Behind the Speed: COBB Tuning Exhaust

Hitting all the right notes with our twin-turbo BMW

 

The 3-liter N54 twin turbo straight six, nesteled tightly into the engine bay of our 335i sedan is actually not the worst sounding mill to come from BMW, not with the new M3/M4’s out there with all their farting, raspy notes. No, this engine will never sound as good as an S54, but, it has its merits, and with the right parts, it can sound very, very good. That’s where COBB Tuning comes in.

 

Yes, that COBB! The company that produces high quality upgrades for BMWs, Porsches, Subarus and Mazdas. Their big sales come from upgrade packages, using the COBB AccessPort to run more aggressive maps with adjustments to boost (when applicable), timing, air/fuel ratio and other power-adding parameters, used in conjunction with intake and exhaust upgrades to extract big power.

 

A bit of a light to show with the snap, crackle, pop.

 

See those brakes? Keep your eyes peeled for our next StopTech install.

 

As far as our 2007 335i is concerned, we’ve already got engine management and tuning taken care of, as well as upgraded downpipes and turbo inlets, but the exhaust sound just wasn’t there. All the whistles, pops, burbles and growls you’d expect from a 450hp+ turbocharged six-cylinder BMW were being muffled in the well-designed but heavy factory exhaust. Surprisingly, there isn’t much horsepower left on the table with just the addition of a cat-back exhaust on the 335i, but sound and weight savings is really what we were looking for.

 

Removing weight from behind the rear axle is a bonus to this fit and finish.

 

To simplify the system and save weight, the COBB exhaust merges the two turbo downpipes into a 3” single pipe, that then feeds into a high-flow suitcase muffler, dividing the exhaust gasses between two 2.5” pipes to exit. The result is a 22lb savings over stock and a sound that leaves bystanders wondering what the hell is going on when your basic 3-series blows by them, winding out 2nd gear to 7000rpm with a backfire and flame into 3rd gear.

 Gorgeous 4" tips slip on to adjust the poke or flush fit.

 

Thanks to beautiful CNC mandrel bent tubing and robotic TIG welds, the exhaust is durable, free flowing and a piece of art in its own right. With V-Band connections, it can be adjusted to fit perfectly, and removed far quicker than a traditional exhaust with multiple flanges, gaskets and bolts. Oh yeah, V-Band means no gaskets either, so this thing will NEVER leak. There are only two gaskets left at the downpipe connections, but they’re donut gaskets, and as long as you replace those every time they’re disconnected, it’s a no-worry kind of deal.

 

A helmholtz chamber in the midpipe eliminates drone or resonance.

 

From fit to finish, the COBB cat-back is worth every penny. The 4” slip fit tips are gorgeously and slip on to dial in just the right amount of flush or poke, which is great for those running different bumpers and valences.

 

The COBB exhaust is kind of like the perfect woman – lady in the streets but a freak in the sheets. Thanks to a helmholtz chamber in the midpipe, there is zero drone or resonance issue in the car. Around town with light throttle, the COBB cat-back doesn’t make much more noise than stock, though burbles are accentuated in all they’re awesomeness upon in-gear deceleration – a characteristic the N54 is known for. But now, the best part; wide open throttle pulls are now a glorious symphony that gives the 335i a downright sinister ‘don’t mess with me’ kind of sound, and we’re happy with that in our little four-door sedan.

 

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