will it mess up my engine management unit and/or O2 sensors if I cut out my catalytic converts and replace with straight pipes? Rest of exhaust will remain unchanged.

Thanks,
Brian
D2 160k
recently rebuilt from head gaskets up.

 

You'll get a check engine light, gain a small yet noticeable if you're really trying amount of power, and gain exactly nothing in gas mileage. I tried it, if I had it to do over I'd just make up some O2 bung adapters with some cat core between the sensor and the pipe instead of having cats welded in, but spacers that are long enough for the sensor plus a piece of catalytic converter core are hard as heck to find since they're 18mm instead of 14mm. Sensor spacers along, sadly, do not work (I tried). Otherwise it won't hurt anything but the environment.

 

I was afraid that cutting out the cats would make the EMU go f-ing nuts. Glad to hear that I dont hafta spend 2k to replace it (I live in a non-emission testing state) Any recommendations on where to purchase a new muffler that wont break the bank?
thanks,
Brian

 

For mufflers, I'd go Borla Pro Xs for a little loud or XL for a little quieter than the Xs, offset 2.5" diameter pipe, $100 on Amazon. Just have it welded in. For catalytic converters, Magnaflow are my go to. Buy those from advance online and get the awesome online discount they have.

 

$2k?????

A complete front pipe and cat back magnaflow system doesn't cost that much!

Am I missing something?

 

Rock Auto has an exact fit catalytic converter for $322 + shipping.

 

roversnorth "downpipe assy w/catalyst discovery II model #RNH109" $2,604.14



no joke. I even took a screen shot of it to prove it. See why I am going with the cut them out and buy new muffler option? lol

 

Long story of how I got to the cut cats off it solution:
engine ran rough and had misfires in 2 cylinders and an exhaust leak at passenger side exhaust manifold gasket.
we tear apart engine and find that i need new head gaskets as well.
R/R head gaskets (they never over headed and were in spec according to the micrometers so no machining needed)
and all other gaskets that come in standard "head gasket kit". Also new coil packs x 2, plugs x 8, plug wires x 8, flush and refill will new fluids.
restart engine, clear codes, then restart engine.
engine idles fine now but is giving me codes:
1300
1319
0116
0300
0301
0304
0306
0307
1514
1553

when you tap on the cats and muffler with a hammer it has that "broken baffles -full of rust sound to it".
engine runs for ah hour then while he make sure all wiring and whatnot is correctly reassembled.
Turn engine off.
Engine wont restart. Sounds like it isnt getting any air and since air intake if fine we apply cut-off wheel to muffler and it now starts and runs (poorly but it runs. Havent pulled new codes yet because I am afraid of damage if I limp it to local auto parts store).

Plan: cut out cats and replace with straight pipe and then add new muffler.
What other suggestions does the teeming masses o' knowledge on here have for me at this point?


Additional info which may or may not be be useful: ~45k miles ago this engine was completely rebulit (not by me or my mechanic but it is listed in the log book complete with receipts - so I am unaware if I am unf*cking someone elses' F-up.

 

Misfires will eat catalytic converters for breakfast. Just cut them out right at the weld, order this scanner (http://www.amazon.com/dp/B005M1AVFQ/ref=cm_sw_r_an_am_ap_am_us?ie=UTF8) and use it with the Torque app on am android device. The app costs $5, it can scan and clear codes along with a ton of other stuff. Very useful. Clear the codes and ease it around for a couple days after you cut out the cats, see of you notice any problems or of any more codes come up. It won't hurt anything to run no exhaust other than your ears. Google is your friend also, you can Google "land rover p0341" or whatever the code is and the first or second link will almost always be a forum post where someone tells what the definition is. Clogged cats cause all kinds of issues, you might just be able to replace and move on.

 

K thanks. My main question is will clogged cats cause 4 cylinders to misfire?

also send me link for OBDII android device as a single line please!