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Jaguar F-Type: Exotic Exhaust Notes Explained

For its blending of all things classy, powerful, and fast the Jaguar F-Type is leaving test-drivers, owners, and auto writers around the globe absolutely smitten.

Then, there's the exhaust note, which is bonkers. The F-Type's V8 engine sounds like automatic gunfire blended with fireworks. The V6 is a smoother, more exotic sound, though equally as saliva-inducing for anyone who likes driving and has ears.

If there's one company that gets, like really gets, performance-car exhaust notes it's gotta be Jaguar. So, I looked up Dr. Garry Dunne, JLR's Senior Technical Specialist of Vehicle NVH and Sound Quality, for a closer look at what goes into making the F-Type output such an amazing symphony of combustion.

JP: How important is the exhaust noise of a car like the F-Type? Do owners ask for or demand a car that's totally gnarly sounding or is this something inherent of all Jaguar models?

GD: Central to the Jaguar Sound Quality DNA is the delivery of a duality -- both an exhilarating and an effortless driving experience. The cars purr at idle. They have an effortless and refined cruising character, with an underlying promise of performance. This promise is delivered through a powerful and purposeful Sound Quality character that builds to a rewarding, crisp crescendo under performance driving.

We often use the catchphrase, "effortless transition from a powerful growl to and edgy snarl" to capture the essence of the Jaguar Powertrain Sound quality. This applies to all Jaguar models.

JP: Is there a regulatory sound limit on how loud a car's exhaust can be? Does it vary between countries? Was much bribing required to be able to exceed that limit with the F-Type?

GD: Jaguar is very proud of the exhaust sound and driving experience that we created on the F-Type. This was developed to meet all of the stringent compliance regulations required by an OEM.

The pass-by-noise level is a well-established compliance regulation that all new cars must meet. There are minor variations between EU/ROW and US regulations, but they essentially require similar noise control limits. The F-Type has been designed to meet the most stringent of all the global regulations. The F-Type does not have different exhaust tunes for different markets -- it is a global car. All JLR products comply with all regulatory sound limits.

JP: How much control do engineers have over the way the car sounds? Is a target sound set and achieved or is the sound just a by-product of other things?

GD: The delivery of the exhaust sound quality on the F-Type is far from being a by-product of other things. We spend considerable amounts of time and engineering resources in the development and tuning of the vehicle hardware to deliver our desired sound.

The initial exhaust system development work was carried out using a combination of expertise and computer aided engineering (CAE), and simulation techniques. Based upon years of experience, the Jaguar team developed a concept for the exhaust system that we knew would deliver the required sound quality character outlined above.

Ultimately, however, the Sound Quality can only be signed off by driving the real car. Therefore the final stage in the acoustic development of the F-Type was a series of iterative tuning loops of the exhaust and intake system hardware on prototype vehicles. Over 50 different exhaust systems with both significant and minor changes were evaluated before the final specification delivering the acoustic performance was signed-off.

JP: So, Jaguar pays someone, with actual money, to listen to prototype models and fine-tune the exhaust sound of cars like the F-Type?

GD: Yes, a whole team of us -- and as there is a lot to do, there will always be a job available.

JP: Can the exhaust noise be manipulated? Is it just the style of muffler? The intake system? The exhaust manifold? What, physically, gives the F-Type its signature noise?

GD: Very much so. All of the items that you mention have a part to play in the tuning of the sound-quality character. Clearly, some items such as the engine configuration (V6 or V8, crank design, etc.) are givens and we need to work around these basic "ingredients." Other items such as manifold design configuration (i.e., equal length, log-type, etc.) also need to be reconciled with other attributes, such as emissions. Thereafter, the intake and exhaust system layout and internals have a major part to play in adding the "spice" to the sound-quality character.

There is a significant amount of acoustic tuning that can be done on these commodities, similar to playing tunes on woodwind or brass instruments to deliver the desired "note." Items include bank-to-bank mixing, tuned resonators, expansion volumes, and perforation patterns.

JP: What causes that delightful pitter-patter drum-beat from the tailpipes when you lift the throttle at higher RPMs?

GD: This is delivered through a combination of the exhaust internal tuning, and fueling calibration.