Not sure what "fits" means when it's just the cats and not the pipes. Example, Magnaflow 94105 Catalytic Converter 94105 - Magnaflow New York (94105) is in the discoweb article as a cat that fits because it has a 2.25" inlet/outlet that fits over the 2 1/8" pipe my 2002 4.0 V8 has. But Advance Auto, Auto Zone and O'Reilly all say "this does not fit your vehicle". The ones they suggest are the same length/width it seems, just different 2" diameter.

Went to muffler shop, nice guys, $85 per cat to weld in for labor. $170 total. Super fair. I asked if he wanted a 2" or 2.25" cat and he said bring 2.25".

Anyone put a magnaflow on their 2002 D2 and want to share which one and why some "don't fit"? I know the driver side is cylinder shaped and passenger is flat oval, but all the aftermarkets come in the same size for both sides. What gives?

 

Aftermarket is universal fit, not disco specific. When I had mine I used the Magnaflow 2.25". Worked well enough. I think I actually even used a 2.5" at one point when I melted one of the 2.25s and nobody had a 2.25" in stock.

 

Sounds great. Thanks!

 

I'm guessing if they are being welded in then the incoming and outgoing pipe diameter isnt so important. As long as the welds are decent. Which might mean using bits of filler material to make up the gap etc.

Only if the cats are being clamped in place would the diameters be an issue, as they might not 'snug up' tightly enough.

I reckon.

 

I just wish I knew what they use to decide "fits" or not. The only thing I saw was all the ones that "fit" were 2" diameter. Other than that, no idea. Oh well.

 

Arnt cats usually clamped in, rather than welded? I might be wrong on that.

But if they are, then 'fits' will be when the tubes sleeve together nicely, whereas welded doesn't matter. Any gaps are filled with mig wire 🤐

Yer man at the muffler shop probably said bring 2.25" cos they 'definitely' fit. In a welding scenario.

 

Yep, I had my ducks lined up for him. My pipes were 2 1/8" at the cats, so 2" would slip inside to weld or 2.25" would slip over to weld. He said bring 2.25". The next was length - Magnaflow 90045 is about 16-17" long and Magnaflow 94105 is 13"-14" long, so he said bring the shorter one.

So we settled on Magnaflow 94105 at 2.25" diameter and 13-14" long.

 

just in case anyone needs to do this job, here's what I ended up doing:

Found a very well respected local welder, who does lots of cats.
Installed two Magnaflow 94105 universal cats with 2.25" diameter pipes. (I provided them @ $75 each from local parts store)
Took the guy about 45 minutes, did not have to unbolt or lower the pipes. He welded in place.
Charged me $200 total for welding.
I walked out the door with my old cats and sold them to the recyclers for $60 each. ($120 total).

Cats ($150) + Welding ($200) = $350 - $120 back for my old cats = $230 total for new cats.

I'm happy with that.

PS: first shop tried to tell me, just as my truck was going in the shop, "oh. by the way, the law won't let us give you your old cats back. not even after several weeks, so we have to keep them." I almost came unglued. I left and found a better shop that was actually honest. My parts are my parts unless we agree in writing that I will give them my parts.