Running no cat on your diesel ruins your engine!?!? Please read and respond

03F350GUY · #1 (**permalink**) 10-04-2009, 11:42 PM

I have a '03 F-350 6.0 and was pretty set on getting a MBRP 4" turbo back exhaust with the cat cut off pipe and then i read somewhere from a guy saying that running no cat can cause the engine to run bad and mess the engine up because of the computer receiving some sort of signal to the engine effected by not having a cat. Is this some Eco nut's bs rambling or is there any truth to this....anyone know anything about negative effects from running no cat?
thanks,
Chris

flamebuster · #2 (**permalink**) 10-04-2009, 11:52 PM

Havn't heard of any ill effects for the engine, only for those who have to pass an emission test and some feel the cat still dosn't help. I baught mine with no cat. and the 4" exhaust and have no plans of changing it.. I am sure someone will chime in with more technical advice.. And welcome to FTE these guys and gals are great.

Egmonster · #3 (**permalink**) 10-05-2009, 12:59 AM

That is BS. Gas engines require "back pressure" to run properly, but diesels do not.

matty169 · #4 (**permalink**) 10-05-2009, 02:41 AM

You DO NOT NEED A CAT. THE END. And it helps to get rid of it.

ford7379trucks · #5 (**permalink**) 10-05-2009, 03:53 AM

cats only harm engines they do nothing for them but cause high egts. if you can get away with it get rid of it.

Egmonster · #6 (**permalink**) 10-05-2009, 04:05 AM

Wow you guys sure hate cats.

ford7379trucks · #7 (**permalink**) 10-05-2009, 04:21 AM

ya id rather have a bully dog. haha no really a SCT

ljutic ss · #8 (**permalink**) 10-05-2009, 05:19 AM

You can get rid of the cat, but you better store it for when your state kicks in emissions inspection.

fgallant · #9 (**permalink**) 10-05-2009, 08:24 AM

What can you guys tell me about removing it and the advantages? My 04 SD rig is bone stock but very well maintained but anything I can do to enhance performance I will consider??

tex25025 · #10 (**permalink**) 10-05-2009, 08:48 AM

Quote:

Originally Posted by ford7379trucks

cats only harm engines they do nothing for them but cause high egts.

That might have been true a couple of decades ago, but that isn't true now. I haven't a drastic decrease in EGTs when I first removed the cat. I had a turbo-back 4" exhaust first, but I left the cat in. There was reduction in EGT's, but that was because I went with a bigger system(by the way, if you don't plan on running more then just a tuner, don't get bigger then 4", you'll actually lose low end power if you go bigger because you're not flowing enough fuel and air to support it with just a tuner). After I removed the cat, there was zero(I repeat, zero reduction(that may very from person to person) in EGTs, just more sound that is the biggest benefit of removing the cat(this happens across the board).

These cats aren't the HP robbing, restrictive cats that my parents grew up with. Had the EPA allowed the EGR valve to mature naturally those probably wouldn't be the headache that they are for diesels, same with DPF and next Urea.

Plugman · #11 (**permalink**) 10-05-2009, 08:56 AM

Quote:

Originally Posted by fgallant

What can you guys tell me about removing it and the advantages? My 04 SD rig is bone stock but very well maintained but anything I can do to enhance performance I will consider??

They already have in earlier posts: By removing back pressure of a turbo charged engine it helps run better. Think of it this way, the more cool air you can flow the more efficient your turbo works, so intake and full exhaust = better air flow and higher performance.

tex25025 · #12 (**permalink**) 10-05-2009, 09:04 AM

Quote:

Originally Posted by Plugman

so intake

Actually this is a big no-no when it comes to the 6.0. A/m intakes do not flow more then the stock intake until you hit 3700 rpms. Peak HP and TQ are at 3300 and 2000 rpms respectively. In order to get the benefit of flowing more air you would have to raise the peak hp/tq rpms and you can only do that thru injector and/or turbo upgrades, not with a tuner alone. 90% of the people out there waste their money on this mod, not only because they don't flow more, but they have also been shown not to filter as much as well.

Now if you want to get the intake because you want it, think it looks cool, and/or cleaning and re-installing that those might have some merit depending on where you stand on those issues, but they do not benefit the majority of people out there with regard to air flow and filtration over the stock unit. If we were talking about the 7.3 then you would have something, but not the 6.0.

janton01 · #13 (**permalink**) 10-05-2009, 09:36 AM

Just a quick question, here in NJ they look at the exhaust sys for mods now. Is it workable to empty out the cat and reinstall the shell. I had the front connect apart but could not get the rear connection to seperate. Will roding out the material inside the cat provide the same reduction in restriction or only total removal. No other mod's other than a cooling system filter.

yz400f · #14 (**permalink**) 10-05-2009, 09:53 AM

My 05 scurge has a Cat.

There ain't nothing in it but air though!

Take it out, get a long bar and an hammer and get at it. ( also need a block of wood to put the end down on.)

Takes an hour or so, but it is not that hard to skin that cat.

janton01 · #15 (**permalink**) 10-05-2009, 10:19 AM

Quote:

Originally Posted by yz400f

My 05 scurge has a Cat.

There ain't nothing in it but air though!

Take it out, get a long bar and an hammer and get at it. ( also need a block of wood to put the end down on.)

Takes an hour or so, but it is not that hard to skin that cat.

Thanks, getting it off is the fun part that aft connection has been there since new likely so it is well stuck. Back to work at it, guess a torch should help. Thanks again.