How can you say that?

I don't see the OP posting about engine operation problems....

 

The increased exhaust back pressure not only robs power, but it can raise combustion chamber temps. which can lead to head cracking, a pretty common problem on these thinwall head castings.

 

Just using my own personal experience. I cut my cat out 9 months after I did the plenum change, not because of engine performance issues, the truck was running perfectly, but because I wanted it gone, and sure enough it was clogged up. Truck is much more responsive and even holds overdrive much better with the cat gone too..

 

How does it sound without the cat? You got a muffler on there?

 

Stock muffler at the moment. Not the best video but;


Little rapsy when you let off from getting on it. It's quiet when driving though, you don't notice it.

Wanna put in a MagnaFlow sooner or later...

 

I actually quite like that! Might have to pull mine off, cept I got emissions round here -_-
Not to thread jack but how did you remove and install pipe?

 

Removing the pipe is a PITA because there isn't much room between the top of the pipe an the bottom of the cab, but I used a hack saw and an air grinder, then welded in the new pipe, which for the same lack of clearance on the top is a PITA too.

 

It all the same size? Ive never actually looked that far up on mine lol

 

No. The cat inlet is 3" and the exhaust pipe after the cat is 2.5". Had to get creative as none of the part stores in town had a 3" to 2.5" reducer, bastards.

 

+10000 to that. Had a SIGNIFICANT increase in low end torque and overall performance when switching to an O/R Y, even on a 100k km truck. The driveability on the highway was so much better, and I gained around 2mpg.

Feel lucky that you have a a SI/SO cat that you could just cut and replace. I have a '97 and had to go with a Jeg's offroad Y and which I need to swap out for the stock one every 2 years to do my emissions test. It is a PITA but totally worth it for the substantial performance/mileage gain/sound increase.

BTW you really need a muffler for that thing, it has the potential to sound infinitely better than it does now