Originally Posted by warot
Not a regular member here, but was reading through. The valve opens only in second gear onwards from around 3000 rpm, but I'm not 100 percent sure about the rpm. This is for acoustic purposes only (think of a trumpet) and torque isn't affected.
P.S. I had an internship at BMW SA in the acoustic section, that's how I know.
Originally Posted by RYANM330CI
You are right on the money
Some of you may not know this but I also work for Patrick BMW. I have been to BMWNA for some classes and they stated that the valve does not affect hp/tq
That's great info. Thanks!
A lot of companies do invest significant thought and engineering into the sound quality of their vehicles. I read somewhere that the current generation Mustang exhaust note was designed to emulate the modified 1968 Mustang featured in Bullitt. Nissan significantly engineered the exhaust sound of their current 3.5L V6 in the 350Z, G35 and FX35.
The Eisenmann and Kerscher exhaust systems actual sound good. They do not make the E90 sound like a boat (too loud and low pitched), a common problem with the in-line sixes with custom exhausts. The 4-bangers sound even worse (think of modified Hondas, WRXs and Evols).