Blazing a New Super Touring 4 Trail in a BMW Chassis

When picking a car for competitive road racing, there are tried-and-true paths, there are some with a shaky foundation, and there are some that require an exploratory spirit. Even if there is some information and a small aftermarket supporting an undeveloped chassis, it helps to be motivated by a bit of idealism. In the case of Svilen Kanev, he was passionately attached to a BMW M240i and went to lengths trying to make it work.

However, it wouldn’t have been possible without TC Design and its understanding of some of the contemporary BMW models that have some transferable parts and enough similarities to give this team direction. Between the two of them, they’ve managed to take the new M240i and make it a contender in Super Touring 4.

When he graduated from track days in this car, his second-ever track car, he found that the turbocharged powerplant, benign handling, and ZF 8-speed had him swooning. A few friends tried persuading him to take a more conventional route into road racing, and being an open-minded person, he gave a Spec Miata a shot.

No matter how hard he tried, he found the Spec Miata simply couldn’t stimulate him the way his Bimmer could. “I found the BMW’s balance was easier to live with, and its breakaway was much more progressive,” he said. Considering he was still learning the ropes, choosing the more accommodating BMW was clearly the right decision—even if it was going to cost more.

He kept his big dream on the forefront of his mind, but Svilen did not go in with his gun half-cocked. Over the course of the following year, he logged 33 track days. The basics of bigger brakes, better tires, and a set of good shocks made the car a reasonably athletic track car, but it was clear that there was far more required to get this under-loved heavyweight into fighting shape.

The first order or business was widening the footprint. In this case, it required a little more than just wider wheels and tires. The factory bodywork is narrow — only 245-section tires fit under the stock fenders. This tire width isn’t enough for the power and torque. On went a Flossman widebody kit that allowed him to fit a set of Apex SM-10 wheels wrapped in 275-section Hoosier R7s.

As it turned out, there is a surprisingly large amount of leather, sound insulation, and various amenities packed into this relatively small car. After trimming all the reasonably easy bits of superfluous weight, Kanev’s M240i dropped from 3,800 pounds to a respectable 3,200, even with a cage and a widebody in place.

A Straight-Six Short of Shining

The B58 has been on the shelf for a short while, and many of its flaws haven’t been well rectified. Thankfully, it’s been an exceptionally robust motor that has stood up to more than two-hundred track hours without any failures. It should be noted that, despite its resilience, it has a frustrating habit of cutting power when things get too warm, which is often.

“It’s got a more complex control loop where you set a torque target, and it calculates some combination of throttle, cam timing and boost to get you there. Lots of variables, lots of variance — throw in the heat management stuff I mentioned, and every trip to the dyno is a bit of ‘which random number are we getting today?’” said Kanev.

Drawing heat from the engine bay has been an eye-opening process — and led the both of them to realize there are a slew of non-intuitive fixes needed here. One attempt at fixing a set of hood vents actually raised the intake charge temperatures, because the turbo’s heat was creating a low-pressure zone, thereby drawing some of the cold air away from the intake. With the vents closed, the motor ran about 4 degrees cooler.

Adding bigger coolers has been a bit of a struggle. “We have been able to mount a larger external charge cooler — the one stacked together with the main radiator. It’s the manifold-side of the cooling loop that is still unchanged.”

The bigger outside cooler has helped by a few degrees, but not enough to keep things in check. To bring operating temperatures down to an acceptable level, they’ll have to find a solution to the irritating configuration of the factory intake manifold, which features an integrated charge cooler. Thankfully, CSF, the company that makes their external cooler has a new intake manifold and internal cooler proposed for production.

With an Epic Motorsports tune, the B58 put out a healthy 265 horsepower at the rear wheels, but the defining trait of the motor is its midrange torque. There’s minimal turbo lag and the motor is quite tractable, but the ramp-rate at around 4,000 rpm is something that needs to be kept in mind. Even the 275-section Hoosiers can be spun with relatively little torque, simply because of the abrupt delivery.

The fuel consumption is significant, but considering its weight and the fact it relies on forced induction, it’s not terribly thirsty. That it has eight gears and good torque means it doesn’t have to rev like an S54, which it rivals in terms of consumption.

Even if the onset is a touch abrupt, that midrange torque is usable. In fact, when Kanev loaned the keys to a capable friend, this friend left the car in automatic mode and went for a few laps around Thunderhill. Despite being in the wrong gear in most corners, he was still able to run genuinely quick lap times.

Electronic Gremlins

The problem is the ECU and the associated control units are modern, and by being as complicated as they are, they’re quite particular. “We’ve learned to be careful about what we can and can’t disconnect,” said Kanev.

Removing various modules has been a frustrating endeavor for them — a process rife with roadblocks and head-scratchers. So much of the car is so closely involved that any removal of certain modules will prevent the whole system from working as a whole.

There’s a whole array of concerns outside of electric problems. Heat has been a persistent plague on Colicchio and Kanev. The B58 has been known for its intake charge temperatures getting a little too warm for ideal combustion.

“If any parameter is outside of the acceptable range of values, it’ll cut power by as much as 50 percent,” Colicchio said.

Relieving the cooling system of some of its burdens has been another goal for the duo. With plans for a secondary oil-cooling system with its own circuit separate from the main cooling circuit, they plan on dropping temps, which creep toward worrying levels on hotter midsummer days.

“To get the car to work requires a lot of reverse engineering,” Colicchio begins. “We can study the ECU, but we can only really see what’s being done — we can’t do much about it. However, we can watch the data relayed along the CAN system and make hypotheses. We’ve managed to sort this car out with educated guesses.”

As frustrating as the constraints of the factory ECU have been, they’ve decided to avoid going the aftermarket route, because it would, as Kanev said, “open a whole ‘nother can o’ worms.” There’s also the small matter of cost — considering the complicated nature of the car, a high-grade ECU a-la MoTeC could add another $20,000 to this already costly build list.

Learning an Unloved Platform

With regard to the car’s breakaway behavior, “the knife edge is pretty blunt,” Kanev said. Though the car was reasonably progressive from the start, it was far from athletic in stock guise. A good set of dampers goes a long way, as does Colicchio’s understanding of the F80 3-series platform — a contemporary BMW with a comparable multi-link design and, obviously, much more aftermarket support.

Thankfully, the suspension packaging is similar at the rear. Even so, it’s all shoehorned snugly in there. The first swaybar ended up snapping due to contact with the rear toe link. The successor, a Bimmerworld piece, has not had any problems whatsoever.

“We’ve tailored the spring rates to suit Kanev’s style and experience,” Colicchio began. Achieving a neutral, benign balance that verges on understeer has been a focal point of their development plan after Kanev had to deal with the car baring its teeth last year.

During a test event at WeatherTech Raceway Laguna Seca several months prior to this year’s NASA Championships, Svilen learned just how the BMW can still bite. Rolling out of the Corkscrew, he lit up the rears and failed to get the counter-steering dialed in quickly enough. The hit was so hard it shifted the engine, punctured the oil pan, and disintegrated the driveshaft. It also knocked off two corners and broke both subframes. Somehow, TC Design was able to rebuild the car in just four weeks.

Plans for the Future

Though a lack of traction hadn’t really been an issue prior to that big snap, it now represents a weak area that the team has to address. The clutch-type differential will be fitted with more and different shims to encourage a more aggressive lock-up under acceleration, thereby minimizing some of the wheelspin issues presented by the torque ramp rate.

Cooling must be addressed. There’s not much room to get more air into the engine bay, but there are a couple plans in the works. In addition to adding a larger oil cooler, Kanev and Colicchio have determined that relieving the overtaxed cooling system will come next. There’s an oil-to-water heat exchanger, with water coming in from the main coolant loop. By building a separate system for the oil loop, they’ll relieve the water pump of some strain.

With an intercooler and a few venting tweaks that don’t drag turbo-heated ambient air past the intake, the two anticipate dropping the 20 degrees needed to keep the engine running within its desired parameters, they’ll have the pace to move up from the middle-rear of the pack to the middle-front. “It’s not consistently fast, but when it’s fast, it’s really fast.”

Though the M240i might not be a front-runner yet. It’s new and unproven, but the potential is there. We should be thankful for those who are willing to search for it.

To keep tabs on this interesting build, visit Svilen Kanev’s Instagram page.