RK Sport header question

[SkyHawk]

Hopefully somebody can help me here. I've got the RK Sport headers. Now, at the Y-Pipe its 2 1/2 but then bottles out to 3 inches. My Catco is 2 1/2 in and out. My problem is on the Y-Pipe the O2 senser is right on the 3" part that I would need to cut off to make it 2 1/2 all the way through. I would have went 3" but I already have a 2 1/2 borla muffler. My question is what would be the easiest way to go from my Y-Pipe to my Converter? Put a reducer on, is that going to build that much back pressure? Cut the pipe and add a piece and weld the nut back into to the 2 1/2 for the O2 sensor? Any of you have this problem with yours? I just wanted to see what your opinuons were on this.

[12secondv6]

I have the rk sport headers
I had the flanges cut off on the y pipe
I have a slightly larger diameter 6 inch pie per side extending down from the header flanges
It then reduces to 2.5 inch y pipe
Where the left and right side join it goes into a 3 inch section for maybe 6 inches long max.
It then reduces back to 2.5 inch
Then my 2.5 inch catco cat
Then 2.5 inch s pipe
Then 3 inch edlebrock cat back
Then 3 inch dump tube
Then edlebrock muffler
Then dual 2.5 pipes

Why have these small sections with larger diameter then reducing to smaller ones??

To improve the scavenging effect for more hp and tq gains
Flowtech makes headers like this.

I say keep the 3 inch section and just have the O2 sensor go in the pipe in that area

[Dan M]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
I have the rk sport headers
I had the flanges cut off on the y pipe
I have a slightly larger diameter 6 inch pie per side extending down from the header flanges
<hr></blockquote>

slightly larger diameter 6 inch pipe per side??

Clarify, please?

[SkyHawk]

<blockquote>quote:</font><hr>Originally posted by 12secondv6:
I have the rk sport headers
I had the flanges cut off on the y pipe
I have a slightly larger diameter 6 inch pie per side extending down from the header flanges
It then reduces to 2.5 inch y pipe
Where the left and right side join it goes into a 3 inch section for maybe 6 inches long max.
It then reduces back to 2.5 inch
Then my 2.5 inch catco cat
Then 2.5 inch s pipe
Then 3 inch edlebrock cat back
Then 3 inch dump tube
Then edlebrock muffler
Then dual 2.5 pipes

Why have these small sections with larger diameter then reducing to smaller ones??

To improve the scavenging effect for more hp and tq gains
Flowtech makes headers like this.

I say keep the 3 inch section and just have the O2 sensor go in the pipe in that area<hr></blockquote>


I keep hearing different opinions. I hear its not good to go 2.5 with the cat then 3 with the pipe to the muffler, then back to 2.5 with muffler. Won't that build back pressure? Wouldn't it be better for me to just run 2.5 all the way through. I one of the beta testers for Bill's kit so I'm trying to figure this out before the kit comes out. Any opinions?

[12secondv6]

<blockquote>quote:</font><hr>Originally posted by DrSquirts:


slightly larger diameter 6 inch pipe per side??

Clarify, please?<hr></blockquote>

Hee hee, 6 inch long section slightly bigger diameter piping than the header diamter [img]smile.gif[/img]

Well, for my application it seems to work.
I'm trying to improve the scavenging effect throughout my whole exhaust to improve hp

My et's and dyno numbers seem to show that this is working quite well
Also fuel economy also

[Dan M]

Whew, ok that's better... 6 inch exhaust, damn.

[12secondv6]

<blockquote>quote:</font><hr>Originally posted by DrSquirts:
Whew, ok that's better... 6 inch exhaust, damn.<hr></blockquote>

[img]graemlins/rofl.gif[/img]