I want to replace the cats on my 2002 F150 Screw. I thought I could just cut out the 4 cats, (2 pre, and 2 cats) and replace them with one set of Hight Flow Cats from magnaflow.

I am so confused after getting off the phone with Magnaflow...They told me I have to replace the precats with 91000 series, and the cats with 94000 series. They wanted to know where the o2 sensors were ect...

Simply, can I cut out the 4 cats and replace with 2 highflow cats.

If so, what is the part number for the Magnaflow Cats for the switch out.

...and are the primary o2 sensors mounted before the precats and the secondary o2 senors mounted after cats, or are they mounted in the bodies of the cats...

in other words, are the sensors mounted with a bung on the pipe both pre, and post cats, or are the sensors part of the cat system.

Tks
Peace
Willfulone

 

im not 100% sure if the sensors are directly on the cats or not, ill have to go look. I take it you have the 4.6 since youve got 4 cats (?)

yes you can replace the stock 4 with 2 hi flo's, just make sure that the oxygen sensors are still spaced as far apart as they came from the factory. You can weld in 2 cats and then drill your remaining rear sensors into your exhaust pipe behind your 2 cats, just as long as they are as far apart as they came from the factory, so that they can accurately measure the same amount of air that is passing by them. At least thats what an exhaust installer told me and thats what a guy i know that had hi flos put on a truck identical to yours. I want to put the 94100 series (shorter cats) on my truck cause im running straight pipes as it is....that will be LOUD!!!
Also, our trucks use the cats that do not need the 'air' hookup or whatever its called, youll see it on the internet if your buying them off ebay...theyre cheap on there.
Hope this is accurate and helps you.

 

I did what you want to do. First I cut off all 4 cats and left the O2 sensors right where they were. Then I put in two Magnaflow High Flow cats (one on each side). I drove it around for a while and found that it wasnt nearly as loud as I hoped or expected it to be. So i ripped those off and had stainless steel pipe welded in there place, that was no easy job. Then I got a set of Steeda MIL Eliminators, you only need one for each O2 sensor downwind of the cats. I now have the loudest truck in my area by far. I had a Flowmaster 40 series on it, I raplaced that with dual Dynomax Bullets off a Y pipe and now it has that machine gun sound I've been looking for for over a year. In short, the best cats, are no cats at all, and if you live in an emmissions controlled area, like I do, I feel bad for ya, but theres always a way around it. And no the O2 sensors are not part of the cats themselves.

 

These are the cats I have sitting in my basement:
http://www.troyerperformance.com/cgi...atalogno=94306


And these are the MIL Eliminators I have:

http://www.crmotorsports.com/Merchan...tegory_Code=F1

 

those cats you have in your basement arent the ones that im looking to puto my truck, im looking to put the 94100 series (shorter than regular hi flos) This will probley be louder than the regualr ones, plus im running no mufflers and im in an area that has never checked for cats,etc, but theres always that chance.

 

They may be shorter, but thats just to save space. The salesman at Magnaflow said, by emmissions controls standards ALL catalytic converters have to have the same amount of packing in them, how its set up inside the cat is all up to the manufacturer, the the amount of packing is all the same. And I also had no mufflers with straight pipes when I was driving around with the so called "high flows". The only reason I didnt put my muffler back on is because I didnt want to have all that work done and end up not liking it, which as it turns out, I didnt. So when I took them off all together I took the temporary piece of flex pipe out and put two brand new mufflers in. All I'm saying is, it sounded the same with the "high flows", and ten times better without them. I know a couple off guys who went through the same thing I did, and if you look around this site you'll find a couple guys on here who did too. But, like they say, to each his own.

 

So you seriously couldn't tell a difference with straight pipes between the stock 4 cats and the two Magnaflow cats? If you'd like to sell them, shoot me a price. Thanks.

 

Oh yea, you could tell there was a difference, but it was no where near what I was hoping it was going to be, you could still tell there was cats on it. I wanted a sound like there wasnt, and I found the only way to get that sound was to run without cats.