Explorer 5.0 stock replacement front exhaust pipes with CATs and O2 sensors - will they work? UPDATED 11/17/24

[skrit]

Trying to keep the 5.0 swap as stock as possible in my EB which means I want to use the O2 sensors and CATs without deleting them and having to reprogram the PCM. Below is a stock diagram

What I'm interested in using is the the left and right cat pipes from my stock explorer manifolds. All the exhaust behind it will be custom. Could an exhaust shop duplicate the O2 sensor locations relative to some universal CATs and just do a complete custom job without messing up what the PCM expects to see?

 

[Broncobowsher]

I don't think the Explorer cats will fit, as in a direct bolt in. But I see no reason they can't be adapted to fit.

First hurdle, I recall the Explorer manifolds don't fit the Bronco chassis. So there is no reference point in mounting the stock cats to. And the modifying starts...
No reason you can't use aftermarket and adapt as well. While some states have strict rules about replacing cats with approved ones, usually anything that is working is fine. I've done an aftermarket cat on a highly modified 302 that had nothing stock in it except the block and passed 1990 emissions.
As for placement, close is good enough. At one time there was a theory that they had to be exactly in the right spot, not that picky in the real world. There are some good rules, such as they should point down into the pipe, sideways if no other option, and avoid going up from the bottom. No leaks, not even tiny ones, before the sensor.

 

[EFI Guy]

I know there are a couple of people that are using the Explorer manifolds. @garberz is the first one that comes to mind. But I don't know exactly what was needed on the exhaust side to make it all work. I can't say if the Explorer exhaust with CATS would fit the Bronco or not since the frame is so narrow.

 

[skrit]

I've got the stock tubular manifolds on and there doesn't seem to be interference but i haven't installed the D44 yet.

 

[Broncobowsher]

I'm questioning clearing the passenger side frame rail.

 

[904Bronco]

Never seen the 96 tubular header with a provision for external EGR?

 

[skrit]

@904Bronco - its a 98ish and those are stock replacements from Dorman.
I'm going to get some flex exhaust pipe this afternoon and do a little mock up on routing. Unfortunately, my donor had the exhaust sections with with the CATs cut out already.

 

[skrit]

Update:

I forgot I saved the original exhaust starter pieces which helps in determining routing.
Pass side looks like it has all kinds of room Driver side... not sure. Lpoks like it turns under the tranny. Maybe the exhaust diagram I have is wrong.

 

[DirtDonk]

I'd never seen the tubular style either. There are aftermarket full headers for the full-size pickups that have the EGR tube, but I think there is the typical fitment issues with a Bronco.
Did the Dormans come with the heat shielding already attached? Or is that your add-on stuff?
If added by you, what did you use?

Thanks

Paul

 

[skrit]

I'd never seen the tubular style either. There are aftermarket full headers for the full-size pickups that have the EGR tube, but I think there is the typical fitment issues with a Bronco.
Did the Dormans come with the heat shielding already attached? Or is that your add-on stuff?
If added by you, what did you use?

Thanks

Paul

They came with it and matched the take-offs which both had frozen and broken flange bolts I didn't feel like drilling out,

 

[skrit]

I did a bit more research and have the wrong exhaust diagram based on the shapes of my original starter pipe take-offs. This one from Walker appears correct.

 

[EPB72]

They came with it and matched the take-offs which both had frozen and broken flange bolts I didn't feel like drilling out,

View attachment 931305

I’ve seen plenty of the style back in the day when more common ,, usually I was replacing them because of cracks or estimatining for customers that decided not to fix ,, cracking was common,,

 

[Yeller]

How about some pics of a 96 explorer exhaust? I can get more, it’s in the garage.

@EFI Guy, I do own something with Ford stuff it’s even stock and unmolested. For now… looking for the correct BW4406

 

[Yeller]

Lightened the dark pic best I could. If the manifold clears the frame I don’t see why the stock pipe wouldn’t work, it is very tight to the trans

 

[skrit]

Lightened the dark pic best I could. If the manifold clears the frame I don’t see why the stock pipe wouldn’t work, it is very tight to the trans

@Yeller Perfect - very helpful. I chose the stock steel manifolds over cast because they were original and I thought cast was more prone to cracking and had poorer build quality. I'm rolling the dice and just ordered the right and left starter pipes with the CAT's for the early 98 (pre February 1998) which I just learned I have. Same exhaust components as 96-97 from what I can tell. After February 1998, it looks like Ford changed to the cast manifolds and longer one-piece pipes with integrated rear cats.

What I ordered probably wont work exactly and will need some mods. We shall see. Trying to decide if I'm going to fool with the double rear CAT's like you have which was stock.

 

[Yeller]

Your welcome!

It might all fit. I’m sure the rear cats would but may need a different muffler, at that point it’s getting pretty long.

Let me know if you need more pics.

 

[skrit]

How about some pics of a 96 explorer exhaust? I can get more, it’s in the garage.

@EFI Guy, I do own something with Ford stuff it’s even stock and unmolested. For now… looking for the correct BW4406

@Yeller can I please ask for a pic of your 96 explorer exhaust on the passenger side where the 2 CATs connect to the double rear CAT's? It looks like they run side by side in that area which won't work with the EB frame. I've received the Explorer replacement CAT's and I believe the one from the passenger side won't work without modifications. The driver side seems to work fine though I'm disappointed in the Walker brand's quality. The bottom heat shield had 4 small tack welds that already failed and the pipe was crimp bent which may not be a problem. The passenger side was made by OEM Industries out of Canada and seems much better quality. I'll mock it up and provide a pic in case someone wants to see.

 

[Yeller]

I won’t be near for a few days but yes they are side by side

 

[EFI Guy]

How about some pics of a 96 explorer exhaust? I can get more, it’s in the garage.

@EFI Guy, I do own something with Ford stuff it’s even stock and unmolested. For now… looking for the correct BW4406

If you find something rare like a Yenko to put that Explorer setup in, I'll wire and program it for free just to ruffle some feathers!

 

[Yeller]

If you find something rare like a Yenko to put that Explorer setup in, I'll wire and program it for free just to ruffle some feathers!

I’d even do it

I do wish the cats weren’t the low point under the car… eventually they will not look the same lol.

Back on topic pics as requested. Hard to get really good ones, it’s tight under there