The straight 6 is meant to be perfect smooth engine without any tricks any other combination needs some of balancing out. Thats costs money so the less you do the cheap it is.

Tho I would say any car thats been sitting on a car lot for months is likely to be a bit lumpy

Edited by slkfanboy on 06/04/2016 at 18:14

All engines are gruff except 6 and 12 cyl. And even Porsche's flat jobs sound like a Duracell bunny in a biscuit tin. Cross plane V8s are the worst - many bhp are wasted trying to keep the NVH at bay - unless you actually like the noise.

To achieve fulll smoothness, they'd need both exhaust and inlet manifolds to crossover between the banks - easy enough for the ports in the vee but long spaghetti for the ports on the outside.

On a V8, the ports for 1st/4th cylinders on one side need to be linked with the ports for 2nd/3rd cylinders on the other side.

So it's usually the uneven exhaust that makes them sound gruff, or glorious dependent on your taste.

About 10 years ago, I test drove a Volvo D5 and the 5-cylinder engine really was gruff - I've heard smoother tractors!

QUOTE >>>

All engines are gruff except 6 and 12 cyl. And even Porsche's flat jobs sound like a Duracell bunny in a biscuit tin. Cross plane V8s are the worst - many bhp are wasted trying to keep the NVH at bay - unless you actually like the noise.

A lot of modern 'sixes' sound like vaccum cleaners, while modern Ferrari V12's sound quite like a highly tuned 'four'.

Edited by Sofa Spud on 06/04/2016 at 22:17