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Time For Cats

saltwater_addict

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saltwater_addict Enthusiast

saltwater_addict

Posted
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My truck has been really "tired" feeling for a while now, and it finally lost top end power, so i put the vacuum guage to it, and found out the cats are plugged. I was looking into hi flow aftermarket cats, such as magnaflows, but cant find any in 2.75 inch. im 99% sure that our exhaust is 2.75, at least that is what i have gathered from aftermarket muffler research. If anyone has bought and welded in some of these aftermarket cats, can you provide me some insight, or maybe even a part #. I cant barely even get up the hills here. Its killing my mileage and i need to get this fixed as soon as possible with spending as little as possible(as usual). Thanks

redvett Senior Enthusiast

redvett

Posted
Posted

OEM cats are high flow. Unless your engine has a bigger cam and head work along with a bore job anything bigger than the stock is a waste of money.

z85violator Enthusiast

z85violator

Posted
Posted

just get buy the 2 1/2s and get the muffler shop to adapt or flare out to 2 3/4. let them worry about it.

saltwater_addict Enthusiast

saltwater_addict

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yah seems like the 3"s would be easier for that since you would have a fat weld on outside but absolutely no restriction, like if they put the 2.5's in the 3's. i dunno i just know i have to get this fixed sooner than later. my truck feels like it has 44's on it. theres no one on here who has first hand experience? ive read posts where they did it, but didnt specify which they used. PLEASE someone help me.

BowTieDude Enthusiast

BowTieDude

Posted
Posted

Whether this is true or not, I don't know but when I asked my local muffler shop last year this is what they told me. They said if you cut out the cats and weld ones in they will either not satisfy the post cat O2 sensors and/or the welds will fracture due to the extreme angles there are on these trucks. This shop has been in business for 20 years and I trust them, they've always given me good advice and they have the best prices local to me.

HyperBuzzin Enthusiast

HyperBuzzin

Posted
Posted
why not just take the old pipe off and gut the bad cats?

 

 

You forgot to add....

 

....And then put a piece of electric tape over the illuminated SES light.

saltwater_addict Enthusiast

saltwater_addict

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i dont see how they wouldnt satisfy the 02 sensors since they have to be 0bdII compliant. i dont even know about the weld fracturing, looks like ill guinea pig for yall. we have emissions test in tx(in all counties that surround houston) but i need to pass emissions tests

cmoore74 Enthusiast

cmoore74

Posted
Posted

Be careful adding cats that are significantly higher in flow than stock. On a previous vehicle I had the OEM cat go bad and I replaced it with a high flow cat. My engine light came on throwing an O2 sensor code. New O2 sensors did not cure the problem. Turns out the cat was too high flowing causing the exhaust temperature to drop below the min required for the O2 sensor. I also lost some low end torque. This was a 1990 Blazer with a 4.3L so it would have been OBD1. Maybe this is not a problem with the OBD2 set-up with the additional O2 sensors, but be careful.

saltwater_addict Enthusiast

saltwater_addict

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well thanks for the help yall, it literally just went out on me. i got it home at about 3500 rpm, oh yah and its freaking monsooning here so i guess itll be awhile before i can post back on what fixed it all.

1ntimid8r Enthusiast

1ntimid8r

Posted
Posted

I just replaced both of my cats with Magnaflows. They are awesome. the truck now has more get up and go than it ever had before!!!

 

I spent the $450 for the 2 cats and "Y" pipe. I recommed it if you have the money. Simple bolt construction, took 2 hours to replace them. No problems with the O2 sensors, etc.

AFD256 Enthusiast

AFD256

Posted
Posted
I just replaced both of my cats with Magnaflows. They are awesome. the truck now has more get up and go than it ever had before!!!

 

I spent the $450 for the 2 cats and "Y" pipe. I recommed it if you have the money. Simple bolt construction, took 2 hours to replace them. No problems with the O2 sensors, etc.

 

 

Did it make the truck louder? Do you have the stock exhaust?

saltwater_addict Enthusiast

saltwater_addict

Posted
  • Author
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it was the actual magnaflow setup? i just saw the weld in's, and yah i might have to look into it. thanks for the replies. ive already had the y pipe off (to pull tranny) and i put never seize on the bolts. makes it go much faster the second time around. thanks for the reply.

HyperBuzzin Enthusiast

HyperBuzzin

Posted
Posted
i dont see how they wouldnt satisfy the 02 sensors since they have to be 0bdII compliant. i dont even know about the weld fracturing, looks like ill guinea pig for yall. we have emissions test in tx(in all counties that surround houston) but i need to pass emissions tests

 

Well, all I know is, the previous owner of my truck had the cat gutted, and eventually I had the SES light. Changed both O2 sensors and still had the SES. Put in a new cat and all's been well since.

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