Can anyone tell me FOR SURE how many catalytic converters are on my 2003 F150 Supercrew with the 5.4L engine? I've asked a couple times now down in the exhaust forum and I've been told 2 and 4... both by people who swear they know what they are talking about.

Can someone up here, hopefully the ever helpful Racerguy, tell me WITHOUT A DOUBT how many catalytic converters I have? Thanks.

 

Well rambo,
according to the 2004 Edition of: Emission control systems application....... all 5.4l engines for ford vehicles with a GVW of 8500lbs or less have 2 cats, with only one exception: natural gas vehicles, which have 2 light-off converters in y-pipe and 1 TWC.
Now the vehicles over 8500 GVW have 1 type TWC cat, again with the exception of the natural gas vehicles which have the same setup as the under 8500 GVW vehicles. If you were wondering a TWC is a 3-way cat.
Hope this helps!
lariatrider rides on.....

 

So that would mean I have one catalytic converter on each side of the Y pipe... I'm wondering if replacing them with high flow cats will make much of a difference in sound or not... any opinions on that? I've been told the stock cats are pretty much high flow cats on the newer models.

 

Rambo I'm not real sure if they are "high flow" or not, But I can tell you this the easiler the exhaust can get away the louder it will be! Another factor is how many miles do you have on the truck (I am assuming the cats are still factory)? I have 115,000 I'm sure a loooonnnggg ways away from what you currently have, but the point is as the cats get more miles on then they will restrict less and less, meaning it will get louder and louder. A buddy of mine cut the cats off and ran straight out the back, no mufflers, no nothing except pipe! Sounded great untill about 20k miles later it was WAY to loud! lots of cracking and snapping on hard take-off maybe thats what you want, but I still have factory cats with backwards glasspacks and it sounds GREAT! A few days after I had it done I thought I would have to take it back and have the glasspacks removed because it had very little sound to it. After about 2 weeks I started hearing a low rumble and its been getting louder ever since, its a good sound not to loud but a DEEP rich tone!I am bias of course! I've had guys with mustangs say they thought it sounded great and I think the mustangs have the absoulte BEST sound if run correctly. Hope this helps if not there is a forum on exhaust a little further down the page and someone there can prob help ya!
lariatrider rides on.....

 

Thanks for the info. I've been talking to people in the exhaust forum, as I'm pretty sure I stated in my first post here about catalytic converters, they just couldn't tell me if I had 2 or 4, so I thought I'd post up here in the forum specific for my truck.

I've got 27k miles on it now, so it will get louder as the truck gets older I suppose. I'm thinking about just chopping my muffler off and seeing how that makes it sound. If I dont like it, I can always just weld it back in place.

 

It has 2 pre igniters (like converters) and 2 converters, So you actually have 4 restrictive units in the y pipe. 2 just off of the manifolds and 2 near the end of the Y.

 

Ah cool, thanks. That is probably why I keep hearing it has 2 and 4 converters. Good to know.

 

If you are looking to open up the exhaust a bit, remove the front preheaters and the 2 stock converters and install 1 High Flow converter on each side. This will keep you legal and will keep the computer in check. You can remove all of them and get the 2 rear O2 simulators to keep the PCM from lighting the check engine light, but you will lose a lot of low end torque. not good for a truck.

 

Yeah, my deal right now is that I have put on a 6 inch lift and I'm running 35x12.50s so I need all the torque I can get.

So, LxMan1, is removing the preheaters and putting in a high flow cat as simple as going to an exhaust shop and getting the old ones removed and installing the new ones? And wont I lose some torque doing that as well?

I also thought of another question, could I simply get a dual in, single out high flow cat? Or would I need to put one high flow on each side?

 

lariatrider---how does the backwards glasspack work ?? I have never heard of that before and i have had the exhaust replaced on just about every vehicle i've owned. I've had glasspacks on but never turned backwards...huh...new one for me.

 

Rambo--- i have an 04 f-150 and there are 4 cats, but i am asuming it has the 2 pre igniters and then the cats so that would be just 2. They sure do look a lot alike though.

 

Inside the glasspacks there are little "cups" sticking up. If you turn the cups around so they don't "catch" the exhaust they will create a deep tone! Imagine holding a cup up in the wind open end towards the wind, there is a lot of restriction, therefore killing lots on the "noise" we like! Now switch the cup around closed end towards the wind, the air flows over the cup but it creates a sound because the wind is rushing over it. Same thing happens within the glasspacks but the "noise" is much more pleasing! This was recomended to me by several exhaust shops and was told this was the "way to go" on the f-150 for the deep mellow tone but not really loud as I don't really like the extreme noise from some! Well thats my pennies worth so if it helps great if not sorry, but in the end you gotta like how YOUR ride sounds!
lariatrider rides on.....

 

Thanks man, i may have to give that a try. The exhaust shop i have been going to hasn't said anything about it, i may have to put a bug in his ear about it. Hopefully he will go for it. I would like a deeper sound. It sounds good the way it is, but it might sound more MEAN with a backwards glasspack on it...lol...is there any certain size thats recomended ?