I was thinking about getting a test pipe for when I go out on the trails later on this year. I was planning on making it to where I could swap back and fourth easily when I get back home. Anyone run without one and was there any noticeable difference?

 

Yep, ever since it rolled off the assembly line!

Dunno, couldn't tell ya. It never had one to begin with.

Obviously I'm ribbing ya (hope you're recovered and can take a little tease). But all kidding aside, peeps gotta remember to be specific when they are asking specific questions that are narrowed by the specific driveline and engine of their Ex.

Stewart

 

Mine never had a cat either.

 

None of the 7.3L PSD powered Excursions did. Just the gassers and the 6.0L PSD Excursions.

I was using the opportunity to mess with Apoc just a little bit. He's a little frazzled from a recent move.

Stewart

 

My new to me 6.0 has it removed...

Now, on my 6.8...
When I did my banks setup with custom exhaust I was recommended not to remove the cat. I'm sure it wasn't about inspections since we don't have any here in Florida.

 

Curious, who recommended it stay on? Forum members, a shop, or Banks?

Stewart

 

Actually, the performance shop that install and custom made everything after the banks system. They said I could go with performance cat or cats but felt it was pointless.

Was installed by one of the most recognized exhaust shops in Fort Lauderdale, so I felt comfortable with his opinion. Please keep in mind this was for the v10 and I'm clueless with the 5.4.

 

Mine is currently removed because I cannot afford a new one right now. I did not notice any power difference with it removed. The only thing I did notice is my truck now stinks like a 1970 Plymouth duster, its kinda embarrassing. When I get some extra ching it will be going back on..

 

ComputerCowboy is the only person I've ever run across who claims to have made any kind of gains without the cat. And I'm hugely skeptical of that.

 

I run with my dog.

 

Slightly lower egt's (100 degrees f), a slight drone. But my power max sounds like a steam engine now

 

I've got a gutted cat on with the banks system. Hard to tell what difference it has made. I know the banks kit has made a huge difference and really opened up the breathing.
Much louder running in the 2200 rpm range now, but I think that is more the banks kit, and sitting in the 80 mph range.
I don't think just the removal of the cat will make that much of a difference with out other changes at the same time. Just my opinion.

 

I took my cat off of my v10 and I love how it sounds. The smell not so much lol.

 

On a v8 - no gains of any kind should be expected.

 

I have no CAT, haven't had one for over a year.
I now have a completely custom dual exhaust, which I designed.
2.5" pipe from each down pipe all the way back, totally separate with some small mufflers on the very end.

I noticed a mileage improvement after removing the CAT on the stock setup, and another slight mileage improvement with the true dual setup.

Currently I get 11.4MPG mixed, pretty much about 50/50, I spend a lot of time putting around town doing errands, but I also do a lot of long trips and 30 miles of highway commute every day.

The dual exhaust setup makes a noticeable difference as the engine winds up to higher RPMs, but may have robbed me a little bit on the bottom end.

I don't care if you are skeptical, I know it makes a difference, not necessarily in power but in mileage. When I bought the truck bone stock the lie-o-meter said 11.2 MPG. I am now getting slightly better than that with an 8" lift and 35" tires and the stock 3.73 gears. I drive it like I stole it on the open road and creep real slow in town.

The things you will notice most about removing the CAT are, it stinks, a lot, it could choke a rhino. Also the CAT muffles the exhaust sound more than the muffler. No CAT is real real loud. That is most of the reason that I creep real slow around town. If I punch it it will set of car alarms, I am not kidding or exaggerating at all. The bark this thing has being basically straight piped is deafening.

I am thinking of getting some larger mufflers and putting them in the middle with an X-pipe towards the front and putting some big six inch tips on the end. That should reduce the bark a lot and lower the tone, right now it is raspy and crackles.

What I also find interesting is that the flutter is still present at about 2100 RPMs. The reason I didn't put an X-Pipe on is because I thought the true dual separate pipes design would eliminate the flutter sound. The flutter is considerably reduced because of the amount of flow I have. I used to have the stock y-pipe no cat and a Flowmaster Super44. The sound at 2K - 2.4K RPMs was awful. It was way louder than my current dual setup. The combination of the exhaust fighting its way through that terrible y-pipe and then bouncing around in the baffled muffler was horrible. The dual exhaust setup that I have now is way quieter. I think with a couple more tweaks I could get it to the point where it isn't stupid loud and doesn't crackle.

The next mod I have in mind is 5.38 gears, I am going to do that in the next couple weeks or so. That will change the sound a lot, because all the shift points will change (particularly the one at about 2100RPM) Also with the V10 being able to wind up it won't be bogged down like it is now. For example if I sit in park and wind up the engine it is pretty quiet, but if I go WOT from a dead stop it makes a ton of noise because the engine is loaded and geared all wrong.

I am pretty psyched to get those gears, this big old pig should be much more motivated.