Exhaust Topic - From The Manifold To The Tail Pipe

[jsvalenzo]

Ok so the order goes..

0. Engine
1. Exhaust Manifold
2. Pre-Catalytic Converter
3. J Down Pipe
4. Catalytic Converter
5. Pipe + Resonator
6. Pipe + Muffler

Perhaps I can explain why this, why now...

Well, first I hope to look into the pre-cat (#2). I suspect there is a blockage in the can. I haven't seen any temperature symptoms, but I got the gaskets already so why not right... (195k mi, oem cat)

If plugged: Perhaps - Weld up a test pipe to attach from manifold (1) to main cat (4). Basically, bypass precat. So manifole straight to main cat. A 4" to 2" gradual reduction. The factory reduced the exhaust from 4" to 2" in a matter of inches in the precat ... is that strange?

Update: New Catalytic Converter!

Also, I have purchased a new Magnaflow catalytic converter to bolt on.

MUFFLER:

The factory muffler measured out to 7.5" round x 16".

I plan to order a Magnaflow (# 11133 ) Oval (3.5"x7") straight thru muffler. It has a length of 14".
The muffler has a 1.75" in/out pipe diameter, and is offset like the oem muffler.

Anyone have experience working on these z5 exhaust systems (?)

[jsvalenzo]

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[jsvalenzo]

Looks like the second o2 sensor is located on the down pipe. The first is attached to the manifold itself. Looks like bypassing the precat will cause a check engine light, unfortunately.

[Kitty]

If you plan on actually running a good cat, magnaflows aren't bad but not the best but better than china cats, just extend the length of the second O2 sensor to be past the new cat.

Use shielded wire and extend the wires on the chassis side of the harness while the o2 sensor is disconnected, not the O2 sensor wires as you can damage the sensor if you improperly solder it.

[irishkev90]

I've been trying to quiet mine down while keeping the Mazdaspeed muffler. It's quieter, but still drones a bit on the highway. Might just get the OEM resonator and put that back in.

Anyway, why do you think there's a blockage in the cat?

[jsvalenzo]

The resonator pipe section will remain in tact here.

Hoping that these exhaust changes will gain back factory performance, or more.

I SUSPECT the precat because when i purchased the car, things weren'nt right, at all. Here and there, i feel sudden power gains/losses.
Unfortunately, a replacement unit is no longer available.
Got the main cat replacement...
Everything else in the ride is functioning fine/ new.
Why not

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[jsvalenzo]

Well... here is the latest:
1. correct magnaflow precat ordered....
2. magnaflow main cat here.. and
3. about to order oval magnaflow muffler...

i take pics when everything is here

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[jsvalenzo]

Here we have the new components:

Magnaflow precat, cat, and muffler.
The oem resonator will remain intact.

Pics of the install / results to come...

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[jsvalenzo]

Pic 1/8


With comppnents removed, this is a glimpse UP the factory exhaust manifold.

Pic 2/8


This is a side by side of the mazda oem and magnaflow. Be prepared for + 1 inch in height.

Pic 3/8


The bracket serves as an exhaust hanger... it must be transferred over.

Pic 4/8


Mounted.

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[jsvalenzo]

Pic 5/8


Side by side of the oem part and the magnaflow.

Pic 6/8


The KEY is: First align the rear section. I repeat, the rear first.

Pic 7/8


The down pipe meets the magnaflow last, using the spring loaded style flange.

Pic 8/8


My in-ability to weld only took me to a local professional for the magnaflow muffler install.

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[jsvalenzo]

I will drive normally and post a performance review in a few miles...

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[farcryNZ]

Looks good man.
I really should take a look to see what's under my car.

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[farcryNZ]

So how has it turned out? Good performance?



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[jsvalenzo]

Funny how nobody returns to the forums, to share the results. In my case, i was correct in assuming the exhaust was a bit congested. The car idles smoother, acceleration is faster also. Definately an improvement in my everyday driving experience.

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[farcryNZ]

Glad to here it[emoji108][emoji4]


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