thermostat ?

yaounto · November 8, 2002

hi all. i have a 2001 5.3 x-cab Z71 w/little mods. one of the mods i have done is to cut one side of the air box out which helped part throttle but now i have a lean condition at WOT. now, what i have heard is if the 190 degree thermostat is swapped out for a 160 degree themostat, the computer will richen the fuel mixture. is this so? if so, would it affect any other systems in a negative way? thanks all.

TxDoc · November 9, 2002

Some info I got from the LS1 forum:

The LS1 guys had the 160 vs 180 thermostat issue come up and the recommendation was: (different numbers, similar idea)

"The 180 thermostat will not change your temperature much at all, so if you want cooler running temps go with the 160 thermo. In order to take full advantage of a colder thermostat, you must have your fan settings set to come on sooner. A thermostat opens at the given coolant temperature (i.e. - 160* for a 160* thermostat), sending coolant to the block earlier or later. It does not directly lower operating temperatures. With the stock fan settings and a colder thermostat, the engine will run cooler on the highway, but as soon as you get stuck in traffic, even for a short time, the temp will creep back up again."

and

" I put a colder thermostat in my car and the gauge reads the same temperature as before! What happened?

Answer: If you've taken the steps to modify the fan settings (such as the HPP3) then you should see a difference in the temperature gauge if you have a 98 F-body. If you've got a 99 or newer, you must keep in mind that the gauge is not accurate enough to show a drop in running temps. It is set up to go to a preset level and stay there even if the operating temperature varies by 15-20F. The 98 gauges will fluctuate as the temperature goes up and down, and GM felt that new car owners might be alarmed with this happening. In essence, the 99 and newer coolant gauge is little more than an idiot light."

How can I modify my stock thermostat to open sooner?

"How to make your own custom thermostat

http://www.ls1.com/customthermostat.htm

http://www.ls1.com/customthermostat_files/image001.jpg

The thermostats on the 98+ LS1 engines are designed in one piece which includes the outer casing.

http://www.ls1.com/customthermostat_files/image003.jpg

The thermostat can easily be dismantled by twisting out the upper portion that holds the springs down as shown.

http://www.ls1.com/customthermostat_files/image004.jpg

The wax which controls the opening and closing of the thermostat through it's expansion if inside the casing. You'll notice the channel at the bottom of the casing.

http://www.ls1.com/customthermostat_files/image005.jpg

Here you can see how the plunger which controls the opening and closing of the valve falls into this channel.

http://www.ls1.com/customthermostat_files/image006.jpg

To make the thermostat opening earlier it is quite simple. All we need to do is make the plunger longer causing the wax to open it earlier. This can be accomplished by placing a spacer at the bottom of the channel where the plunger sits. People have found that using a spacer of .06 - .09 will yield a thermostat which will open between 172-180 degrees.

May not be the final answer to your question. But, may give you something to consider.