header cyl pairing gains?

[dichotomous]

this will be for an A3 with oldschool injen CAI, magnaflow catback, and no electronic tuning (yet). I want to replace the shorty header + stock cat with a raceheader since the current header is cracked and the cat wont survive swapping. I will be welding a high flow cat into the midpipe. My concern is will 1-2 3-4 pairing on a raceheader give me any noticable difference between 1-3 2-4 or 1-4 2-3 pairings? will either be smoother or have more lower end power or more midrange or without tuning is that going to be more determined by my midpipe diameter or the flow through the cat?

[talonXracer]

Alot of factors are figured into your question,,,Are you after torque, midrange, or top end power only or a combo?
Not only is cylinder pairing impostant but primary and secondary length need to be considered, as well as your type of HF cat and catback design and construction.
A Tri-Y design header with a 1-4,2-3 pairing, seems to be about the optimum for midrange-(minor topend), torque production.

[dichotomous]

Alot of factors are figured into your question,,,Are you after torque, midrange, or top end power only or a combo?
Not only is cylinder pairing impostant but primary and secondary length need to be considered, as well as your type of HF cat and catback design and construction.
A Tri-Y design header with a 1-4,2-3 pairing, seems to be about the optimum for midrange-(minor topend), torque production.

I'd like a smooth, heftier powerband all the way through, it would be nice to scream on top, but not at the expense of much power in the lower and midrange. I'd love to get really technical and design the build to what exactly I want, but mainly I just want it a bit better than now, with more midrange AND top end if possible. and the bigger thing is that I gotta do this with easily and cheeply available parts, the DCRH or JRRH or OBXRH or the Hytech RH, cant afford the BC or SSR deals. I know you have a SSR header and its tuned to how you want your engine, that'd be sweet but I was gonna try to stay under $500 for the header and HF cat.

basically, I just want it better in as many places in the RPM range as possible, while being relatively cheep and easy too.

your thoughts on HF cat options?

[talonXracer]

For a cat I would most assuredly use the Car-Sound platinum spun cat and use it exactly as I did with the SSR header, it will mean cutting the EP3 length midpipe to a DC5S length and rewelding the flange, any muffler shop can do that all at the same time rather cheaply, for most all headers except the JRrh. (and the hytech headers are about the same price as the SSR) I really liked the JRrh when I had it, I thought it provided the best range of gains over the DCrh, something useable around town all the time, midrange gains with some top end gains(just not as much as the DCrh though). IIRC with the JRrh you can use the stock EP3 length midpipe when adding a cat, like this,
http://i54.photobucket.com/albums/g96/talonxracer/IMG_0340.jpg

[dichotomous]

For a cat I would most assuredly use the Car-Sound platinum spun cat and use it exactly as I did with the SSR header, it will mean cutting the EP3 length midpipe to a DC5S length and rewelding the flange, any muffler shop can do that all at the same time rather cheaply, for most all headers except the JRrh. (and the hytech headers are about the same price as the SSR) I really liked the JRrh when I had it, I thought it provided the best range of gains over the DCrh, something useable around town all the time, midrange gains with some top end gains(just not as much as the DCrh though). IIRC with the JRrh you can use the stock EP3 length midpipe when adding a cat, like this,
http://i54.photobucket.com/albums/g96/talonxracer/IMG_0340.jpg

thanks for the fast reply, I saw a hytech on fleabay for less than the DC usually goes for, so that may be a scam.
I figured on cutting the midpipe, and adding the cat in there, my buddy has a mig welder so that wont be a problem, we were thinking originally of building a custom header from a stock header (cutting off the collector and having the first pairing there since 1-4 are on top and 2-3 are on the bottom, then figuring out the secondary length and diamters, adding a cat after the final collector) but I dont know that this would actually end up cheeper or better.

[v1c10us]

that would probably turn into a mess, im not doubting you or your friends skills, but although many parts on a car are the same durn thing and I see no point in paying extra for a namebrand cold air intake or SRI, because in my opinion they are just tubes, sure length can play a factor in low end vs high end but w/e.
but for a race header there is a good bit of R&D involved in them, even if its just once company and then everyone else copies them.
I'm pretty sure that diameters of piping have to be picked very specifically based on the length of piping as well as runner length and order so that you can have the exhaust pulses meet in an organized time. You dont want 2 pulses reaching the collecter at the exact same time because there wouldnt be enough room to push all the gas down the pipe, and some if it would have to go back up into other empty runners and would make more work for the motor to accelerate the reversed gasses.
So just buy one, as fun as making your own sounds you'll probably be dissapointed.

[dichotomous]

I was wondering about the definition of low-end, midrange and topend.....
cause these headers are all designed for use with most of the K series engines, and the A2 revs significantly higher than the A3, enough so that the top end of the A3 would likely still be midrange on the A2. so if a header is designed to fit and work with both engines, but tuned for top end flow for peak power, which engine's top end? cause flowing well at 8,000rpms is going to be very different than 6,000rpms.... on the A2 things dont really get interesting until about 6000rpms anyways (or at least last time I drove one it felt like this was a major change point, Vtech maybe?) and I consider my main area of wanting serious power to be between 4,500-6,500rpms, which is pretty much the midrange of an A2. so wouldnt I want a header designed to flow best for midrange, just to get top end out of my car?

[dichotomous]

this pipe from DC sports looks different than their typical very long tube sequential paired 421, it looks more like a JR but longer secondaries and a flex-pipe, good buy?
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=33631&viewitem=&item=110265510409

[talonXracer]

I think that DC did have a 4-2-1 tri-y header as well when they first started making Kseries headers, but it didnt sell very well.

[v1c10us]

low end mid range and top end is sorta in the eye of the beholder.
I've aways takin it as more of a throttle relationship.
I know that I can very gently touch the gas and get my car to redline over a period of time, just because im at redline though that doesnt make it top end.
a little throttle = low end
more throttle = mid range
wot = top end.
Of course rpms does come into effect, as well as things like compression(if im not mistaken a motor with higher compression would probably have faster exhaust gas) but I would try not to take into account the extra 1k rpms you could use with the a2, because you'll hardly be using them and thats not where you want your exhaust tuned for power