new headers vs. muffler

[auspex]

all righty, i'm looking at purchasing either a new muffler w/new fast cat or headers and a new fast cat.

I'm looking at replacing the furthest down the exhaust cat with the Magnaflow Highspun 2.25 cat. But to my question....

As far as headers, I'm leaning towards the OBX Equallenghts. I keep hearing they don't sound as good as the Borlas, but they perform bettter. I'm leaning for bang/buck performance, so the OBX are really looking nice. Anyone had BAD experience with these?

It's either that, or a new prodrive muffler. I've heard good things, it isn't outrageously priced, and seems a bit unique.

If you had to choose 1 or the other...which and why? I'm not sure which stock item is the greater restricter.

THanks for reading.

mike


ps. either way, i plan to get the other in the up coming months. I'd also like to replace my midpipe and most of the cats....essentially just leaving the mag high flwo....any suggestions?

[Plays_with_Toys]

So you have stock piping right now? Doing headers and a high flow cat would be a detriment if you kept your smaller stock piping behind that. The exhaust would go from high flow to restriction, so incoming exhaust gasses would hit a brick wall of other slowed down exhaust gases.

Its best to treat the entire exhaust as a huge drinking straw. Free it all up.

So, I would start with cat, midpipe, and axleback. Then the next upgrade would be headers. OBX get rid of most of the sound I've heard, however, there still remains some burble because of the firing order of the motor, and the performance gains are supposed to be more substantial and worth the loss in sound and the extra price over the borla knock off OBX headers.

[ten80]

OBX headers + magnaflow spun cat + resonator + prodrive muffler = sexy ducatti sound :grin:

I love my combo, except my headers have a rattle in the merge collector. Some have this problem and some don't.

[auspex]

exact answer i was looking for.

the bottleneck issue made sense, just wasn't sure how MUCH of an issue it would be.

To further this question..

I plan to con't to upgrade, so would 2.5" piping be the way to go? Or, if it is, and I DON'T go turbo or whatever, would I be hurting my performance?

the plan as of now is 2.25", is that going to be suffice?

Even in the future I don't plan on putting out huge #'s. Maybe a small turbo, some EM, and support mods......maybe even a 22t or 20t.

thanks

mike

[ten80]

2.25" is ideal for all but the most modded N/A cars. You won't be able to go turbo with the obx headers, but you could use wrx headers, up pipe, and down pipe and have your cat pipe slightly modified to meet up with the down pipe. In that case, I would do 2.5" piping, however, you must assess the REALISTIC posibility of actually going turbo. Most people talk about it, find out that it's a PITA on an N/A car, and give up.

[Huffer]

Even 2.25" piping will work for a time with a turbo'ed car - it's actually a tad bigger than stock pipe on the 02/03 WRX I think.

Most people with 2.0L engines that are boosted (think classic GC STis) stick with 3" diameter exhausts. Any bigger and they lose torque.

[Plays_with_Toys]

I've read that 2.5" loses low end torque, but gains better flow above 4k RPMs. So depending on where your driving range is, dictates which way to go. As a daily driver, you'll be at lower RPM's alot cruising, passing, etc... If you autocross alot, you might be keeping it in a lower gear, so you might be at 4-5k RPM's for a big chunk of the course, which would have better results with 2.5"

[auspex]

again, good answers...haha

as ten80 mentioned, i really have no clue when i'd turbo the car. this small wave of mods may be all i'm capable of doing for a while ( i've got twins on the way!!!! yeah!!!) so i'll probably stick with the NA for quite a while, and thus the 2.25 should be great.

thanks for the help.

mike

[Wiscon_Mark]

For exhaust flow's sake, I'd go with the muffler first.

[Huffer]

^^ nah, I'd start with the header. the major gain with the header is the change in flow direction, and merge collection.

[rougeben83]

My original route was catback first, then headers. Mostly because I waited to get a good deal on the headers, while the catback was just done locally.

I did 2.5" too, going to a STi muffler. TBH, unless you know you're driving one or the other, you won't notice the small difference in exhaust diameter in daily driving situations. What matters more in how you maximize exhaust velocity (which is really what people refer to as "backpressure") is what muffler and resonator you choose. The design of the resonator (louvered vs. straight) and the muffler (straight-thru, chambered, glasspack, etc.) will play a bigger factor in how well you exhaust will give you performance gains.

Either diameter, the engine will noticeably rev faster and be more willing to get to the sweet spot in the power curve (3-4.5k).

I have a big 18-20" resonator with my catback, which will be replaced with a straight pipe when the turbo goes on my car this winter.

[cbroo]

:)

[cbroo]

So you have stock piping right now? Doing headers and a high flow cat would be a detriment if you kept your smaller stock piping behind that. The exhaust would go from high flow to restriction, so incoming exhaust gasses would hit a brick wall of other slowed down exhaust gases.

Its best to treat the entire exhaust as a huge drinking straw. Free it all up.

So, I would start with cat, midpipe, and axleback. Then the next upgrade would be headers. OBX get rid of most of the sound I've heard, however, there still remains some burble because of the firing order of the motor, and the performance gains are supposed to be more substantial and worth the loss in sound and the extra price over the borla knock off OBX headers. What about runnin high flow cats, I've noticed a huge difference switchen out my cats. but, with a new cam. you can greatly feel an hear some sound increase with a little pick-up, I've experienced first hand, go AVO if they make the older gens.

[Reason]

If I could do it again I would do my header first, high flow cat the muffler. I only did it a diffrent was depending on the deal at the time. If you see a muffler at a really good price go for it. Same thing with the cats or header. You have the money and you can score it cheap just go with the deal. If anything thats how I did it with any of my parts.

[LunchBox04V]

I agree with the guys that are saying start from the muffler and move foward. I am running 2.25" from the second cat, back through a magnaflow. Sounds good, and was a nice boost in responsivness, lots of fun!

Here is my question though, besides Borla, does anyone else make a header for the single port EJ22? The last time I checked on the Borla site they wanted something like $650! Also, how does it proform and hold up over time?

[Wiscon_Mark]

The Borla pretty much sucks, and you don't have any other choice, to put it succinctly.

[ten80]

www.rs25.com (http://www.rs25.com) is the best place to find the single-port headers and they sometime pop up on ebay for $250-300ish. You can also have one built relatively inexpensively since the single-port design is stupid-simple!

[Reason]

Starting from the muffler back is ass backwards.

[Wiscon_Mark]

Not it's not. Starting from the front is adding more restriction because you open it up and then choke it all over again.

[rougeben83]

I agree with the guys that are saying start from the muffler and move foward. I am running 2.25" from the second cat, back through a magnaflow. Sounds good, and was a nice boost in responsivness, lots of fun!

Here is my question though, besides Borla, does anyone else make a header for the single port EJ22? The last time I checked on the Borla site they wanted something like $650! Also, how does it proform and hold up over time?

There's a singleport borla header on RS25 right now. Check it out in the N/A parts classifieds. He wants $250 shipped for it (you may offer a little less, best part about dealing privately).



I did what a lot of other guys did, I started which whatever I could get done better/cheaper/etc. and worked on the other parts until I got a deal.

The overall goal is a full exhaust right? There really isn't anything bad about running one or the other first, as long as in the end you have all the parts there.

BTW, I've gotten four headers since I got the subaru :wink:- real borla headers $180 (sold that later), new knockoff borlas $130 (on the car now), another set of borla headers (came with my turbo kit, sold that), and TWE equal length headers $150 (being ceramic coated at the moment).

Take home lesson is that if you wait for the right opportunity, you can get GREAT deals on exhaust component, worse case scenario is you pay retail - and that always sucks :twisted:

[Perdue]

I had a terrible time with my Borla Header. Thin metal, weak welds. After taking it off twice (once to have the collector rewelded to the primarys correctly, and again to have a crack in the stainless fixed), I finally took it off for good, because it started leaking between the primary tubes and their flanges that seat against the heads. I wouldn't pay $10 for another one of those headers, much less 650.

Ninja Edit: Just to be clear, this was a single port header.

[Plays_with_Toys]

I wonder if single or dual port heads flow better. If dual port flows better, then it might be cheapest and best in the long run to swap heads and then get the borla knock off headers.

Perdue, where'd you get a knock off single port header? I thought the knock offs were all dual port.

[Reason]

I'm happy with my dual port Borla knock offs.

[Wiscon_Mark]

Perdue, where'd you get a knock off single port header? I thought the knock offs were all dual port.

He didn't have knockoffs. He got the actual Borlas.

[rougeben83]

[quote="Plays_with_Toys":2p5ti1yn]Perdue, where'd you get a knock off single port header? I thought the knock offs were all dual port.

He didn't have knockoffs. He got the actual Borlas.[/quote:2p5ti1yn]

Yeah, there's actually a couple of them being sold on NASIOC right now if you're willing to reweld...It's like 1/3rd of the price, of course I would put that towards having someone just weld the crap out of all the seams and joints on the borla


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