Forced Induction For Track Work: Supercharging Two Popular Platforms

Among E46 M3 and S2000 owners, power is almost considered a four-letter word. The majority of those who regularly lap these cars, for reasons of simplicity and cost, prefer to optimize their car’s handling and braking performance in pursuit of impressive lap times. Also, they typically pride themselves, though usually tacitly, on their ability to lap quickly without a big motor to lean on. However, the ratio of grip to power usually falls in favor of the former with most of these builds, which forces the builder to consider whether a significant bump in grunt is worth the time, expense, and possible hassle.

Two of our fastest drivers decided the relatively cost-effective path of forced induction to determine if more power makes a worthwhile difference with these two popular HPDE platforms.

Seigo Ma had been swooning over the videos of the Arvou S2000, a lightweight AP1 using an HKS supercharger to make a touch more than 400 horsepower. The already capable package could exploit that power bump well enough to lap the technical Tsukuba circuit in a remarkable 53.887 seconds.

Seigo wanted to double his engine’s output, but worried that the famously fragile platform wouldn’t be able to handle it. So, in an attempt to get some much-needed encouragement (and see F1 in person), Seigo took a trip to Tokyo. Three days in, he visited Arvou to consult with Mr. Shibata, who encouraged him to take the plunge.

Back in San Francisco, Seigo started speccing his own HKS kit. He did his homework and chose the option of the smaller pulley needed to make 400+ horsepower. After he installed the kit, he sent his car to Blacktrax for the first pass at tuning his Hondata Pro ECU. They were able to make a knock-limited 350 horsepower at the wheels available over a very narrow powerband. “It only revved to 7,000 safely. That lowered redline, the shorter AP2 gearing, and 4.3 final drive made it a challenge to drive; it required constant shifting.”

To make the most of his new kit, Seigo ordered a higher flow fuel pump, 1050cc injectors, colder spark plugs, and a surge tank with an integrated fuel pressure regulator — all the items needed to run E85 safely. A retune of the Hondata brought power up to a knock-free 420 horsepower available at 8,500 rpm. “Power delivery was like a stock F22, but with a lot more at the top end,” Seigo said.

Even with 285-section rear tires and an OS Giken differential to help meter out that power, the bump in grunt was challenging to manage. “Second gear was pretty much useless,” he added. It also proved too much for the factory gearbox; breaking fifth gear broke on his second track day at that power level. To get himself back on track, he picked up a used AP1 box and a larger supercharger pulley to drop boost and lower the power output.

Relocating the oil cooler made lowered temps enough to run full sessions on moderately warm days.

The AP1 box’s longer gearing combined with the lowered output — about 360 horsepower — helped Seigo get to grips with the car at his next outing. Usable power, strong traction, and drastically improved top speeds has helped him keep up with higher horsepower cars that previously left him in the dust. Before braking for Thunderhill East’s Turn 1, he was traveling at 133 miles per hour — roughly 15 miles an hour faster than he ever had before.

The only notable issue with the car were creeping supercharger oil temps, which he resolved by relocating the supercharger’s oil cooler under the right headlight. With that upgrade, the car has been mostly reliable.

On moderately warm days, the car can run full sessions without issue. Only on the hottest days does it begin to falter, but it still works well enough to run three consecutive laps before engine oil temperatures get too high.

A drawback of running E85 is that combined with the new powerplant, it gets quite thirsty. “I burn half a tank per session, so I’ve gotta bring a few jugs of e85 with me every day. It’s still cheaper than running 91 octane and is much safer for the engine though.”

For Christian Fernandez, power was the last box to be ticked after aero, weight reduction, and a solid suspension setup. He’d already set impressive times with his E85-fed E46 M3, but he wondered if there might be an easy solution to extract a little more from his S54.

Dan from RCrew, Christian’s dependable mechanic, made him an offer on an ESS supercharger kit which promised easy power and little-to-no hassle.

As Christian had already installed a larger pump and 550cc injectors in preparation for corn juice, there wouldn’t be much more he’d need for a successful install.

“Multiple YouTubers who’d used the same kit complained of overheating issues, though. The front-mounted intercooler wasn’t necessary with this entry-level kit, so I decided to take the band-aid solution and install a water injection kit to keep intake temps low.”

On a Dynojet, HTE Performance tuned the stock ECU to handle six pounds of boost from the the supercharged S54 put down 487 horsepower — 157 more than what the atmospheric, E85-fed motor had made on the same dyno.

The bump in power is felt largely at the top of the rev range; making the motor feel similarly linear in its delivery, but notably faster at the end of straights. “It’s pretty easy to put the power down, but the extra 3-4 miles an hour it nets at the end of the straights forces me to reconsider my braking points.”

This bump in straightline speed doesn’t overwhelm the current cooling system, which consists of a larger radiator, an oil cooler, and the water injector. “Even on 80° days, the needle never moves past the ¾ mark!

That said, I’m not sure I’m getting all that peak power over a whole session. It probably needs an intercooler.”

The blower hasn’t made maintenance a nightmare, but it has exposed a few leaks that weren’t an issue before. Running a leakdown test revealed a leak from the valve cover seal and around the aftermarket injectors, which never seat properly and require a washer for passable fitment.

Both drivers are content with their new engine setups, which have proven to be reliable after the little issues were addressed. Seigo bought a usable 150 horsepower and 2.5 seconds at his regular tracks. “So far, it’s been money well spent,” he said.

Christian is content with the improvement, though the M3 was never lacking power in the way the S2000 was. To be fair, the former has gone a step further in addressing all their supercharger’s shortcomings, while the latter has taken a more relaxed approach.

There’s still more to be done before the bare-basic ESS kit offers track-worthy performance, but once it’s sorted, there’s no reason it shouldn’t have that funny effect of shortening straightaways — so much so that Christian will have to start thinking of braking point right after he starts to accelerate.

Elie's E46 M3: Not Too Much, Not Too Little

For Elie Mansour, the E46 M3 is one of the most driver-friendly machines he’s ever driven—and he’s driven just about every trackday staple.

In 2003, Elie started tracking in the States with a fourth-generation Camaro, but to him, a man who grew up watching smaller vehicles hillclimbing in his native Lebanon, the Camaro seemed somewhat cumbersome.

“Everybody was driving the Subarus and Evos, S2000s, and a handful of E36s then.” His natural affinity for the capable E36 led him to buying one of his own, but its lack of power and regular maintenance left him wanting a little more. “For about six months, I considered swapping an S54 into my car, then my friend let me drive his E46 M3, and it just felt so much sturdier. When I factored in all the associated costs of swapping the new motor into the old car, I realized that I’d be better off buying an E46.”

Photo credit: Brett Smrz

Wisely, he avoided building one from the ground up. The Imola Red ‘02 he procured already had been partially stripped and fitted with an Autopower cage, big Brembo GT 355 brakes with Cobalt bads, and a set of Ground Control coilovers. As a precaution, he removed some of the failure points. Simple and effective, this platform needed nothing more than a set of solid mounts and bushings before Elie logged fifty events his first year with it.

Building Upon a Brilliant Foundation

Despite the running costs and the growing appetite for better parts, this busy first year didn’t tax him too much. The reliability of the car was astounding; changing the pads every dozen days and the oil about half as often. Then there was the ease of operation. “The E46 is one of the most driver-friendly cars I’ve ever owned; it has great headroom, great visibility, ergonomics, and it’s easier to drive than any other car at this performance level.”

Relatively simple operation, a moderate amount of weight, more that adequate power, a reasonably comfortably size, and—assuming one buys a good example—a manageable price. In so many ways, the E46 M3 is the ultimate Goldilocks car: not too much, but not too little.

Perhaps all this versatility came with one setback: weight. Being reasonably large and somewhat plush, the weight became more and more of an obvious hindrance the harder he pushed. Removing the sound deadening and carpet, then replacing the standard Getrag six-speed with a ZF five-speed allowed him to bring the weight down to 2,825 pounds.

It only followed that he would sharpen the chassis with whatever means readily available. After adding Ground Control swaybars, he sought out a set of revalved shocks to suit the lightened chassis. A knowledgeable friend practically gave him a set of used Motons that’d been collecting dust in a shop, but further inspection revealed the fronts were damaged beyond repair. At that stage, his friend admitted that he used JRZ parts to rebuild the other Motons he’d been given.

They shared a laugh, then took the expedient solution: using a set of JRZ RS Pro two-ways to replace the faulty fronts. With a little tweaking, he found the two brands to complement each other. “The two work well together, and the JRZs are so much easier to service than the Motons. It’s an unusual mix, but it was a no-brainer for us.”

With the footwork seriously improved, the slapped on a set of Pirelli DH crubs and began impressing the bystanders. His aggressive, tail-out driving style honed through years of messing around on gravel roads had to be tamed somewhat to go faster, but at least he was never limited by a lack of car control.

With the car handling well, he turned his attention to the powerplant. The S54 is, with the right sort of maintenance, a fairly robust motor that might get a little too much negative press. That said, it needs some uncorking before its sonorous scream can be fully appreciated. Along with an AFe intake, an eBay header, a Bimmerworld exhaust, and a BSpec tune, the motor made a healthy 323 horsepower at the rear wheels.

While the motor is stout, tracking can elevate temperatures to a worrying level. The iron block’s chances of overheating diminished greatly after he added a Bimmerworld motorsports thermostat and oil diverter, a CSF radiator, and a custom built electric fan, he’s been able to keep the iron block cool, even on sweltering summer days. “Don’t forget: a high viscosity oil is a must. During the summer months, I change the oil—usually 10W60—every three or four track days.”

With the motor fortified and the suspension sorted, the car was as dependable as any thoroughly thrashed track tool, really, and Elie prioritized seat time over all. Nearing his hundredth track day, he’d pushed the M3 to about as far as anyone was capable, and the few shortcomings in the car started to make themselves apparent.

Ready for a new challenge and a little more stability at speed, he decided to call on Trackspec Motorsports, who were then sponsoring him, and ask for a contribution in the form of a modest aero package.

The takeaway here was that he hadn’t simply reached for the biggest wing prematurely. He and Trackspeck went through a series of different combinations before settling on the G-Stream wing and their tegrid-constructed splitter, which was chosen for its durability. The result was, well, just watch the footage below to see the car in action:

Even Monkeys Fall From Trees

And then, perhaps as some sort of divine/cosmic payback for 180,000 miles of faultless operation, the motor coughed its last breath. He tucked the car away to the back corner of his garage and helped a few friends build their E46s with his two decades of knowledge,

It still sits in the corner, but another S54—again built for reliability—is almost finished. When the motor is implanted in its new home, he’ll address the two remaining flaws he’s noticed. “The OEM LSD acts like an open differential now; trying to get any traction out of Buttonwillow’s Turn 2 is futile.”

Besides that, it needs a few more safety modifications to move into the next realm of competition: NASA ST4. Trackspec Motorsports will likely prototype the cage, and along with a fire system, full window nets, and a restrictor to meet class restrictions, he should be ready for wheel-to-wheel. He’s got the car control and the courage, so the transition shouldn’t be too difficult.

Peter Phung's Widebody M3: Wide and Wonderful

Search YouTube for Hans Stuck Jr. romping around the Nurburgring in his M3 GTR. The widebody, V8-swapped E46 in that famous clip was as gorgeous as it was quick. Peter Phung hadn’t actually seen that video until I mentioned it to him a few days ago, but several years back, he’d found another image of that car that encouraged him to try building his own version of what some see as the ultimate E46.

Immediately after picking up the car, complete with moonroof and a six-speed, he handed it off to someone else like a negligent father. He wanted to attach the DTM Fiberwerkz widebody kit sitting in the corner of his garage, and so he entrusted one shop he knew little about with the task.

It became a pretty significant job since black paint wasn’t exactly doing it for him—mainly because he’d already pictured the ultimate iteration of this car as one with a white base. This M3 was meant to be an homage to the original GTR, which is doused in white with the M-tricolor striping. He handed it off to the professionals and waited eagerly for a pretty car to come back to him.

Peter posing beside his sister Florenza with the car wearing a simpler livery.

Once back in his hands, he was mostly impressed. The paint looked great, but the bodywork was terrible; he noticed cracked fenders and excessive fiberglass reinforcement pretty soon after. Oh well—it was meant to be a track weapon, so he moved on and started addressing the shortcomings of the stock suspension. The first round of mods consisted of Turner swaybars, and TC Klein coilovers, Brembo big brakes, and a set of Bimmerworld brake ducts.

Besides the stripped cabin and the lightweight Recaro buckets, the diet consisted of a few things: aluminum door panels, two fixed Recaros, a DTM Fiberwerkz hood, an RKP carbon roof, a removed rear deck.

Interestingly, the extra tire and width came at a serious cost to any track-dedicated car. Though made from fiberglass, the bodykit added another 200 pounds to the tally. Even after gutting the interior and taking other weight saving measures, the car still weighs in at a slightly doughy 3,100 pounds.

TC Design installed a gorgeous half-cage and made the necessary subframe reinforcement problems, then Auto Logic replaced the rod bearings with WPC coated rod bearings and refreshed the VANOS with the Beisan kit. After that, Auto Logic cleaned the combustion chamber, performed a five-angle valve job and administered the Epic tune. If the car had been given to the wrong people initially, he made sure that everyone else who touched his dream M3 were top-tier.

The one persistent gremlin that plagued them, an overheating issue, was traced to the A/C condenser. Once they chucked that in the trash, the car ran cool in the scorching summer temperatures. Powerful, tractable, and reliable—the S54 with a little work is something special.

Along with a custom fitted Borla cat-back and long tube headers, the naturally aspirated package pumps out roughly 360 horsepower—more than enough power for a heftier E46 M3.

Peter’s thinking was that if the extra weight offset its above-average power output, the wider footprint would have to compensate. To make the most from this, he deicided that he needed a better suspension system, upgraded to a full 2 way adjustable MCS pro suspension, added a set of spacers, and fitted Titan 7 wheels measuring 18 x 10.5”. Peter then added camber plates, a stiffer front sway bar and rear traction arms from Ground Control. Even with the stock differential, the combination of massive tires and a soft rear makes the BMW sticky, predictable, and easy to lean on.

There’s a constant through this build, and that’s that his entrusting the car with enough gifted people to make up for the few bad apples who got their greasy mitts on it way back when. Once he had the gifted guys at 101 Paintworks fix the widebody, he was finally satisfied with this ambitious build. Finally, the showpiece part, the amazing widebody, the thing that distinguishes this from all the other E46s, was fitted like it was supposed to be.

“It handles well, but I’d say it looks better than it performed than it did during the first phase. I did want it to look good—so at least I accomplished that goal,” he said with a chuckle. After going though five years of changes, upgrading to better performance parts and more than doubling his original budget, the car performs as good as it looks.