I'm about to do an exhaust overhaul on my '08 but I've got a few questions before I do it. Currently I've got a Roush off-road exhaust. I really like the tone of the exhaust but wish it was louder and I wish I would have bought the one that exited in front of the rear passenger tire. I think I've sold my dual rear exit kit so I'm about to purchase the side exit kit, high flow cats, and all the necessary clamps/hardware to do the install.

Here are my questions......

A) Will the Maggie cats be a direct replacement? I'm guessing that I'll need some extra pipe to finish the job with O2 sensor bungs welded in.

B) Why can't I just replace the cats with pipe and weld bungs in for the O2 sensors?

C) Will any standard O2 sensor bung work?

Sorry for all the questions. I want to get things right the first time so that I won't have any downtime with the truck since it's my only daily-driver. The weather is still too chilly and too wet for me to ride my bike everyday.

Hopefully I'll be the first with VIDEOS of a Roush Off-Road with high flow cats!

 

i thought the o2 sensors were before the cats, i dont think you have to mess with them, but i do think that you will have to weld the cats on, im about to do that my self except i will be using long tubes with hi flow cats and a dynomax bullet

 

That would be awsesome to hear hi-flow cats with the Roush Off-Road. A definite first.

Yes you will need some pipe to make up for the pipe difference. Your cats are about 16"s long I belive, and the Magnaflow cats are 12".

You can, but do you have the skill and supplies for the job? If you remove your cats and replace with pipe you will not only be illegal but you will have the good ole CEL ( check engine light ) which can be disabled by either O2 sims, or custom tuning.

O2 sensors are different by size. You best measure the bung and get replacement ones to make.

The front O2s measure fuel, and air, and are below the manifolds. The rear O2s in 2006+ cats are mounted in the rear cat.

 

Not a problem with skills and supplies. I've been working in a fab shop for 12 years now and have unlimited access to tools -- mig, welders, sawzalls, torches, grinders, cut-off tools, etc. I've also got about 50,000 square feet to do it in. So supplies and skills are definitely not a problem!

Do they make some king of clamp that will allow me to replace the new cats/pipe without welding? I can do the welding if I have to but I would prefer to do it with clamps so that I can put the cats back in place when I sell the truck or if I just decide it's too loud for some odd reason.

 

Yes you can. Regular stainless steel clamps can do the trick.

 

Awesome. So far I've got my list as follows (tell me if I'm missing something)......

(2) Magnaflow 94106 cats
(1) piece of 2 1/2" pipe
(6) 2 1/2" butt-joint band clamps

On the Maggie converters are the inlets/outlets straight 2 1/2" or are they slip-in/slip-over type connections? I'll have to order some slip-fit clamps if they are not straight 2 1/2". I've still got to figure something out on the O2 sensors and then I'll go ahead and order all my stuff. I'm going to try and see what kind of bung I need for the factory sensors and go from there. Any idea what size they may be?

Hopefully the ROR will sound good with high-flows!

 

Sounds good, but I would suggest the basic U clamps over band clamps. The band clamps dont hold as strongly as U bolt clamps. Yes the converters are flanged/slip over ends. They will fit snug & tight over 2.5" which is what you want. Not really sure of a size, i'm gonna guess 1/2". Oh the ROR will sound awesome, especially with the 94106s!

 

I just went outside and took a good look under the truck and it will be a little more work than I thought but nothing that can't be done. I've got two cats and four O2 sensors on my truck. Two sensors in a straight piece of pipe coming off the headers and two in the cats. There are no pre-cats on my truck unless I'm missing something. There are elbows welded to the engine side of each cat going up to the headers so I would actually have to cut the pipe between the elbow and the header. Then I would have to put an elbow on each of the Maggie high flows. The lead wires for the O2 sensors are the exact length as well so I would have to extend them to make them reach the bungs in the pipe after the cats.

If I just cut the cats out and welded the new ones in it would be much easier but I want to be able to revert back to the stock exhaust. I'm very tempted to just cut them out, put the new ones in, and be done with it.......

 

Sounds about right. Hope it works out for you. If I were you I would just put them in and be done with it.

 

I've got it all on the way! I'm almost positive the O2 sensors are 1/2" and the place I called are almost sure they are as well. Here's what I got......

(2) Maggie 94106 cats
(2) Zinc plated u-bolt clamps
(2) 6" pipes with O2 sensor nuts already welded in
(4) butt joint band clamps

I don't really like the idea of just butting the O2 sensor pipe to the high-flow cats and existing piping before the y-pipe but I think it'll be okay. The butt-joint band clamps are should be strong enough to hold everything in place and I'll probably put a few tacks on there just to be safe.

Should have some videos up for everyone within a couple weeks. Hope it sounds good!!

 

Congrats, look very forward to hearing it.

 

I guess I'll just cut the O2 sensor harness in half and add wire to extend it. I'll have to add about 6" of wire to make the new connection. I don't really like that idea but it's the only way I know of doing it.