Air tube?
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Air tube?
Sorry for another long post but all this is new to me.
I have a 1993 F250 with 351w engine. The exhaust needs to be changed and i was thinking of going to duals, however the cat has me a little stumped. There is only one cat. On this truck the Y pipe is welded to a flange with a 4X6 oval opening and the cat has a matching flange with 4X6 oval opening. Rather than replacing the cat with a similar one and then going with a single in dual out muffler, I wanted to replace the cat with a dual in dual out model and then connect to a flowmaster dual in dual out muffler. The problem is that the stock cat has an air tube connected to it and no dual in dual out cat that I can find has an air tube. Do I have to use the air tube?
Thanks in advance
I have a 1993 F250 with 351w engine. The exhaust needs to be changed and i was thinking of going to duals, however the cat has me a little stumped. There is only one cat. On this truck the Y pipe is welded to a flange with a 4X6 oval opening and the cat has a matching flange with 4X6 oval opening. Rather than replacing the cat with a similar one and then going with a single in dual out muffler, I wanted to replace the cat with a dual in dual out model and then connect to a flowmaster dual in dual out muffler. The problem is that the stock cat has an air tube connected to it and no dual in dual out cat that I can find has an air tube. Do I have to use the air tube?
Thanks in advance
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Joined: Sep 2002
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From: kansas
Air tube?
Yeah you'll need the tube. The cat needs the air to keep from plugging up. You could try plumbing the tube in ahead of the cat. However, this probably isn't completely E.P.A. compatible. Do you have to live with inspections? If so ask the local inspection agency. I understand the emission laws are interpreted differently from state to state. Some states may accept moving the tube. I doubt that california would.
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Air tube?
No we dont have inspections here as of now but I wanted to keep it legal. Are there two types of cats then? Ive seen cats with air tube fittings, some without and even some with 2 air fittings. What are the different types for? Just trying to learn before I tear it all apart.
Thanks
Thanks
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From: kansas
Air tube?
I know there are different types of cats. Some are high flow, some not. I think the diff. is in the shape of the catalytic material itself. There may also be varying compounds or types of cat materials. Please note the "I think" and the "may". I do not have any serious facts to support these statements. But all cats require air to burn off impurities and keep the cat clean internally. Those cats without the tube fitting are most likely for an application where the air is put into the exhaust before the cat. For ex. my 92 4.9 had two cats. The first was fed air through tubes fed into the exhaust ports in the head. The second was fed air through a tube. Although it went into the pipe before the second cat.
As to the two tubes on one cat, I don't know. I would guess that it's a universal setup. Having multiple tubes lets it fit multiple applications? Maybe somebody else will have a better answer for you. Cause that's all I got. Sorry I couldn't be more specific.
Catchya later.
As to the two tubes on one cat, I don't know. I would guess that it's a universal setup. Having multiple tubes lets it fit multiple applications? Maybe somebody else will have a better answer for you. Cause that's all I got. Sorry I couldn't be more specific.
Catchya later.
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From: Midwest
Air tube?
My 91 f-250 has a 460 and has the long single cat with two air tubes from the factory. All the f-150 trucks I have seen have the single air tube which would lead me to assume the dual air tube is a 460 specific application. However with 180,000 miles on it one of the tubes rusted off, so I welded it closed on the cat and haven't had any noticeable ramifications from this cheap fix.
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Air tube?
Thanks very much. The Dynomax cat seems to be exactly what Im looking for. It still doesnt have the rating of the oem cat but I think Im going to go with it anyway.
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