Header primary size - is 40mm too small?

[confuzion]

Hey all,

B18CR in an DC2R

I hunted for a while looking for some 2nd hand JDM headers and wasn't too keen on the 4-1's that were around, so I bought some 4-2-1 M&M Honda headers from http://www.nengun.com/m-and-m-honda/exhaust-manifold and are on their way. They are a reputable JDM brand and very popular over there.

During a period of boredom I did some more research and noticed that all the other good brand headers use something like 45mm pipe diameter primaries.

In your opinions will I be losing alot of power compared to a header using 45mm primaries?

I'm keen to do a before and after dyno, but if the common census is that they are crap I might just sell them now..

Thanks all

[ek9rx]

the 40mm header will give good low to mid range torque in my opinion, it will only start to be restricrive when u start to add more power. what size is the collector?

[confuzion]

Thanks, that makes sense..

This header goes into a 40-50-65mm stage. 65mm seems to be the norm with the other brands also so pleased with that at least..

Cheers