Cat. Converter removal

tomasnc · **Posted:** Sun Aug 21, 2005 10:52 pm

I read months ago I think on the old L.O.S.T. board of a guy would gutted his cat. converter. I can't imagine doing this to a new car but has anyone done it to their vehicle?

Someone said the ceramic element is easily shattered with a line-up bar , rebar. etc.

I am curious to know if having no converter will affect the computor?

Thanks,

Tom

Bonehead · **Posted:** Sun Aug 21, 2005 11:22 pm

I'm kinda wondering too, if they are anything like the "cat" on a Powerstroke, its more like an anti-puffer with just a screen at either end of the camber to keep it from smoking. I'd lose mine in a heartbeat if I knew what it would do.

n3qik · **Posted:** Mon Aug 22, 2005 8:21 pm

I am the one. Yes it is a ceramic element. No effect on the computer. The only negitive is increased in smell so far. I am looking at a glasspak for replacement muffler.

Bonehead · **Posted:** Mon Aug 22, 2005 9:58 pm

n3qik wrote:

I am the one. Yes it is a ceramic element. No effect on the computer. The only negitive is increased in smell so far. I am looking at a glasspak for replacement muffler.

I don't think you want a glasspack...........diesels and muffler packing don't like each other to much, you need to look at chambered mufflers (thats what I doing)

tomasnc · **Posted:** Mon Aug 22, 2005 11:21 pm

n3qik, the smell is the thing that I still find missing on my CRD.

You don't smell the diesel odor that I get from my Cummins.

Have you picked up any better mileage or performance?

Thanks!

Tom

boxhead · **Joined:** Fri Jul 08, 2005 11:14 pm **Posts:** 186

Someone on one of the forums said they did this and had all kinds of problems and had to replace the CAT. (error codes, etc.)

Danno · **Posted:** Tue Aug 23, 2005 9:08 am

After gutting my cat my CRD didnt throw codes right away but it soon did. All were related to to what turned out to be a bad EGR. After it was replaced I have no codes and the CRD runs much better than when it was new. Gutting the cat shouldnt cause the CRD to throw codes.

I believe the MPG did get a bit better, in the city keeping my foot off the gas(which is hard to do) i get 25-26. Driving like I stole it I get 22-24 so not bad. Seems to be a bit more low end power and I feel that the Turbo lag is a bit less.

n3qik · **Posted:** Tue Aug 23, 2005 7:23 pm

BoneHead- I put a glasspak on my old 99 6.5L deisel truck, ran great w/o much noise, just a nice low bass rumble.

tomasnc- I had a bad EGR valve, so any gains in milage/power where masked my that.

boxhead- That guy put on a stright pipe from turbo back, He never got back with what codes where set. With the amount of EGR problems we have. I think the exhaust was not related to the CEL.

kd4yor · **Posted:** Tue Aug 23, 2005 10:15 pm

KEN,
I'm right here. I agree the timing was ripe for the EGR valave to fail and I was getting 299 and 401 codes. DC was just a major PIA to deal with. I was forced to replace all of the parts BEFORE they would even look at my dying trans at the time.
Pat

Dutchy · **Posted:** Wed Aug 24, 2005 5:40 am

Guys, why should anyone want to make the CRD louder and give off more smoke and smell?
This is a diesel engine developed in Europe, we spend 30 years fine tuning diesel engines to make them more powerfull, cleaner and meaner.

The CRD engine is not a common diesel engine you are used to in the US and taking out the cat will upset the whole set up, it will damage your engine in the long run and make your vehicle illegal in most states.

As a by product you will ruin the chances for the CRD to succeed in the US as people in the US still think diesel engines smoke and smell and by taking out the cat you will prove them right.

The only way to get more power is by getting a chip (cheap) or have the whole engine reworked by a professional tuning company. (expensive)

It is a diesel so treat it with respect or it will kick your booty.

kj lad · **Posted:** Wed Aug 24, 2005 10:44 am

Hey Dutchy, Where you been?

Ian

LibertyCRD · **Posted:** Wed Aug 24, 2005 2:59 pm

One of the things I love most about a diesel is the sound. I'm going to keep working until I figure out how to make it LOUD. That's what everybody here loves about diesel-power! Screw emissions crap. All it does is rob power from the engine, making it work harder and burn more fuel which is harmful to the environment to begin with. I say rip it all off, open up your diesel, and get some power and sound out of it!!!

Dutchy · **Posted:** Thu Aug 25, 2005 6:41 am

Hey man, it's your KJ and your warranty!

Why not try to take away the soundproofing on the underside of the hood, then take the plastick cover off the engine and buy yourself a K&N filter and a sport muffler and to top it off, chip it to 180 BHP..
This will make it sound louder, make it more powerfull without destroying your engine and our world

.

Remember it is not an old fashioned Cummins engine you deal with, it is a hightech precision engineered computer managed common rail turbo diesel engine, it needs the cat not only for taking out harmfull fumes and old fashioned diesel smells, it uses the cat to check the burning process (Lambda) and adjust it automaticly to get the best power at the right time.

Here in Europe, when we see a diesel trowing out smoke and awfull diesel smells we know the engine is about to die, not a nice sight, and loud diesels ar frowned up on and called tracktors. :wink:

LibertyCRD · **Posted:** Thu Aug 25, 2005 8:33 am

Dutchy wrote:

Remember it is not an old fashioned Cummins engine you deal with, it is a hightech precision engineered computer managed common rail turbo diesel engine, it needs the cat not only for taking out harmfull fumes and old fashioned diesel smells, it uses the cat to check the burning process (Lambda) and adjust it automaticly to get the best power at the right time.

Here in Europe, when we see a diesel trowing out smoke and awfull diesel smells we know the engine is about to die, not a nice sight, and loud diesels ar frowned up on and called tracktors. :wink:

Odd thing is...those "old fashioned" Cummins engines have hundreds of thousands of miles on them around here. I know a guy with over 500,000 miles on his original engine. And the high-tech Jeep diesel seems to be having trouble for a lot of people already. Hmmm... I think it's because of all the emissions junk the government requires. Companies are not allowed to just build a good solid diesel engine anymore. They have to jump too many hurdles and meet too many requirements and then the engine gets over-engineered and turns out to be junk.

But oh well... you are right I should start with simple stuff like muffler, intake, removing the sound proofing, maybe a computer chip to make it run a little better. I won't take the cat apart right now because I don't want a $10,000 fine! :roll:

Katmandu · **Posted:** Mon Aug 29, 2005 1:47 am

Dutchy wrote:

Here in Europe, when we see a diesel trowing out smoke and awfull diesel smells we know the engine is about to die, not a nice sight, and loud diesels ar frowned up on and called tracktors. :wink:

Here in the US, people (like my brother-in-law) modify the hell out of their Cummins by doing things like...Running straight pipe, cranking up the fuel pump timing (to make it REALLY SMOKE!!) and go driving around town and go WOT next to PEDISTRIANS walking along on the sidewalks!! It's hilarious to see them jump out of the way coughing and hacking away!!

LMAO!!! God I LOVE this Country!!! :mrgreen:

gundrted · **Posted:** Mon Aug 29, 2005 11:33 pm

something to keep in mind with taking the cat off .... you could blow your turbo out. my dad has a ford f250 with a 6.0L d and if you take the cat off that the turbo spins up so fast that it can burn it self out. i wouldnt req taking it off

Bonehead · **Posted:** Tue Aug 30, 2005 6:15 am

gundrted wrote:

you could blow your turbo out. my dad has a ford f250 with a 6.0L d and if you take the cat off that the turbo spins up so fast that it can burn it self out.

Huh?

(sorry couldn't help myself)

The turbo will only spin as fast as the volume of air coming out of the exhaust manifold pushs it. The VGT part of the turbo is on the exhaust side of the turbo and basicly changes the the size of the housing around the impeller allowing it to "spool" faster. The only way to get more air volume out of the engine is to get more in , different airbox ,higher flow intake, higher flow head and such. But the liminting factor in all this is the physical size of the turbo, like I said the turbo can only move (and spin) so much air volume and that it no matter what because of it size.
Now with that being said I do know that these nrewer diesel require some backpressure or the lose torque, newer computer controled engines in 18 wheelers don't like straight pipes like the older ones did. Friend on mine put a set of 6" straight pipe on his '04 Kenworth with a 600hp Detroit and said it castrated it and end up puting the factroy exhaust back on.
I think I've rambled on enough............. :lol:

Oh yea , if I can get mine to spin up real fast woohoo no more turbo lag :wink:

I intend on leaving my cat on but do intend to change the exhaust after the cat ,unless someone come out with an exhaust that goes from the downtube back then I'll replace the whole thing.

gsbrockman · **Posted:** Tue Oct 04, 2005 9:24 pm

Dutchy wrote:

As a by product you will ruin the chances for the CRD to succeed in the US as people in the US still think diesel engines smoke and smell and by taking out the cat you will prove them right.

One of these days, the wife's CRD will hopefully pour out some unburned #2 like this :

Greg

CRDMiller · **Posted:** Thu Oct 20, 2011 5:33 am

Guys.
Guys!

I have had a straight pipe for a long time on the crd and it does not adversely affect performance at all. I am using 3 inch mandrel bent tubing with a 3 inch flex joint.
The biggest difference except for sound levels were the lowering of egt under hill climb or towing conditions. Expec noticeable under low speed operation. Such as running up sand dam at superstition mountain.

Other benefits are increased idle torque. It took more brake effort to effect a stop at low speed than previously. also coasts better.

Bonehead;
Our turbos are VGT, with var. vanes. NOT var. volute such as you describe. (for instance those found on Cummins ISX engines)
Turbos do not work off of back pressure, they work by using the expansion of gasses caused by rejected heat from the exhaust system. This is how turbos add efficiency to engines. Turbo diesel engines are around 40% efficient with the rest of the btu from fuel going to atmosphere. We reclaimed some of that rejected heat in order to compress the intake air charge.

VGT's are also used to INCREASE egt's (by providing excessive boost and thus increasing back pressure) in order to increase hydrocarbon burn off and reduction of NoX not just in cyl but also in the dpf or rhodium/palladium catalyst.

I work as a diesel mechanic and we often dyno engines after rebuild. The exhaust system in our 1000hp water dyno cell works under negative pressure. E.G. In some cases simply hooking the engine up to the exhaust system in our shop would spin the turbine at low speed. Diesel engines are not designed to require an exhaust flow restriction to operate normally or in an enhanced state. Reducing exhaust system back pressure can not result in a catastrophic failure of an engine. The opposite is actually true. Excessive back pressure under high volumes of flow allow hot exhaust gasses a longer pereiod of time to dissipate into surrounding materials such as the turbocharger, bearings, head, liners, etc.

Excessive exhaust back pressure such as would be caused by a plugged air filter, damaged/plugged dpf, bent exhaust plumbing etc can cause engines to drop valves, kill turbo seals, etc etc etc. Excessive back pressure raises egt's and generally damages engine components.

drtydzel · **Posted:** Thu Oct 20, 2011 10:54 am

I cut my exhaust off and did a straight pipe a year ago and it runs great and i think we picked up 1-2MPG with it the only down side is i get a little more soot on my garage floor when we start it up. Does not sound anywhere as good as a Cummins but i did it for the mileage gains

Cat. Converter removal

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