Straight pipe and gut the CAT?

[tschwab]

Would like to hear from those that have straight piped their 12V and what are your impressions (performance and sound).

Also would like to hear from those that have gutted the CAT, has this helped performance, lowered EGT's, made the truck sound different/louder, any problems passing emissions?

Has anyone purchased the muffler elimination kit from Genos Garage and how did it work out?

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'98. 4 Bright White Quad Cab SLT, 2WD, 12 Valves & the BIG "P" Pump! 3. 54, AT, Trailer Tow PKG, Camper PKG, OEM Cab Lights, TST #8, Three pod A pillar gauge mount, EGT pre-turbo, 4" Exhaust Turndown, K&N Air Filter, 5th W. Hitch, Pace Edwards Roll-Top, Tint, 265 Michelins and turbo silencer ring AWOL!

23,876 miles - 1/7/01

 

[DavidGardner]

Terry
I removed my cat at 94000k and I could not notice any difference in power. The sound though is a little louder. You can hear the turbo better and if you have an exhaust brake installed you can hear it better when it is used. I bought the cat elimination pipe from the local Dodge dealer and they wrote on the receipt that it was a test pipe. Covering their a$$ probably. Any way I still have the factory stock muffler and like to listen to the Infinity sound system to well to make it any louder than it already is. Besides my wife still likes to ride in the truck and I dont want to make it so loud that it is oncumfortable for her. Just my opinion.

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95 slt, reg cab, 2wd, auto, BD exhaust brake, primelok fuel filter relocator, K&N air filter, Cat sleeping in garage by fire, TST 230-605 fuel plate, Bill Kondolay modified trans, 98,000 miles going strong. "Who says six in a row don"t go?

 

[Banshe]

Got a gutless kitty this past weekend. When I cranked my truck up, sprayed all kinds of black crapola all over my car! Also sounds just slightly louder than before. The only improvemnet I've seen so far, is a quicker cool down. My primary intereset was to reduce EGTs when under a load. Won't know if this affected the EGTs until I tow here in about 2 weeks.

"Banshe" Bill

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'95, 2500, 4X4, ext cab, white, 3. 54 rear end, auto transmission
Griffin Radiator, Banks Power Pak, Kondolay TC, Kondolay VB, 16cm Turbo, 4" exhaust, Horton Fan, Bosch 215, BD Governor Springs, Brite Box, Mag Hytec transmission Pan, aux transmission Cooler, Bully Dog Propane, Wiley Coyote strapped to my grill

 

[Scollins]

Tschwab,
Where in Western Washington are you located? I've got a '98 12 valve that I just straight-piped. Maybe we could arrange a time to meet so that you can listen to my truck (inside & out) and decide for yourself. I live in Renton and I work in Bellevue.

Anyway, I removed the muffler and the cat. I don't like the idea of gutting the cat, because it is VERY expensive to replace. Better to just let it sit in the garage. For my truck (regular cab, long bed) I needed a 3" pipe that was 5'4" long, with both ends flared to 3" inside diameter. Dan Fast Mufflers in Bellevue charged me $18 plus tax for the pipe. 3 hours of cussing, banging, swearing, cutting and more swearing later, I was set.

If I was to do it again, I would break out the Tiger Saw and just cut through the stock pipe and order a slightly longer replacement pipe.

As for the sound, it is louder, sometimes MUCH louder. Going uphill, hard into the throttle, it is LOUDER THAN LOUD, both inside and out. No sneaking up on the wife anymore in this thing! #ad


So far, I like the sound. But, I might install a Dynomax Ultra Flo in the future, just to cut down on the noise a little bit.

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Scott Collins
'98 Ram 2500 4x4 12 Valve Cummins. Slightly BOMBed! #ad

Renton, WA


[This message has been edited by Scollins (edited 01-25-2001). ]

 

[illflem]

Terry,I would never gut the cat,you never know when you might need that $600 piece of worthless on a diesel junk. Use a test pipe.

David,the cat elimination pipe has been called a test pipe by most everyone for as long as cats have been around. I bought one for a Toyota about 20 years ago that had-TEST PIPE FOR VERIFICATION OF CATALYTIC CONVERTER OPERATION ONLY NOT FOR PERMANENT INSTALLATION stamped right on it. It's still on it. One of the main companies that makes test pipes is called Test Tube,they always seemed a little heavy duty for temporary installs to me.

 

[RPhCummins]

Terry

Ditto to most everything above. I did the cat and muffler removal and welded in a little over 5 ft of 3" pipe. I think it sounds great. Performancewise, the turbo may spool up a bit quicker. It's just nice to let the ole' girl breathe the rocky mountain air easily. Before it was like breathing in thru your nose and exhaling thru a soda straw. Now things are better.

As said before on this site. "If its too loud there is a chance you may be too old. "

Have fun.
RPh

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1996 Long Box Club-cab, K&N filter, misplaced silencer ring, kitty and muffler are history, totally stock otherwise, 255/85 R16's, just waitin' to get bombed, Rocky Mountain Elk Foundation Member, Pioneer stereo system.

 

[mikepvg]

Removed my cat & muff @ 122K. Installed K&N oval @ same time. Don't know which procedure helped but it definately had more power after. Much easier to bridge that ridiculous gear gap between 3 & 4. Put silencer ring BACK IN & all was ok. LOVE that DEEP throaty sound between 1400 & 1600 rpm when accelerating w/o the loud whistle from turbo. Even "significant other" does not mind straight pipe since you do not really notice it @ hwy speeds over the clatter of the pump anyway. She DID MIND THAT WHISTLE!!! Is loud in town, but does sound cool. #ad
Had to torch both off. Muff shop welded on a nice SS pipe in place of muff for $30 (& repaired a few holes!) right after the "Dodge Cat Test Pipe". I definately would do it again. #ad


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94 2500HD 5sp 4. 10LSD 4X4 ABS w/GearVendor OD, K&N Oval w/ Pre-Filter, "STRAIGHT" Exhaust, Geno's Fumotovalve, 122,000 miles. NRA Member. V1.

 

[1tuffram]

I was at the emission shop on monday for my first emissions test. I talked to the guy about the cat (since I want to remove mine). This is what he said. He told me that the cat is not exactly like a catalytic converter on gas engines. He kept refering to the cat as a "cat trap", he was vague on the explaination, but said it doesn't really burn the emission stuff all that well and acts sort of like a particle trap. I am confused on this, but that was all he said. He did say that cats on diesels are useless junk because all diesel emission tests are for opacity and not hydrocarbons, etc. like on gas engines. The cat appearantly has little to do with what they are testing for... SMOKE particles.

I then asked about removing the cat. Guy said if vehicle came with a cat it has to be on in order to pass inspection part of the emission test. Said if his book says the truck came with a cat or other emission equipment and it is not on the truck he can not pass the vehicle (even if it passes the opacity test with flying colors). Said you would not get fined for cat being off, you just have to put it back on in order to get the pass emission papers to renew your registration. Was told I would have to pay the $45 even though did not pass and then pay $45 again when came back with the cat on.

If anyone can further explain the "cat trap" I would appreciate it. After listening to his vague explaination I question why it is even on the truck since emission testing is only concerned with smoke and the cat apparently does a poor job of "burning" any of the emission stuff it was designed to. Is the cat suppose to "burn" off some of the stuff which causes the smoke?? If not I see no use for it and will replace it with the "test pipe" and simple slap the cat on for the annual emission test.

For what it's worth I use Amsoil's Diesel fuel concentrate and cetane boost. Guy said my opacity readings was cleaner than what he normally sees on Dodge trucks. Guess maybe the stuff works.

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'95 2500 SLT 5 speed 4x4

 

[SMorneau]

I am dumping the muffler and cat tomorrow. A straight section of 3" will go in their place. I will let you know about the noise.

I don't know about lazy goverment employees but maybe Mr. Clinton could pardon you on the cat removal (estimated cost $1,000,000).

 

[danandamy]

You may ALREADY be on Clinton's pardon list, heck there's so many you may just not know it yet #ad
LOL!
My kitty received a labodomy a little over a year ago. Left the shell on so I can pass safety inspection. As per the above post, if it came with one it has to be on there to get a sticker. Even gutted, it seems to help muffle the sound a little bit. My straight exhaust after that is kinda stealth. Dual 2. 5 straights out each side. It gives me the option of smoking rice burners on either side of me #ad


Daniel

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95 2500 SLT Laramie 3. 54, automatic,Herculiner bed liner, JVC cd out of factory infinity system, southwest grill gaurd (a favorite amongst the deer population), K&N chunked, AFC adjusted, dual straight exhaust out of "gutless" cat, Geno's dual EGT/boost gauge, TST #6 plate slid all the way forward, AFC housing slid all the way forward, silencer ring removed
"Don't be scared V8's, it's only a 6 cylinder"

[This message has been edited by danandme (edited 01-25-2001). ]

 

[Archive]

I am going to the shop in the morning to take my Muffler Elimination kit I got from Geno's to get installed, Since I live in Ga. Diesel's are NOT YET required for emissions. The big debate for me is the cat. Since it is indeed worthless. But I will keep it if they decide to test diesels. Anyone in Ga. running straight pipes?

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-- email address removed --

 

[chrgr446]

Just put 4" from turbo to 5"chrome tip no muff no cat. You can not belive how loud this thing is. No really, this thing is incredibly loud, I mean at 2000 rpm the noise is deafining. (but it's sooo cool) I think I'll leave it for a while. Turbo spools up quicker and cools down quicker. Performance is tough to compare as I did the gov. spring kit at the same time (hows 110 mph with 4:10 gear?)

Originally posted by tschwab:
Would like to hear from those that have straight piped their 12V and what are your impressions (performance and sound).

Also would like to hear from those that have gutted the CAT, has this helped performance, lowered EGT's, made the truck sound different/louder, any problems passing emissions?

Has anyone purchased the muffler elimination kit from Genos Garage and how did it work out?

 

[The patriot]

I put a test pipe on about 4 months ago. I noticed a good drop in EGT and spool up time.
I did NOT pull the muffler.
When I took it to the inspection (N. J. 's inspection is historically a B!TCH) the wife noticed two workers conferencing by the truck. I suppose it required to much thought, so they passed it. #ad

I might have got lucky. I have an 98, and the "over valved" trucks have no cat. Mine is properly valved, so it's supposed to have one.

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98 Quad cab 4X4 2500 12 valve,5 speed,3. 54 rears, 8' bed. Boost and egt gauges but basicly stock except for a "properly adjusted" AFC. Cat in the garage. Uniden HR 2510, Texas Star 1200 amp. 59,000 Mi as of 10/21/00.
NRA life member. High power/IDPA.

 

[illflem]

Tuffram,good info. The only reason the cat is a soot trap is that it clogs up and becomes more of a filter,not what it was designed to do. Here' what Chevron has to say about cats;

"Catalytic converters can be used to remove pollutants from diesel exhaust. Oxidation catalysts, similar to those used in gasoline cars, convert unburned hydrocarbons and carbon monoxide to carbon dioxide and water. These converters are not as effective as the ones in gasoline vehicles. Sulfur from the fuel tends to deactivate the catalyst, and the particulates in the exhaust gas build up on the catalyst and physically block the exhaust gases from the catalyst's surface. The cooler temperature of diesel engine exhaust, compared to gasoline engine exhaust, also reduces catalyst efficiency. Fortunately, hydrocarbon and carbon monoxide emissions from diesel engines are inherently low, so after treatment to remove these pollutants is rarely needed. "

What I glean out of this is we really don't need a cat,it becomes worthless anyways and will restrict your exhaust flow when it clogs. My feeling is that DC was gasping at straws to meet EPA regs and that the EPA approved it for who knows what reason.

If your testing is what tuffcat describes it may be best to gut the cat or to put it back on before the inspection. It won't be as hard to remove and reinstall as it was the first time unless you reef down on the clamps like Dodge did. I also think that the rule that if it came with the rig it's required to stay on the rig also applies to the muffler. There are free flowing mufflers to circumvent this.

Tuffcat did the inspector actually look in a book and under your truck for a cat. If he did I'll bet he only did it because you said something. My experience is that most govt employees are inherently lazy. I have yet to hear of one person on this site or elsewhere failing the test due to a missing cat,but it could happen. I'm sure glad that we don't have emissions testing here where I live,but if ever happens I've got my cats sitting in the boneyard where they belong,just waiting.


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95' 25004X4,AT,Driftwood,Banks Stinger,Warn fender flairs and running boards(work truck)
95 3500,5 speed 3:54,BD E-brake,Driftwood,Banks&Psycotty,34,000 GCVW apple and tractor hauler(works harder truck)

 

[BertM]

Scary, I am on Wade Green Road. Give me a call and you can hear a 3" straight with a #6 plate and RE-0880.

 

[rich m]

Originally posted by RPhCummins:
Terry

Ditto to most everything above. I did the cat and muffler removal and welded in a little over 5 ft of 3" pipe. I think it sounds great. Performancewise, the turbo may spool up a bit quicker. It's just nice to let the ole' girl breathe the rocky mountain air easily. Before it was like breathing in thru your nose and exhaling thru a soda straw. Now things are better.

As said before on this site. "If its too loud there is a chance you may be too old. "

Have fun.
RPh

the environment's important.
so's your health.
It would be bad for a health professional to set a bad example. With this in mind, consider that 2 out of 3 TDR pharmacists recommend that the cat be neutered or removed from your environment... . the third lives in Iowa, and I don't remember whether his is gone, too... could be unanimous #ad

#ad

"kinda like givin' the truck Proventil and Ex-lax all at the same time!"

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mildly BOMBed 98. 4 1B7KF23D4WJxxxxxx-- BD's #5 plate and 210HP injectors--BD Brake and the associated transmission bomb goodies (except for TC,currently), 4" open exhaust (short),Psychotty, camper shell, Warn front receiver, G159Unisteels on Rickson 19. 5's. . CD player is bone stock, so are the seats. PrimeLoc, also remote spin-on filter for the auto trans... Pyro,Boost and Trans temp from Isspro,
Westin nerf rails(black),
bent welding rod to hang celphone on dashboard...
240HP on Dynojet from 75-105mph drumspeed.

[This message has been edited by rich m (edited 01-26-2001). ]

 

[1tuffram]

illflem,

Thanks for the info. It helps clear things up. The inspector guy seemed a little unknowledgable. I asked what the up-coming emission regulations would consist of and he told me he had not heard of any new regulations. I said something to the effect I thought there was suppose to be new regulations sometime around 2004. He said "nope, and I'd be the first to hear about any". From that point on I had my doubts. He did say "IF" new regulations where to come out they may start testing for hydrocarbons, etc. If that is the case it will be a whole lot harder for diesels to pass. He said as it is now you have to be belching out big black smoke clouds to fail. He said the emissions testing is really a bunch BS and a way for someone to get some money because newer diesels built now days are designed well enough "they are pratically guaranteed to pass".

As far as if he actually inspected for a cat I don't know. I was not allowed in the shop, he closed all the doors and told me to wait in the office (this really bothered me big time, I don't take well to my baby being out of sight when work is being performed). After the test I asked what he did and was told the process, part of which was a visual inspection for emission equipment. I asked if that meant a cat and he said yes sir. When I asked him how he knew what to look for (since some model years don't have a cat) was told there's "a book" which lists all the different diesel engines, makes, years, etc and what emission equipment the vehicle came with from the factory. Basically if it ain't there you pay the $45, fail the test, and return when the equip is installed and pay all over again (guess this is better than being fined or turned into the EPA). I also think he said you have like 30 days or something to be "in compliance". Don't know what happens after that. There was a sign on the wall that said for light duty vehicles(our trucks)you are allowed so much money to spend to get the vehicle "in compliance" (think it is $750 for light-duty and $1500 for heavy-duty) if you still fail the opacity test the district manager can (at their descretion) sign a waiver or something so you can register the vehicle. The inspector could not tell me much because he has never seen this happen. The only truck he ever saw fail was because the owner had a bad batch of fuel, once the fuel was replaced the truck passed.

After listening to him tell me they are inspecting for cats, I am hesitant to gut the cat. I may only be a matter of time before they wise-up to this trick and if emissions testing is going to get tougher in the future they may very well be looking for stuff like this and they may not look too lightly on violations of this nature. Maybe I'm a little paranoid now, but who's to say "big brother" is not monitoring all the boasting of gutted cats / catless exhaust system here (we already know DC is watching). Just a little something to think about.

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'95 2500 SLT 5 speed 4x4

[This message has been edited by 1tuffram (edited 01-26-2001). ]

 

[hank]

Tschwab
Lost my kitty a couple of weeks ago and have about 100 miles on the ole girl since (47k total). I've noticed quicker turbo spool up, 50-100deg lower egt, too early to tell improvement in mpg. Was running 19. 5mpg avg. The first time I got on it hard I noticed a large belch of gray-black smoke in the rearview mirror. I don't now from which part of the exhaust system that came from but it had to be clogging up something. Since then virtually no smoke at any throttle. The sound is sweet but a little on the "sharp" side. Im considering a Banks Dynaflow muffler in place of Geno's Muffler Eliminator kit just to mellow the sound a little.

 

[zzman]

You have to get a open pipe,see signature,
they sound like a 18-wheeler inside and out
[I use to drive one] #ad


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97 3500 SLT REDext cab duelly p/u 5sp 3:54 2wd 245/75R16
3" straight exhaust stock torque plate slid full foward star wheel tweeked
105,000 miles still with plenty of ZOOM... ZOOM... ZOOM

RON Z

 

[JEmmons]

Put in the muffler eliminator and gutted my cat almost two years ago. Neighbors run to the curb with their trash at 4am when I leave for work (think the garbage truck is here). #ad
Low rumble sound, lower EGT, turbo spools up sooner and cools down quicker. It adds the little extra attitude that the Cummins needs. You will turn some heads going through town.

98' clubcab 4x4 12v auto 3. 54rear.