We've talked a fair amount about a
header for fuel economy. I think its safe to say that almost no aftermarket header is going to be designed for that purpose. So, I'd like to step through the process of designing a header for the Metro's G10 1.0L 55 hp engine as an example of how you would go about designing a header for your own car.
Now, lets keep in mind that this probably is not worth it cost wise. Even with the Metro being a 3 cylinder, and materials being very cheap (under $100 for a stainless header), the fuel economy gains are just not going to justify that cost. That being said, I'm not sure I'll actually make a header for the Metro, but I do want to run through the design for those who are interested.
To run through the design, I'm going to pull info from multiple different places, but the bulk of my info is from:
Header's by Ed - Infopak
It is a paid for product, so I can't divulge too much from it. However, I will refer back to it as we go along.
I've also tried to get in contact with mwebb as he seems to know a good amount about engine and header design.
So, Ed says the keys to a good header are (links go to the steps in this thread):
1)
tube diameter
2)
tube length
3)
collector size
4)
collector length
5)
equal length tubes
6)
efficient collector shaping
7) efficient port matching
In my next post, I'll start going through these 7 steps to design a fuel economy header for my Metro.
As a teaser, I have started drawing up a header for the Metro in SolidWorks. Its just roughed in thus far and will definitely change as I haven't taken any real measurements of the engine. But, here is a sneak peak.
