PDA

View Full Version : Header design


JeffYoung
05-04-2008, 12:42 PM
Anyone use this resource before?

www.headerdesign.com (http://www.headerdesign.com)

The primary size it recommeds for my car is AMAZINGLY small....1.25"
lateapex911
05-04-2008, 02:11 PM
No fun for rotaries
evanwebb
05-05-2008, 07:09 PM
The results for a 1.6 VW motor look to be pretty similar to what Stahl sells for a header. I couldn't figure out what length to make the exhaust after the collector, did i just miss that in the calculator somewhere?

Jeff your motor is basically two banks of 1.8 liter 4 cylinder motors, right? With a fairly low peak HP RPM, and not really high peak HP number either, right? That size primary might sound about right. I think the vast majority of all commercial headers are probably way too big, the size is a marketing tool...
evanwebb
05-07-2008, 12:51 PM
Hey I just bought this software ($45) out of curiosity, anyone interested in sending me some info I can enter it and see what it comes with for header & exhaust design...

http://www.maxracesoftware.com/pipemax36xp2.htm (http://www.maxracesoftware.com/pipemax36xp2.htm)
Greg Amy
05-07-2008, 12:54 PM
Evan, turn on your PMs and send me a note about what info you need... - GA
JeffYoung
05-07-2008, 01:14 PM
Ron and I have thought this for a while. "Old school" thinking was bigger is better. Now, smaller primaries is thought to increase exhaust gas velocity and therefore scavenging. I agree with you, smaller is probably better on a low rpm hp peak car.

I saw your pm. I'll get you the information I have here shortly.


The results for a 1.6 VW motor look to be pretty similar to what Stahl sells for a header. I couldn't figure out what length to make the exhaust after the collector, did i just miss that in the calculator somewhere?

Jeff your motor is basically two banks of 1.8 liter 4 cylinder motors, right? With a fairly low peak HP RPM, and not really high peak HP number either, right? That size primary might sound about right. I think the vast majority of all commercial headers are probably way too big, the size is a marketing tool...
erlrich
05-07-2008, 03:07 PM
Ron and I have thought this for a while. "Old school" thinking was bigger is better. Now, smaller primaries is thought to increase exhaust gas velocity and therefore scavenging. I agree with you, smaller is probably better on a low rpm hp peak car.
Maybe old news, but here is a pretty good overview of header design theory: http://www.ssheaders.com/header.htm