I have true duals with no catalytic converters and Flowmaster 40 series mufflers. Does it make any sense to drill holes, weld in bosses, and attach all four o2 sensors if I don't have catalytic converters? Will the 02 sensors still trip a CEL for improper catalyzation or something?

Thanks to anyone who understands the 02 sensors and catalyst system.

 

Actually, my "Check Gage" light doesn't come on with the o2 sensors disconnected and no cats present. It shows that it's on when I connect my OBDII scanner, but it doesn't actually light up on the dash.

Also, I don't care to spend money on converters that I don't need just to get rid of a light. My concern is that my gas mileage is being compromised from the lack of O2 sensors.

 

The front 02s do indeed effect part throttle driveability.

Rich

 

i know Magnaflow makes performance cats......you might look into getting them.....

not having them on an engine designed to have them will decrease the performance of them because the computer will change the fuel map for the engine if it doesnt see the cats/O2 sensor readings....

 

Put the o2 sensors in, and get o2 simulators, then you don't need cats...

 

The rear 2 sensors are there to monitor catalyst condition for OBDII. They have no effect on performance or mileage.

The front 2 are important and do 2 things:
-Feedback control of the mixture during closed loop operation - good for fuel economy and emissions (when used with cats).
-Determination of the open loop fuel multiplier - corrects mixture for open loop performance.

 

Is WOT considered open loop?

Rich

 

Yes. The PCM learns the long term fuel trim in closed loop to drive the short term fuel trim toward zero. LTFT is also used to calculate an open loop fuel multiplier. This helps to correct for fueling errors caused by production variability or in service problems like a dirty MAF sensor (within limits, of course).