I used to work with a guy who had a 95 5.0 F150 with the cats removed and dual Flowmasters. Sounded just like the 5.0 Mustangs that run around with the same set up. In my opinion, one of the best sounding exhaust set ups you can run...

Does anyone know if the cats can be removed or gutted on one of the newer F150s without too much trouble. 04-up??

 

I had a 95 mustang gt and that was the best sound i couldve asked for. i got tons of props on how it sounded. DEFINITELY do it.... and save money too. i never had any problems out of it. the cats were just cut off and had straight pipe put there. DO IT!!!

 

If I recall right, when he took off his convertor, he got better gas mileage as well and a ton more power. I think you would be happy with the results.

 

The 97 and up cats actually flow very well. If you need more flow get the Magnaflow Cats. You can get them as low as 65 bucks if you look around.
That way you will still be legal and not polluting the environment. Go from 4 stock ones to 2 hi flows and you should be fine.

 

I was thinking more for sound, not really for power. The cats wouldn't come off until the warranty is out. I was just thinking anyway. I didn't know it had 4 cats on it.

 

Do cats work? Two weeks ago I had to smog a van that I sold. It passed all the smog tests except for HC, hydrocarbons. California allows 35 parts per and the van was registering 47 parts per. We tuned it, put some stuff in the gas tank that was supposed to help, put new gas in it because it hadn't been driven much for the past year or so and smogged it again. It tested at 47 parts per again. Bummer. Was told (again) by the smog tech that the cat was worn out and needed replaced. New cat. Smogged again and it registered 6 (six) parts per, the state average. I was amazed, the vehicle had 140,000 miles on it and I could hardly believe how low the emissions were. It made me realize why the Inland Empire, the San Bernardino, Riverside area is not nearly as smoggy as it was when I grew up there. From the mid 60's to the late 70's there were days and weeks on end when you couldn't see the mountains, over 7,000 ft mountains even if you were only a mile or so away from them. Today's air still gets smog but it is nothing compared to then. With the reading on the van with the new cat, I now understand why. Bill

 

The clogged cat was your problem......like many other things, when they go bad, not only do they not do their job, they efficiantly make things worse in multiple ways. When the cat clogs it backs uip, superheating the exhaust (to the extent on some vehicles of making the piping glow red) This backup of foul things will increase the output of emissions. You'd have been amazed to see what would have happened had you removed it and tested it without one. Your reading would have most likely been in the same area as with a new one, within a couple percentage points anyway. I have tested this theory and it works. The worst emissions outputs from the internal combustion engine come in the first 5 or so minutes, before the cat has achieved operating temperature and become functional. Your engine actually burns quite cleanly when at operating temperature. Does the cat help, well sure for a short stint when it is new, but as it ages it will begin to hinder more than it helps. Take it for whatever you believe its worth, but I have tested this theory on a 4.0L ford engine and found it to be true. (the benefit of being an emissions inspector at one time years ago)

 

High flows, or gutted cats will make it sound a lot more like an old muscle car

 

NomNomNom

 

NomNomNom

 

I would suggest getting a pipe to flow through and keep the cats to pop in for emissions inpection ( didn't read the whole forum so i have no idea if you have e-check or not ) If not, weld the pipe in, I would suggest dualinmg it out though, like y pipe the cat and ride the rest true duals, Do you have mufflers also? or running without mufflers? IF so, then running true duals with clear cats, oh yeah deffening baby

 

NomNomNom

 

nope, I dont have emissions, the lower half of P.A. does though, i'm in Northern P.A. almost boardering the N.Y state line.

 

I think your question about performance is a loaded one. When you run a free flowing exhaust, you will gain horsepower. The question is where? With a more restrictive exhaust, you lose horsepower at the top end of the curve, but gain torque at the low end. For race cars, they run the least restrictive exhaust possible because they rarely see less than 4K RPM, and you will gain power there. For everyday driving however, you will see a drop in power at lower RPM's due to the free flowing exhaust. So, do you want to see a bigger number on the top of the dyno sheet?, or do you want usable power for everyday driving.