I've finally added the hi flow cats to my true dual flowmaster exhaust system. The results: a much deeper sounding tone and faster acceleration. This definetly gave my 2000 5.4 a big pickup. I'm going to say about 30hp. I removed the 2 stock cats from each side and replaced them with 1 free flow cat. then balanced it out with a X-pipe. I am very pleased with the results.

 

That sounds great. I'm in need of new cats also.

Can you tell me who makes the cats you got/where you got them?

If you have a part number, that would be cool.

I'm having a hard time finding new cats for some reason...I've been told that I gotta go to the dealer. And Magnaflow/Carsound wants to sell me new cats and pre-cats...

Are you getting a check engine light?

 

Hey bud, The company that made my cats are eastern catalytic I think. But you only need one on each side, between the 2 oxygen sensors. It will not trip the check engine light. I ordered mine from my local muffler shop. Just go in and tell them that you want to replace your 4 stock cats with 2free flow models. They can order them and put them on for you. Don't let magnaflow try to sell you an extra set of cats when you dont need them!! If I can be of anymore assitance just let me know. I hope this helps you out.
Oh yeah, are you running true duals? What years is your truck and what motor does it have. I'll see if I can't help you out.

 

I thought the trucks had 4 cats stock??? Maybe I am confused.

 

We do have 4 cats - two pre-cats, and two cats.

The high-flows replace the cats and get rid of the pre-cats.

Well, I finally was able to determine what cats I need! Got some Magnaflows from am E-Bay vendor, $66 shipped/each.

Right now, I've got a DI/SO Magnaflow setup. But I plan on switching to true duals with an x-pipe in a little while. I think I need more flow now that I'm blown... Plus I want it to be louder now!

What duals are you running, F150Flare?

 

Living in CA, I wouldn't trust that going from 4 cats to 2 would be smog legal. There are specific guidelines for replacing a cat (both at federal and state levels). If you live in a state that has an annual inspection, talk to an inspection station first and get something IN WRITING.

And for you guys who think it is cool to remove a cat, remember that removing any emission device from your vehicle is a federal offense.

 

hey i've got a flowmaster catback exhaust with dual out the rear. What can i do to make this system better, you guys talking about replacing the cats and adding x-pipes? I have a 1997 2WD XLT, will any of these options you guys are talking about able to work for my truck? your help will def. be appreciated! anything to make this exhaust louder and more powerful will be awsome!
tHanks!
John

 

Yeah I live in San Diego as well. I would love to change out the cats to some highflow ones, but I am scared of the consequences. Cali sucks.

~Colby

 

I'm running the 40 series flowmasters. They have a great deep sound and sound really aggresive when climbing the RPM range.(thanks to my new cats and x-pipe.) I've always loved the flowmasters but I've also heard that magnaflow is very good as well. Best of luck in you exhaust setup bud, I hope that I was helpful. Let me know when you get a finished product and tell me what you think!! Jordannot Mike

And as far as the emmisions testing goes, the cats I bought are guaranteed to pass inspection and are 50 state smog legal so I always check myself so that I stay street legal. Even though there is no emmsions testing in South Carolina. If you do live in an area where they do just be careful and CYA Cover your A$$.

 

They are...IF they are installed in the same location and the same configuration as the stock converters.

 

hey you guys that have had hi flos added on, how much did the shop charge you to do this? How much do you think it would cost total to have hi flos put on, and true dual 2.25" straight pipes run out under the back bumper with new chrome tips would be? Im thinking $350-400.

 

The cats are about $65 each, including shipping , on E-Bay.

Can't tell you about the labor, Brown Santa hasn't delivered the cats yet.

 

I bought the cats and the True X pipe and had them put on my true dual system for $295 for everything. Just shop around, you'll find a good deal somewhere