Budget E9X BMW M3 Upgrades: 20whp for $600

The mission was simple, but that didn't mean it was going to be easy: gain 50 hp at the wheels with an E9X BMW M3 without breaking the bank. In truth, the idea carelessly came to us over coffee, as internally combusted banter eventually reached a crescendo, bursting into all-out bench racing. And thus, the idea was born, the challenge was made, and immediately even we questioned our judgment. In reality, while used E9X M3s have fallen in price, nothing about the aftermarket upgrades for the fourth-generation BMW M3 are, well, cheap. To add insult to injury, many claim the 4.0L naturally aspirated V-8 in the BMW M3, the S65, comes in such a high state of tune from the factory that expecting huge power gains from aftermarket additions just isn't in the cards. But as it turns out, a call to Tom Guagliardo at European Auto Source changed our outlook from pessimistic to downright excited.

"Believe it or not, there is a ton of power left on the table with the stock S65 motor since the concessions to civility BMW had to make from the factory significantly hinder outright horsepower," Guagliardo explained.

OK, so BMW left some power on the table to appease the passengers, but what about the affordable part of our equation?

"We've had great luck with the Macht Schnell line of parts for the E9X M3s both in regards to price and performance," he said.

Price and performance, come on, who are you kidding? Again, our pessimism waned with a simple Google search that revealed bolt-on parts that were well within reach of most enthusiasts' budgets-and so, a star, err, a story series was born.

Could we really gain an affordable 50 hp at the wheels with an E9X BMW M3, a car that’s already highly efficient and notoriously expensive to modify? We grabbed some Macht Schnell parts and headed to European Auto Source (EAS) for several days and nearly 40 dyno pulls to find out. Welcome to Part 1 of 3.

The Plan

As mentioned, our long conversation with the BMW gurus at EAS proved there was considerable power left on the table with the E9X M3 from the factory and that we could in fact add performance mods that wouldn't cost a fortune. But could we really hit our goal of 50 hp at the wheels on an already highly tuned motor?

"It takes the right package of parts that work in unison, but we often see bolt-on E9X M3s gain between 40 and 50 hp at wheels with the right modifications," Guagliardo said. After some debate, we decided it was most applicable if the modifications were broken into three parts. The first two will build a solid foundation of horsepower in the hopes of gaining 50 whp. The last installment will take the project one step further by adding modifications to bolster driving dynamics.

"Most customers start with quality underdrive pulleys and an intake followed by exhaust components and a tune before adding suspension and aesthetic mods," Guagliardo explained. And so we heeded his advice, by starting our quest under the hood.

Step 1: Macht Schnell Performance Underdrive Pulleys

In recent years, companies like Macht Schnell have proven that properly designed units can strike the perfect balance between civility and performance.

"There's always a balance with underdrive pulleys, and some kits are so aggressive at slowing down the accessory drives that the cars can have battery charging issues, overheating problems, and the power steering can become heavy," Guagliardo said.

As I'm sure you already know, underdrive pulleys do just that, they underdrive the accessories, thus diminishing parasitic drag and in turn, increasing power. The underdrive process is typically achieved by under-sizing the crank pulley and oversizing the accessory pulleys (like the lowest gear on a bicycle that utilizes the smallest front chain-ring and the largest rear cog).

In most cases, the majority of the power increases comes from turning the accessories at a slower pace. However, in some cases these underdrive pulleys have a secondary benefit: reducing the moment of inertia, thus improving acceleration and spool-up. The smaller diameter and lighter weight pulleys make it easier for the motor to rotate them from slow speeds, thus increasing overall acceleration.

The underdrive pulleys we speak of are not to be confused with an undersized and overdriven supercharger pulley that increases rotor speed and therefore boost from its decreased circumference.

But enough Physics 101, what about these particular Macht Schnell pulleys for the E9X M3?

"They're made from T3 hard-anodized 6061-T6 aerospace aluminum to exact tolerances for performance without the reliability concerns of inexpensive units," Guagliardo said.

As if Macht Schnell hadn't done enough homework already, the company went one step further to ensure maximum user-friendliness.

"They were smart enough to use off-the-shelf belts so that it's easy to get a replacement from a local parts house in the event a belt snaps on the road," Guagliardo said.

As I'm sure you already know, if the diameters of the pulleys change, so does the required length of the belt-the OEM belt isn't compatible with underdrive pulleys.

The Macht Schnell pulleys were designed to increase performance without compromise, and with a retail of just $295, there's little financial compromise, either.

After consulting with the BMW gurus at Macht Schnell, we started the power party with their Performance Underdrive Pulleys. Here’s a look at the Macht Schnell crank pulley against the stock unit. It’s machined from T3-hardened, 6061-T6 aerospace aluminum so it’s not only lighter than the OEM unit, but it’s also smaller in diameter. This helps lower the moment of inertia and underdrive the accessories to cut parasitic drag and gain power.

The Macht Schnell Performance Underdrive Pulley kit also comes with a power steering pulley that is lighter than the OEM unit and also underdriven. Unlike other companies, Macht Schnell was careful not to overly slow the accessory speeds so as not to create overheating, charging, or power steering issues.

We begin the installation process by removing the intake system. Adam Koch of EAS starts by removing the upper air-inlet tube.

A few screw, nuts, bolts, and clamps later and the airbox assembly exits the engine bay.

Next up, the fan assembly will need to be removed to free up enough space to access the pulleys.

It’s a tight fit, but with some patience, the power steering pulley can be accessed. Once the three bolts are removed, release the belt tension and then the OEM pulley can leave the party.

Next comes the removal of the stock crank pulley. Again, take your time and remain patient while removing all six bolts.

Here’s a peek at the EAS power steering pulley mounted in place. Don’t forget to follow the factory torque settings and sequences.

Be sure to transfer this factory shim over to the Macht Schnell unit—it mounts between the bolts and the pulley. Again, be sure to follow all factory torque settings and sequences when tightening the bolts.

After installing the supplied belts and setting the tension, it should look like this. Simply reverse the removal process of the intake and take your M3 for a spin. In our case, we left the car strapped to the dyno throughout the test to keep the dyno results consistent. Continue on to see how much horsepower the pulleys were worth on our stock ’11 E90 DCT M3.

Step 2: Macht Schnell Stage 2 Intake Charge Kit

In the world of internal combustion engines, more air equals more power. But with a few caveats, cooler air is more densely packed with oxygen, thus increasing power, and lastly, the smoother the airflow into the throttle body, the better.

"Macht Schnell spent countless hours in SolidWorks software perfecting the design, testing flow rates with Cosmos, fluid dynamics simulation software, and testing prototypes on the dyno and track to ensure they had the best possible product for the E9X M3 platform," Guagliardo said.

He went on to explain that this endless testing proved the stock airbox was extremely efficient, unlike its supporting components.

According to the power pros at Macht Schnell, they increased the flow of the stock intake by 30 percent through focused attention on the points of restriction. The charge pipe was enlarged 18 percent, and while the external surface has an OEM-like textured finish, inside it's glass smooth and sans the corrugated steps of the stock unit. The smooth, uniform design diminishes turbulence and increases airflow.

The air filter adapter housing is also larger in size and features smoother transitions. The large oiled cotton gauze air filter increases airflow while preserving the OEM filter's 99 percent debris collection efficiency to meet ISO 5011 standards. It's also reusable, so it should last the life of the car.

Macht Schnell went one step further to ensure ample power gains with its Stage 2 intake by incorporating a pair of Intake Charge Scoops that mount behind the roundels, directing incoming air into the intake track. But an intake is more than just a design statement; it's also about the fit and finish.

"We've had great luck with the Macht Schnell components since they retain factory functions like the PCV, use OEM-style clamps and connectors, and are constructed of high-quality polyethylene," Guagliardo said. The last parameter of importance is build quality.

"The textured finish on the charge pipe looks just like it's OEM, and the unassuming raised logo is transparent to all but the most trained of eyes," Guagliardo said.

He's right. Unless you're looking for the intake, it's easily missed, and the fact that it feeds into the stock airbox further reinforces its OEM-like appearance.

It also comes with all the clamps, bolts, and hardware necessary to install the intake in roughly an hour. We should add that it's also affordable, with a retail of $399.99.

Here’s the second piece of our dynamic duo of affordable bolt-ons for Part I of this series, the Macht Schnell Stage 2 Intake Charge Kit. It comes with everything needed to give your S65 some lungs, including a cotton gauze air filter, intake charge scoops, intake charge pipe and filter adaptor, heavy-duty rubber intake couplers, and Euro-style Worm clamps.

We won’t rehash the airbox removal process, but once the airbox is out of the engine bay, separate the upper and lower halves so the OEM internal parts can be swapped for the Macht Schnell components.

Have a look at the factory air inlet adapter. The Macht Schnell unit (pictured left) is not only much bigger than the factory unit and devoid of the large kink in the lower left, but it also features a high-flow gloss finish. The Macht Schnell intake is said to outflow the stock unit by 30 percent.

Macht Schnell conducted extensive research on the OEM E9X intake system and concluded that the efficient factory airbox wasn’t the restriction; rather, the factory charge pipe was the bottleneck. The Macht Schnell charge pipe (pictured left) is 18 percent larger than the factory unit and devoid of both the kink in the lower corner and the corrugated construction that creates power-robbing turbulent air. The Macht Schnell unit still retains the factory PCV function as well.

Another reason the Macht Schnell intake increases power is its larger oiled-cotton air-filter element that improves flow while still maintaining the OEM filter’s 99 percent debris collection efficiency to meet ISO 5011 standards. It’s also reusable, so it should last the life of the car.

To maximize airflow to the intake while the car is in motion, Macht Schnell also includes air-charge scoops that direct incoming air from behind the roundels and into the intake. To access these, the roundels must first be removed.

This is the only required modification for the install; these small holes that must be drilled to secure the air-charge scoops.

The Macht Schnell air filter requires a different retention pin. Don’t worry, the kit comes with an appropriately sized unit.

Connect the charge pipe to the intake manifold plenum, followed by the air-inlet adapter, air filter, and airbox lower. Make sure and secure all of the clamps before installing the airbox lid. Here’s a peek at just how gargantuan the new intake system is.

Next, you’ll want to install the airbox lid and secure all of the factory bolts.

Dyno Time

What started as a quest for an additional 50 whp suddenly became a quest for the ever-elusive number all but the strongest naturally aspirated E90 M3s fall short of-the magical 400-whp mark.

But when our test subject, an immaculate '11 DCT-equipped M3 owned by Jeremy Stanton, threw down impressive baseline figures despite heavy stock wheels and ambient temps hovering in the mid-90s, suddenly the hunt for 400 whp was all consuming. How much did it make in stock trim? Try a stout 352.56 hp and 261.68 lb-ft at the wheels.

With that addition of the Macht Schnell Performance Underdrive Pulleys, peak power jumped 7.09 hp and 4.24 lb-ft for totals of 359.65 hp and 265.92 lb-ft at the wheels. As expected, the gains were consistent throughout the entire curve.

Next came the Macht Schnell Stage 2 Intake Charge Kit and it, too, didn't disappoint with nice gains below 4,500 rpm and significant increases from 5,000 rpm up to the 8,400-rpm redline. The Stage 2 intake pushed power up another 12.83 hp and 2.71 lb-ft for new totals of 372.48 hp and 268.63 lb-ft at the tires. We were within striking distance of the infamous 400-whp mark, but more importantly we gained 19.92 hp and 6.95 lb-ft with the addition of two affordable modifications.

Driving Impressions

To think the engaging E9X M3 could transcend its already visceral experience at speed would initially seem like a farce, but the addition of the intake and pulleys transformed our all-motor phenom. Throttle-response boarders on telepathic, as every millimeter of throttle input rewards the driver with instant feedback. Its eagerness to rev has only intensified, just as outright acceleration is even more robust, and the increased intake howl is intoxicating.

If not for the increased performance, simply returning the stifled S65 its voice that was so drastically stolen by the evil bearers of the red tape is worth the price of admission. Transitioning to WOT is a tantalizing experience, as the intake howl fills the cabin with harmonious anger-words do it little justice.

We won't be performing acceleration tests until the last of the engine modifications, but the seat-of-the-pants feel confirms what the dyno is suggesting.

Only a trained eye will catch the faint Macht Schnell raised logo on the charge pipe. The unit uses a textured finish for an OEM-like style. Now it’s time to hit the rollers and see what these mods were worth.

The Next Step

It's hard to believe we've already boosted power by nearly 20 hp and 7 lb-ft at wheels for less than $700 on a car that's supposed to be infamously expensive to modify and cantankerous at best.

As impressive as the dyno numbers might be, it's the newfound experience behind the wheel that's worth its weight in gold. Honestly, the increased enjoyment from the cockpit is that much better. But hang tight, we've got plenty more in store. Until next month.

Baseline Performance Figures:

All data acquired with a Racelogic VBOX Sport. Launches were conducted without launch control and on OEM Continental tires. Launch control was not used due to inconsistent times from the excessive wheelspin on the unprepared surface.

0-30: 2.71 seconds
0-60: 5.35 seconds
0-100: 11.1 seconds
Quarter-mile: 13.67 @ 113 mph

After establishing a baseline, we left the car on the DynoJet 224LC dyno at EAS throughout the entire process. This was done so that strap tension would not change, thus skewing the results.

With a mere 11,000 miles on the ’11 DCT-equipped M3 owned by Jeremy Stanton, we expected stout numbers. We weren’t disappointed with a baseline pull of 352.56 hp and 261.68 lb-ft at the wheels. The Performance Underdrive Pulleys alone netted consistent gains from bottom to top, eventually reaching a new peak of 359.65 hp and 265.92 lb-ft at the wheels for peak-to-peak gains of 7.09 hp and 4.24 lb-ft at the tires. The addition of the Stage 2 intake pushed power to a new peak of 372.48 hp and 268.63 lb-ft at the tires for gains of 12.83 hp and 2.71 lb-ft at the tires. Total gains from the baseline were 19.92 hp and 6.95 lb-ft at the tires for solid improvements that won’t break the bank.