I have long wondered why a V8 exhaust sounds so different from our V6's.

A crossfire SRT6 has a bore and stroke of 89.9x84, about .53 liters per piston. A mustang 5 liter 2013 B&S is 92x92, which is .625 liters per piston. In my view that is not a big difference.

Accounting for engine dispacement, a 3.2L is pumping as much volume at 3100 rpm as a 5 liter is at 2000 rpm.

Accounting for exhaust impulses out the tailpipe, a 6 cyl has 3 per revolution. 1500 rpm would be 4500 exhaust impulses per minute.
A V8 has 4 per revolution, so 4500 exhaust notes would come at 1125 rpm.

Do these factors come into play in the final sound of the engine? Will the proper exhaust components make a Xfire sound like a Mustang GT?


And on a related topic, why dont we get the burble and popping sound when downshifting the autostick that you get when you downshift a proper stickshift?

 

Bump. Any thoughts from engine or exhaust guys?

 

As a long time engine mechanic let me throw my 2 cents in. Have you heard a v10 or 12? There is a difference in it and a v8. Or a 2cylinder 4 stroke v twin. The exhaust pulse from each of these engines is quite different. I compare it to a flap of cardboard in a bicycle spoke wheel. Remember this we did when kids? If you had a wheel with 2 spokes and one with 6 spokes and one with 8 spokes and one with 10 spokes. All turning the same speed. The sound and volume of the clicking spokes with each wheel is very different. Then in a car you have to consider the design diameter and length of the exhaust tubes and any bends they make as well as the design of the exhaust manifolds. In addition the shape of the cylinder and exhaust ports and volume of them. That's why 2 different design manufacturer v8 engines in 2 different cars with the same exhaust setup can sound so different.

 

I would think the size of the valves on the exhaust side would have to be figured in as well and duration. Great question though. I loved my old Chevy V-8
s. Ford V-8 's always had a higher note as well. European engines always had that low mellow tone sound.

 

Your correct that duration and lift as well as type intake manifold also have an effect on sound. Also placement in the cylinder of the valves and spark plug and shape of combustion chamber.