KCS

iTrader: (20)

Is there anyone out there with a formula for peak piston speed? I've searched and searched, speedtalk and eng-tips even.

DanO

lots of threads here about this topic... do a search.. Here are a few

(I went to "seach this forum" button and typed in "Piston speed")

https://ls1tech.com/forums/showthrea...t=speed+piston

https://ls1tech.com/forums/showthrea...t=speed+piston

https://ls1tech.com/forums/showthrea...t=speed+piston

KCS

iTrader: (20)

I appreciate the help, but I still don't see what I was looking for. Those links you provided spoke mainly of mean, or average, piston speed. I am looking for peak piston speed which I know involves somewhat complex algorithms. Thats what I am looking for.

The second link does contain an online calculator, which will have to do for now I guess.

Thanks though,
Kent

405HP_Z06

iTrader: (11)

I'm not familiar with a formula for 'peak piston speed'. Piston speed is a variable number based on RPM and stroke. Here's the formula for Piston Speed in feet/minute.

Piston Speed (FPM)= (2 x Stroke (inches) x RPM) / 12

or

Piston Speed (FPM)= (Stroke (inches) x RPM) / 6

Could you be looking for Piston G's @ TDC?

racer7088

Kent the speed talk deal had one with peak piston speed. You need to know rod length and stroke and rpm but it is usually around 70-78 degrees ATDC.

A 4 inch stroke and 6.125 rod have a Max / Mean Ratio of 1.65 so at 4000 FPM Mean piston speed you have a peak of 6600 FPM instantaneous piston speed. This is around 75 degrees ATDC again.

405HP_Z06

iTrader: (11)

Okay, I understand what your looking for. Does this spreadsheet calculate what your looking for?
Spreadsheet

Alvin

iTrader: (2)

I have the formula, its not that easy to type here with sin's and cosine.. Not sure what the best way to share it is...

If you can find a formula for piston position just take the derivative of it.. thats what I did

383jake

iTrader: (2)

dont know if this helps, but.. stroke x RPM/ 6= average piston speed of feet per minute

405HP_Z06

iTrader: (11)

See post #4

383jake

iTrader: (2)

i see it now... my bad

405HP_Z06

iTrader: (11)

I calculate the peak piston speed to occur at 72 degrees for the parameters above. Trying to figure out what I did wrong, how did you arrive at 75 degrees?

405HP_Z06

iTrader: (11)

No bad, it's all good.

racer7088

405HP,

You are going to be right as that sheet I saw was only in 5 degree increments so you are closer and are probably right as well!

KCS

iTrader: (20)

Yeah, pretty much except I would like to know the actual formula before I have to rely on a spreadsheet. Thanks for the link though.

405HP_Z06

iTrader: (11)

Here is a link that provides what your looking for. He designed the spreadsheet I posted earlier.

http://www.wfu.edu/~rollins/piston/

405HP_Z06

iTrader: (11)

Correction , I figured it wrong initially. It should be 73 degrees instead of 72 degrees.

ProductionS14

http://www.csgnetwork.com/pistonspeedcalc.html