FUBAR'd catalytic converter and muffler

[skunked]

Now I know that most of us here DON'T run cats but a word to those of that do. I just had the muffler shop run a backpressure test on my GW and found the cat was dead and had taken the muffler with it. Had it replaced and what a differnce it made, better acceleration and MUCH better sound. If you are having poor acceleration and bad miliage you should check you cat and muffler. I had always heard that this could make a difference but never knew how much.

[carrotman]

Your trusted vacuum gauge will show if your exhaust is clogged.

[Careful34]

How does a clogged cat mess up the muffler?

[Poley]

just cut off the CAT and never look back!!
unless you live where they have emissions. that must suck!

smile.gif

[89er]

How can I use a vacuum guage to check the cat/exhaust? Got one - never used it.
Thanks.
R.

[krejr]

Yes, I live where they have emmissions, and it does suck. But fortunately, we only get "smogged" every two years, so we could not-quite-legally get smogged, then take out the CAT and replace it in two years. I just may do this.

[SBJeep]

krejr - I just did this on my '79 F-150. I had the shop put on 2.5" three bolt header flanges and make up a straight pipe to match. The interesting thing is that when I took off the cat and put in the straight pipe, there was no increase in power. The new hi-flow cats aren't very restrictive. I can see right through the honeycomb pretty easy. The only catch with the GW cat is that we have the air tube on the side, so some connector would have to be made there.

I knew the cat in the GW was clogged when it wouldn't keep up speed on steep grades. It would downshift to 2nd when pulling even the slightest grade. After the cat was replaced and a stock style muffler put on, it never downshifts on grades even when loaded to the ceiling and pulling a 2000# trailer.

[ March 09, 2004, 06:11 PM: Message edited by: SBJeep ]