Why Unequal Length Headers Make Subarus Sound So Unique

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Your car sounds nan measurement it does because of a staggering number of factors, but immoderate cars person 1 peculiar standout property that contributes truthful heavy to nan sound, it's indispensable. In this case, we're talking astir nan headers utilized by Subaru, which are much unequal than Jeff Bezos' slope relationship and yours.

The patron saint of automotive awesomeness, Jason Cammisa, demonstrated conscionable really large of an effect header magnitude has toward Subaru reside successful Episode 2 of his Know It All bid connected Hagerty's YouTube channel. In 1 clip, you tin perceive nan warble of a WRX STi's turbo flat-4 and nan banal unequal magnitude headers. In nan 2nd clip, a modified WRX pinch equal-length runners sounds — arsenic accurately described by Cammisa — for illustration a Honda Civic. 

So what's nan subject here? Well, Subaru uses boxer engines that support nan halfway of gravity debased and equips its cars pinch unequal magnitude headers apt because it keeps nan packaging tight. The flanges that connect to nan heads cod successful a azygous pipe, but alternatively than way to a cardinal turbo flange pinch adjacent magnitude runners, 1 cylinder bank's pipes tally underneath nan engine. There it joins up pinch nan different cylinder bank's pipe, which is specified inches from nan turbocharger exhaust inlet.

Slow down a signaling of a WRX pinch OEM headers to look astatine its waveform and you'll spot a beardown beat followed by a anemic pulse. Meanwhile, a WRX pinch adjacent magnitude headers would nutrient a waveform that looks rather even. You tin spot this intelligibly successful JC Media's YouTube video connected nan topic, which references nan pursuing schematic from Come And Drive It. 

In banal Subaru WRX/STi manifolds, nan exhaust gases recreation retired of each cylinder's exhaust ports, walk done nan superior runners, meet up successful nan first group of merge collectors, past get sent to a last merge collector. During this process, 1 slope has to walk done a secondary runner pinch a flex associated successful nan middle. To decorativeness it each off, everything gets propelled done nan turbocharger and retired done nan exhaust pipe. 

Since nan recreation region for nan engine's pulses varies from cylinder to cylinder, nan severity of each beat is different by nan clip it reaches your ears. The sound is unsmooth because 1 beat carries much measurement than nan other, and what you perceive is mostly those spaced retired harder pulses.

While each this explains why nan exhaust sounds nan measurement it does, nary of it explains why Subaru chose this design. It's improbable nan banal exhaust is nan merchandise of observant audio engineering, for illustration what Yamaha did for nan Lexus LFA's intoxicating vocalizations. Rather, utilizing unequal magnitude headers is apt a prime based connected packaging concerns, weight, and limiting nan magnitude of worldly used. Plus, successful theory, by placing 2 of nan cylinder banks wrong inches of nan turbocharger, much exhaust power tin make it to nan turbine instrumentality much quickly. Remember, you can't destruct turbo lag, but you tin astatine slightest trim it.

Of course, location are plentifulness of aftermarket adjacent magnitude headers for Subarus, and it's not conscionable because there's a contingent of enthusiasts who dislike nan WRX warble. Equal magnitude runners do person different advantages that tin effect capacity and motor longevity. 

For instance, making nan runners adjacent magnitude reduces variations successful cylinder temperature, which tin origin ringing and piston failures much often connected 1 broadside of nan engine. Also, reducing power makes sound little likely, and since turbo cars are perpetually moving to conflict knock, they request each nan thief they tin get. Equalizing nan exhaust unit seems to present smoother power, arsenic well, because nan turbocharger gets a steadier watercourse of exhaust gases, alternatively than a strong, contiguous watercourse from 1 cylinder slope and a weaker, delayed watercourse from nan other. 

If you want to sphere nan sound of your Subie – or your Saab 9-2X Aero, a.k.a. nan Saabaru, a weird and nosy car I really utilized to ain – then there's immoderate bully news. It turns retired that improved unequal-length third-party headers tin connection capacity adjacent to aliases nan aforesaid arsenic equal-length headers without eliminating nan tone. However, if you want thing much certifiably insane, get a Wrumer to plug into your OBD2 larboard and play immoderate motor sound you want done nan speakers, including a V12, a rotary, aliases moreover a lawnmower. On 2nd thought, conscionable get different headers.