HOW TO: Mazda 626 Headers on 2.0 Protege

[codex]

I think he's talking about a gasket that can be used to go between the 2 halves of the header, where it goes from 4-2.

 

[Kreepaevox]

Subbed, how about this header?

93-97 FORD PROBE/MAZDA MX6 MYSTERE 2.0 4CYL FS-DE.... is it the same as the 626 one? I'm tired of the toy look of the 4-1. Will this fit our Proteges? As it is for FS-DE, but I'm worried about fitment issues... at least in the header part, the actual catback I'm gonna do a custom exhaust anyway and finish it wit a Racing beat muffler... what can I say, I like the sound

 

[Installshield 2]

I know some of this is over a year old, but it still applies...

The FS was in a bunch of different cars with completely different exhaust systems...and because of that, comparisons between 4-1 header systems to 4-2-1 systems are meaningless, as there are other variables to consider.

The stock protege exhaust system has a very long mid-pipe, and because of that, most aftermarket headers are relatively short....but some FS equipped Mazda's had much shorter mid-pipes (the 626 for example, compare the first page header pics to that of a protege header...you'll see what i mean)...The way a header couples definitely does make a difference in where it helps VE, but in general...as 4-1 is usually better for high end, where a 4-2-1 is considerably better at mid-range...if everything else is equal...

and thats the tough part for 3rd gen proteges...none of them are 'equal'. You have the ebay 4-1 systems for like $100 that bolt right in...or a carefully designed and tuned 4-2-1 from AWR...both keep the same overall length...the AWR benefits from quality design, and consideration that an FS in general is not going to rev high enough to really exploit the 4-1 benefits...but overall...nearly ANYTHING is better than the factory crush bent down-pipe and pre-cat...so no matter what you do, you'll feel a difference.

then there are the real systems. The Japanese 4-2-1 header systems are specifically tuned (the Mazdaspeed header being a factory available part, but the Autoexe uses a chrome plating and the same dimensions), and over 8" longer than the systems for the stock exhaust. The problem with these though (i purchased a Mazdaspeed header in 2006'ish)...is that you have to modify the mid-pipe to accept the longer primaries, much like what the OP had to do with the 626 header.

comparisons between all these headers has never been done. And as i said, any of these things will give a noticeable bump simply from removing the crap the car came with. Anyway though, a short 4-1 is better than a short 4-2-1 for high end peak power...but a short 4-1 vs. a long primary 4-2-1 is trickier, and will depend on other modifications made to the engine.

 

[Kreepaevox]

Considering that FSs don't rev to the stratosphere, a 4-2-1 header would be a very solid option. It makes midrange so boss. Also the 4-1 from OBX/Ebay the midpipe is too small. the 4-2-1 from the 626 looks so much beefy

 

[xdarkox]

Hi there,
sorry to revive old thread, but I need your help or anyones help, to give me a good advice on my egr tube- header problem. I bought that M2 header for our cars, everything fits right on , but infamous egr bung for egr pipe won't. I may try to take the corrugated gas line route, but I need some info what is the best way to remove pipe, I can get any tools in there, that nut is a 27mm , thats a big wrench. disconnecting coolant lines , or removing intake. is there any ghetto way to just bridge the gap between header and pipe.

 

[RichardC87]

subadub

 

[P5_2003_tuner]

EGR valve and header meeting

So it isn't necessary to have the egr meet at the headers because my header fitting is way off as well

 

[tlott01]

And the zombie thread stirs again...

I'm pulling an EGR tube from a 99' 626 at the local pull-n-pay that looks like it will at least line up
with the nipple on the header, not sure about the intake manifold end yet but I've got my fingers
crossed to avoid that CEL. If not I'll use the corrugated gas supply line.

After my initial test fitting of the header to the long block on the engine stand, it looks like the
#1 cylinder header tube (passenger side) makes contact with one of the coolant bypass lines coming
out of the thermostat housing. Will this be an issue, or does the coolant flow through it quickly enough
to negate the heat transfer?

Just wondering if anyone else has encountered this.

I pulled one from the same 626 and that end is bent exactly like the one on my P5, the other end
that attaches to the heater hose is a little longer. The part #s are different between the 626 & P5
and the 626 PN# is the same as the MX-6 that my Manzo 4-2-1 header is supposed to fit.

Just wondering...
tlott01

 

[hornsfan10609]

You can just cap the nut on the header with a 1/2" cap and cut the EGR tube to let fresh air into the EGR. No CEL, most people put a filter on the tube as well.

 

[tlott01]

OK, maybe I didn't properly explain my problem with installing a Manzo MX-6
header on my Protege5.

I've got an EGR tube from a 626 that fits my intake manifold and the header
bung - no issue there. The stock EGR system will remain fully functional and
will not create a CEL event.

My concern is that the #1 cylinder tube on the header makes direct contact
with one of the coolant bypass lines coming out of the thermostat housing.

The bypass line made of steel so it won't melt, but it's about 2 or 3 inches from
the contact point to the rubber o-ring that seals the tube into the thermostat housing.
If the coolant doesn't remove enough heat (caused by the direct contact) from the tube,
that rubber o-ring could definitely melt and cause big problems. Just wondering if anyone
else has encountered this issue before.

My choices seem to be: 1. Knock a dent into the portion of the header tube that
makes contact to create clearance, or 2. Buy or fabricate a spacer using the header
flange as a pattern/template to space the header tube away from the coolant line.
Method #2 will be more labor-intensive, but putting a dent into a header tube defeats
the very purpose that they are intended for (increasing exhaust flow out of the engine).

Has anybody encountered this problem before, and if so, how did you solve it?

Thanks,
tlott01