I just received my Warpspeed b-pipe this afternoon, which I ordered Monday. The pipe itself looks good, however as soon as I opened the box I noticed the diameter of the pipe looked rather small. I measured it and sure enough the inside diameter of the pipe is exactly 2". I know on their web site they say: "WarpSpeed Performance mandrel bent "B Pipes" are the same 2.25" or 2.5" diameter throughout". Which lead me to believe I had received the wrong size pipe. I called Warpspeed and spoke to Dallas, who told me when they give pipe sizes they are giving the outside diameter, not the inside diameter. I also have a Warpspeed y-pipe + straight pipe (both of which have an inside diameter of 2.5") Now, I have the following questions:

(1) For those who own a Warpspeed b-pipe, is the inside pipe diameter 2" as well?

(2) What is the inside diameter of Stillens' (or any other after market company) b-pipe?

(3) Is a 2" inside diameter sufficient for the Maxima? Or should I return it in exchange for one with a 2.5" inside diameter?

This is NOT a complaint by any means, I am just seeking advice. I have included 3 pictures of the Warpspeed b-pipe just for reference.

I've always heard that its best to have the same diameter all the way through. However I can't confirm this, its what I've heard.

I have a budget B-Pipe its 2 1/2" T-304.

I don't think I would settle for a 2" especially if you are going to do any power mods and want best performance.

That's what I was thinking, I guess I just needed to hear it from someone else. I'll call Warpspeed tomorrow and see if they can make me one with a 2.5" inside diameter, if not I'll buy else where, but I'd prefer to stick with Warpspeed. Thanks Jim.

Umm, that's a 2.25" b-pipe, the standard size everyone makes. The Stillen and Courtesy are both 2.25" pipes. There isn't really a huge need for a 2.5" b-pipe simply because the stock muffler inlet is only slightly over 2", too large of a step at any junction creates turbulence and unwanted backpressure downstream.

Second look at your tape, it is a 2 1/4" not 2" as guido_sst indicates.
He is also right about the stock muffler being just over 2" as well.
However, the outlet of most Y-Pipes is 2 1/2 as well as the inlet and outlet of the stock cat.
Thats why I wanted 2 1/2 all the way back. I removed the inlet from my 2k1 muffler and had it expanded to 2 1/2 so all was the same size from front to back. I will eventually install a 2 1/2 muffler as well or at least try one out.

Well I the difference of that space may be a large one. but in its location behind the Cat Converter I don't think it's going to create a huge difference between the 2 sizes. The important thing has been removed from the stock B pipe that crimp.

he's talking about inside diameter not the diameter of the whole pipe

Yes you're right, I was talking about the inside diameter of the pipe. I am also aware that the total pipe diameter is 2.25". I've searched and gotten conflicting results, but have come to the conclusion that both the Stillen + Courtesy b-pipe is a 2.25" diameter. Can anyone confirm if this is the inside diameter or total pipe diameter?

I just happen to have a Stillen B-pipe in the trunk of my car. I went out and measured its inner diameter just now, and it comes out to just over 2 1/16" where I measured it (at the cat end flange). This would give a nominal 2.25" outer diameter for a pipe with a wall thickness of around 3/32".

Great that's exactly what I wanted to hear! For some reason I was under the impression that the Stillen and Courtesy b-pipes had a 2.5" inside diameter, I don't know where I got that from. Thank you very much, you saved me from a major headache.

Glad to be of help! The reason my b-pipe is in my trunk is because along with a y-pipe, test pipe and a HKS muffler, it's just too loud for me, so I put the stock b-pipe with resonator back on. Now it's just right! So I'm interested in how loud your Warpspeed b-pipe is compared to the stock b-pipe.

WTF, I ordered mine over two weeks ago

Someone tell me if I did this correctly, because I'm having MAJOR fittment issues. I loosely attached the whole thing to the car, front back and crush joint(fully comressed). Then I attached the muffler and then cat converter then raised the center to insure proper height from the cross memeber. Tightend EVERY thing down, I ever replaced all of my rubber exhuast hangers. My tail pipe point pretty far to the center of the car, it almost rubs on my RSB. and i still have that ziiiing noise at high RPMS. I'm really loosing patience with this. Please help.

Exhaust tubing is measured and sized from the outside diameter while actual pipe (schedule 40 or schedule 80) is measured from the inside diameter. Typical exhaust tubing thickness is .063" so you actually lose .125" or so on any diameter tubing. The stock tubing is 2".

We are currently offering the B pipes for the gen 4 and 5 in 2-1/4", we are bending 2-1/2" this week for the gen 4 and have a batch of 2-1/2" we are fitting for the gen 5 this week. We have (mandrel bent of course) bent some 3" for the gen 4's this last week and will be fitting them later this week, most will be matched up with our 3" Y pipes and our new 3" metallic substrate converters.

Our experience has shown the 2-1/4" do better on the automatics, same goes for the gen 3's.


Anachronism: you may have received yours by now but not sure what your name is. You can email us and we'll check on it.

regards
Dallas