Header Nostrils

[Wannbe]

Thanks to Bob, I have a new to me Stock Header. My plan is to create a new header that looks stock, but with 2" tubes. My question is, the header has these v grooves in the middle for some reason.

Are these for strength?
Do these carry into the head?
Would there be any benefit to taking a pencil grinder and removing them from the header and head?

I'm trying to have a good plan in place when I start this because weather here is unpredictable and would not want to miss an opportunity to ride. I'm also including a picture, so some of you guru's here can give your valued opinion.

 

[HansO]

Well ...... For what it is worth, all the custom headers makers don't bother putting them in and I have seen 4 different ones, so I would see no reason that you need to keep them

 

[martym52]

Thanks to Bob, I have a new to me Stock Header. My plan is to create a new header that looks stock, but with 2" tubes. My question is, the header has these v grooves in the middle for some reason.
Are these for strength?
Do these carry into the head?
Would there be any benefit to taking a pencil grinder and removing them from the header and head?

I'm trying to have a good plan in place when I start this because weather here is unpredictable and would not want to miss an opportunity to ride. I'm also including a picture, so some of you guru's here can give your valued opinion.

That is because Rocket motors have twelve valves, the exhaust ports are Siamesed so the inlet to the header is configured to that. Maybe someone can enlighten us more on that subject.

 

[Trirocket3]

LEAVE them in the head, clean up only or risk messing flow up.

I left them out of my 2" headers.

 

[Mittzy]

Rebands are made with them in place. Lushy has told me they are there for a reason.
Pic of Reband flange.

 

[Idaho Red Rocket 3]

I agree. If they are there leave them. Triumph did a lot of research on intake and exhuast flow. If they didn't serve a valuable purpose they would not be there.

 

[TOMCAT]

I have a set of Lushy's custom flanges and run a Reband system .. both have them.

 

[Wannbe]

Idaho, if triumph did their research we would not be trying to rid ourselves of these headers. We could change exhaust and be good to go.

 

[1olbull]

This is interesting.
They look to me to be restrictive.
Anyone know why, or how they would help?
Do the CES have these?

 

[martym52]

Port velocity is key in producing low end grunt (torque) four valve configuration gives better low end port velocity with increased volume. At higher R.P.M.'s the volume is present for continued volumetric efficiency. The exhaust port design appears to be a method to maintain velocity for better cylinder scavenging at all engine speeds. With a supercharger scavenging is less relevant as in TriRockets case, forced induction cures many power-exhaust problems.