ok, I'm sure that this has been talked about before on here, but i'm going to have to ask for imput from people that have done this.

my 1998 ram 5.9L auto 4x4 , I want to remove the cat from the exaust system.
these trucks have the O2 sensors before the cat and after the cat.

now by removing the cat how will this affect the truck performance and the readings from the 02 sensors, engine light and such?

what problems am I going to run into?

should I remove the cat and install a straight pipe in place or just remove the cat and clean it out knock out all the stuff inside it and reinstall the origional housing?

any and all thoughts are greatly welcome...thanks Dave

 

Hey Dave,

I have a 97 5.9 4x4 that I removed the guts (see also gutting the cat threads) after it plugged up, causing me some issues. What I've noticed after gutting it is the following:

1) louder (haha)
2) a little more top-end RPM, but loss in torque
3) under heavy load (towing) it will trip the O2 sensor CEL

All of which are no big deal, once I am done towing it resets itself, and all is well again. I have run mine like that for about 6 months, and am actually going to put a CAT back on it again, probably a magnaflow from Summitracing, as its just not enough of a gain for all the little annoyances that I've run into.

A lot of guys on here have had different luck with different exhaust configurations, good luck!

 

i buried my truck in a mud hole about 6 inchs under the door handles. ( quick drop off) i then noticed my truck did nto run correctly the next day. i then had the truck to the point it did not start at all. i had to get the cat, gut it. and then i put in place of the muffler, and glasspack from cherry bomb. that is all i run and i noticed it is alot louder then almost any truck i have come across but i sounds good, not a mbad kind of loud, i have accually gotten alot of complimants by it. and i did get a few more rpms out of it, but i felt no loss of torque or power, but i do have a constant check engine light now, becasue i have both my o2 sensors bad. and need of replace. although it is my case aswell. i am going to be buying a magnaflow cat from summitracing, but that will be next year when i do my exhaust full dual all the way out the rear

 

with the new flowmaster cat or even with the guys that gutted out their cats, did you notice any improvement in MPG ?

 

I changed my muffler to the super 44 flowmaster...awesome sound! I didn't notice any major change in mpg...maybe a little less off road and l little more hwy.

 

I am going to assume that the 98 has the same problem the 99 has, in that the cat acts as a Y-pipe... if so... have funn haha your best bet to look legal is to cut it off, gut it, and put it back on.

 

yeah it is "y" just before the cat, I'm just worried about gutting it now and throwing the o2 sensors off and tripping the engine light and putting computer into default mode and loosing low end power and mpg
just repaired the plenum and put the after marked alum plate on in place of the metal cover
runs much better, just looking to get a few more mpg out of it
has anyone took the cluch fan off and install a elect fan to get any gains?
or has anyone put the royal purple oil in the diffs and such to see any gains?

 

get a highflow , its like not having a cat, made my truck like 3 times louder

 

i have the e-fan setup and never really noticed much a difference. it made it rev up a little quicker. other than that i never felt any difference, or seen any mpg difference,+ or -.

 

Forget try to gut it when you have the Y-pipe setup. Just get a magna flow cat. And if the cat is clogged somewhat, you are doing the work you've done no good by running it like that.