Hello,

Please i need only 100% accurate answer.
I have read several posts, some saying its 1.75" others 2.0" and even 2.25"

I want to buy a header for my b16 so i need to know what collector size should i get!

thx

 

bump!!!

 

should i be hopless!! no body got an idea!!

 

2.25

 

It all depends on where you measure it.

I have a '99 B16A2 Si motor in my ride. I blew out the stock cat, when I puked a distributor, a while back.

I just went out in the garage and measured it.

The flat flange that mounts to the collector is indeed 2.25", but that includes the area for the metal squish ring. The tube diameter is actually closer to 2".

The exit diameter (the side with the "donut" gasket) is tapered. Basically, it's 2", but the inside diameter of the pipe is about 1.75".

So, I guess all of those sizes are correct, depending on where you measure it.

 

woww, thats great details.. thanks man.
so mainly i should look for a headers with 2.25" collector.
Will a 2.5" work?

 

On a b16 I would go with 2" everything...2.25" at most

I had 2" on a stock sir2 b16 a while back and switched out to 2.5 and lost quite a bit of low end, which on a b16 you need the most of.