how fast do the pistons travel at 9k per minute?
05-31-2004, 11:50 AM
#22
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Originally posted by ACLR8
fpm to mph is an easy conversion . . . . . if we are just talking about converting units at this point.
7959 ft/min *1mile/5280 ft*60 min/1 hr = 90.44 mph
BTW, jankemi don't you just love excel for this stuff!
fpm to mph is an easy conversion . . . . . if we are just talking about converting units at this point.
7959 ft/min *1mile/5280 ft*60 min/1 hr = 90.44 mph
BTW, jankemi don't you just love excel for this stuff!
ok so you showed me the mph that the crank spins at. but the piston in fps, is not 7959. its 4906 at 9k. so what is the mph of the piston. i said 63 mph or so, but if you think in your head, there is no way if that piston continues a linear travel, that its on going 63 mph. thats slow as hell. id bet that the pistons mph as it passes a given inch of cylinder wall, exceeds 200 mph @9000 rpms. but hey, im just imagining whats going on in there.
05-31-2004, 12:16 PM
#23
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My calcs are piston speed, using the excel spreadsheet in the link provided by VTEC4-2. The first two are in fpm, the third in mph.
steven975 calculated crank speed.
I don't know where the 4100fpm speed limit comes from . Perhaps that is an average, not a peak? Or perhaps that is why S2000 engines like to pretend that they are Iraqi roadside bombs so often? Just guessing.
steven975 calculated crank speed.
I don't know where the 4100fpm speed limit comes from . Perhaps that is an average, not a peak? Or perhaps that is why S2000 engines like to pretend that they are Iraqi roadside bombs so often? Just guessing.
05-31-2004, 01:45 PM
#24
The '03's pistons whiz at 4906 feet per minute at 8900 rpm, whereas the '04's slugs rip along at just 4761 feet per minute at 8000 rpm.
Haha, only 3% slower, yet slugs?
Haha, only 3% slower, yet slugs?
05-31-2004, 02:04 PM
#25
The average speed is the total sum of swept distance up and down, over the elapsed period of time. It has nothing to do with the maximum instantaneous speed (which is, of course, higher) which occurs at the piston at a certain degree of rotation of the crankshaft, usually 70-80 degrees away from TDC (from what I've read).
I got my quote about lubrication vs. piston speed here: http://zccw.org/Tech/Engine/06-97LongShort.html
Basically it seems that hydrodynamic lubrication is not reliably sustained above that piston speed. Now Honda has been doing some special stuff with bearing materials, I would suspect they have found some way to stretch the envelope.
Here's another link I found, this one has an excel spreadsheet
on page 2:
http://e30m3performance.com/tech_articles/...tech/rod-ratio/
Another link, with online Calculator:
http://www.slowgt.com/Calc2.htm#PistSpeed
I got my quote about lubrication vs. piston speed here: http://zccw.org/Tech/Engine/06-97LongShort.html
Basically it seems that hydrodynamic lubrication is not reliably sustained above that piston speed. Now Honda has been doing some special stuff with bearing materials, I would suspect they have found some way to stretch the envelope.
Here's another link I found, this one has an excel spreadsheet
on page 2:http://e30m3performance.com/tech_articles/...tech/rod-ratio/
Another link, with online Calculator:
http://www.slowgt.com/Calc2.htm#PistSpeed
