V2 vs. V4 torque things that make you go hummm

J

Jasson

New member
Umm, without really diving into it, I believe that number is just a unit conversion. It converts HP to ft-lb * rpm.

HP is a power unit (work * time), and ft-lb is a work unit. RPM is a speed that is not in standard unit.

So, quick lesson:

550 ft-lb*60 sec/min / (2*pi rev/min) = 5252 ft-lb sec

Ok, so I dove into in...
 
ELTWIN got it dead on.

But once you put these into the hands of an operator, the results are not so clear.

Its easier to ride a V-twin especially in high stress situations such as unknown roads since you dont have to spin it so hard all the time.

So the human factor and reality once again brings us to hunt for the magical "balance point" of low rpm ease of use and enough torque and power.

This magical balance point shifts and maufacturers build their own interpretations to take on the conditions at the time.
 
Summed up very nicely Hart! That's got to be why why we all love Ducati's because they manage to achieve that magical balance so well.

Brett, you are spot on with the 5250rpm crossover point mate. I have built many successful competition based engines over the last 25 years or so and every one that has been on the engine dyno has crossed over at precisely that point regardless of torque or horsepower peak output! Gotta love that maths.
 
EL Twin, your reply (post#21) was spot on.. Perhaps if you substituted BTU's instead of the word heat perhaps the OP and others would have understood that you were using the word"heat" as a description for energy vs heat as in temperature..

Just a thought..

Good job..

RC
 
You know, you guys are pushing the engineer in me here... BTU is merely a unit of energy, the same as Joules.

My personal grievence (if you can even call it that) is using the form of thermal energy instead of mechanical energy to describe the engines. IMO, it just makes more sense to use mechanics to describe the work they do.

Now you all probably thick I'm some anal jackass...
 
Correct, BTU's & Joules are simply "measurable" unit's of energy = mass=torque=Hp... The list goes on..

Wait till the BB rolls over to the other side.. Then I'm back to our regularly scheduled idiot.

RC
 
Thanks RC! BTU's are not actually in my engine building vocabulary but I have heard of them.
I was doing my best to put it in laymans terms for those less technically endowed to follow. I'm not an engineer, just been building engines and studying the 'science' of them for a long time. Learning some of that 'other' stuff improved my results through better understanding of the whole process.

My understanding of the process is that it's the pressure from the expanding nitrogen that provides the energy to push the piston. The 'heat' is necessary to expand the gas so it can do it's work. That's probably Very oversimplified from an engineering POV but it's the simple truth as far as the engine sees it.

Cheers mate. I have learned a little more!
 
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