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.

Dustin's Supercharged M3: A Lesson in Applied Economics

He wasn’t intimidated at the prospect of buying and tracking an E46 M3, but Dustin Furseth felt some pressure to build one in a way that would allow him to balance his checkbook. That’s a normal concern, but with a baby on the way, he couldn’t afford to get in over his head.

But with the car’s reputation and its strong aftermarket support, as well as his knack for finding a little sponsorship here and there, he turned this basic road car into a approachable, reassuring, and still-somehow-comfortable track toy in only a few years. It also makes 500 and change.

For the first few seasons of track work, Dustin was known to leave a child’s car seat by his parking spot at the track; sometimes he’d drop his boy off at daycare before putting in four or five sessions. He wanted to make the best use of his time, clearly. For that reason, after adding MCS one-ways and Ground Control arms, he hired a coach for several weekends and refined his driving style.

His approach was an intelligent one. After one impressed coach suggested he try a more competitive form of motorsport. Dustin finally had the confidence to step up, and after a friend recommended Global Time Attack, Dustin entered his modest M3 in Street Class.

In time attack, he found a sparring partner in Karl Taht, whose S2000 was, on average, a hair faster at technical tracks. Dustin’s M3 usually had the upper hand at faster tracks, but the two were trading tenths regularly and pushed to get the most from themselves and their cars.

Not interested in mega power or hiring someone to fabricate piping, Dustin picked this easily-installed kit.

When Karl decided to turbocharge his F20C, he inadvertently dropped the gauntlet. Dustin responded by modifying his S54 with a trick head and some big Shrick cams, but it was no longer a reliable motor. After a year and a half, it popped.

When it came time to rebuild, he considered another attempt at a highly-strung engine, or, as his friend had, he could try forced induction. A little research convinced him he could bring power up by 200 and still save some money over another strung-out S54 if he could bring himself to boost a stock engine.

With an ESS G540 supercharger kit, he had to upgrade the clutch to a Clutchmasters FX725, beef up the cooling system with a Mishimoto rad and oil cooler, and add a little ducting to ensure air flows through the right channels and isn’t recirculated at the backside of the radiator.

Now, the boosted S54 is a real powerhouse—legitimately GT3 RS-strong, distinctive, and resilient. Even though the blower makes a peak of 515 at the wheels, it doesn’t change the delivery or the driving experience that much from when the engine made 300 at the wheels.

The blower doesn’t really change the shape of the curve, it just elevates the curve a few hash marks higher on the dyno chart. It feels intuitive. What is most different about the new powerplant is that there is appreciable torque where there once was none. It’s not peakier than the engine was originally, it feels like there are a few more cubes available.

An RS Future splitter helps encourage a neutral balance at speed.

The power was easily transferred into propulsion before the blower, but the new grunt alters the way Dustin has to depress the pedal. With eight pounds of boost at his disposal, he can spin the wheels for a hundred feet after a second-gear chicane if he’s out to impress a passenger.

However, the car’s grip and poise means it still takes a lot of provocation to do so. In other words, car can still be leaned on mid-corner and generate strong drive off the corner, provided he’s not using the wrong gear.

There is the matter of gear selection. The hairpins which rewarded a second-gear exit now have to be taken in third; the power delays throttle application in sections where the car is traction-limited. Not everyone considers it, but if a bump in power means it takes longer to deploy it, is it worth the addition?

Going from a 275-square setup to widening the rears with 295s has made the car border on high-speed understeer.

The answer is yes. Even when it does light up the driven wheels, the rear remains planted. Maybe that’s the APR GT250 wing imparting some stability, but even in slow hairpins, the factory LSD does a stellar job.

This staggered setup promotes a little understeer, but it’s a minimal amount of push and it’s really only noticeable in faster corners if he’s hasty putting the power down. Yes, there is an iron lump up front, but the big motor doesn’t make itself noticeable unless the throttle’s stabbed mid-corner. Line things up after a committed flick into the corner, then power out with encouraging neutrality.

For all this fun, he’s had to pay another fee on top of the supercharger’s purchase price. The oil breather, after enduring high revs, would mist onto the belts, which would underdrive the water pump and overheat the engine. After a quick fix involving a rag and some hair ties, the engine hasn’t given him any other headaches.

“The brakes have been a great addition. When I put something on my car that I believe in, I try to explain it to people as best as I can.”

The added strain on the brakes from a middleweight with serious power made it necessary to go for a big brake kit. However, he wasn’t keen on spending the money needed to buy the AP Racing kit he had his eyes on, so he found an affordable alternative.

Underneath his Apex VS-5RS, he opted for PB brakes front and rear. The fronts use eight-piston calipers and 380mm rotors, and the rears use six-piston calipers with 356mm rotors. Complete with the motorsport-grade bobbins, knockback springs, and floating rotors, the kit has proven itself track-worthy. The calipers are finished in a subtle shade of silver that blends in beautifully, too.

By milling down used pads bought from endurance teams, he’s saved himself money and time. The rotors rarely need replacing, the pads last thirty-odd sessions, and even with the old Mk20 ABS, the car inspired a lot of confidence in the braking zones. Higher speeds and ~3,000 pounds put some real strain on the binders, but the PBs have handled that well.

And despite all that focus and performance, it’s still very much the sleek machine Dustin bought seven years ago. Yes, the wing and RSFuture splitter, and N15 vents leave nobody doubting its role as a track toy, but Dustin’s insistence on leather-wrapped Recaro Pole Position NGs and the retention of most of the interior prove he’s after a little more than speed alone.

It doesn’t come as a surprise that Dustin is an architect—he has to weigh aesthetics and functionality as part of his job. The soft shape of the car, the silver and carbon-black scheme, and the simple execution make it a stunner that you can sit and drink in for minutes, even if it doesn’t call your name from across the paddock.

In other words, it’s a complete car—and not many cars built on a careful budget are truly complete. Dustin did his homework, though, and even with a full plate, he got where he wanted to be quickly. Stay in school, kids.

Modifications

• EE G540 Supercharger Kit

• Rogue Engineering section 1 and 2

• Agency Power section 3

• Epic Motorsports tune

• Naturally Agitated Stage3 VANOS (ported for higher oil pressure)

• SAP delete

• Electric fan conversion

• Turner power pulleys

• Sachs clutch

• Mason pedal box

• APR GT250 wing

• CSL carbon roof

• CSL trunk

• CSL diffuser

• Hard Motorsports splitter, upper canards , and carbon door cards

• MCS 1-way coilovers

• Apex VS-5RS 18x10”

• PB BBK with 8-piston 380mm fronts and 6-piston 356mm rears

• Hawk DTC30 pads

• Sparco Seat

• Schroth harnesses

• Custom 4-point cage
  
  
  
  
  

James Snell's Supercharged S2000: Bold is Better

Four years ago, James hadn’t even considered tracking a car. Though he was definitely a dedicated gearhead, he preferred lowriders and rock crawlers, mainly. Some of his friends had taken the track day plunge, however, and a few of them were adamant he branch out a bit.One Saturday morning, he drove out to Streets of Willow with a few eager buddies and everything changed.

The giddiest of his friends also had good taste; he brought his S2000 along and threw James the keys. He also had trust and good manners—he only asked that James bring it back in one piece. The casual introduction had clearly had an effect, because, just one month later, James had bought one for himself.

Good Hands

It was no ordinary S2000, either. This AP1 was previously owned by a Ballade Sports employee, so it’d been given lots of love and attention. Along with some choice body modifications, it came fitted with KW V3s, a square set of RPF1s, an exhaust, an intake, a halo-style seat, and an F22C motor with roughly 40,000 miles. For someone dipping their toes in the water, James couldn’t have been luckier—the price he picked this one up for would irritate a lot of prospective buyers these days.

The car came with an OEM AP2 front bumper and CR lip, a replica CR trunk wing, and a full carbon hardtop weighing only seventeen pounds.

As nicely sorted as this example was, the AP1 is not a forgiving car. “The first few times I drove it, I probably spent more time spun off-track than I was on-track, but I didn’t care. I set a 2:14 at Buttonwillow 13CW and I felt like a rock star. I may’ve been going off a few times every event, but—and I can’t stress this enough—I was having the time of my life.”

“My motto then was: ‘If you’re not spinning, you’re not trying.”

However, he adapted rapidly. “Smooth is fast in that car. The more I softened my inputs, the better the car responded. My lap times fell, and I set my sights on a pretty significant goal early on. The aim was to set a Buttonwillow 13CW lap under two minutes on 200TW tires without the help of any aero.”

As James learned, trimming the first few seconds is easy. Three years passed before he was able to whittle his times down to something nearing his goal, but he didn’t care too much. Again, the thrill of driving and learning the nuances of the S2000 were the wind in his sails.

One of his biggest hurdles with the car was learning how to gel with its nervous behavior. “I was usually leaving some on the table because the rear was on a knife edge,” he said. It would give him the willies when the S2000 would rotate at higher speeds, but James realized that he had to suppress his instinct to lift his right foot. Backing out in that situation doesn’t always work well in this very pointy car.

After getting enough experience with the car’s edginess at higher speeds, he returned to Buttonwillow on a set of A052s which were well past their prime. Even after spinning the car six times, he didn’t falter. That day, he was determined to find those last few tenths.

When he saw a 1:59.7 appear on his AiM Solo, he whooped. “I went from setting a 2:14 in the same car, essentially. Sure, I moved from a Nexen to an Advan, but the car was identical otherwise. That gave me the permission, if you like, to take the next big step with this car.”

Forget Incremental Improvements

At this point, James was nearing his sixtieth track day in the car. To give it a commemorative special touch, he decided to douse it in a shade of green most often seen on Porsches. “I’d wanted a GT3 RS in Lizard Green, but I couldn’t justify the cost—I could buy a duplex for that money.”

Getting the professionals to paint it that color wasn’t cheap, either. Instead of forking out enough to buy two new motors, he set up a makeshift paint booth in his garage, studied YouTube, spent a thousand in materials, and gave it a whirl.

Not surprisingly for a car with such battle-worn exterior, prep took far longer than anything else. So much of the original panels were beaten beyond the point of sensible continuation. In the place of the old panels, he added J’s Racing front fenders and rear bumper, as well as a set of ASM rear over fenders. Over the course of four months, he spent three-hundred hours replacing panels, sanding, and swearing. The painting itself only took a few hours.

Then came a Voltex Swan Neck and a Racebred Components 3” front splitter. Along with the aero, he added a set of JRZ RS Pro coilovers and a Karcepts front sway bar which made a “night and day difference—it was almost a new car. I think the V3s were well past their prime, and I might’ve handicapped myself with those. When I finally got the right equipment, I immediately dropped my best at 13CW to a 1:55.7.”

Ready for Some Overdue Jam

The motor had been through the ringer and in July 2020, the motor dropped a valve. He spent the summer rebuilding another 2.2-liter Honda short block with a Port Flow Design cylinder head built by Tom Fujita. With Supertech dual springs, valves, and retainers, he’d be able to beat on it without worry. However, it was still lacking a little jam.

For that reason, he unsheathed his credit card one Black Friday and ordered an HKS GT2 Supercharger. That was the first of many modifications needed to double an F22C’s output.

With the guidance of Son Vo and FormulaS, the new engine package was fortified with a V-mount intercooler, plenty of ducting, 1300cc injectors, an AEM V2 ECU, and all the custom piping needed to keep the motor running cool.

Plans for a Forced Induction Future

The beauty of this supercharged motor is that it will remain as tractable as it was pre-blower, but with nearly twice the power at the top-end. Because of its linearity, it should be tractable, even with the stock differential.

To ensure over 400 horsepower is put to the pavement cleanly, he’s also widened the footprint a little with a set of Titan7 T-R10 wheels measuring 18X10.5”. Though he hasn’t settled on a specific tire, he’s thinking a square set of 295-section Hoosier A7s. Not only will the car put the power down, but it will stop in a fashion that might let him reuse his original braking points. Well, maybe.

“After seventy-five track days, I’m still ear-to-ear. Actually, I’m like a kid on Christmas the day before a track day. I purposely don’t drink caffeine from noon onwards so I can sleep. It doesn’t really work; I end up getting up at 3 AM and watching racing videos on YouTube until I leave.”

“What I’m looking forward to more than anything is that, once I pass Sunset, I’ll no longer feel like checking my e-mails.”

With the major drop in time he enjoyed after the last big step in modification, maybe his new goal of a 1:49 at CW13 is in the cards. Whether it is or isn’t, it’s certain that he’ll be grinning the whole way there.