Go Back  R/C Tech Forums > General Forums > Electric On-Road
Comparing Pistons >

Comparing Pistons

Comparing Pistons

Old 03-05-2010, 06:43 AM
  #1  
Tech Legend
Thread Starter
iTrader: (274)
 
Cain's Avatar
 
Join Date: May 2002
Location: West Fargo, North Dakota
Posts: 32,872
Trader Rating: 274 (100%+)
Default Comparing Pistons

Was curious about this so I figure some of your gurus out there can answer.

Is there a formula you can use to compare pistons to each other?

Example:

- Piston 1 - 2 hole with 1mm holes, what would be an equivalent 3 hole piston and same question in reverse?
Cain is offline  
Old 03-05-2010, 07:19 AM
  #2  
Tech Elite
iTrader: (9)
 
seaball's Avatar
 
Join Date: Sep 2001
Posts: 4,304
Trader Rating: 9 (100%+)
Default

assuming the same thickness and overall diameter of the pistons, you can probably compare them using the formula for calculating the area of a circle (pi * r^2). sum the area that the oil will flow through and that should be ballpark.

if you're switching between piston mfrs, things like the edge radius and hole tapers can affect the dampening as well, and are much tougher to calculate/predict.
seaball is offline  
Old 03-05-2010, 07:33 AM
  #3  
Tech Master
iTrader: (8)
 
PitNamedGordie's Avatar
 
Join Date: Nov 2003
Location: Highwood, IL
Posts: 1,789
Trader Rating: 8 (100%+)
Default

Originally Posted by seaball View Post
assuming the same thickness and overall diameter of the pistons, you can probably compare them using the formula for calculating the area of a circle (pi * r^2). sum the area that the oil will flow through and that should be ballpark.

if you're switching between piston mfrs, things like the edge radius and hole tapers can affect the dampening as well, and are much tougher to calculate/predict.

So do you mean like this?

I am running Tamiya 4 hole pistons bored out to 1.4mm.

(3.1416*1.4^2)*4 = 24.63 square mm?
PitNamedGordie is offline  
Old 03-05-2010, 07:42 AM
  #4  
Tech Elite
iTrader: (9)
 
seaball's Avatar
 
Join Date: Sep 2001
Posts: 4,304
Trader Rating: 9 (100%+)
Default

Originally Posted by PitNamedGordie View Post
So do you mean like this?

I am running Tamiya 4 hole pistons bored out to 1.4mm.

(3.1416*1.4^2)*4 = 24.63 square mm?
close.

3.14 * (0.7^2) * 4 ~/= 6.15 sqmm

realistically, pi doesn't even need to be there for the relative comparisions, but let's not ahead of ourselves.
seaball is offline  
Old 03-05-2010, 08:15 AM
  #5  
Tech Master
iTrader: (8)
 
PitNamedGordie's Avatar
 
Join Date: Nov 2003
Location: Highwood, IL
Posts: 1,789
Trader Rating: 8 (100%+)
Default

Originally Posted by seaball View Post
close.

3.14 * (0.7^2) * 4 ~/= 6.15 sqmm

realistically, pi doesn't even need to be there for the relative comparisions, but let's not ahead of ourselves.
Gotcha

Oh and uh..I knew r was radius not diameter
PitNamedGordie is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.