Talk Morgan Forums Morgan Sports Cars Morgan Aero 8, 2012< Plus 8, SuperSports, Coupe & Aeromax The Plus 8 Squeal is Gone!!

Now the systems are generally moving to electronic actuation for these tweaks. Instead of using vacuum they use the engine management to electronically switch the flaps in the exhausts in order to make the "sporty" sounds.

On the Audi selecting sport mode results in electronics opening two flaps in the rear exhausts making it louder. It also results in the CPU making loud popping and banging on change up/down.

I liked the deeper engine noise but hated the pop/bang. I also hated having to press sport on every journey and the engine/gearbox map aggression that came with it.

If you unplug the electric valve control cables it causes the flaps to stay open and the deeper noise is permanent without having to press the buttons and suffer the pops etc. However it throws up yet another fault light on the dash and may lead to possible warranty issues.

In the end I fitted this little gizmo.
http://www.jbsautodesigns.co.uk/product/...nvalved-systems

It inserts into the control cables in the back boxes and fakes out the cable messages so making the CPU happy yet leaving the exhausts open without the button pressing etc.

Peter I would not worry at all about the "illegal for road use" claim, its rot. If the Coupe can get through a roadside check and the MOT with the dual sidepipes then our sensible cars have nothing to fear.

Alistair,

I'd actually like the Plus 8 to make more noise...
The dB check at Castle Combe showed a modest 86dB at 4500 rpm.

On the C43 I can have the exhaust noise whenever I want, it has a separate on/off button without engaging the pops and bangs.

I'm beginning to discover that whatever the mode, vigorous acceleration results in a lot of noise!

The quad rear on your +8 do seem to be the most subtle of the options. They do look nice on the rear of the car and are definitely best for retain neighbours as friends. I often think the rear end of the Coupe and the S2 are missing something. Also the near 4000 mile tour we did this spring/summer showed the volume of the sidepipes even at cruise levels. It got a bit wearing due to the NVH.

I suppose the modern car designers infatuation with exhausts has rubbed off on me. Four for sport, hidden/turned down for Derv, two for normal, one for base model. Then you realise they are often fake trim bits built into the bumper and the normal exhaust box is hiding behind them.

The complexity of the ECU managed sports exhaust is amazing these days. Its all a software tweak (or a hardware bodge to tweak).

Some of the stuff from the RS6 I had (common to AMG and others)

Two modes (probably more in the future and with Hybrid being added to sports cars)
Normal - Loud blat on startup to shout look at me. Flaps closed. No popping on change up/down. Open throttles wide and the exhaust flaps open. Go above 4000ish revs flaps open wide.

Sport - Loud blat to start. Flaps open wide all the time. Additional "exhaust crackling from unburnt petrol" sound added to change up and down. More aggressive engine and gearbox maps applied.

I spoke to an F1 thermodynamics chap and he said it is usually only on the very rear exhaust box that these options are applied. They work more on noise than power although on some of the cars they can give up to 5% more power in the open mode compared to closed mode at high revs/full throttle.

On the RS6 it was 600bhp with the factory tune and sports exhaust. You could to stage 1 & 2 tuning (if you were nuts and did not mind blowing the warranty) up to 680/720bhp with the normal exhaust but above this you needed to change/remove the cats and up the drainpipe size from 2.5 to 3 inches front to back to free the engine to go higher. I had a go in a 720bhp one because you always want to don't you. It was like having a warp drive fitted but totally unusable. Too heavy for a track car and too fast for public roads. My old GTR33V at 550bhp was far more subtle and usable, and probably faster.

Life was so much easier when you just got a 1x1 wood baton and knocked out the baffles.

I have long found it hard to associate the words "Audi" and "Subtle" in the same context.

Now, it seems, "German Sports Saloon"and "subtle" are incompatible.

Just read, in last month's edition of EVO magazine, a comparison between the new AMG E63 saloon and the new Porsche Panamera S. The AMG was adjudged the better weapon, by a short head, 5* vs 4.5*.

The most amusing bit was the comment that when in Sport+ mode by pulling the two flappy pedals back for 5 seconds the car was made into a 603bhp RWD device and set up for drifting....

Really, a 2 tonne, 603 bhp drift tool??? The definition of unsubtle.

It's a shame that pulling both ears back for five seconds doesn't result in a comparable increase in ability........

I watched a documentary about Pagani. One section was about the exhaust.
Titanium. A German specialist tuned a resonator box to the sound note spec that Pagani wanted. It was then baked to create a particular purple colour. I think it was the Huyara car. There was one on display last weekend at the REME open day at Lynham.
Years ago a chap who played rugby at our club used copper tubing to make an exhaust. A distinct note...it didn't last long though!
Another trick was to drill holes in the exhaust. You needed a friendly MOT chap once a year. Experimentation could produce good sound.

Some hope.

Seem to recall that using copper pipe for exhaust produces a toxic gas?