I have a 96 Z28 and I am in the process of getting some work done to the car. Valve seals, CDI, Magnaflow Cat-back, new plugs, wires, and I have to keep the Cats because it has to pass an inspection in a year or so. My question is about the Magnaflow High Flow direct fit cats? I am a day away from making the call to go with those, Just wondering if anyone here has any opinions about those???

Thanks for any advice.

Here is a link to the cats.
http://www.hottexhaust.com/detail.asp?PRODUCT_ID=23518
http://www.hottexhaust.com/detail.asp?PRODUCT_ID=23517

Exhaust
http://www.magnaflowstop.ca/product/15620

 

offroad y-pipe and some o2 simulators, that way you can get rid of the cats and the o2 sims will not cause you to throw a code, just have to have someone that doesnt care about a visual inspection, if you dont wanna do that high flow would be fine

 

Magnaflow Highflows or Random Technology are good choices if you need to keep cats. Meteoralp's solution will work if they only scan your car for trouble codes, but if you have a visual or a "sniffer" test you'll need to keep the cats.

 

those cats will help increase your horsepower, but only by about 5 or 10. The Cats that GM used on the Z28 and corvette were already pretty good and there is not alot of loss there so not alot of gain with the performance cats. As for the sims they fool the computer into thinking there are cats in place but they can also hide an issue that is actually happening in the engine that does require repair. If you just core the cat to pass a visual inspection you will also gain a CEL for catalyst effency above threashold (cant remember the number) so be careful about doing that.

Massey

 

The aft-cat O2 sensors don't actually tell you anything significant about how the engine is running. If there are any issues that will be detected by the pre-cat O2 sensors. In all reality you don't need to invest in expensive O2 sims either, you can put a series resistor in the O2 sensor signal line to decrease the voltage drop across the sense resistor in the PCM. This effectively tricks the computer into thinking the aft-cat O2 sensors are sensing lean and are within the acceptable range of values. That said, you do have to preserve your O2 sensors to utilize this method. I haven't looked into it, but if the Camaro PCM is anything like my Subaru, you can just remove the sensor entirely and the car is ok with it....

 

The GM PCM will know if the o2 sensors are missing. You will get a CEL stating the o2 sensor circuit voltage high if you remove them.

Massey

 

Alright, thanks for the info.

 

your car should run fine without the rear o2s, but it will throw a code yes.

you could have someone delete the rear o2's from your car and leave the sensors in there if you wanted. that way you pass the visual inspection and your car doesn't throw a code for missing the o2's. just an idea

 

Thanks for the info and link. Just ordered the set for my 96 SS

 

You just order a set of those Cats?

thanks everyone for the input, mine our on order along with the exhaust. The guy is telling me about $800 for labour to put exhaust, cats, valve seals, CAI, PCV, plugs and wires.

How does that sound? I think its pretty decent. He has a performance shop.

Also I thought I would only really be gaining about 10 HP with everything. But with the exhaust, cats and CAI, what do you guys think I will gain in total? I also think I will notice a difference with the valve seals in because I've only driven it with the blown ones.

Will the high flow cats affect sound at all??