Xride

While planning out my exhaust I came ot a block.
Cats or No Cats?

I plan on hooker LTs
and then duals out the back
this is a daily driver too, so I want the best power gains and still driveability.

so I was thinking a highflow cat in each pipe and then bullet mufflers in hte rear.
With this I would keep my O2 sensors right? no cats then no O2 sensors?


Or would I be better off to run a dual cut out so it would be like open headers and then when closed would go into a 3" with a cat and then through a magnaflow

also do I or should I keep my egr and air stuff? (do they effect milage at all?
I'm in alberta and hte only emision laws we have are you have to be able to see through your exhaust.

AdamZ1LE28

You would keep your front oxygen sensors, but you would have to put o2 simulators in the rear ones (the ones that would be after the cats)

AxeGrinder30thZ

No cats. Plain and simple.

Xride

Why are no cats better?

I mean I've looked through a cat, and it doesnt seem like flow would be disrupted much if at all.

BitCypher

IMO, do yourself and the environment a favor and buy a set of Carsound 2.5" or 3" cats for $32ea off of eBay and you'll be very happy with the flow and the sound. I did this and it cost me $88 to have two dual carsound 3" in/out cats shipped to my door.

The "performancepeddler" store on eBay has what you're looking for...here's a good starting place: http://cgi.ebay.com/ebaymotors/ws/eB...tem=2458950210

Good luck!

Xride

Thanks, I think I might go dual cutouts for openheaders and then into a single with dual cats (or is one good?) then though the Magnaflow still.

Xride

Ok been thinking a bit, I have to get O2 bungs welded into the headers and get O2 sims too. and I can just remove all the air and egr stuff?

AsianSensation

Why not just Jet Hots, they have provision for EGR, AIR, and have O2 bungs.

fastbird96

Removing the air and egr will set off codes and that annoying SES light will come on. They must be programmed out to keep the light from coming on. Other than the light there are no negatives to removing them.

Xride

I have to order them from the states then. meaning they cost about 200 more then buying hooker LTs here and having them coated here.
I have other things I can use for that 200, the local coating place will even warrenty there work too. so if it all chips off I can get them to do it again. pain in the *** to take them off to get them coated, but I got 5 years too.



Getting them programed out could be good too though couldnt it? I mean would the little bit of tuning for the headers hurt? and getting the skip shift taken out. and I want to do 1.6 RRs too, and then next year when I do the cam it'll be easier to program for it too.
otherwise I can still have the egr air and o2 welded in right?

FacelessZ

Do not get O2's programmed out...do not use O2 simms...simply use your old O2's (you'll run a bit rich) and buy some O2 extensions.

Xride

how does that work then?
the first 02s go in the headers, and then the second set behind hte cats right?
now If I run cutouts to make open headers and hten have the cats after the Y wouldnt that jsut mess everything up? and get real off readings?

I dont get it?

FacelessZ

If you plan on getting long tubes, then they'll most likely have O2 bungs welded into the collector of each header. This is where your O2's go. Since the bungs are pulled from out of the engine where they used to be on your stock manifolds and moved down and towards the back of the car, you're going to need a pair of O2 extensions to run from the stock O2 wiring to where the O2's are now located in the O2 bungs of the long tubes.

As far as readings go, leave that to the PCM...but do NOT go with O2 simms and do NOT delete your O2's out. The readings from the O2's are bad enough as it is, deleting them out will cancel any reading they were getting and cause you to run badly. Same goes with the O2 simms. They send false readings to the PCM, thus making you run worse than you would if you would have just kept your original O2's

AsianSensation

For OBD2, it's okay to delete the post cat O2s. SES can be taken care of through programming or O2 sims.

FacelessZ

Falsely "fixing" an SES light through programming isn't always the smartest thing to do...sure it'll work, but I guarantee you'd be running better with REAL O2 signals being sent to the PCM...