20EVOLUTION01
Member
I got My Header! I can't wait to put it on. Still have to weld the EGR Bung and the Second O2 sensor. Can't Wait! Looks beautiful.
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With thickness, you're going to have to go with the closest piping to the desired thickness you want. If it calls for 1.8" Primaries, go with 1.75".iluvmacs said:I've been playing around with the header design program for a while, and have come up with a few trends:
Primary pipe diameter changes by less than .25" thickness, which would seem to make fabrication difficult.
Primary pipe length is around 32". I assume that this is primarily for exhaust pulses, which can be reduced by a factor of 2, 3,4, etc. The difference being how many times the pulse wave travels the length of the pipe.
I just wanted to note that the only header with primary pipes anywhere near that length was the ES equal length (non-shorty), and the ractive 4-1. The AWR looks like it has 8-10 inch primaries, and narrow collectors.
Comments?
I call them Tri-Ys myself, but not everyone knows the reference. They do promote a broad torque range, and can be less peaky than a 4-1. But chances are, a well designed 4-1 can make almost as much low RPM power as a Tri-Y, but peak HP is no comparison. 4-1s make substantially more up top....PR5Matt said:The 4-2-1 is just the 4cyl version of the old Doug Thorley tri-Y v-8 headers. They are supposed to promote a broad torque range.
I agree. You should see my beautiful 1 3/4"-1 7/8" step primary ceramic coated Bassini long tubes for the 'Stang. I can't wait to put 'em in! I just got them 3 weeks ago. Much better than the Mac 1 3/4" headers.Gen1GT said:I call them Tri-Ys myself, but not everyone knows the reference. They do promote a broad torque range, and can be less peaky than a 4-1. But chances are, a well designed 4-1 can make almost as much low RPM power as a Tri-Y, but peak HP is no comparison. 4-1s make substantially more up top....
In short - don't stick to the stock cams. Don't even CONSIDER the JDM cams if you are serious about making all motor power.