I'm thinking of reinstalling the cat on my 04.5, mainly for the noise reduction.

When I bought this truck, it was the first 3rd gen (non-cali) with a cat and everyone was convinced that they were problematic...so I jumped on that bandwagon. I removed my 04.5's cat so long ago, I don't even remember if there were any changes in performance. It was also before I installed gauges and SmartyJR...so I have no idea what, if anything, it did to EGTs/performance. I have probably 200k without a cat...

I want to remember it did little for mileage reduction (no clear improvement afterward)...I have those numbers recorded, so I can look that up myself. Does the cat significantly increase the EGTs?? Was there any real benefit to taking it off in the first place?

Thoughts?

 

I think you're going to get more flow through your exhaust without one.

Why don't you install a straight through diesel muffler?

 

But is the added flow meaningful? Does the cat really add that much restriction?

I already have a 30-inch Magnaflo on a mandrel bent 304SS system...

 

Yep the cat does restrict a lot.

 

the cat really does restrict a lot. You might end up just plugging it up and blowing it out the exhaust if you have any other modifications. It does quiet it down, but not as much as a muffler would. I know you can plug them up on gassers pretty easy. I have a buddy with a 1998 F150 that has an Edge module and he put duals on it from the manifolds back with 2 new cats, and he ended up blowing the dead chunks of the cats out the exhaust after 5,000 miles.

 

I am running 500hp through my cat and have had no problems my highest egt was a little over 1200deg while running on 1/8th mile drag strip. and it takes most if not all of the highway drone out

 

Steved,

You still have the old CAT, right? Hold that POS up to a light, take a gander through it from one end to the other, and then you tell me if it restricts anything! I ditched mine, the entire system, and went with a 4" turbo-back mandrel bent system. HUGE improvement in spooling and MPG's, but that was probably compounded by my other aspiration mods. I can honestly say, I believe reinstalling that CAT wouldn't exactly be in your best interests, unless you are trying to pass an emisions test of some sort. Companies make CAT-delete pipes, haven't seen any CAT-install pipes for a while.

 

I have looked through it...its amazingly open...add to that the surface area of the overall diameter, and it probably has the same open space as an open pipe.

I want to remember I saw no improvement in performance, but again that was too long ago. I did review my logs, and I got just as good of mileage back then as I get today...there was no apparent mileage increase.

They sell cat delete pipes for a reason...people BUY them, it doesn't mean they do a thing for performance.

---AutoMerged DoublePost---


I can only assume the cat is intact? Is it the OE cat?