Thread: My new header

Thanks. Not tested yet as I'm still busy with the new intake manifold but yes perhaps i should wait till after the dyno for ceramic coating.

Spot on Haulin i was trying to replicate some honda header i saw online.

Did you go with 2.25" pipe off the collector? and is that id or od?

You must be also using the PLM megaphone which tapers up to 3.5" then back down to 3" at the flange

What are the diameters of the PLM primaries at each step? I went with 1.73 stepped to 1.89 but I now wish I went bigger for some reason. I'll wait till after it's dyno'd and decide if I want to add another step and bigger collector or perhaps build another one with bigger primaries altogether.

I went 2.5" between the collector and the megaphone. The megaphone is a different brand and flares out to 4" and then back to 3".

I'm unsure of the diameter of the steps. It is stepped though.

The B series PLM V2 collector is 2.65" (od I think) but I'm using a piece of 2.25" pipe right off the collector, since its been dyno'd many times the 2.25" collector made the most power on the sr20. I always wondered why they went 2.65" on the PLM? I'm not using a megaphone. I just went 2.25" right off the collector and tapered it to 2.65" then to 3" where it would bolt to the converter.

It'll be interesting to see the differences with the smaller diameters once you get it on the dyno.

Still a great job!