty of speed to test your manhood. Luckily for us, we were on Ford's 145-mph speed limiter by the start-finish line, and so got to bubblefoot it through the banking. That's a good thing in a car without a rollcage, proper racing seat, five-point harness, or head restraint--believe us. We tried the softest, mid-range, and firmest shock settings and definitely enjoyed the firmer settings. We actually turned the fastest lap time by an insignificant margin on the mid-range settings, but preferred the firmest settings for track use.

Fontana is a smooth track, save for right before entering the oval section. Here the infield course is sometimes routed wide over perpendicular service roads, and this was the only place we wished for more suspension control. Actually, what we needed there was a Trophy Truck suspension, so it's hardly a meaningful complaint.

We did not adjust the sway bars. These can make a huge difference, but the car's balance was good, time was limited, and we were most interested in the shocks. We've found that adjustable sway bars are a big help in setting up the car the way you like it, and require no further adjustment unless meaningful changes in weight or power take place. We liked what we felt, knew we were close to optimal on the bars, and left it at that.

Big kudos to the Brembos, too. The first session brought on a light softening of the pedal, but once we let the brakes cool in the garage between sessions (one heat cycle), they were strong and consistent the rest of the day. Braking a 4,000-pound car from 145 to 25 mph every two minutes, followed by three more hard brake applications in-between, will uncover any brake weakness. And we didn't find any.

What was a handful was the shifting and traction control. You can only shut off so much of the traction control--and with this much torque instantly under foot, you want to think long and hard before pushing that button--and with the transmission shifting sort of when you think, there was something of a lottery regarding traction on corner exit. If the TC cut in, the gig was up in a big way, followed by a long pause until the computer was absolutely confident things weren't going upside down, followed by another explosion of power.

Two things helped. Most effective was to square the corner exit a little, getting the car pointed straighter than we would have liked before squeezing the trigger on those Roush-assisted ponies. The other was to manually shift the transmission.

The downshifts were made under braking and were easy enough. The upshifts were made just as soon after acceleration was obtained, so if exiting a corner in Second, as soon as the throttle was down, you put the shifter in Third. The trans then automatically shifts smoothly and quickly into Third, at which point you immediately slide the shifter into Drive. If you try to shift the automatic right at redline, it's too late--the rev-limiter kicks in, the car noses over big time, and it's generally ugly. Let the auto do its thing on the upshifts.

But don't let all this rambling about shifting cover up the fact that this car hauls. The power was intoxicating and let us turn a low 1:58 lap. That's Corvette ZO6 territory, and let's just say we hardly ever saw the GT2 Porsche race car sharing the track with us.

After three sessions, the fuel tank was empty and we elected to go home with everything still in one piece. Fun as it was, we had already learned the Eibach car was track-ready and it's adjustable suspension was good for fine tuning. We also proved the suspension didn't abuse the tires (that was up to us!), the brakes were right there, and the whole thing balanced enough to be a fun track driver.

Once outside the gate, we re-filled the gas tank at the same station we had filled it about six hours earlier, and headed home with the air conditioning on. Amazing.

Horse Sense: If open-tracking a modern Mustang GT, we would add a catch can to the rear-axle vent. It does tend to weep under sustained high speeds in turns. Bob's Auto Sports (www.bobsautosports.com) has a nice one if you are in the market.

Speed Ventures

Helping us more than once with track testing has been Speed Ventures (www.speedventures.com), an open-track group run by Aaron Bitterman. Speed Ventures puts on professional open-track events along the U.S. West Coast, plus Nevada, and because it's has been doing it since 2001, the outfit has it down to a science.

We like running with Speed Ventures because the rules are logical and straightforward, and enforcement is even. Their fastest run groups feature open passing (yes!) and somehow, while no more expensive than any other group, Speed Ventures doesn't seem to attract squirrels who can't keep their cars on the asphalt. They even order pizza if enough folks sign up by 10 a.m.

Expect three to five run groups and about two hours of track time per event. Entry fees vary by track, but Bitterman likes to keep them around $190 if at all possible. That, or a little more, is not bad for a big track like Fontana.

5.0 Tech Specs

'11 Mustang GT

Engine and Drivetrain
Block Low-pressure cast 319 aluminum w/pressed-in, thin-wall iron liners
Crankshaft Forged steel, fully counterweighted, induction hardened
Rods Powered metal forging, I-beam, no balance pad
Pistons Hypereutectic, short-skirt, flat-top w/four equal valve reliefs; moly friction-reducing coating; oil-jet cooled
Camshafts DOHC w/Twin Independently Variable Cam Timing
Cylinder heads Aluminum, four-valve per cylinder
Intake manifold Roush Performance lower with air-to-water intercooler
Power Adder 2.3-liter Roushcharger
Fuel system Port fuel injection, returnless
Exhaust Magnaflow after-cat
Transmission Six-speed automatic
Rearend 8.8-in

Electronics
Engine management Copperhead with Spankin' Time tune
Ignition Stock coil-on-plug
Gauges Stock

Suspension and Chassis
Front suspension
K-member Stock
A-arms Reverse lower
Struts Eibach R1
Springs Eibach R1
Brakes Brembo six-piston calipers w/14-in rotors
Wheels HRE
Tires BFGoodrich 265/30ZR-20 Rear suspension
Shocks Eibach R2
Springs Eibach R2
Control Arms Stock
Brakes Stock
Wheels HRE
Tires BFGoodrich 285/30ZR-20