High-Flow Cat Question

[Petrucci914]

I know on the Vibe there are two catalytic convertors. The base has the O2 sensor before them and the GT has one before and one between the two. If I went with a highflow cat can I get away with using just one and having custom pipe done or do I have to have 2 cats? Thanks

[Lancer]

You have two of them. One just after the exhuast manifold and the other after the second cat.You can run fine with just one cat. As long as your second O2 sensor is after it. Otherwise you'll have a CEL on ALL THE TIME. Like me. (my actuall working cat is just before my Borla muffler.?? Don't ask. )The first O2 sensor is for the engine to read air/fuel ratios. The second O2 sensor is ONLY for emissions purposes.

[Petrucci914]

I thought the GT only had 2 O2 sensors and the base had one?

[tcam]

I'm pretty sure that both models have two 02 sensors. I know that the GT does for sure, and I don't see how the base could go with only one.

[vibegtcouple]

my 04 gt only had one cat and 2 o2 before and after the 1 before is no big dill you just need to sim on the after on , me my self have a test pipe on my the and got a o2 sim from ebay and i have no codes just need to find some on with a stock cat and the cut your off or just cut the new one . i work for gm and i set a p0442 code and warnty a new cut . then gm would just went the cat not the hole pipe now put on a test pipe no cat and open pipe if you would like pics just let me now i will take some

[tcam]

Quote, originally posted by vibegtcouple »my 04 gt only had one cat and 2 o2 before and after the 1 before is no big dill you just need to sim on the after on , me my self have a test pipe on my the and got a o2 sim from ebay and i have no codes just need to find some on with a stock cat and the cut your off or just cut the new one . i work for gm and i set a p0442 code and warnty a new cut . then gm would just went the cat not the hole pipe now put on a test pipe no cat and open pipe if you would like pics just let me now i will take somehmmm.....sry but I can't understand what ur trying to say.

[tcam]

So Lancer, would that JP Performance custom mid-pipe that you showed me still work with a Vibe GT? I assume it would, but I guess I wasn't aware that the GT exhaust was different from the Base exhaust.Sry to go a bit off topic , but am now very curious.

[vibegtcouple]

sorry about my that i mixed up all of my words in the last one here is the o2 you need http://cgi.ebay.com/ebaymotors...ZWDVW

[Lancer]

Trust me, I've been under there enough to tell you that you have 2 O2 sensors. If you have an aftermarket cat then you shouldn't have a CEL problem as long as you hook up your 2nd O2 sensor up after the cat.I'm starting to hear that the JP mid-pipe comes in 2.25". I'm hoping they can make mine larger (2.50") and able to mate up with a celica gt header. Some peeps @ MO got theirs in from a group buy and are not happy about it being smaller than the implied diamiter. So I'm guessing it would fit, but I'm not sure how the performance would be?

[vibegtcouple]

i now i have 2 o2 you just need one sim for the back o2 the frist o2 is to read before the cat and the 2 cat is to read the air and fuel coming out of the cat you just need to sim the 2 o2 sensor the frist one is going to read good all the time . trust me

[Mase]

All Vibe/Matrix models have ONE cat. Not two. The 1st bulge in the exhaust is a restrictor chamber used to channel air and help with torque. The 2nd bulge is the actual cat conv.

[tcam]

Quote, originally posted by Mase »All Vibe/Matrix models have ONE cat. Not two. The 1st bulge in the exhaust is a restrictor chamber used to channel air and help with torque. The 2nd bulge is the actual cat conv.lol, I'm glad you cleared thatup cuz I had no idea why the heck we had two Cat's.

[Lancer]

Quote, originally posted by Mase »All Vibe/Matrix models have ONE cat. Not two. The 1st bulge in the exhaust is a restrictor chamber used to channel air and help with torque. The 2nd bulge is the actual cat conv.What the heck is a restrictor chamber?I guess I should have taken a picture of my cat. after it was removed from the car. It IS a cat. And a cat. converter IS a restrictor. The first CAT. is to reduce startup emissions and burn off the hydrocarbons from the extra-rich mixture used in a cold engine.All though mine is now sort of a expansion chamber since I had it hollowed out. It got burned up from the s/c heat and fuel then emptied it's contents into the second cat.