Re: Compression Ratio's Yet Again

[Craig Overend]

Dave,        good to hear its working, what sort of engine are you building? Craig. David Costello wrote: ahh I worked it outCraig Overend, if you change the " - TDC " in the chamber cc part of your formula to " + TDC " it's more accurate if you use " - TDC " then as you decrease the distance from the piston to deck when the pistons at TDC the compression ratio decreases too, if you use " + TDC " then the compression ratio increases as it should Dave ----- Original Message ----- From: David Costello To: OzDat Mailing List Sent: Friday, June 28, 2002 5:44 AM Subject: Compression Ratio's Yet Again  Guys I'm having trouble getting my brain around something to do with calculating compression ratio's. I know the formula I'm using is correct, I've tried using figures for motors I allready know the compression ratio of and it's been spot on every time. the thing that's got me stumped is if you increase the piston height value, the final compression ratio decreases.  I'm having trouble understanding how that works, shouldn't it increase compression since it's bringing the piston closer to deck? I've tried using 2 compression ratio calculators as well, and exactly the same thing happens. The compression ratio calculator doesn't have a "piston height" option, but it does have "piston below deck" field, and if you bring the piston closer to the deck then exactly the same thing happens....compression ratio DECREASES this has got me stumped :(maybe I should stop trying using mathematical formulae at ungodly hours of the morning :) hehe Dave --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ --------------------------------------------------------------------- --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ --------------------------------------------------------------------- --membersozdat------------------------------------------------------- OZDAT Mailing List Please Note:- Send (un)subscribe requests to [EMAIL PROTECTED] Send submissions to [EMAIL PROTECTED] No unauthorised redistribution of this email http://www.ozdat.com/ozdatonline/index.htm http://www.ozdat.com/ozdatonline/listindex.html http://www.mail-archive.com/membersozdat@datascribe.com.au/ ---------------------------------------------------------------------