Are High-flow cats really needed for a stage 1 daily ??

[Mikemann0]

I’d just get 25K or 30K miles on the stock cats if possible then switch them out for piece of mind

Yes I'm in no hurry just doing the homework and seeing what others have done - Best bang for the buck so as not to waste money.

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[jewc75]

The tuner is just as important as what brand of cat you go with. Too lean you will melt the cats, too rich and you will plug them. Either scenario could lead to a knew engine.

This is why most people will tell you to pick a tuner first, then get their thoughts on what mods to do to get the most out of your combo. By most i dont mean just whp.

 

[Mikemann0]

The tuner is just as important as what brand of cat you go with. Too lean you will melt the cats, too rich and you will plug them. Either scenario could lead to a knew engine.

This is why most people will tell you to pick a tuner first, then get their thoughts on what mods to do to get the most out of your combo. By most i dont mean just whp.

I haven't ordered anything yet but I am leaning towards Palm Beach Dyno for tunes.

 

[amschind]

No.

Let me be clear, I have maybe the second best (street legal) exhaust on a Powerboost, and I just had to have the SPD crosspipe replaced because it cracked. I don't think that had anything to do with SPD's build quality (which is exceptional), but it's an issue which comes from SPD. If SPD sold just cats, then it's pretty easy to justify the upgrade along with a custom exhaust, which should cost cats+muffler+custom job=$1000. However, $2400 shipped is a a bad deal for several reasons. 1) it's set up as a kit, which would be convenient, except that their kit Y's into a single 3" pipe and 2) if you're going to push both banks into a single 3" pipe, none of the other changes are going to do much beyond making the exhaust louder. With most stuff, you have to fix the choke point, and the stock cats aren't the choke point until you open up the exhaust after the Y.

This is not an insurmountable problem: you can do what I did and run a pair of 3" pipes all the way back from the SPD kit to mufflers. I chose a Flowmaster 80 series BB because I want performance and not sound, and it comes out as a single 3.5", but if you just want noise, you could fit dual 3" glasspacks. This will cause issues, as the joints in the SPD kit need to be there, so welding that up will cause cracks, in my case at their weld right beneath the transmission. I don't hold that against SPD, as the weld that failed was a gorgeous MIG or possibly even TIG weld on stainless, and it cracked because the pipe couldn't flex. However, SPD does force you into buying a kit which you must pay for regardless of whether that kit can even survive in your installation. I made the choice to overpay for them to bend and weld stainless pipes to get the cats, but I don't think that's a good move for most folks.

Finally, if you are really chasing performance (others, not the OP) and have a 3.5 or 2.7, you will run into limits on the stock exhaust manifold. Full Race said they would have one out in January for the 3.5, but now it's September. I think they'll manage it, but until that's available, the exhaust manifold will choke all 4 front cylinders at 3500-3800 RPM with stock turbos. On a Powerboost it's an even greater challenge, as moving beyond the stock single 3" requires an exhaust heat exchanger delete. That was my initial goal for doing anything to my exhaust, but it will 1) leave CELs on and 2) require you to pull the coolant heater temperature sensors or the truck will enter limp mode for reasons known only to Ford. My truck is registered in Texas so it's a non-issue for me, but others aren't so lucky.

So the big question is: are exhaust upgrade worthwhile? Yes, IF and ONLY IF you rip out the entire system from the cylinder heads to the tail pipe and open it up AND have an engine tuned to use it. In the case of the 3.5 and 2.7, the stock exhaust manifold is so badly designed that folks who don't plan on replacing that with a part that is not yet available shouldn't expect anything more from their efforts than a louder truck. Further, the stock tune will not take advantage of a full suite of bolt-ons, so in addition to that full suite (cold air intake, intercooler upgrade, radiator upgrade, full exhaust as above) you will have to tune once you

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