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
  
  
  
  
  

Dan Avon's E46 M3: A Study in Taking Things Slowly

One doesn’t need to have a big V8 or a turbo to go quickly at most of Northern California’s medium-speed tracks. They don’t necessarily need a featherweight, either. The E46 M3 sits somewhere between the two. Weighing in at 3,200 pounds and making a healthy 300-odd horsepower with moderate torque, it straddles the fence between momentum car and muscle car. With the right touch and a few chassis mods to help bring out this middlewight’s best attributes, namely its handling, it remains a hard car to beat. 

Dan Avon took a comprehensive approach to tuning his 2004 M3; engine power, grip, balance, and braking performance were all valued evenly throughout this build’s three or four stages. Most importantly, he’s learned how to gel with the car by fine-tuning its handling so that it complements his driving style. 

Its first iteration as a mildly modified road car was fun, though he felt the plush nature of the M3 was limiting its on-track performance. That didn’t concern him much as he was still driving it to work, to the grocery store, and through the canyons. The motor made ~285whp with a set of Status Group Tuning headers and a Dinan muffler, and with a full interior,  it weighed ~3,400 lbs with driver and a half-tank of gas. Despite those less than stellar figures, the broad powerband of the motor and the playfulness of the car were satisfying enough to overlook its shortcomings.

Except some. The factory suspension was not up to snuff, so he added TC Kline D/A coilovers, rear camber arms, and polyurethane trailing arm bushings. Even with these modifications, it was very much a street car. His growing fascination with developing the car and improving his lap times meant he’d stuff track wheels in the car before driving it to the track, but it was still doing double-duty. 

He started stripping the car slowly and systematically to help give it a feeling of agility. Being a plush car, it wasn’t hard to remove a couple hundred from the total. It then became clear that the Brembo brake kit wasn’t really as inspiring as he thought they’d be, plus the consumable costs were high, so he eventually swapped those for a set of PFC binders. 

With an AFe Stage II intake and a Epic Motorsports tune, he now had 300 horsepower at the rear wheels. Again, he made sure to address every area of performance through the various stages of modification, so even if the improvements seemed insignificant on paper, it felt more alert, competent, and encouraging. The M3 was always meant to be more than just the sum of its parts.

Weight reduction became more and more important to him as he learned to push harder, so after five years of worsening this car’s civility, Dan decided that the M3’s days as a street car were over. He chucked most of the carpet, door panels, and roof liner to get it down to a respectable 3,100 pounds with driver and a half-tank. 

Increasing his cornering speeds and just generally working the car harder revealed some of the limitations of the factory differential. When he installed the renowned OS Giken 1.5-way differential with aluminum bushings, he could generate much more propulsion off the corner, even if the rear was moving around slightly.  At the same time other areas of the rear suspension were addressed with various mono-ball bushings in place of the previous poly bushings.

Not that it was ever tailhappy. His setup was neutral to oversteery; an extremely satisfying and manageable balance that helped yield some great lap times. Still, he wanted to experiment with a little aerodynamic grip—even if that risked the near-ideal balance he’d achieved..

With a Bimmerworld rear wing and a homemade front splitter, the car had even more stick in the braking zones and the few high-speed corners at Thunderhill and Sonoma. The upside was that the lap times immediately fell by a couple seconds.

Unfortunately, that aero grip came at a price. The once playful car was suddenly arrested at the front end; a persistent mild understeer kept him from enjoying the car like he once did.

In an attempt to take some weight off the car, particularly off the front, and restore some of that neutral handling he once enjoyed,  he added Supersprint V1 headers and Section 1 midpipe, a Bimmerworld cat back race exhaust, a Ground Control hollow front sway bar, a rear-mounted Antigravity battery, and Bimmerworld carbon headlight blanks. These measures saved nearly 200 pounds in total, but the push was still plaguing him.  At least the car was significantly quicker.

Frustrated with the balance but happy to see this car evolve into a no-compromise track toy, he continued to stiffen and harshen. Why not?  He’d already decided to start trailering this dedicated track car, so he had no reservations about adding a rear half cage from TC Design, Turner Motorsport solid aluminum engine and transmission mounts, a set of MCS three-ways, and a Racetech 4119 halo-style bucket. 

Life has gotten in the way in the last year, but he’s still fascinated by the car—and hopes to return to regular lapping days in the near future. “I’ve always enjoyed tinkering and seeing what improved the car and what didn’t. I’ve used my AIM system to determine exactly where the tweaks paid off. I guess that’s what motivated me most of the way.” 

He’s still frustrated by the current balance, so he’s pondered two possible paths to follow once he gets back into the swing of things. Either he removes the aero and tries to optimize the mechanical grip of a lightweight car, or he finds the biggest, meanest cattle plow of a splitter he can find to give the front some much-needed aero grip. Either way, he’ll be measuring incremental improvements and sticking to his basic philosophy of addressing every aspect of performance and taking baby steps. Seeing how quickly this middleweight, mid-powered M3 navigates Northern California’s best tracks, it’s certain this steady, methodical tuning approach works.