Thought of the day: Richer sounds

An Italian supercar manufacturer once commented in an unguarded moment that the sales success of any supercar was decided by how it looked, how it sounded, and how it drove, in that order. He was probably over-generalising to make a point, but there is a lot of truth in it. Just think about how many Ferraris are only driven from the villa to the marina and back, or even worse, barely driven at all. I was particularly interested by his second choice, how a car sounds. When I was in Italy last year for the launch of the Maserati Gran Cabrio, I was captivated by the gorgeously unique noise the car made when the sports exhaust was switched on. In fact, many ‘seen it all, driven it all’ journalists were slipping out in the evening just to take one of the Gran Cabrios through the backstreets of Trieste to hear those exhausts bouncing back from the ancient stonework. It sounded superb even at 5mph, edging along in a traffic queue. I discussed it with their design team, and they admitted that a great deal of time and effort had gone into tuning the exhausts for their tone, and the research budget for this aspect of the car’s development indicated just how seriously Maserati take the sound of their cars.

I was reminded of this at the launch of the 991 cabriolet earlier this year. At press presentations of this type the differing specifications and options are always discussed, and at this particular launch we were given detailed predictions of sales volumes not only of the cars themselves, but also of the lucrative options list. The switchable sports exhaust was an option, but Porsche anticipated 50% of cars ordered would have it specified. And I’m not surprised, because with the standard exhaust, or with the Sport setting not selected, the cars sounded, frankly, a little tame, at least until the engines were wound up the rev range. The sports exhaust transforms the car, and makes it the best sounding 911 since the air-cooled era, with a healthy distinctive rasp as it revs, and some pops and crackles on the over-run. And just like the Maserati Gran Cabrio it even sounds great in the 5mph traffic queue test. At around £2000 for the option, it is barely noticeable on a £70K car.

For many, the noise a car makes is a vital component of the whole driving experience.

I know some 911 owners will argue that the beauty of the car is how it drives, and not how it sounds, and I totally agree that the unique driveability is reason enough for buying one. But the little boy in me wants it to sound good too, and that 50% figure of new buyers who will specify the sports exhaust suggests I am not alone. Which is fine for all of those people about to visit their local Porsche dealer to specify their new 991, but what about those of us for whom a new 991 remains firmly on the wish list alongside early retirement and fair treatment from banks?  Maybe we have a much-loved 996 or 997 that we just wish sounded as good as it drives. To be fair to Porsche they recognise this wish, and in exchange for a handful of fivers they will retrofit you a switchable exhaust. Actually, unless you have very big hands it might be better to make it fifties, because the total cost including labour is a little over £4500. I’m not going to suggest that this is an unreasonable sum, because there is a lot of work involved, but that could easily be 20% or more of the car’s value compared with maybe 3% if you specify the option on a new car.

I suppose we will just have to put the exhaust on that wish list too. Or will we? One of the joys of running a Porsche in Britain is that we are endowed with a host of small, niche companies who can help out in times of trouble, and often for a fraction of the cost of visiting the main dealer. A stainless steel exhaust specialist called Hayward and Scott in Basildon, Essex, is a good example. They can make your 911 sound exactly as it would with an original switchable exhaust, but for a considerably smaller handful of notes.

On a standard exhaust, gases travel from the engine, through the exhaust system to the silencer, and then exit suitably quietened through the tailpipe. On switchable exhausts there is an extra pipe by-passing the silencer and exiting in the tailpipe, which allows some exhaust gases to remain un-silenced. A valve, operated by vacuum pressure, opens this extra pipe when you want your car to sound sportier (which in reality is probably most of the time).

Hayward and Scott, with the kind of keep it simple approach that often marks out really skilled engineers, worked out that it was possible to weld in a pipe on the standard exhaust system, that exactly replicates what a switchable exhaust does, except that it is not switchable. In practice this does not matter, because at low revs the exhaust gases just follow the path of least resistance and flow through the silencer as normal. But as the revs rise and back pressure builds in the silencer, gases start to flow through the by-pass pipe with a predictable impact on the exhaust noise.

And it really works too. I had it fitted to my 996 earlier this year, and I can dawdle up my road late at night without disturbing a single neighbour, yet when I open it up on the bypass the noise is glorious. Totally, unmistakeably Porsche, and sounding exactly the same as those switchable exhausts many of us have lusted after. And the cost? About £350, including removing and refitting the silencers from your car, which saves you over £4000 to put towards your new 991. But you never know, with your current 911 sounding that good, you may not even want to change it.


Thanks to Chris Dearden for his Thought Of The Day

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