Need to know info about these how do they work are they any good is there a difference between before cat and after cat sims? Please advise...

 

from what i understand, the precat o2s measure your emissions coming out the engine. the postcat o2s show how efficient your cats are. if your cat isnt working properly, itll throw a engine code. the sims are used when you get rid of your cats with full length headers. they send the proper signal to your pcm that way you dont get that annoying light. there shouldnt be a differance between pre and post because the sim isnt measuring anything, its just sending the proper voltage to keep the pcm happy. you shouldnt need precat sims untill you get radical with your engine. by that point though, you would have to have tuning done and you could just disable the o2s through ls1edit or something.

 

AFAIK, you wouldn't want to disable the pre-cat O2 sensors, because they are what measure the air/fuel mixture through the engine, and they determine how much fuel to give the engine. I don't know how else you'd set the air/fuel mixture without O2 sensors on a fuel injected motor?

 

Where do you get them.. Yes I have done away with the heavy cats.. I have four o2 sensors.. Does that mean I have to get 4 sims?

 

So I only need to get post cat sims?

 

you only need 2 sims....one for each rear o2 sensor.

removing or putting sims on the front sensors would be like cutting out your eyeballs. the are ESENTIAL to the function of the fuel injection.

not sure where you get your info...but even with radical setups...you still need the front sensors.

 

And they can be obtained for a fair price where?

 

didnt know that pre o2 controls a/f ratio. thought that they just show emission levels. did notice that whenever sims are brought up they strictly the rears. are the factory o2s able to work with a pumped up car or is there a limit to what they will work with since gm probaly didnt have 600 hp cars in mind when outfitting the emissions?

 

I was also curious about the 02 sims. I purchased some longtube headers and from what I am aware of I will either have to get 02 extensions or 02 sims from my understanding. The third option is to have them removed from the computer. I was wondering if I plan on keeping this car emmissions legal would removing them completely with lt1 edit or custom tuning from pcmforless show up when I went in to get it Imission tested?

I guess I would understand better if I knew exactly what the rear 02's were for.

 

the o2 sensors don't deal with "emissions" per-say. they tell the computer whether the car is running lean or rich, which has to do with howmuch fuel is being added.
to a degree that is diffferent from emissions.

Shark, if you installed longtubes then you will need o2 extensions to extend the stock wiring down to the front o2 sensors, AND if you don't have cats or a reprogram you'll need o2 simulators to get rid of the SES

as for buying sims...any of the site vendors will have them, all pretty much the same price. just check around for sales and discounts.

 

Tbyrne Has them... Are they having any group sells...or 10% off sells anytime soon? 89.95 for a pair is their price.. Can that be beat?