Racing on a budget doesn't have to mean driving something old or slow. With the prices for used 135i Coupes hovering around $30,000, this could be your next track car.

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May 31, 2012

SINCE THE ECONOMY’S NEAR-COLLAPSE IN 2008, DOWNSIZING HAS BEEN A WAY of life for most of us. Even those who were still doing well saw fit to scale back a bit, toning down the expense and ostentation in favor of something more appropriate to the mood of the day.

Miami residents Alberto Esquenazi and William Brand—a used car dealer and a producer of TV commercials, respectively—weathered the downturn just fine, but both wanted to scale back their automotive expenses. Rather than stop racing altogether, they decided to downsize, Alberto from an M3 and William from an Audi R8 V10. While that formula might lead some people to a Spec E30, both Alberto and William decided that the 135i Coupe would be their best bet for a fun, fast racer.

“The M3 is just too heavy,” Alberto says. “The 135i is a better-handling car.”

We’ll see about that in a moment, but one thing is indisputable: The 135i is far less expensive, with low-mileage models available from around $30,000 from either a BMW dealer or a private-party seller. And while the car’s handling is a little underwhelming in stock form, plenty of aftermarket fixes are available, and so are plenty of options for getting more power out of the N54 engine in the 2009-2010 cars or the N55 fitted to 2011 and 2012 models.

Enlisting the hot-rodding and race-prep services of Miami’s Active Autowerke, Alberto and William have taken full advantage of the 135i Coupe’s potential for performance. Whether that’s enough to turn these underrated coupes into M3 killers we’ll soon find out, because along with the two 135i Coupes, we’ll also be driving Ricardo Fernandes’ E92 M3 here at Homestead Miami Speedway. This car, too, has been modified by Active Autowerke for full-on track duty, and it’s already won a few trophies in 2012.

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Before we get to Ricardo’s M3, however, let’s have a look at this pair of 135i Coupes, which look like twins but are actually quite different beneath the skin.

The N54 advantage

William’s car is a 2009 135i Coupe, powered by the brilliant N54 twin-turbocharged six that was introduced in 2006 to much acclaim and more than a few technical problems with the car’s fuel injection and cooling systems. Most of those were fixed during the engine’s production run, and those that weren’t were cured when the N54 was replaced in 2011 by the N55, a single-turbocharged six. BMW claimed an identical crankshaft output of 300 hp and 300 lb-ft for both engines, but the N54 always felt zippier, and it was no surprise when a hot version of this engine found a home in the high-performance 1 Series M Coupe, Z4 35is and 335is even after it had been replaced by the N55 in the more pedestrian models.

According to Active Autowerke’s Karl Hugh, a stock N54-powered 135i delivers around 262-265 horsepower to its rear wheels, which equates to around 308 hp at the crank (assuming a 15% parasitic power loss through the drivetrain). That’s a little more than BMW claims, whereas the N55 tends to fall slightly short at 250 rear-wheel horsepower or 294 crankshaft hp. The N54 typically delivers around 218 lb-ft of torque and the N55 some 217 lb-ft.

The N54’s superior stock horsepower compared to its claimed output suggests greater potential and makes the N54 a better starting point if you want to make big power. So does the N54’s use of a traditional throttle instead of Valvetronic, which eliminates the throttle body in favor of using the intake valves to control the entry of the air-fuel mixture to the combustion chamber. Valvetronic enhances fuel efficiency, but it also renders one of my favorite pieces of turbo technology unnecessary: the pressure release valve that makes a satisfying whoosh! off-throttle. Childishly, perhaps, I think that sound is one of the best things about a turbocharged engine; fortunately, Active Autowerke sells a valve that really brings it to the fore.

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A more audible pop-off valve isn’t the only modification that Active Autowerke made to William’s engine, of course. While leaving the internals untouched, they reprogrammed the N54’s computer for a higher boost level and ignition timing while fitting a cold-air intake and an Active Autowerke Signature exhaust complete with downpipes. Crucially, the company also installed its own intercooler, which increases the core size by 88% to drop charge air temperatures by close to 30° F in the intake manifold. That allows a gain of 12 rear-wheel horsepower in itself, and it obviously helps the N54 to reach its potential without overheating. (Stock N54-powered cars tend to go into limp-home mode after just a couple of laps on the track, especially in hot weather.) The car also has two Active Autowerke oil coolers to cope with its impressive 328 hp and 370 lb-ft output at the rear wheels—an improvement of 63 hp and 152 lb-ft!

Elsewhere, William’s car has been fitted with a limited slip differential (essential for putting that power to the ground), KW Clubsport coilover suspension, an Active Autowerke strut tower brace, a bolt-in Active Autowerke custom roll bar and the requisite racing seats and harnesses (here by RaceTech and Schroth on VAC mounting hardware). A StopTech big brake kit uses two-piece, six-piston aluminum calipers against 355mm slotted iron rotors with aluminum hats up front and four-piston calipers on 345mm rotors at the rear. The wheels are Breyton Race GTSR cross-spokes that measure 7.5 × 18 inches at the front and 8.5 × 18 inches at the rear, mounted with Michelin Pilot Sport Cup tires in 225/40-18 and 265/35-18 sizes.

N55: New and improved?

Though outwardly similar, Alberto’s car is in fact slightly different to William’s. As a 2011 model, it’s powered by the N55 single-turbocharged six with Valvetronic, which when modified with Active Autowerke’s software, intake and exhaust system produces 304 rear-wheel horsepower and 345 lb-ft of torque on Active’s Mustang dyno. That’s quite a bit short of what William’s car puts out, but it’s a 54 hp/128 lb-ft improvement over stock, so the Active Autowerke mods are obviously effective on the N55 as well as the N54.

The N55 never suffered from the cooling problems of the N54, but Alberto’s car has been fitted with Active’s intercooler and twin oil coolers nonetheless; better to be on the safe side where engine temps are concerned. Active’s oil coolers increase oil capacity by at least a quart, which itself can help relieve oil temperatures, and neither car now overheats even in Florida’s sweltering summers.

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Alberto’s car doesn’t have a roll cage, but it does have the same Active strut brace, RaceTech seats and Schroth harnesses as fitted to William’s car, as well as the same StopTech brakes. Alberto went with Breyton wheels, too, but here in 8.5 × 18 inches at all four corners fitted with 245-section Hoosier racing slicks. This more-neutral setup was made possible by sticking with KW Variant 3 coilovers instead of upgrading to Clubsports as William did. Not only did the larger diameter of the Clubsports force William to use narrower tires on the front axle, the Clubsports’ firmer damping rates reduce traction on imperfect surfaces.

“William’s car jumps around too much,” Alberto says.

“We’re still sorting out the handling,” William admits.

Since this is my first trip to Homestead Miami, I start out riding shotgun while Alberto goes out for his first session. The layout has some good left-right combinations and a lot of hard braking zones at the end of both short and long straights. Only the fastest run group will be using the NASCAR banking for this Hooked on Driving track day, but all of us will use the long straights between banked turns as part of the road course.

Brake chatter, no matter

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One or more of the 135i’s brakes is chattering badly, so Alberto pulls in early to have it checked by his mechanic. No problem is detected, but the chatter is still there when I take the wheel for the second session. The car slows just fine, and further inspection shows the imprint of a brake pad on one of the rear rotors; if someone applied the e-brake while the rotors were still hot, the pad could have left quite a bit of material attached to the rotor, or the localized heat might have warped the rotor. Still, the brakes work fine but for that juddering through the pedal.

A bigger obstacle is the seating position. Even though the racing seat has fore and aft adjustment, I’m stretching a bit to reach the pedals, and I’m further away from the steering wheel than I’d like. More ridiculously still, I’m sitting so low in the saddle that my chin is level with the window sill—Alberto is a lot taller than I am, and he’s mounted the seat fairly low to accommodate his helmeted head—which gives me a view of the side-view mirror and the A-pillar on left-hand turns. Fortunately, William is riding in the passenger seat to guide me around Homestead Miami’s unfamiliar pavement.

I’m only guessing at the left-hand apexes, but I can tell with absolute certainty that Alberto’s car handles much better than a stock 135i. First of all, there’s virtually no understeer, which is the defining characteristic of a 135i on a race track. Second, the car rotates extremely well, and throttle inputs have an immediate effect on the car’s attitude, allowing the driver to make very subtle adjustments. Although higher speeds might show a few flaws, my first outing in Alberto’s 135i reveals a very well-sorted race car, one that’s both easy to drive and fast.

A stock 135i is by no means slow, but the Active Autowerke software mods plus intake and exhaust have made this car a rocket. The N55’s power is inherently easy to use, and the Active mods haven’t hurt that a bit. As I mentioned earlier, Alberto’s car is delivering a peak of 304 hp (at around 5,600 rpm) and 345 lb-ft of torque (from 2,500 rpm, where the dyno starts measuring, to around 4,100 rpm) at the rear wheels. That puts Alberto’s car within 26 horsepower of an E92 M3…and 110 lb-ft beyond if we’re talking torque. Just as importantly, torque no longer dips by about 15 lb-ft at 3,100 rpm like it does on the stock N55 engine, making delivery much more linear throughout the range.

Shifting through the Active Autowerke short shifter is direct, requiring an ideal amount of effort to change gears. The car hooks up beautifully, and its predictable handling makes it easy to drive. Needless to say, if I’m getting passed while driving Alberto’s car, the fault is with me, not this 135i Coupe!

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The control car: a full-race E92 M3

Before I drive William’s N54-powered 2011 model, I’ll take a turn in the third car on our list, Ricardo Fernandes’ E92 M3. Although it’s by no means stock, Ricardo’s car is serving as a control car of sorts, because the M3 constitutes a known quantity against which to measure the performance of our subject 135i Coupes.

This particular M3 was bought used for the specific purpose of being turned into a race car, and that meant removing everything deemed superfluous to racing. That included not just obvious things like carpeting and rear seats but also every unnecessary electrical element and length of fiber optic cable. Ricardo wanted a car with the M Double Clutch transmission, and he also wanted the track-tuned DSC programming that comes with the Competition Package. Competition Package also includes Electronic Damper Control and thus iDrive, and both of those items have since been removed along with the screen on the dash.

It might have been easier to start with a simpler build configuration, but M Driving Mode does have its advantages, and most top-level race cars use something similar. Still, I’m told that dismantling parts of the fiber optic network that run these systems presented a particular challenge for the guys at Active Autowerke. “The digital motor electronics are integrated into the network, so it’s always looking for the missing components until they’re manually and electronically removed from the programming, one by one,” Karl told me.

The M3’s Dynamic Damper Control shocks weren’t suited for racing, so they were jettisoned in favor of a set of KW Clubsport coilovers. At the same time, the stock wheels were swapped for a set of stylishly simple five-spoke D-Force wheels from Bimmerworld. Measuring 9 × 18 inches, these 18.2-lb. wheels have been painted matte black and mounted with Continental racing slicks that measure 275-25-18 at all four corners for neutral handling. Behind the wheels, a really sexy set of StopTech Trophy brakes replace the single-piston stock setup with massive six-piston calipers up front clamping 380mm slotted iron rotors on aluminum hats and four-piston calipers at the rear working on 355mm rotors.

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The motor’s internals were left untouched, but Active Autowerke reprogrammed the DME while removing the unwanted elements, also fitting a muffler-less version of the Signature exhaust that lets everyone know when Ricardo’s car has just ignited.

With less weight, easier to drive

Ricardo’s car has basically been converted to M3 GT4 spec: lightened by about 400 or 500 lbs. and with race-ready suspension and brakes but not too much in the way of engine tuning. Sure enough, it feels as well-sorted as a factory racer, with smooth, consistent power delivery and absolutely divine handling. The Active mods have given the S65 V8 a bit of a boost, for sure, upping rear-wheel output from 330 to 344 hp at 8,000 rpm and from 235 to 246 lb-ft between 4,240 and 6,000 rpm, after which torque tapers off only slightly while horsepower continues to climb. Although peak output isn’t vastly improved, power delivery is, with torque remaining much more consistent and horsepower showing good gains in the midrange, especially.

The engine doesn’t produce overwhelming power by any stretch of the imagination, but it does produce strong, smooth, usable power that makes this car really easy to drive, especially when paired with the M-DCT transmission and the M Differential Lock. A naturally aspirated engine is always easier to manage than one with forced induction, and race car drivetrains don’t get much more user-friendly than the M3’s.

That’s especially true when they’re coupled with a lightened, well-sorted chassis, and it’s hard to overstate the benefit of dropping 400 or so pounds from an M3. BMW claims a stock weight of 3,704 lbs. for an E92 M3 of average specification, and reducing that to around 3,200 makes this car feel less like a GT and more like a proper sports car. It responds much more quickly to inputs from the throttle and the brakes, and it changes direction so readily that it’s almost dreamlike. Where a stock M3 never lets you forget that you’re shifting a lot of weight every time you take a corner, Ricardo’s car simply gets the job done, changing direction with the ease of a much smaller vehicle.

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It doesn’t hurt that it’s been stiffened by the addition of a roll cage, or that it’s riding on a set of well-sorted KW Clubsports, which give a smooth ride even over the little dip where the banking transitions to the infield road course. The Continental slicks, too, are providing tons of grip, far more than I’m able to use on this unfamiliar track and in a borrowed car. I’m leaving a lot of potential left unexploited, of course, but even so I’m not getting passed in this M3.

On the contrary, I’m actually making quite a few passes after just a couple of laps, and I’d be making more still if I could make optimum use of the StopTech Trophy brakes. Every time I go into one of the hairpins at the end of a straight, I’m applying the brakes harder and later, yet I still find myself having braked too early. I’m dialed in to BMW’s stock braking performance, and the margins for fade that I’m programmed to leave in simply aren’t necessary.

This is a stunning machine, undoubtedly the best M3 I’ve ever driven. I’d love to spend all day driving it. Indeed, I’d need all day to approach the limits of braking and adhesion, but it’s time to drive our second 135i and see how it stacks up against the first 1 Series racer as well as this spectacular M3. It won’t be easy, but it does have one thing working in its favor: the magnificent N54 twin-turbocharged six.

Fast, but tricky!

Stock, an N54-powered 135i makes around 265 hp and 218 lb-ft, but the N54 in William Brand’s car has been tuned to make 328 rear-wheel horsepower and 370 lb-ft. That’s not much less than the 344 horsepower of the tuned S65 in Ricardo’s M3, but it’s 124 lb-ft more torque, and it’s being fed to rear wheels that are four inches closer to the fronts. The 135i rides on a 104.7-inch wheelbase where the M3’s measures 108.7 inches, and the extra stability is the first thing I miss when I get behind the wheel of William’s 135i. At least I can reach the controls properly in this car, which allows me to push a bit harder right from the start, and to explore more of the performance that this hot little coupe has to offer.

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After trying out Ricardo’s Trophy brake setup, which had more power than I could learn to use in just one session, it’s a relief to get into a car with regular StopTech brakes. These feel more familiar, but they still have plenty of power and more potential than I’m able to exploit. They’re strong and well-balanced, a perfect match for this very rapid car.

It’s fast, all right, but more importantly it’s responsive. The N54 is simply one of BMW’s best engines ever, and it feels a lot more alive than the N55 in Alberto’s car. As modified by Active, the N54 puts out 25 lb-ft more torque; on top of that, the boost comes on more forcefully and the revs increase more quickly. (The boost also releases on closed throttle with that satisfying whoosh! through the blow-off valve, something that isn’t possible with the throttle-less Valvetronic N55.)

The extra power and the force with which it comes on highlights the trickiness of the 1 Series chassis, as does my improved knowledge of both the Homestead Miami track and these race-ready 135s. The faster you go, the more you miss those four extra inches of wheelbase. While the difference gives the 135i a bit of an advantage over the M3 in cornering agility, it’s not enough in my opinion to make up for the reduced composure when the track surface gets tricky.

The softer suspension and lack of a roll cage in Alberto’s car masked this a bit, and so did the slicks that helped it hook up really well. With the added stiffness of a roll cage and firmer Clubsport shocks, William’s car doesn’t have quite as much “give” as Alberto’s, and the lower friction coefficient of its Michelin Pilot Sport Cup tires makes finding traction more difficult. The offset tire sizes necessitated by those Clubsports also mean that William’s car has a bit less grip at the front than Alberto’s, and that it’s somewhat less willing to respond to minute steering adjustments from the throttle.

This is a really fast car, but it’s also fairly difficult to drive, and cutting a quick lap takes a lot more skill and concentration than it does in Ricardo’s M3. Small mistakes can have big consequences in a 1 Series, as Alberto demonstrates when he spins his car into a wall just before lunch. It was a tiny lapse, he tells me, yet it did significant damage to his car’s front bumper and cooling system. The more-forgiving M3 might have let him get away with the same mistake, which makes the M3 preferable in my opinion. I also like M-DCT on the track; both 135i Coupes are equipped with the traditional manual gearbox, which William chose for the driver engagement he’d missed in his DSG-equipped R8.

William and Alberto obviously relish the challenge posed by the 135i. They’ve both got a lot of racing experience under their belts in their native Colombia and here in Florida, and they clearly enjoy these cars a lot. So do I. They’re really fun to drive, fast and well-sorted. Even so, I’d take Ricardo’s M3 over either of them if money were no object.

Money is an object, however, at least for most of us, and that makes these lower priced but still very quick 135i Coupes a darn good alternative. They’re readily available as used vehicles, too, making them a good option to a 1 Series M Coupe with similar performance. And just like the 1 M Coupe, a 135i will tax your skills while teaching you a lot about fast, precise driving in the process.

Hmmm…maybe it’s time to starting searching those Craigslist classifieds for an N54-powered 135i!

Thanks to Alberto Esquenazi, William Brand and Ricardo Fernandes for trusting me with their cars at Homestead. That was fun!

Also from Issue 108

  • 25 Hours of Thunderhill 2011
  • BMW Technology helps Bryan Clay jump farther
  • Pressure sensitive: Non-U.S. M550d sedan
  • Buyer's Guide to the E36 325is, aka M3 Lite
  • MKO of Germany's wild V8-powered 2002
  • The legendary 700 RS of Hans Stuck, et al
  • Baur 323i TC1 Cabriolet by Koko Manouelian
  • Before electric i cars, BMW built hydrogen 7
  • Monterey, Pebble Beach, Legends of Autobahn
  • BMW Wins Sebring! Jonathan Summerton
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