hi guys,
im looking for some advise on my 1991 305 tbi camaro. i want to fit a flowmaster exhaust and de-cat the system, do you know if it will affect the o2 sensor and have an effect on the running. rest of the set-up is standard.
thanks

 

Removing the cat wont give you any problems with the O2 sensor since its before the cat. Im also planning to de-cat my 91 Z28

 

Here are a couple pics of my no-muffler "cat back" exhaust that I put on my 91 RS. I got it off Ebay for about $140. It's pretty well designed, has a mounting flange to bolt to the cat, and also has another bolt-together flange right before it swoops up and over the rearend. It has a nice growl to it when accelerating or under a load, but it's actually very quiet at highway speeds. And my cat still has all it's guts intact.
The first pic shows the complete system. The second shows just the back section after I welded it all together, welded on the hangers, and painted it.


[IMG]local://upfiles/10318/B2FEA76600634158AB77781D7139ABAF.jpg[/IMG]

[IMG]local://upfiles/10318/38BA7CD2B0064A2CB4C600D67C330283.jpg[/IMG]

 

it looks to me that the o2 sensor is past the cat on my car as its in the system mid way down the centre pipe about level with the passenger seat

 

Hmmmm....I have an air tube that goes to the center of the cat, but never had an oxy sensor in the lower portion of the exhaust. And after the cat is smooth sailing.

 

Lies man the o2 sensor in my 91 rs tbi was plugged into my stock headers and since i have changed them i really havent had any problems aside from the check engine light will sometimes come on. i think that you should get new headers!!!! headers so far have been the best thing that i have done to the car and i have noticed a big improvement in the hp/ performance of it. All and all i would suggest you just go to a muffler shop and ask they will be able to tell you what will fit under your car(when i went they said that the pipes i wanted to put on wouldnt fit and i would have to buy "flat?????pipes????)

 

Turns out my car is a japaneses import and has 2 o2 sensors in it !!! one in the headers and on behind the cat!!! im hoping i can just take the rear one out without too much trouble.
i do really fancy the idea of headers but god thereis so much plumbing!

 

Yeah man! Well good luck to you! when i put my headers on i just ripped a bunch of s*** off lol, i was like hmmm it doesnt look important! I say just go for it man

 

Just buy a high flow cat from Catco. Do your part and be green, unless it is not a daily driver.

 

i ran open headers on mine for a while, shouldnt be a problem

are you looking for a whole exhaust or just looking to get rid of the cat/change the muffler