Um.. wouldn't the smell and fumes be a dead give away and give them a reason to look up under the truck? Just saying.

 

It actually didn't change the smell of the exhaust. It just smelt like putting a new muffler on as the paint and oils start burning off from getting hot

 

I wouldn't consider a hi-flow cat a waste of $100. Sure you can straight pipe it but that is also illegal and worse for the environment. I am no enviro-**** (I have a lifted Jeep and a V8 dakota lol), but I guess it more or less is just from being on off-road forums and no cat talk making the hobby look bad. I have run magnaflow hi-flow cats on both of my Jeeps and plan to get one for my truck too. Never tripped a CEL or anything and sounds great!

 

I have a magnaflow on my truck now; after wasting my time with a catco.. before that my cat had blown out (Different story there) but when it was blown out.. it was more or less a strait shot, no resistance.. and I did several pulls with it 0-60 and stuff like that.. MPG and all that..

The difference between no Cat aka "Gutted" more or less LOL.. to the MagnaFlow I have on now.. are not even noticeable. Plus my truck does not smell like an old Ford/Chevy.. I know here in Texas you roll into get your sticker; they smell that smell they are gonna check your CAT.. if its not even there you have a problem... or they are going to know its not working by the smell and fail right then on the truck no matter what OBDII says.

 

I wouldn't consider a high flow cat a waste either. It did smell different for the first couple days but after that it smelled normal. The engine sounds less muffled. I haven't placed the non fouler plugs on yet and I still have the CEL light on. At least I know what the problem is and can fix it. I'm waiting until I get a chance to throw a new exhaust on then do the cat and exhaust at the same time.

As for gas mileage, before I got about 170 miles to a fill up, my last two fill ups have been 185. A little better but it varies how I drive a lot.

A cool toy I use is called an ELM327 BT sensor. It plugs into your OBDII port and pairs with your phone to record a whole bunch of engine stats including instantaneous fuel mileage, fuel flow, and voltage from various sensors (including the o2 sensors). It's like $30. You might want to check it out to measure engine stats like that.

 

The only reason that I removed my cat is because I didn't have the extra money to replace it and it was blown out any ways. Eventually I will put one back in

 

ok now that are talking about cats why do you talk about 1....? mine has 3 cats....

 

Mine has one. Single 2.5" i/o exhaust on a 3.9 v6. Isn't the v8 5.2 a dual exhaust?

 

Depends I guess.. My 97 which is EPA not Cali emissions only has 1 Cat; others and I think they did it to all the 4.7's (I could be wrong) made them all with cali emissions.

 

All come stock with single pipe exhaust.

Where are you guys getting your hi-flow cats the cheapest?