Budget E9X BMW M3 Upgrades: Part II

They said it couldn't be done. Adding 50 whp and exceeding the 400-whp mark in an BMW E9X M3 on a realistic budget was impossible. The naysayers said titanium race pipes, precious composite intakes, aftermarket cams, and other top-shelf parts were the only recipe for big, naturally aspirated power on the high-revving S65 V-8. But we believed with the right combination of affordable bolt-ons, we too could join the elusive and exclusive, naturally aspirated E9X 400-whp club without dyno tricks or other delusions.

This isn't to say we don't admire titanium exhaust systems, carbon-fiber intakes, magnesium components, and top-shelf parts. We do. But those aren't in the cards for most of us. Instead, our improvements come incrementally, after extensive research into a carefully selected group of parts proven to perform together in harmony without costing a fortune. This usually doesn't come in one wave, but in small steps over several years. With this in mind, we set our sights on the affordable approach to the big 400.

"There's a misconception that the already highly strung S65 V-8 in the BMW E9X M3 is maxed out from the factory," said Tom Guagliardo at European Auto Source (EAS). "It's not, but it needs well-placed modifications to enhance its breathing."

Relieving restriction is one thing, but what about relieving the financial strain when it comes to buying these modifications? "That's another misconception—that E9X cars have to be expensive to modify," Guagliardo said. "Owners now have the choice of buying quality components at affordable prices or springing for higher-priced components made from exotic materials. No matter what they choose, they'll still see tremendous improvements in performance." We sat down with the team at EAS and devised a plan to unlock power by relieving restriction, cutting parasitic drag, and optimizing ECU parameters. We wanted an additional (and affordable) 50 whp without resorting to a power-adder.

Part One Recap

Link: Budget E9X BMW M3 Upgrades: 20whp for $600

In Part One, we began our bolt-on bonanza with Macht Schnell Performance underdrive pulleys and Stage II intake charge kit. To ensure a proper install, we not only commissioned the BMW gurus at EAS for help, but we also strapped our low-mileage '11 DCT-equipped E90 M3 to their in-house DynoJet 224LC to measure the gains. As it turns out, those additions were worth 20 hp and 7 lb-ft (measured at the wheels) with considerable gains across the entire powerband, all for just $600. If you're looking for affordable power gains on your E9X, this is the best place to start.

The Plan: Part Two

With the inlet side of the S65 uncorked and parasitic drag greatly reduced by the underdrive pulleys, it was time to relieve restriction aft of the motor as well as bring it into a better state of tune. After hashing details with EAS, we opted for a full stainless steel exhaust system and a software reflash instead of a pricey titanium system. "From a power production standpoint, a well-designed stainless steel system will make just as much power as a titanium unit," Guagliardo said. "It just won't save as much weight."

Last time, we added 20 hp and 7 lb-ft at the wheels. This time, we relieve restriction and perfect the tune in search of that magical 400 whp. The World Series is to baseball what 400 whp is to the E9X community. Join the 400 club with bolt-ons alone and you’re a one-percenter. In our case, it would mean overall gains of nearly 50 whp, an astonishing feat considering the limitations of pump gas and nothing more than stoichiometric pressure.

Macht Schnell X-pipe

The stock X-pipe on the E9X M3 is notorious for killing power. It's widely regarded as the most restrictive portion of the factory exhaust system. This is mainly due to its four catalytic converters, a pair of primaries, and two secondaries. Unsurprisingly, EAS recommended we ditch the stock unit for a free-flowing cat-less alternative. "Simply replacing the up-pipes with cat-less test pipes helps," Guagliardo said. "But the most effective method is to replace the entire unit with an aftermarket X-pipe and up-pipes."

Having crunched the performance-per-dollar numbers, we went for a Macht Schnell stainless steel race X-pipe. At $1,095, it's a steal considering it's made from 2.5-inch tubing with impeccable welds and quality that fights above its price point. Other noteworthy features are a pair of resonators that cut drone and preserve power, smooth transitions, and an X-pipe design that promotes exhaust scavenging. More on that later. The unit also includes four OEM oxygen sensor provisions, utilizes factory mounting hardware, and bolts into place for a tidy install. No low-hanging contraptions, just a free-flowing X-pipe system that unlocks power and sheds more than 13 pounds compared with the heavy stock unit.

The entire Macht Schnell stainless steel race X-pipe system bolts into place using stock mounting hardware.

X is greater than H.

There’s nothing worse than a droning exhaust system. Macht Schnell includes a pair of resonators in its X-pipe to help cut drone and lower decibel levels without hindering horsepower.

The Macht Schnell system also comes with up-pipes that connect the X-pipe to the factory exhaust headers. The units come with the four oxygen-sensor provisions, but an aftermarket tune from someone like ESS Tuning is required to negate the CEL when ditching the catalytic converters.

Here’s a closer look at the impeccable welds and the stainless steel construction of the Macht Schnell up-pipes. These are a great deal, costing much less than their titanium counterparts while still dropping 13.2 pounds over the heavy stock midpipe.

X-pipe vs. H-pipe

As many of you already know, there are traditionally two different types of midpipes in the world of V-format motors: H-pipe and X-pipe. Some systems feature a Y-pipe that blends the exhaust from both cylinder banks into a single system downstream. But in most cases, a vee engine employs a dual exhaust system.

Before delving into midpipes (and without going into a lecture about laminar flow and velocity), just understand that exhaust flow isn't constant like water from a garden hose. It's a succession of pulses, or bursts of air from cylinder firing events. Smooth flow is best for power, but a poorly designed system can create a turbulent atmosphere and disruptions in flow that hinder horsepower.

Engineers discovered the key to power (and sound quality) was to balance pressure between the two banks. At first, H-pipes were the hot ticket. They actually look like the letter H. A balance pipe is placed perpendicular to the two primary pipes to act as an overflow, equalizing the pressure and promoting more power. H-pipes are popular with muscle cars or in applications with minimal space where an X-pipe simply won't fit. H-pipes enable balanced exhaust pressures, but flow seeks the path of least resistance and the majority of exhaust gases continue toward the tailpipes rather than making a 90-degree turn into the balance pipe. Why do you care? Because this phenomenon doesn't encourage exhaust scavenging.

The X-pipe also balances exhaust pressures between the banks, but promotes exhaust scavenging. Again, without venturing into serious engineering jargon, an X-pipe merges pulses from both banks into a single X-shaped pipe to scavenge (vacuum out) the exhaust from the primaries. Exhaust scavenging uses those pulses to accelerate gases through the system.

X-pipes aren't without their faults. The shape is harder to package under a car, and the placement of the crossover in relation to the motor also has an effect on power. Every combo is different, but a general rule is that the X-pipe should be as close to the motor as possible to maximize power.

MXP Mevius Exhaust System

If ever an automotive component were as much art as it were a performance product, the Mackin Extreme Products (MXP) Mevius stainless steel rear exhaust section for E9X M3s would be it. Perfect welds, 2.4-inch SUS304 piping, highly polished quad exhaust canisters... and those 3.5-inch burnt exhaust tips are nothing short of jewelry.

The MXP is more than just bling, though. It was designed to be as powerful as it is pretty. The large piping feeds into those four lightweight canisters that preserve performance and sound. The massive tips are also available in chrome and are adjustable for the bumpers of both the coupe and sedan E9X. The system retains factory brackets for an OEM-like fit. It's also more than 10 pounds lighter than the stock system. Retailing at $1,895, it costs a fraction of other systems. The sound quality is second to none, with a supercar-cool tone.

The beautiful Mackin Extreme Products (MXP) Mevius stainless steel rear exhaust section uses the stock hangers for a factory fit.

The MXP Mevius system is proof that you don’t need to break the bank to get a top-notch system. The burnt finish on the quad tips is also exquisite.

Note the quality of the welds. The MXP system uses four straight-through mufflers rather than a large single unit to save weight while still producing an aggressive yet street-friendly tone.

High-quality merges help preserve flow for increased power and a crisp sound. The MXP system is an octave higher than other systems, giving it a supercar tone more akin to a V-8-powered Ferrari under WOT.

We paid another visit to EAS for the installation and dyno time. The heavy factory rear exhaust section is the first thing to go. Adam Koch and Sam Morin of EAS make quick work of removing it.

Next is the factory X-pipe. Don’t forget to remove the OEM panels followed by the oxygen sensors and the attachment clamps.

Now the OEM X-pipe must be discarded. All four O2 sensors must be unplugged.

Since the Macht Schnell X-pipe uses factory hardware, it’s just a case of moving the applicable items to the new unit. Don’t forget the four O2 sensors. Completing this process before the X-pipe is installed will make life a lot easier in the near future.

With everything mounted to the X-pipe prior to returning underneath the car, it simply bolts into place. Here Nick Tsui joins Adam and Sam to help with the install.

With the X-pipe in place, it’s time for the beautiful MXP back system. Its installation is equally easy, thanks to individual sides that eventually bolt together.

It also uses the OEM hardware for a stock-style fit that’s as tidy as they come.

As expected from components of this caliber, the MXP back system and the Macht Schnell X-pipe harmoniously join forces.

EAS is renowned for attention to detail. Adam was meticulous with the alignment of the quad exhaust tips.

With everything torqued to factory settings, we fired it up and listened to the S65’s new lungs. We also heat-cycled the system several times before rechecking the torque. Because the cats have left the building, a CEL was inevitable. But ESS Tuning had the fix.

ESS Tuning E9X M3 NA E-Flash ECU Performance Software

Amazing hardware is useless without a proper tune orchestrating combustion. Since the S65 is highly strung, we couldn't trust anyone to tune it. We opted for one of the best in the business: ESS Tuning, BMW specialists with 800hp-plus M3s all over the country and experts at maximizing naturally aspirated models.

This software optimizes dozens of parameters for more power and better driveability. Improvements come from precise adjustment to air/fuel ratios; VANOS and ignition timing; and the ability to raise the rev limit to 8,600 rpm, delete the speed limit, fix "check engine" lights (CEL), delete the cold-start cat-igniter idle, sharpen throttle response, and a ton of other behind-the-scenes tweaks.

Other great features of this affordable $895 unit include an OBDII adapter that allows users to revert to stock tune, clear and check codes, upload tunes from ESS, and much more. We had ESS email a custom 91-octane pump-gas tune that also included the aforementioned raised rev limit and the removal of the speed limiter (should we ever find ourselves on the autobahn).

Quality components need a solid tune, hence the ESS Tuning E9X M3 NA E-Flash ECU performance software. ESS builds some of the fastest BMWs in the world and has applied its extensive knowledge to this software.

Adam uploads the ESS Tuning custom naturally aspirated 91-octane tune. Should we make changes that necessitate a re-tune, the provided OBDII port connector and cable make it easy to get tunes from ESS via email.

With the new pipes in place and the ESS tune uploaded, it was time to strap the LeMans Blue E90 to the in-house DynoJet 224LC dyno at EAS to see what the latest additions were worth.

Dyno Might

Despite blistering temperatures in the high 90s, the moment our low-mileage E90 M3 belted out a healthy baseline of 353 hp and 262 lb-ft at the wheels, we knew 400 whp might be in reach. The Macht Schnell Stage II intake and underdrive pulleys pushed power to 373 hp and 269 lb-ft. The combination of X-pipe and exhaust system increased power throughout the entire powerband, with even larger gains arriving near redline. The peaks rose by 22 hp and 14 lb-ft for new totals of 394 hp and 283 lb-ft.

We let the car cool while EAS uploaded the ESS 91-octane tune. With water and oil temperatures back to baseline, we spun the drum to the tune of another 4.61 hp and 3.13 lb-ft for totals of 399.05 hp and 285.88 lb-ft at the wheels. The whole shop let out a collective groan as we came up less than one pony shy of our goal. The ESS tune not only increased power from idle to redline, but raising the rev limit to 8,600 rpm provided a spectacularly strong top-end charge.

Ultimately, the 100-degree ambient temperature was the culprit, as EAS consistently sees upwards of an extra five horses in cooler temperatures. Nonetheless, we were ecstatic because even though we didn't hit the magical 400, we did add 46.5 hp and 24.2 lb-ft with nothing more than pump gas and affordable bolt-ons. If that's not impressive, we don't know what is.

Performance

All data was acquired with a Racelogic VBOX Sport. Launches were conducted on OEM Continental tires without enabling launch control. Using launch control on an unprepared surface produces inconsistent times from excessive wheelspin. Our unofficial track has a slight downhill grade, which is reflected in the data. The differences between the baseline and the new results are more important than the outright figures.

Sound Check

Measuring decibels (dBs) is a dark art. Ambient noise, instrument of measurement, placement of said instrument, and many other variables can easily skew results. Some perceived noise can't be measured in dBs, but frequencies. The point is this isn't the most accurate form of sound measurement, so instead of focusing on the measurements themselves, the most important aspects are the differences between stock and modified.

All sound levels were measured with a Radio Shack Digital 2055 meter. Stationary levels were checked from a tripod mounted in the same location relative to the car with similar ambient sound levels. In-car tests were conducted on the same stretch of road, at the same speed, gear, and rpm (two days apart).

Driving Impressions

This E90 M3 is a whole new animal. Few naturally aspirated project cars have seen such dramatic increases in performance and driving dynamics with so few modifications. From the moment the S65 fires up, there's no hiding its transformation. The exhaust note is hair raising and intoxicating, whether it's the crack of a rev-matched downshift or the crisp tenor under wide-open throttle.

With the stock car, traction in the lower gears was always a problem. Now the car is some 25 pounds lighter and packing an additional 46 hp and 24 lb-ft; it's startlingly quick. The thrust is felt from bottom to top. Power comes on sooner and hangs on much longer, thanks to the hardware and the ESS Tuning software. It's in "take me to jail" Third and Fourth gears where the car absolutely flies, as the power and revs produce a car that never stops pulling.

Power and good sounds aside, dynamics are also improved with heightened throttle response and faster shifts for an almost telepathic connection between the right foot and the throttle bodies. Boost is the future, but nothing can replace the amazing personality of a highly tuned naturally aspirated engine.

The Macht Schnell Stage II intake and matching underdrive pulleys gave us 372.48 hp and 268.63 lb-ft at the wheels. Adding the Macht Schnell X-pipe and MXP exhaust system increased power throughout the entire rev range with new peaks of 394.44 hp and 282.75 lb-ft. The ESS Tuning software pushed output another 4.61 hp and 3.13 lb-ft for 399.05 hp and 285.88 lb-ft.