Factory catalytic converters -VS- Magnaflow cats?

Status
Not open for further replies.

DR1

Joined
Aug 17, 2014
Messages
749
Location
Florida
Is there any difference in sound and performance between factory cats on a 2000 F150 , compared to the Magnaflow catalytic converters?
 
Nope. I put a Magnaflow high-flow cat on my Jeep last summer. Made no difference at all. My original cat was broken inside from off-roading and smashing it. Nice and quiet too.
 
If both diff. cats have that screen it will slow down air flow no matter what. I'm curious if its a absolute 100% fact that having no cats on a 2000 f150 v8 it will decrease in horsepower? I wish I could find an actual dyno demo video showing this test.
 
Originally Posted By: lawnguy
If both diff. cats have that screen it will slow down air flow no matter what. I'm curious if its a absolute 100% fact that having no cats on a 2000 f150 v8 it will decrease in horsepower? I wish I could find an actual dyno demo video showing this test.


No cats? Yes, it's 100% proven that bone stock Modular motors like to have a little back pressure in the exhaust, regardless of 4.6/5.4/6.8 or the chassis it's installed in.

You have 4 cats on that 2000. Only the front two are monitored by the PCM. Have an exhaust shop cut out and straight pipe the rear two cats. No check engine light, and a decent "seat of the pants" gain in power.

Google/youtube "F150 rear cat delete" or "Crown vic rear cat delete". You'll see.
 
The sound level should be the same. Remember, the mufflers and resonators have much more of an effect on the sound than the cats do
smile.gif
 
Originally Posted By: slacktide_bitog
The sound level should be the same. Remember, the mufflers and resonators have much more of an effect on the sound than the cats do
smile.gif



You would be surprised. I swapped in an offroad X pipe on my 98 Mustang GT replacing the factory 6 cat H pipe and it was substantially louder.
 
Where are the 02 sensors located at in relation to the front or rear cats?

Originally Posted By: 14Accent
Originally Posted By: lawnguy
If both diff. cats have that screen it will slow down air flow no matter what. I'm curious if its a absolute 100% fact that having no cats on a 2000 f150 v8 it will decrease in horsepower? I wish I could find an actual dyno demo video showing this test.


No cats? Yes, it's 100% proven that bone stock Modular motors like to have a little back pressure in the exhaust, regardless of 4.6/5.4/6.8 or the chassis it's installed in.

You have 4 cats on that 2000. Only the front two are monitored by the PCM. Have an exhaust shop cut out and straight pipe the rear two cats. No check engine light, and a decent "seat of the pants" gain in power.

Google/youtube "F150 rear cat delete" or "Crown vic rear cat delete". You'll see.
 
If you have emissions testing (or even if not, nobody anywhere likes to sit behind an obnoxiously stinky vehicle), you should at minimum ensure you find a cat with a CARB rating.

My 91 BMW was having issues with high NOx emissions. Everything ran perfect, so it was resolved to be a catalyst issue. IIRC failing was around 1200ppm, and my OE cat was on the cusp. Swapped in a manga flow and I barely passed. Somewhere in the 1170s, as I recall. Two years later, failed again.

Bit the bullet and got an OE converter, I passed with 14ppm.

So the OE converter was around 100x better.
 
Originally Posted By: JHZR2
If you have emissions testing (or even if not, nobody anywhere likes to sit behind an obnoxiously stinky vehicle), you should at minimum ensure you find a cat with a CARB rating.

My 91 BMW was having issues with high NOx emissions. Everything ran perfect, so it was resolved to be a catalyst issue. IIRC failing was around 1200ppm, and my OE cat was on the cusp. Swapped in a manga flow and I barely passed. Somewhere in the 1170s, as I recall. Two years later, failed again.

Bit the bullet and got an OE converter, I passed with 14ppm.

So the OE converter was around 100x better.


The BMWs Boysen exhaust weighed about twice what My jeep's system weighed. About 275 K miles it failed emissions for NOx, I replaced the original O2 sensor and treated the fuel with some pink glop that was designed to help jet liners burn cleaner. It worked and I got another 3 yrs out of the cat. Your experience with after mkt cats exactly meshes with tales from the E 28 forum.
 
OE cats are made to CARB standards(more precious metal in the washcoat) - and they flow better. Aftermarket cats might not flow as well and don't last as long. I had 2 Walker CARB-compliant cats welded in after my OEM Futaba ones died due to misfires and while the car did pass smog I noticed a huge drop off in performance. The Walkers were much smaller than the OEM Toyota cats. The inlet/outlet were the same but the catalytic substrate was much smaller.
 
Last edited:
Status
Not open for further replies.
Back
Top