98k1500 Exhaust

[Sadistic11B]

Well this is my first post, so here it goes. I had a brand new gm long block swapped after the old one finally gave up the ghost @ 173,000 and some change. My question is this, Ive had the SES light on before the new motor went in and it was for a catalyst deficiency. Obviously the computer is still throwing the catalyst code so I figured its either a bad 02 sensor(s) or I actually need new cats. Im guessing that its probably the cats, since theyre roughly 12 years old. I was wondering what the advantages were to having a hi-flow catalyst system versus just stock replacement parts, other than sound level. I found a link here on the net, http://www.racepages.com/products/?N=11920...9925+4294967257 , The one I think i need is at the very bottom of the page, but im not an expert so who the hell knows what I need. Any suggestions, comments. Oh, also looking into getting a nice set of extremely low maintenance headers (if such a thing exists). Thanks again. maybe i can attach a pic of my ride, cross your fingers

 

[mcreyaufmiller]

The high flow cats are much better, they do not have the back pressure of the stock units so they allow more exhaust. The best thing is that they are cheaper than the stocks. In most cases, you can sell the olds to a scrap yard for more than the cost of the new ones installed. I have recently gotten a quote from a recycler for $110 per for the stock truck cats, I have an exhaust guy that installs high flow units for $50 each.

[gregrocks89]

i ran magnaflow high flow cats and i didnt have much care for them. but thats for me. They still threw my 02 sensor all the time. But your truck could be different. I just cut my cats out. i've done it to every truck i owned

[nubuilder]

I went with a custom 2.5 inch system. I used MagnaFlow 99006HM 2.5 inch universal high-flow (they also carry a universal 2.25 and 2 inch). I paid $83 each. I too was occasionally getting a code BEFORE the new exhaust. It said that the cat on the passenger side was not performing optimally. I guess this is common in these trucks (only the one cat throws the code all the time). I had replaced both rear O2 sensors and it still did it (again, these were replaced 2-3k before the exhaust was done). Anyways, if you have completely stock exhaust and headers, MagnaFlow makes a direct bolt in but it is something like $310. The part number is 23453 (I was looking at it, but I have Thorley Tri-Y headers; not compatible at all). I think it is either 2.25 or 2.5 inch. It goes from stock/shorty headers back the the flange after the cats. It is a nice setup, but will only work if you have stock exhaust.

 

I've had my exhaust for 2.5 months now and still no codes what so ever.

 

As far as I can tell, the only difference is that high-flows are a lot cheaper (and you will only get like $5-15 for them at a junk yard).

[91CamaroRS]

Just cut the cat. The cats on my 98 failed in 2005 back when my dad owned it. At the time it had mabye 70000 miles. Now it has 117000 and still running strong!