Momentum header people! I have a quick question
 

What's the inside diameter at the header to cat flange?

OEM DE is 2.25"

And some guy at Z1 said he THINKS theirs is 2.5" and that they made many improvements to the Momentum design, so I can't take his word

I will be back home tonight and will provide with true number as I still have them on my wall waiting to be modified

On top of my head if I remember correctly, the Inside Diameter at the exit flange was around 2.125'' which should give about 2 1/4'' OD.

Ok, because I bought TPs that are 2.25"

And I looked at my HR TPs and though, FUUUUUUCK... Those are bigger...
And if the Momentum headers have a 2.5" exhaust going to a 2.25" would make turbulence and you're choking it down


And my only solution is to either MAKE a HR flange and weld it to the headers, or MAKE a DE flange and weld it to my HR TPs
(I have a small window because the headers come in Friday and I gotta go weld it on my lunch, and Saturday I drive out to the dealer with my box of parts to install)

The momentum header is slightly less 2.25", my z1 test pipe 350z is 2.5" or bigger oval

First pic momentum, 2nd pic is test pipe
Attachment 75143

Attachment 75144

so I just verified again with a caliper and the average Inside Dia is around 2.115'' +/-0.015''
add 2x .065 (thikness) the OD would be very close to 2 1/4'' (2.245'' +/- 0.015'')
this is the true Momentum and not the Z1 copy.

:tup:

You guys are AWESOME to say the least!
I wish I could rep you guys more!

Thanks again guys!!!

Headers just came in!!! Awesome to have a set of brand new Momentums!

brand new Momentum ? or Z1's Copy ?:tup:

Brand spankin new Momentums

Owner never opened the box

Did you get them form that 350z owner I mentioned or did you find another source?