Anyone ever noticed a decrease in gas mileage after installing a 160* thermostat?

The logic I was given is that LTx motors are designed to run at 185-200* and if the temps are not in that range that the computer will increase fuel to accomodate? Any truth?

 

The computer won't "increase fuel" directly because the coolant tmep is lower than expected......... but.......

The problem with lower combustion chamber temps is that the combustion may not be as complete, leaving you with unburned HC's blowing out the exhaust pipe. If these unburned HC's (which are already wasted fuel) are accompanied by unused oxygen, the O2 sensors will see that O2 and artificially richen the mixture, causing a further loss of fuel efficiency and increase in emissions.

But that's all theory. Whether the loss of fuel efficiency or the increased emissions are measurable is debatable. Interesting thread in the "Advanced Tech" forum regarding increasing coolant temp to increase fuel mileage.

 

Many people who freak when they hear 160 fail to understand the LT1 came with a 180 stock.

Not that I am arguing for or against it but I think a lot of guys use bad tuners and that is where they economy goes away.