So I have an 05 f150 KR 4x4 and I'm bout to run true duals.. But I have 4 cats my question is can I delete the two rear fat cats on each side and leave the front cats with all 4 O2 sensor (won't have to take 2 upstream off) only thing I'd have to do is get the exhaust shop to tap holes for the rear O2 sensors
Also if Ford got rid of the 4 cat system anyway then why wouldn't taking all off and adding 2 Mag 94106 hi flows in place of the 4 old..
So essentially taking 4 off and replacing with just 2 new

 

^^^ Yes. a very common mod.

Or use 94136's - already have O2 bungs.

https://www.f150online.com/forums/ex...ml#post5132871

MGD

 

I swear you guys are like super awesome forum gods that was incredibly fast I'm on another forum and still haven't had anybody comment I wish this forum had an app!!

But back to original post so this indeed possible and will work with no problems?

 

Also as I've already order the 94106 cats do I need to tap the downstream O2 sensor in the cat or in the pipe after the cat? I just ordered them off eBay so I can cancel if need to

 

I revised my first response.

You can't tap into a cat - you can use the 94136's instead - already 'bunged'.

Read the link I provided - O2 placement is important.

MGD

 

So what would suggest? Just stay with my order of the 94106's or cancel it and get the 94136? Is there an upside to getting those as oppose to the other? And is it hard to tap the holes in the pipe

 

It's yer call. Either will work - one is just easier.

You don't tap the pipe - you weld the threaded bungs onto the pipe where you drilled new holes.

Refer to that link. Remember - 10 o'clock to 2 o'clock.

MGD

 

I'll prob just stay with the 94106.. Do I need to buy the bungs or will an exhaust shop have them?

 

A competent, reputable shop should stock them.

MGD

 

Well if they don't have them then I'll go somewhere else haha thanks again

-Forrest

 

It does, for Android:

https://play.google.com/store/apps/d...autocomm&hl=en

 

Stupid iPhone 😒

 

I would personally risk the re-stocking and shipment fees to get the 94136 cats as the general 20 something year old exhaust master at the local shop will probably pi**-whine about having to mount bungs into the cats, also the risk of it being done 'quick' and possibly allowing for an exhaust leak or the heat to overtime degrade the welds.

I had a 2004, removed the rear cats and it sounded fantastic. I didn't drop the Y pipe assembly though and wished I had to achieve a leak-free system and clean smooth welds.

Either way you are on the correct track and doing it the right way so I have nothing but a thumbs up. I just want to emphasise how the 94136s will be a much more hassle free and guaranteed clean install for the O2 sensors.

 

any have any sound clips of this? I don't want my truck to be too loud.

 

Before rear cat removal.

After rear cat removal.

In progress.