I just recieved my DC Sports header header and measured the outside diameter of the pipe and it's 2".
Now I'm wondering why are cat back systems 2.25 and 2.5 inches usually? Or is it just the other headers
like pacesetter and such have 2.25" at the pipe connecting to the cat? With the DC sports header am I better
with staying 2" all the way back to the muffler? I planned on making a custom stainless cat back with 2.25" pipe but
now it seems pointless to go from 2" back up to 2.25. I'm staying N/A with no plan on changing that.
Thanks for any help on this.
How long did it take to get the header. And where did you purchase it?
I wanted to get another one.
About the piping,
DC Sports's research concluded that the 2" piping was better over the power band for the system.
Or something to that effect.
But I didn't think the outside diam was 2".
If it is, that just means it would match up to the factory system better as factory outside diameter is 2".
As for catbacks out there,
Those sizes are also O.D. sizes.
So a 2.25 would be like 2.125 and a 2.5 would be a 2.37 or so.
You can still do the 2.25 all the way back.
Thats what I'm doing.
Just takes a little more work.
-M
Remember....syringes go in the RED waste basket.
Dang,
Thats about the lowest price Ive seen recently on that.
Keeping it 2" all the way back means you wouldn't have to touch anything really.
Going 2" OD mandrel is just a pretty verision of the stock piping anyway.
I mean, unless these mandrel bends your finding are like $5 a piece or something, save the money.
If youre getting your exhaust done at a shop, the pipe size should be irrelavant.
So you're better off with 2.25 or whatever.
Otherwise, at 2" OD is just stock.
-M
Remember....syringes go in the RED waste basket.
I wanted to go with the GM SC and also use the DcSports header, but I figured it was 2.5" in diameter...this 2" shocks me. Should I still get the Dc header if I play to use the GM SC?
I thought that the stock piping was more like 1-5/8" piping...? and if you can get mandrel bends cheap, I don't see any reason to go bigger than 2", but the compression bends are usually cheaper, but you lose a little flow with them, so maybe go 2.25" or more. just don't get the crinkle bends (or w/e those are called, maybe crimped?)
btw, is that the header for the LD9 or ECO?
The reason the end of the pipe measures at 2" is so that you can bolt it up to the stock catback. If you get any premade catback exhaust, it will narrow down to 2" at the flange that's meant to bolt up to the cat. Any of them. Magnaflow, RK Sport, Megan, Thermal, Vibrant, I don't care which one, they all narrow down to that diameter at the cat flange so that it will bolt to the stock cat. They're not made with the header/high flow cat mods in mind, they're made to bolt to a stock manifold/cat combo. And the headers either expect you to cut the stock cat off and have it welded to the supplied partial downpipe, or have your own piece welded in.
What you have to do is custom work. I believe since you're saying the pipe is 2", you're talking about the pipe they supply with the header to eliminate the cat. Before that pipe, I imagine it's larger than 2" (try measuring right after the collector). You will have to have custom piping cut and welded on the header downpipe (including or not including a cat, up to you), and then have the correct diameter welded to the catback as well. If you're going with a custom catback, basically they could weld everything from the header all the way back to the muffler together with whatever size you want, although I'd suggest at least one flange somewhere to help allow the system to flex slightly.
My suggestion would be...
DC Sports header, welded to
2.25" high flow cat with a 2.25" flange
2.25" flange welded to 2.25" resonator (longer the better), welded to
2.25" piping back to a 2.25" inlet muffler
Doing it right is gonna cost you a few bucks, but that's what other people have done here, and what you've got to do to actually have the least restrictions possible.
The magnaflow dual exhaust from Rksport definitly isn't 2" on the catalytic end though
Lance Sharpe wrote:The magnaflow dual exhaust from Rksport definitly isn't 2" on the catalytic end though
Can't imagine what other size it would be. How else would it bolt up?
I'm pretty sure it was all 2.5" If it helps to clarify, I used a Pacesetter 4-1 header, direct fit magnaflow cat and the rksport catback. This was on a 96 2.2. It all bolted right up.
A direct fit Magnaflow cat would be the stock size - i.e. direct fit, unless I'm mistaken. So it would just bolt right up, everything would - but in your case what you have is larger than stock collector on the header to a stock size cat, to a larger than stock catback...but the cat is a bottle neck, being stock size. Why would a company make a catback exhaust with a flange to connect to the cat, and NOT have it be the stock size? Can you imagine people buying the exhaust just to find that it doesn't bolt up to their car, meaning they either have to have the flange cut off and a smaller one put on, or a new cat put on? That's what people end up doing quite often when they get a full exhaust but for someone just going out and buying a catback and bolting it up to their car, they'd be awfully pissed if it didn't just simply bolt on.
I dunno, people go around and around about exhaust stuff and even sometimes with pics of something, they'll still debate it. I don't have any pics (yet) of anything myself to prove these points but later this summer I should, as I'm planning full exhaust for my '98 2.4. But back when I bought my (now ex) wife the Megan catback, I measured the piping at the muffler, at the place where the saddle clamp goes, and at the cat connection. It was 2.5" outer diameter all places except the very end where the cat connected - there it was 2." (Some people still tried to claim it wasn't 2.5" even after the pics showing it was.) All other catbacks I've seen for any other cars do the same sort of thing.
as long as the flange bolts and stuff line up, the pipes wouldn't necessarily have to be the same size, except with particular types of flanges that allow the exhaust to flex (not a flex joint, that's different). on my '99 Z24, the stock header and cat are one piece (the cat's separate from the collector, but there's no joints or flanges) after the cat is a flange between that piece and the resonator and the rest of the exhaust. if that flange had a 2" to 2-1/4" pipe bolted up to it, it could fit, assuming the bolt holes match up between the flanges. you'd just go from stock size to an inch or more bigger with no transition
