Its finally here!
The much anticipated BMW I8 custom exhaust.
Dont mistake this for a simple pipe, the Yorkshire DPF Centre Team have poured months of work into making this exhaust sound and perform better than any competitors exhaust.
This isn't an exaggeration. In the making of this exhaust we have constructed and tested no fewer than 17 different designs! Thats not counting alteration or tweaks!
This exhaust manages to make the I8 sound like it should.
Other exhausts may make the I8 louder, but the issues with them are mainly price, and noise.
The noise of the I8 (or lack of) is essentially what makes it an I8, so to destroy its ability to be quiet is sacrilege, but by the same token, when in sport mode it should sound like a super car.
This isnt helped by its 3 cylinder engine! resulting in most aftermarket exhausts sounding like a briggs and stratton lawn mower, or a mini cooper, one or the other is the inevitable result.
We eventually arrived at a finished product which takes advantage of the manufacturers "waveforms".
When a sound-wave is generated it "osolates" at a certain frequency.
These frequencies can sound terrible if there are other frequencies in the vicinity that do not "overlay" each other correctly and at the same time, in the I8 the sound generator attempts to fill in the VOID of noise with an artificial 3 cylinders, the problem arises when fitting any aftermarket exhaust, because the noises made by said sound generator both inside and outside the car , no longer " line up" with the frequencies generated by the engine, this is something all exhausts manufacturers have simply accepted and said " well its louder".
The result is two choices...
a harmonic sounded but very quiet and artificial stock noise that is only balanced when a stock exhaust is fitted,
or out of phase noises that arnt controlled but are loud with an aftermarket exhaust.
We didn't just want it louder. We wanted the I8 to sound like it looks.
For this reason we took it a step further and dug into the science behind why the I8 sounds the way it does, and in doing so changed the way it sounds entirely.
We found that the out of phase noises where impossible to change, removing the sound generator is out of the question and changing its characteristics is also just as inconvenient.
Instead we achieved the impossible and made the exhausts waveform follow directly opposing to the cars "stock" wave-forms made by both the sound generator and by the engine itself.
By tuning the exhaust finely we achieved something extremely difficult called "phase cancellation"
Phase cancellation is an acoustic phenomenon in which two or more “out of phase” sound waves result in weakened or lost frequencies. When two identical frequencies are cycling 180° opposite each other, complete phase cancellation occurs.
This phenomenon is often unwanted in other applications however here it is exactly what we aimed for.
By employing phase cancellation by overlaying the two wave-forms perfectly we achieved a noise at all revs that sounds nothing like a 3 cylinder engine at all, and perfectly harmonises with the cars own "waveform". It really must be heard to be believed.
This is all without the use of a valve! Just science and hours of testing!
Sound waves cycle at a specific rate per second designated by the wave’s frequency, which we also refer to as “hertz.” Hertz are specifically defined as one cycle per second, and a complete cycle consists of a peak and a subsequent trough equal in amplitude. When we say that a frequency is 500 Hz, for example, we’re literally referring to a sound wave completing 500 cycles per second.
Two of the same frequencies starting their cycles at the exact same time (“in phase”) are perceived as an increase in amplitude. This concept is referred to as constructive interference.
On the other hand, if the same frequencies are travelling at different or opposite rates, they are out of phase. At 180° difference–in which one cycle is at its peak and the other is at its trough–destructive interference known as phase cancellation occurs. The perceived sound is loss of the out-of-phase frequencies.
This effect is most noticed by shifting to comfort where you will find a drop in volume, this is because the phase cancellation is no longer happening, because the sound generators have backed off.
Imagine it like a sound amplifier, built into an exhaust, with built in magic and no speaker, and your not far away from what our exhaust does to you car.
We achieved that by revising our design until we achieved a pitch and tone that matched that generated by the engine and the sound generator modules, in this way we slowly found a design that changes sound with the car as it accelerates WITHOUT the use of a valve.
ALL UNITS ARE HAND MADE AND TAKE TIME TO BUILD. PLEASE UNDERSTAND.
ORDER NOW TO AVOID DISAPPOINTMENT!