I am considering buying a cat delete pipe and was looking into info on the matter. According to a magazine that was testing the performance of a cat back and full replacement, the gain was negligible. They only gained 6 hp and 9 ft lbs at 3500 rpm. This was on a stock truck, the exhaust was the only mod. I don't normally see 3500 rpm. I was considering the change for the mileage. I have read some of the sigs and claims in other threads and some people claim 2-3 mpg. Could they have started with a really dirty cat or does it make that much of a difference? I believe that the mods I make need to help me in the rpm range that I drive in. Any input?

I dont see how you could go wrong on a turbo'd vehicle by opening up the exhaust. Less back pressure should equal more intake velocity right? so in turn, less back pressure = MO POWAH !! at least thats my thoughts on it.

But will it improve the mileage? No power gain really according to the article.

I think the biggest gains you'll see is that your exhaust temps will be lower and/or drop faster when you get your rig to camp. I don't think that anyone on this forum actually has seen much of a gain in MPGs (of course, now that I say that, I'll have twenty people posting that they saw a 2 - 3 MPG gain when they lost the cat (but they really didn't)).

Joseph

I didn't see any mpg gain in neutering the kitty. You'll gain as noted a bit lower egt's (about 100), a bit of a different exhaust note, and a swift kick in the nutz if the "man" catches you (that's why mine is neutered not removed).

I see said the blind man.................

Best thing I've done so far was getting rid of the cat, I gained mileage, lower EGT's and runs better. I think my kitty was clogged.

i have a buddy that cut the cat and muffler out and put a piece of pipe in its place, sounds better, runs better, and gets a little bit better fuel mileage.

kinda out of the blue but if I took off the front pipe and took a long bar and smashed it back into the cat enough times would it break up the honey comb stuff or would I just end up clogging it? I dont have a welder and Im holding off on a front pipe because I built my exhaust from the cat back and dont want to mod it to fit that yet. just wondering thanks. sorry for jacking the thread...but it seemed like a good place to post

just had my kitty and muff removed today:D sound is awsome, dude at the muffler shop made delete pipes for both, fit them, welded them, and charged me only an hours labour , whole bill taxes in was 175 cdn skins.cheap like borscht i thought:D i'll have to get back to ya on any mpg increases tho :beerchug: did notice a definite throttle response increase tho :D

Throttle response is good...............

Throttle response is good............... seems better than it was in stock form

Got rid of my kitty and the biggest thing that I noticed was how much quicker the turbo spools. I don't need to give it as much throttle when on the highway if I want to pass someone or am going up an incline. Once I added the intake the turbo spooled even better. As far as mileage I think it helped me b/c I changed my driving habits now that I don't need to get into it as hard to get the boost to build. The cat delete alone lowered my egt's and did give me a slight mpg gain but combine that with an intake and cat back exhaust and you will see some noticeable mpg gains.

kinda out of the blue but if I took off the front pipe and took a long bar and smashed it back into the cat enough times would it break up the honey comb stuff or would I just end up clogging it? I dont have a welder and Im holding off on a front pipe because I built my exhaust from the cat back and dont want to mod it to fit that yet. just wondering thanks. sorry for jacking the thread...but it seemed like a good place to post

Yes, that method works, but it is better to just take the front pipe completely off the truck so you can tip it on end to get the debris out, or it can plug your muffler if it is a stock one.

Your 02 shouldn't have a cat unless it came from Calif. A stock non-cat take off down pipe will bolt right in there. Later! Frank

Exhaust is not a "performance mod". Gains will be small. Exhaust is something you do before you add power, or just to be nice to your truck, because anything that restricts exhaust will hold EGT higher, thereby passing along the heat to the turbo. Less heat on turbo over time = longer turbo life. Less restriction also equals faster spool. Don't forget to re-route the PCV to atmosphere. That little sucker puts the oil vapor in the system pre-turbo and it is worse than the higher temperatures for the life of the turbo.

dane

A 4" is a big performance mod when towing. I can run almost 10 MPG faster up a 6% grade with 12.5K on the back without running the EGT past 1250. Later! Frank

cat was on the 02. man I miss that one............