Re: exhausts questions

[geordie]

No scientific basis here, but I am under the impression there is an optimum pipe size for flow too small and it's restrictive, too large and you don't get the air speed you need.   Ideally, you would have a small pipe for low rpm and a larger pipe for higher rpm when more gas needs to flow. and everything inbetween but we all know that pipes can not change size all by themselves :D   So a typical exhaust system is a compromise of some sort, whether it is midrange pipe size optimised for midrange power or larger pipe size optimised for high end power.   ----- Original Message ----- From: maldat To: [EMAIL PROTECTED] Sent: Tuesday, April 27, 2004 4:12 PM Subject: Re: exhausts questions I use 4-1 headers that are quite long, the 4-1 collector is just about under the seat. I also use a exhast thats one size down from 2"..everyone else had 2+" and my car was faster..??   Malcolm "new theory, you can move more air quicker thru a smaller pi[pe than a big one.... what do you guys think of that?.   ----- Original Message ----- From: Jeff Oldham To: [EMAIL PROTECTED] Sent: Tuesday, April 27, 2004 1:51 PM Subject: RE: exhausts questions There is some debate about exhausts being too big & not providing enough back pressure. But i think its only the first part of your exhaust (the headers) that affect this. that why some new exhaust systems run variable exhaust manifolds as it affects your torque at various revs.   go to about halfway down on this web page for some info.   http://www.autospeed.com/cms/A_46/article.html     I am running 4-2-1 motivator extractors into 2 1/2 with 3" tail pipe & turbo muffler. the 4-2-1 (or "y" extractors) give a slightly more spread torque range than 4-1 I think 2 1/2 inches is biggest that will fit in the rear cross member of a 510 without enlarging the hole :)   When i got rid of the bit of curtain rod that was on my car i noticed not more power but that the engine felt like it could rev out further easier.   BUT i could have it all wrong so ask some professionals :-) cheers Jeff            -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of kla Sent: Sunday, April 25, 2004 12:47 AM To: [EMAIL PROTECTED] Subject: exhausts questions I've been wondering about sports exhausts, as i was thinking of getting a system installed (extractors to the back) and i was wandering. as a general rule. sizes. obviously too small means not enough flow, but what about big? what happens when you get too big, and what is generally the best size for a 1.5litre (standard, non-turbo etc.) if its too big do you get a dead space effect where it cant move enough of the air or what? cheers. --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/[EMAIL PROTECTED]/ --------------------------------------------------------------------- --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/[EMAIL PROTECTED]/ --------------------------------------------------------------------- --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/[EMAIL PROTECTED]/ --------------------------------------------------------------------- --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/[EMAIL PROTECTED]/ ---------------------------------------------------------------------