JDM FSZE Sport20 AWD 4-2-1 headers on USDM FSDE

dorkidori_s13

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2003 Mazda Protege5
Does anyone know if the Sport20 AWD 4-2-1 headers have any fitment issues on the USDM FSDE? I have the opportunity to pick up a REALLY nice set of MaximWork 4-2-1 headers, but it looks like the area that connects to the secondary cat section is longer than the USDM header in that area. Anyone out there have any experience with JDM FSZE headers?

Also, I currently have an OBX header sitting at work that needs jet coating and Ive been reading that the 4-1 headers give peak HP gains in the higher RPMs... does any know exactly what RPM range the 4-1 headers affect vs 4-2-1 headers?
 
Not really sure on the first question but I've read a couple times the OBX headers help around the 4-4.5k
 
My eBay 4-1 headers love to play at 3800 and up. Hard to describe but feels mushy in lower rpm range. I find myself punching it more often than not. In my experience they feel similar to a gutted cat, with more effect. Going to try the eBay 421 626 header next as it is ment to smooth out this low rpm effect. There was a howto some where here.

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I have done lightened underdrive crank pulley as well as wp/ps/alt lightened pulleys to counteract the low rpm torque loss. I don't feel I have any difference in torque from doing hdr. Car is sport auto and figured it'd be more pronounced in auto vs manual. The P&P intake manifold with VTCS removed could have slight effect on this too I suppose. Point being car never felt any worse at low rpm with hdr than it did before doing hdr. Still have hi-flo cat in midpipe too, along with flex fitting and 2.25" pipe.
 
Well my P5 has an MP3 tuned ECU so the VTCS is never initialized (butterflys stay open). I am planning on swapping over an MP3 intake manifold I have sitting next to me here at work once I get it powder coated (just because I can). I think I may just keep the OBX header option I have as I dont want to spend $350 on that FSZE header at the moment then have to have the secondary cat piping rewelded due to the lower j-pipe area being longer on the ZE header. If the OBX header basically frees up power from 3500 to redline, Ill be happy with that as I have an FSZE intake cam and Corksport exhaust cam sitting in my garage waiting to be installed which will perform well with the higher RPM area flowing a bit better. Also planning on having some custom piping done under the car with a full 2.5" setup all the way back to the OBX axle back with a 2.5" hi-flow Catco cat welded in.
 
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I was thrilled with my "obx style" header. Bolted directly to the stock mid. Even wasn't a struggle to mate the EGR. The fit is tight next to my oil pan ( stock) didn't see if you have an awr pan in your build thread might have fitment issue if so.

I have to admit to being some what jelly of your cams ( been looking for awhile) . I would say go for it! love to hear what you think of them

Had a similar set up fab'ed for mid to cat back, haven't installed as requires dropping rear cross member to slid in and I am being a wussy.

One word of warning re: headers. Police notice them, I have been pulled over for achieving the limit rapidly, no ticket ever issued and the reason given every time was "you wanted my attention, you got my attention".
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sound from an exhaust has a lot to do with what type of muffler you run. your straight N1 style exhaust is a fairly loud exhaust to begin with. i ran N1 style exhausts on my S13s for the past 15 odd years, theyre ALWAYS loud. i switched to an HKS sport exhaust which has an oval style muffler, and the sound dropped considerably (very little drone in the cab as well). im running an OBX oval style axle back on the P5 and its actually very tolerable.

also, keep in mind i live in las vegas... police here are very lax when it comes to anything but Hondas or insanely loud V8s. My OBX axleback is super low key as it is, so im really not counting on having any issues with the cops or exhaust noise.
 
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My full OBX hdr/Magnaflow hi-flo cat/resonator/Magnaflow race series oval muffler with full 2.25" piping has a very low frequency that sets off all alarms in parking garages yet has no drone on hwy and also doesn't attract unwanted attention unless higher up in rpms. As long as I grandpa it around (like it needs to be at it's age) it isn't hardly any louder than stock............OK, delusion passed but not so much louder than stock that it gets noticed by anyone wielding a tkt book.
 
Oh okay, wasn't aware the oval can helped. I have learned some thing. There is one for sale ( racing beat) locally, I will try that out ( along with the 'grampa' tip) might stay just under the radar. Does a dual or split muffler tip help or just look rice?
 
oval vs round didn't make difference on mine, had both. Oval will hide better and not hit curb if backing in somewhere. Oval tip or multi tip may or may not fit in bumper cutout without trimming or muffler hanging lower to clear bumper.
 
oval vs round didn't make difference on mine, had both. Oval will hide better and not hit curb if backing in somewhere. Oval tip or multi tip may or may not fit in bumper cutout without trimming or muffler hanging lower to clear bumper.

talking about this (exact catback i have on my S13)...

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versus this...

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There is a HUGE difference in sound that comes from the exhaust in traditional style high flow mufflers vs N1 style straight thru designs.
 
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