HOW TO: Mazda 626 Headers on 2.0 Protege

HKPRO5

Member
:
Supercharged Protege5
How To: Install 626 Headers on 2.0 Protg

***I am not responsible for any damage you may do to your car, this is only a guide***

photo27-1.jpg


There are a few things that need to be done for this to work. Now there are a few ways to do this, but this is they way that I did it. The only thing I don’t have is how to hook it up the stock piping. They way I did it was weld a pipe to a v-band flange that continued on with the rest of the exhaust. No cat was added. for now =)

You will also have to flip the hangers to face the other direction. If not that piece will not be supported.


6/10/11 UPDATE.
Ok So I had to put in two o2 bungs as the locations on the header were way off.

As for the down side pipe, ill be using a Honda Accord (1995) header gasket. I will have to bore out the bolt holes. Other than that it should fit well.

(dont mind the air filter...lol)
photo3-12.jpg


As for the EGR i ended up capping the side on the header, and adding a breather filter on to the intake side.
photo5-6.jpg


Parts,
1. 93-97 Mazda 626 2.0 long tube header.
2. Gaskets
a. Head to Manifold
b. Manifold Top to Manifold Bottom
c. Header Outlet to Test Pipe
3. High Temp Gasket Sealer (I just used it just in case)
4. o2 Sensor Plug & Bung
5. ***Optional*** for easier EGR fitting ” NPT CAP & Breather Filter
6. 36” Corrugated Gas line (size specs in Pic)
a.1/2NPT Adapters (comes with kit)
photo25-1.jpg




Before you start ripping the car apart. There are a few things that you will need to do.
1. Find placement of the 2nd o2 sensor bung and weld it in.
2. Get the measurements and build the mid pipe


1. Im not going to go through taking off the old manifold and the cat. Do that first. Ensure that the piping is not hot. Remove the o2 sensors, putting them in a safe location for the duration of install.

2. If you are going to be using the EGR, take off the EGR line at the intake manifold. Install Corrugated Gas line.
B. This is the route that I went I used a breather filter on the EGR line. The fitting
On the manifold was capped using a ” NPT cap.

3. Install upper manifold first. Use this for the manifold torque spec.
http://www.mazdas247.com/forum/show...orque-specs&highlight=exhaust+manifold+torque

4. Install lower half. Start with the test pipe and then with the hangers. Work your way to the upper manifold. Install gasket and 3 bolts/Nuts.
5. Install o2 sensors, you may need to use a Spark Plug Non Fouler for the 2nd O2 sensor.
 
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AzteCypher

black ops modifications..
:
2001 Mazda Protege LX
Excuse my ignorance but what is the advantage of using a 4-2-1 header design versus a 4-1 design? From what I've read 4-2-1 allows for better gains down low versus gains up high for the 4-1. Is this correct?
 

HKPRO5

Member
:
Supercharged Protege5
From what I understand is that the 4-1 makes more top end power and the 4-2-1 makes more bottom end and mid range power
 

HKPRO5

Member
:
Supercharged Protege5
Ok I found a replacement gasket for the up headers and downpipe. I went with a header gasket for a 1995 Honda Accord. Bolt holes have to be bored out on the gasket though.
 

njaremka

Wiggity-Wack-O-Tack
Contributor
:
2012 Mini R55
very cool! i wanted to try this on my car way back before all the protege headers were available, but never got to it. i have a ractive ont he car now.

what exhaust are you running behind it? how's the sound through that thing? how does the power band feel?
 

HKPRO5

Member
:
Supercharged Protege5
Custom 2.5" exhaust. with a resonator and N1 exhaust. (3.5" outlet)

Sounds pretty mean, esp with the supercharger.
 
:
2002 323 Protege
From what I understand is that the 4-1 makes more top end power and the 4-2-1 makes more bottom end and mid range power

4-2-1 headers produce less of a peak gain, but the power is spread over a wider rpm range. Though given the exhausts available the 4-2-1 headers available (maxim, autoexe) will out shine all the 4-1 headers ive seen so far, merely cause of the design of the 4-1 headers on the market. The ebay 4-1 headers and the OBX header have primaries that are much to short and the collector isnt great either (IIRC they are tuned for an rpm range of about 10k rpm) they do however have a better design then stock hence the performance gain :).

Those of us with a FP engine would notice little in teh way of performance increase with the OBX or ebay header due to the better manifold used on the FP :)
 

AzteCypher

black ops modifications..
:
2001 Mazda Protege LX
Question for you guys. I installed my header on my 1.6 about a month or 2 ago. I removed the EGR tube and capped both ends (header has a plug and the block has a plate I cut up and bolted on. Now I'm getting a check engine light with a P0401 code. This code indicates insufficient EGR flow. Me question to you is this. Should I remove the plate that blocks where the EGR tube used to connect to the block or is it just that my EGR valve needs cleaning. I see that a breather filter was used on the EGR valve in the pics up top hence why I'm asking. Thanks!
 

AzteCypher

black ops modifications..
:
2001 Mazda Protege LX
Alright, gotta see if I can find it because I think I got rid of it. Silly me.