RE: Ford Sierra 5.0: You Know You Want To
Discussion
RoverP6B said:
The GT350 videos I've seen show that it's clearly a cross-plane, making traditional V8 thunder. If it was a flat-plane, it'd make a tedious flat drone like a Ferrari 458 does.
It's a flat-plane crank engine, and with a 8,250rpm redline. Every one of the shed loads of US articles already published on the car confirm that.
RoverP6B said:
So, why do Ford's official videos show it making a cross-plane noise? You can't get that sound with a 180-degree crank.
Says whom? You?Personally, I'm inclined to listen to the people who built the f
king engine rather than some random forum member guessing based solely on engine sound. Especially given some of the utter drivel you've posted on this forum over the years.Brief technical breakdown of the engine for anyone who isn't bewilderingly moronic
http://www.edmunds.com/ford/mustang/2015/long-term...
Edited by ManOpener on Friday 5th June 15:32
The whole nature of the classic V8 sound, evident in Ford's official videos, is that it's produced by exhaust pulses from opposite banks hitting each other in the exhaust. If you have a 180-degree crank, you don't get those exhaust pulses - you get the noise of two synchronised inline-four-cylinder engines. That's what you hear from any V8 Ferrari, or a Cosworth DFV, for example.
RoverP6B said:
The whole nature of the classic V8 sound, evident in Ford's official videos, is that it's produced by exhaust pulses from opposite banks hitting each other in the exhaust.
No, it's not. Many, if not most, V8 engines, whether cross-plane or flat plane, have entirely distinct exhaust systems for each bank that don't actually meet at any point- effectively mimmicking the arrangement of an inline 4 for each bank of the V.The "classic V8 sound" is produced by the irregular firing order typically assocaited with 90° (cross-plane) V8 engines. However, it's perfectly possible to utilise the same irregular firing order on a 180° (flat-plane) V8. Oldsmobile flat-plane V8s, for instance, use the same firing order as typical cross-planes. I'm also fairly sure that some crossplane V8s have used a regular firing order- the BMW S65B40 springs to mind but I'm not 100%.
Edited by ManOpener on Friday 5th June 15:43
I'm somewhat rusty on the theory, I concede, but there's still an element of exhaust pulses hitting each other - which is what gives the chunter characteristic of any 90-degree V8. However much you muck about with firing order, a flat-plane-crank V8 will still make the noise of a pair of 4-cylinders.
ManOpener said:
No, it's not. Many, if not most, V8 engines, whether cross-plane or flat plane, have entirely distinct exhaust systems for each bank that don't actually meet at any point- effectively mimmicking the arrangement of an inline 4 for each bank of the V.
That's not really true both my v8's have both banks joining into a single system and most dual systems run a balance pipe or x pipe.
RoverP6B said:
I'm somewhat rusty on the theory, I concede
Rusty, as in utterly clueless. RoverP6B said:
but there's still an element of exhaust pulses hitting each other
No there isn't. It's to do with irregular exhaust pulses, which are a product of the firing order.A flat-plane crank will typically alternate between odd and even (so left bank and right bank) with each firing sequence, and will therefore never fire two adjacent cylinders in sequence.
A cross-plane crank will typically have at least two points in the firing sequence, one for each bank, where two cylinders on the same bank fire in in sequence. There will also be a point somewhere in the cycle where to adjacent cylinders fire in sequence.
Handy visualisation:
Flatplane
Crossplane
And more...
RoverP6B said:
However much you muck about with firing order, a flat-plane-crank V8 will still make the noise of a pair of 4-cylinders.
No, it won't.Coatesy351 said:
That's not really true both my v8's have both banks joining into a single system and most dual systems run a balance pipe or x pipe.
You're right, most dual systems (on crossplanes at least) do run some kind of connection between them such as an X-pipe (that completely slipped my mind), but they are by and large distinct and the purpose there is simply equalising exhaust pressure.Edited by ManOpener on Friday 5th June 16:07
Gassing Station | General Gassing | Top of Page | What's New | My Stuff