The old CAT and O2 sensor problem

[1961Mustang]

Hey all, just a quick question/clarification here: ok so I put the flowmaster super 44s on my 91 coupe, and it doesn't sound much different. I wanted it loud! My technician says its because my car has 4 (!) cats. Now, if I take all four cats OFF and just run pipe where they were, will it trip my O2 sensor/check engine light? An off-road h-pipe is not in my budget. I'm told the O2 sensors are up below the headers (I have Mac shorty headers) and so I should be able to just pipe it through and remove the cats. Also, if i do end up tripping the check engine light, will it run badly or just be a light on that's annoying? Thanks for any help and EXPERIENCE.lol. (Ps I have no emissions testing where I live and I'm not worried how loud it is)

 

[ttopstang]

Just installed a x pipe with no cats on my brothers 92, exhaust sounds great and no CEL. He has the 40 series flows and the taking the cats off made a huge difference.

 

[BlownFiveLiter]

There will be no check engine light with no cats on any OBD I car. There's no downstream O2 sensors to determine whether your cats are working properly.

 

[jrichker]

There will be no check engine light with no cats on any OBD I car. There's no downstream O2 sensors to determine whether your cats are working properly.

He's right... follow his advice.

 

[1961Mustang]

Yeah I am hoping it will make a big difference. A shop told me it would be about $200 to take the cats out and put a pipe in on each side. I am thinking about having this shop do it. But, I was wondering if those "flexible exhaust piping" things at autozone are any good? I could just cut the cats out myself and clamp the flex pipe in place. Good or bad idea?

 

[Gearbanger 101]

Yeah I am hoping it will make a big difference. A shop told me it would be about $200 to take the cats out and put a pipe in on each side. I am thinking about having this shop do it. But, I was wondering if those "flexible exhaust piping" things at autozone are any good? I could just cut the cats out myself and clamp the flex pipe in place. Good or bad idea?

Tell the guy at the muffler shopt to keep his money. You can buy a brand new catless one (in a 2 1/2" diameter too boot) for about $75 less than that?

 

[1961Mustang]

Right, but then how much to cut out the existing pipe and cats and install the new cat less piping? I have to think of TOTAL cost, not just parts.

 

[Gearbanger 101]

Right, but then how much to cut out the existing pipe and cats and install the new cat less piping? I have to think of TOTAL cost, not just parts.

There is no cats to cut out, or pipe to instal. The whole system is bolted together and changed out. If you've got a jack and wrenches you can do it all yourself, right in the driveway with hand tools. Here's an example.

http://www.americanmuscle.com/bbk-orhpipe-8693.html

 

[1961Mustang]

Ok I concede. I decided to skip the shop, I didn't really trust em anyways...I got a BBK x-pipe off road h-pipe on order from LRS. Thanks all!

 

[Gearbanger 101]

I got a BBK x-pipe off road h-pipe on order from LRS. Thanks all!

So which one is it....the X or the H-pipe? H-pipe = muscle car sound, X-pipe = sports car sound. Both sound better than stock.

 

[1961Mustang]

On the website they are collectively called "off road h-pipes" some with h-pipes and some with x-pipes. The one I got was listed as an "off road h-pipe with an x-pipe crossover section". Lol