4-2-1 or 4-1 Header ??
- Thread starter SgtPecker876
- Start date
SgtPecker876
Member
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- Mazda Protege5
So the 4-1 OBX header would do fine for somewhat gains for the price of them? What I just read I kinda understand but not fully understand. All this stuff is new to me. All the replys has been great but I feel that I'm still in the dark.
Mad Hatter
Member
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- 02 Axiom, 02 MP5
SgtPecker876 said:
They're all about equal. Except the price. Understand? My suggestion, unless your loaded, is to go with the obx or ractive.
Installshield 2
Gothenburg Superiority
This is the only exception...From what I remember you don't really gain much of anything with that header...but it is the only header option we have the keeps you completely legal...00RedProtege said:
I should have clarified, all the long tube headers that eleviate the primary cat give more or less the same gains...this shorty does not, and it still keeps the stock downpipe...one main area where the brunt of the gains come from...
So...if you have to stay legal...keep the factory collector, or get the shorty...and get Wagners down-pipe married to a high flow secondary cat...that is still 100% legal (still except for CARB's under hood inspection bs though)...and you will get about 3/4's of a long tubes gains..mostly from the downpipe...
twilightprotege
Member
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- 2001 323 Astina SP20 (P5)
yeah isnt it illegal to change a cat unless it's older than x years?
luckily in oz....what's emissions testing? usually they heavily focus on the old heaps that chew up leaded petrol at 20L per mile (aka american trucks LOL)
luckily in oz....what's emissions testing? usually they heavily focus on the old heaps that chew up leaded petrol at 20L per mile (aka american trucks LOL)
Installshield 2
Gothenburg Superiority
its different in every damn county, state, etc. over here...For instance where my Dad lives they don't even do any type of emission related testing at all at yearly inspections...but where I live, which is one county away, they do...but only to the degree of checking your gas cap (and taking 40 bucks) to see if it is not air tight...And the inspection system works based on the county in which your title's address is located...mine being where I live, so I can't get a inspection done with a different counties procedure...The CARB agenda is filtering everywhere though...and if they start underhood inpsection bulls*** I will flop a nut straight big time...(meaning your car passes sniffer tests, but fails because your parts are not government tested...s*** will get ugly)...
twilightprotege
Member
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- 2001 323 Astina SP20 (P5)
i guess i'm quite lucky here emissions wise. australians have general embrased fuel efficienct 4cyl cars with a good 60% of cars sold being 4cyl (guess).
back to the topic, if you can afford it, a custom 4-1 is great, then well designed 4-2-1, then cheap 4-1 then cheap 4-2-1.
back to the topic, if you can afford it, a custom 4-1 is great, then well designed 4-2-1, then cheap 4-1 then cheap 4-2-1.
00RedProtege
Member
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- 00 Protege ES
Installshield I want to make sure I understand you correctly, buying the wagner headers will not gain anything because i will still have the cat and stock downpipe??? If this is the caes then why do they sell these types of headers???
00RedProtege
Member
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- 00 Protege ES
Ok. Now I understand. Thanks for the info Senor.
Maxx Mazda
Contributor
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- Stock P5
I've got a ractive 4-1 on my P5. (See sig for other performance mods) and I can vouch that it really does pull hard above 4000 RPM.
I'M ******* PISSED! I just spent 20 minutes responding to this thread, and then when I hit 'reply' it made me log in, and my response was gone.
Anyways, I disagree with everyone on this topic. A WELL DESIGNED 4-1 header will outperform ANY 4-2-1 design. A 4-2-1 only minimizes pumping losses, but a 4-1 header takes advantage of pressure waves to help pull in a fresh intake charge. It was to be 4 equal length primaries though, and they have to be stacked on each other, which limits ground clearance. Basically, no-one has made a proper header for the FS, since it needs 37-38" primaries and a 13" collector to work properly. I wish I had the will to rewrite what I had written before it got erased, but check out this site, and register. It's the single best resource for header design information anywhere...
http://www.headerdesign.com/index.asp
Read it, learn it and crunch some numbers, then we'll continue this conversation.....
Anyways, I disagree with everyone on this topic. A WELL DESIGNED 4-1 header will outperform ANY 4-2-1 design. A 4-2-1 only minimizes pumping losses, but a 4-1 header takes advantage of pressure waves to help pull in a fresh intake charge. It was to be 4 equal length primaries though, and they have to be stacked on each other, which limits ground clearance. Basically, no-one has made a proper header for the FS, since it needs 37-38" primaries and a 13" collector to work properly. I wish I had the will to rewrite what I had written before it got erased, but check out this site, and register. It's the single best resource for header design information anywhere...
http://www.headerdesign.com/index.asp
Read it, learn it and crunch some numbers, then we'll continue this conversation.....
twilightprotege
Member
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- 2001 323 Astina SP20 (P5)
i wondered when you'd make a comment 
FunkyBuddha
Tuned by Slick Nick
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- 2003 Spicy Orange MSP
As with Maxx Mazda..the ractive 4-1 actually fattened the tq/hp curve near the middle. Instead of having the powerband high up. There are a couple of dyno's of the ractive header in this section. Pulls hard after 4k rpm and all the way up to around 6500rpm.
hey, i don't know which one is better but since your only choices are OBX and Ractive, I would go with either but most especially OBX. I had the Ractive header and I had issues with it rubbing against my oilpan. Since everyone else here doesn't have that problem even on an automatic, I probably got a defective one. Don't expect a header to your car super fast, but expect a little pull in the upper rpms with the Ractive header. As for myself, I'm saving up for an OBX header because I like how the collector is positioned in the middle and not next to the oil pan like Ractive which left a dent! Hopefully Chris at SPD can hook it up..
Hey Toucci it's RektuM! How dem wheels?
Hey Toucci it's RektuM! How dem wheels?
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- 2002 BJFW, 2007 BK3P, 1979 SA22C, 2005 BK3P
i am running a group buy on the OBX header, click the link below
I installed the Ractive 4 to 1 and you can feel about a 10hp difference. Had to install a resonator because the car was way too freakin loud, sooo not cool! Feels like I lost about 5hp after resonator install, go figure. No cats though! Still a good hp boost in the mid to upper rpm. Sounds really freakin nice (deep) sound coupled with 2.25in exhaust and magnaflow muffler. I was expecting about 20hp gain but I was way wrong. Header alone won't do much, you should do cold air and possibly cams and then the little motor will breath way clearer. It's been a yr or 2 since install and car is thoroughly broken in with about 4k in performance mods(N/A and A/T) and my p5 is running so friggin sweet right now it's just awesome. No strange noises or sensors, a little hard on gas but I'm hard on the pedal. Gotta make sure no carbon build-up,he-he. I think the header's a good buy for the buck, just don't expect monstrous gains from any one bolt on. N/A 4ever! Later.
