Any knowledge about a Magnaflow replacement catalytic converter?

[Guanciale]

I'm considering replacing the catalytic converter section on my 1987 NA. (The original pipe is cracked at the O2 sensor bung. Seems easier to just replace the whole thing.)

Magnaflow makes a model 23796 that they list as a "direct fit." That sounds great, but what concerns me is these reviews that suggest it doesn't actually fit:

https://www.amazon.com/MagnaFlow-23796-Catalytic-Converter-compliant/dp/B000JKLEII

Anybody have some experience with this item, or other alternatives to the pricey original cat? I'm not looking for a performance upgrade or major change in the exhaust sound, just something that works. Thanks.

[djnolan]

I am no expert but I think "generic" catalysts may not just bolt right up and you might need to cut the pipe and use clamps or weld it in instead which is not as sturdy. It might also be substandard metals that will rust out sooner. The one listed is also non CARB (california) certified.

I would look at either a used genuine replacement or welding the cracked one.

[Paul Revere]

I recently went through the exhaust on my ‘87 n/a to solve a minor leak, and also because I needed to re-seal the oil cooler.

After researching many options, and strongly preferring to keep a stock setup, I ended up having it ceramic coated from the manifold to the exhaust tips.

For less than the cost of an aftermarket setup, I get to keep the stock exhaust note, and have a great looking exhaust. The underhood and underbody temperatures are noticeably reduced, and the entire exhaust should be much more corrosion resistant. Happy to provide more info if you decide to repair vs. replace.




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[9FF]

Originally Posted by Paul Revere

...The underhood and underbody temperatures are noticeably reduced, and the entire exhaust should be much more corrosion resistant...

Looks good but I cannot see the benefit of doing anything past the manifold. Temps are just not that high under there, plus don’t cats need the heat to work properly and exhaust systems corrode from the inside out.

[v2rocket_aka944]

Originally Posted by 9FF

Looks good but I cannot see the benefit of doing anything past the manifold. Temps are just not that high under there, plus don’t cats need the heat to work properly and exhaust systems corrode from the inside out.

Makes sense all the way to the cat, to me. Looks great though!

The nature of how CA smog tests work, even if you do your damndest to get the car HOT before the test, it might be sitting idling for a few minutes before getting onto the smog dyno.

I put header wrap from my 2-1 collector all the way to the inlet of my cat in an effort to help the cat by any means necessary, LOL

[RedCarGuy]

I bought a universal 2.25" magnaflow 53005 cat that I'll weld in place of the stock setup with some extra piping to make up the difference in length. Since you need to repair or replace the part by the 02 sensor, it may be easier to replace the whole thing. I would find a good muffler shop or speed shop and get a quote from them before buying that one.

[DannoXYZ]

Originally Posted by Guanciale

Anybody have some experience with this item, or other alternatives to the pricey original cat? I'm not looking for a performance upgrade or major change in the exhaust sound, just something that works. Thanks.

The universal cats work great. Just need to cut & weld them into place that's all. Here's exhaust on my 951 that PO had installed a universal-cat many moons ago. I needed to replaced it because NOx emissions had been slowly climbing past 6-yrs.

I used Magnaflow 3" cat with proper CARB EO# for this car (actually same EO# for 944/951 in 2.5" and 3.0" sizes). I made two cones to fit to original exhaust, 65mm on one and 68mm on other end.




I made sure it's oriented properly with EO# easily readable for smog-techs. After driving it for a while, it changed to same brown colour as rest of exhaust (stainless 409 probably). The smog-tech look at it and didn't even bother reading EO#. Passed with lowest emissions I've ever seen on a 944/951.

Some smog-testing tips:

1. use 25% denatured alcohol in tank. Alcohol carries its own O2-supply and lowers HC. Alcohol also lowers combustion-temps and NOx emissions

2. keep cat HOT by driving it hard before pulling into smog-station. Do NOT turn off engine when arriving, leave it idling. And make an appointment so you have minimal wait-time to get on the rollers

3. use DME's FQS-switch to set to -6% fuel/-2.73 degrees ignition timing. The lower fuel reduces HC and in CA you're allowed up to +/- 3-degrees timing. Reducing ignition timing lowers NOx emmissions