engine configuration question - torque related
Discussion
Was wondering about this the other day for no reason other than pure intrigue.
If you had to design an engine from scratch, ignoring space constraints and other packaging issues but it has to be a 2997cc engine with an 86mm stroke and 4 valve heads, which would be the torquiest layout?
I know there are other issues like inlet manifold design, port sizes, valve sizes, chamber design etc but for argument's sake, let's imagine they're all the same.
Bearing in mind that this engine size, at a push, could be anyting from an inline 4 cylinder to a V12, there's quiet a lot of options.
Like I say, no real reason, just wondered!
(I chose 2997cc as it's 86mm x 86mm in a 6 pot, which seemed like a good datum point)
If you had to design an engine from scratch, ignoring space constraints and other packaging issues but it has to be a 2997cc engine with an 86mm stroke and 4 valve heads, which would be the torquiest layout?
I know there are other issues like inlet manifold design, port sizes, valve sizes, chamber design etc but for argument's sake, let's imagine they're all the same.
Bearing in mind that this engine size, at a push, could be anyting from an inline 4 cylinder to a V12, there's quiet a lot of options.
Like I say, no real reason, just wondered!
(I chose 2997cc as it's 86mm x 86mm in a 6 pot, which seemed like a good datum point)
Edited by Robmarriott on Thursday 2nd May 12:12
As I understand it the torque characteristics are mostly down to the stroke and the RPM range you're interested in using it. (I'm happy to be corrected, of course, but that's how I understood it!)
I6 is a pretty good setup for smoothness and low/mid-range torque, as seen on many commercials.
I6 is a pretty good setup for smoothness and low/mid-range torque, as seen on many commercials.
when you say torque do you actually mean lots of power low down? in which case you need good cylinder filling at low rpm, so good trapping efficiency and long tubes are your friend (ignoring blowers). if you had a particular application in mind it might help, but i'm not sure what number of cylinders would be best .. low number of cyls for less drag losses, lots of valves and short cam durations etc .. we need an engine designer or someone with lots of experience in tuning engines of various specs to answer it really.
Nope, I mean torque.
Where that torque is doesn't really matter in this hypothetical situation.
All I'm really interested is would be if an engine which has identical properties in every other way as mentioned above, would make bigger numbers if it had a different layout.
Other than the cylinder bore, every other variable would need to be identical so in a 6 cylinder engine, the valve sizes would give x area in mm2 so in an 8 cylinder engine they'd need to be smaller per cylinder to give the same amount of overall valve area (x mm2 again)
That way, it's literally just down to configuration.
Like I say, I have no practical application for this data, just wondering!
Where that torque is doesn't really matter in this hypothetical situation.
All I'm really interested is would be if an engine which has identical properties in every other way as mentioned above, would make bigger numbers if it had a different layout.
Other than the cylinder bore, every other variable would need to be identical so in a 6 cylinder engine, the valve sizes would give x area in mm2 so in an 8 cylinder engine they'd need to be smaller per cylinder to give the same amount of overall valve area (x mm2 again)
That way, it's literally just down to configuration.
Like I say, I have no practical application for this data, just wondering!
If you want to chase the biggest max torque figure (not sure why you'd want to, but still), you'll be looking at making most power at low rpm. So my semi-educated guess is a few very long cylinders (as few as are commensurate with getting good filling, given the fairly fixed valve area) and a big f*ck off flywheel.
The Black Flash said:
If you want to chase the biggest max torque figure (not sure why you'd want to, but still), you'll be looking at making most power at low rpm. So my semi-educated guess is a few very long cylinders (as few as are commensurate with getting good filling, given the fairly fixed valve area) and a big f*ck off flywheel.
the more rpm the better the tuning potential to a point where friction takes over so max torque will probably not be at low rpm whatever "low" actually means.Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff