I just had AR long tubes put on my 08.They plugged the 2 places on the x pipe where the 02 sensors should be,but still have the 2 sensors in the block (which i did not know that there was 02 sensors in the block) anyway is that a common install & will there be any problems? Thanks

 

There are no O2 sensors in the block. They are in the headers before the CATs.For the front O2 sensor, look in the header collector ahead of the CATs. They are necessary if your car has been tuned to run in closed loop.

The O2 sensors behind the CATs are there just to monitor the efficiency of the CATs and will set a Check Engine Light when the CATs don't meet certain parameters. Many tuners turn off the rear O2 sensors in the PCM software which will prevent the CEL light.

The photo below is of the Dynatech headers and CATs. The front of the car is to the right.

 

I did not think that there was 02 sensors in the block,would not make since.The place where the 02 sensors should go in the X pipe is before the high flow cats & they just plugged the 2 holes with nuts.The tuner did plug in his laptop & did something & then took it for a ride.Is it OK to run with no 02 sensors? down here we have no emission test.What is a closed loop? Thanks

 

If you don't have rear o2 sensors you should get a code unless the used software to turn them off.

 

Is it OK to run with no O2 sensors? Yes and no.

If the car is primarily used for racing in which case its in WOT most of the time, then yes its OK to run without front O2 sensors. At WOT, things happen so fast that the PCM does not make adjustments to timing and fueling during WOT. Its uses a series of fixed tables based on rpm, load, temperature, etc.

If the car is primarily used one the street, then no, its not OK to run without front O2 sensors because the car is in open loop 100% of the time. In open loop, the PCM has no feedback on fueling when not in WOT...such as cruising down the highway. So you could be rich or lean during cruise both of which could result in engine damage long term.

Its to your car's advantage to run in closed loop with the front O2 sensors working properly. Closed loop is the term the software programmers use to describe how the computer takes constant feedback from the front O2 sensors to make adjustments to the fuel injectors so it will be correct. The loop is the computer tells the injectors how much fuel to inject at a particular RPM and engine load. The O2 sensor tells the computer if its lean or rich at which point the computer adds or subtracts fuel, the O2 sensor sees that and tells the computer if its lean and rich. See, that's a loop.



What are your car's mod?

 

You are sharp MezMy mods are.#1-Comp street cam #2-K&N air intake #3-Borla stringers#4-AR long tubes.

 

What Com Cam model specifically? Who tuned it?

Unless the cam is outrageous, there should be no reason to run without the front O2. They are your friend.

 

It's a custom grind 4-224112R---lift>.581 intake & exhaust. Duration@ .50> 224 on intake & exhaust.Lobe lift .3420.lobe separation 112.0.It's not a radical cam,with the tune i was told by the shop that did the work that it would give me around 60 rwhp.That was done last year & 3 weeks ago i went back to the shop to have the long tubes put on.I'm going to a place to put it on a rack,because i called Comp cam today & they said that there was a place on the collectors to put 02 sensors,but i did not see that when they unboxed the headers,.,..Will let you know later.Thanks again Mez.

 

Sounds like a nice set up. Let's us know what you find out.

 

The sensors on the block must be the knock sensors.

 

you are correct

 

Well Mez:I feel a lot better now.When it was on the rack yesterday i looked over the install & there are 2 02 sensors on the top of the collectors,that is why i could not see them from up top,so all is OK now in my mind.I want to think you for all the excellent information that you gave me,.,.Again Thank You very much.