3-way cat removal

[ORL240]

I had my 3-way cat removed on my 95 240sx w/ 96 ka24de (pretty sure it's obd2) about 2 years ago because I heard it was extremely restrictive and I didn't have money for header. This is the cat that sits immediately after the stock exhaust mani. I had a friend that owns a muffler shop remove it and weld a 2" elbow that connects to the pseudo cat under the car.

My questions is does this have any negative effect on performance or fuel economy. My seat of the pants dyno told me that car is a little quicker thru the rpms w/o cat and fuel economy has pretty much stayed the same. But I have the check engine light on, w/ code 105 & 41 coming from ecu.

Search'd but all cat posts were bout s13's or passing emissions.

Modified by ORL240 at 3:56 PM 12/21/2005

Modified by ORL240 at 4:18 PM 12/21/2005

Modified by ORL240 at 6:22 PM 12/21/2005

Modified by ORL240 at 4:39 PM 12/22/2005
Modified by ORL240 at 5:13 PM 12/22/2005

[ORL240]

N-E thoughts.Actually have wrong error code posted. Have to pull ecu tonite and I will post correct error code.

41 is air intake temp sensor which is broken on my engine.

Modified by ORL240 at 8:30 PM 12/21/2005
Modified by ORL240 at 4:40 PM 12/22/2005

[ORL240]

Bump

[240sxDann]

not exactly sure, but just a random guess off the top of my head, maybe the o2 sensor is getting a different reading then its supposed to with the cat on?

[ORL240]

Will this cause a/f mix to run rich?

[89 240 SOHC]

I think a lack of a cat will lean it out at high RPMs and rich it up at idle

[kamikazestorm420]

i catalytic converter should not affect your motor at all.

its just there for emissions.

if you look inside .. it looks like a filter(?)

[navysnail]

modern motors use the second O2 sensor to check cat performance and make sure it is doing it's job. obviously if you remove it, the second O2 is going to see a signal way out of spec and will throw a code. the stock cat is not really that restrictive on it's own, besides its a federal offence to remove a cat from a vehicle. all that said, you can put a device called an O2 sim in place of the second sensor which will stop the sensor from throwing a code. oh, and by the way, on OBD II, you h ave to have the codes cleared by a scanner, cant do it yourself. that might cost a little too.

you may seem to feel an increase in performance, but i can pretty much guarentee you that it's in your head.

[ORL240]

May just be slightly different exhaust note that has me thinkin more power. But if I understand what your saying navysnail removing the first cat on these s14 ka's won't affect much of anything other than throwing the ecu error code?