I have a 90 f 150 4x4 you guys said a could remove all my cats and put exhaust on but my muffler shop won't cut the first cat off because he said it heats up th o2 senor and if you get read of it my truck will always run rich and crappy. My buddy tried to get them to put true duals on his 94 with a 302 and they said they wouldn't do it for 500 hundred dollar. It would run like crap they said if you remove the first cat but they said they would cut the last of second cat off but is would not be true duals is this true. Has sombody done this before. Please post.

 

I can't imagine how removing the cat would make it run rich. The O2s is in front of the cat, in the connector between the two pipes. They are probably more worried about the legal issues of cutting a cat out of a truck.

Jared

 

Also, nothing on a truck gets hotter than a CAT, I think it heats up to 1000 degrees or more. So removing the CAT would cool down the exhaust system.

 

how bout the air/fuel mix after the spark ignites?



They're right when they say it wouldn't be true duals, because that would mean only one of two tail pipes had a cat on it. There is a coupler that puts the two pipes into one before the cat. Maybe the cat is a double in single out... i don't remember off hand.

I can't see how the O2 sensors would get harmed.

 

[updated:LAST EDITED ON 09-Jan-03 AT 00:15 AM (EST)]That is a load of crap. Look at everything yourself: The O2 sensor should upstream from the cat, and the cat has nothing to do with its reading. As far as heat, O2 sensors are self-heating; they don't rely on absorbed heat. As far as rich vs. lean, it shouldn't really make a difference on your truck, but if it were going to be one or the other, it would make the truck run lean, because of the freer flow of gases.

Now, everyone else has brought up a good point about the shop not wanting to cut it off, and who can blame them. The potential fines are huge. I do a lot of work on vehicles for people, and I would never cut a cat off of any vehicle that was not mine or someone who I knew VERY well, for liability reasons. Of course, if that is really the reason that they won't do it, they should tell you the truth.

With that said, the guys at the shop are probably either ignorant or liars, and I wouldn't go back there.

Edit:

This is my disclaimer. A catalytic converter really does reduce the levels of several known pollutants by as much as 10 or even 100x, and does so with a *relatively* minimal sacrifice in power. I am not a tree hugger, and none of my vehicles have catalysts on them, so don't think that is what I am saying. I think cats are a great idea most of the time, and have no qualms with the fact that they are mandatorily installed on vehicles. However, if the only reason you want to be rid of your catalyst is just to say you did, or impress people with how loud your truck is, than I would question whether the benefit is worth the increased emissions. If, on the other hand, you really think you could use that extra 5 or so horsepower, I say go for it, and it is a great time to learn to use a sawzall and take things into your own hands. I just want to emphasize that I feel it is not a decision to be taken lightly..........

 

They said they wouldn't put exhaust on even if i cut the cats off two different auto companys. Is there away to test the cat when my exhaust is really cold first thing in the morning then drive my truck around a bit and let it warm up and test it later for different voltage rating or something.I kind of see what they are talking about because that cat gets pretty hot and the 02 sensor is just a few inches away in metal pipe that is the best conductor of heat.