Catalytic Converter replacement

[pugsy]

Question for anyone out there that's tried this:
I'm looking to scrap the double catalytic converter setup on my 92' 4.0 and replace with 1 Magnaflow converter. Would I be able to run a couple feet of pipe from the Y-pipe that attaches to the exhaust manifold to the CAT, or does that CAT need to be upstream right against the y-pipe like the original set up?
Reason is, if I'm going to replace the cat, I'd like to move it further back to keep heat off the Tranny and RA bushing. I would assume I wouldn't need the heat sheild anymore over the tranny thereby allowing easy access to the Tranny for repairs in the future if need be.
If anyone's done this, let me know if you had any issues, etc. with relocating the cat. Or if this is not a good idea, please let me know why.
Thanks,

 

[Turdle]

You cats need all the heat they can get--closer is better--

BTW
go look at this ebay item--

130137101646
copy and paste that number into the ebay search--

 

[BrooklynBay]

Here's the link: http://cgi.ebay.com/ebaymotors/ws/e...0137101646&category0=&fvi=1&item=130137101646

 

[Maniak]

I've heard that too, that the cats need to be close.. But..

I have a single cat, and it sits right next to the transmission (wide part). I asked an exhaust shop about using a bullet style converter (smaller, but more expensive) and he suggested just moving it back another 4 inches or so so its got some air between it and the trans (its about 1" away now, moving it would put is about 6" away).

I'm going to get a 2nd opinion, but I figured I'd at least tell you what they told me..

btw.. that Cat on the ebay site (Item number: 130137101646) is the bullet style I was looking at.. and is really cheap there.. (was $100 at the shop in town)

~Mark

 

[snoborder42]

coming from my own experience, put the cat in the same location or as close to it as possible. I replaced the cat on my dad's f150 and put it further back, it still runs fine but its seems to have lost some low end power.

 

[MountaineerGreen]

The converters are dependent on close proximity to the engine for heat- moving it back would only reduce its effectiveness. Keep it as close to the motor as possible, use heat wrap or a shield to protect your trans.

 

[Maniak]

I've got header tape from the collectors all the way to the Cat (not on the cat itself) and even a few inches past the cat. It still getting things hot. The 700r4 is wider than the a4ld..

I can (and will) build a heat shield for the exhaust that rus in front of the Trans (right near the converter), but there is no room for a shield between the frame rail and the trans.

I'll keep digging, but so far it is looking like I'm going to use a physically smaller Cat since I do see many places saying to keep the cat close (and I understand how the cat uses heat to work)

~Mark

 

[Jason94sport]

I used the Magnaflow direct fit replacement cat. Works well & it's OEM fit.

 

[pugsy]

Thanks for the inputs! Didn't know about the heat thing and proximity to the engine.
I guess if my cats aren't clogged, I might as well keep them in place (to that point, how do you know when they're clogged and time to replace?). I'm totally stock, so no point opening up the exhaust if the intake is still factory.
I will need a new heat sheild though, mine is rotted out and almost falling off.