is there a better header out there

[dazzlesa]

i was looking at my header. the ID of the outlet of my header is 1.75". is there a better one out there for my 1987 ITB civic?
thanks rick

[Jeremy Billiel]

I would think that at least 2" would be better than 1.75". Have Matt put on a new collector and run 2". If you don't want to invest, put the car on the dyno and remove the exhaust system and see what gains there are. Then go larger as long as the engine wants less restriction.

[JeffYoung]

Go here:

www.headerdesign.com

Run the program (it's free). I think you might be surprised at what the current thinking is on primary ID and outlet ID -- think smaller is better as it scavenges better and flows faster.

[dazzlesa]

i ran it through the program at it came up with a 2" collector. is it worth changing it?

[Marcus Miller]

i ran it through the program at it came up with a 2" collector. is it worth changing it?

What performance factor did you use?

[dazzlesa]

i think i used 6. i remeasured my outlet and it seems to be 1 7/8. what do you use for a exhaust pipe diam? 2 1/8 id?