I just completed a CAI & Corsa's & Tune. Tuner now suggests a 160 degree thermostat. Is this worth it? What are the pro's & cons? Thanks Harry

 

Pros: Reduces hotspots, keeping KR at bay.

Factory PCM starts to pull timing at higher ECT's, this will keep you out of those zones.

Cooler running will allow the PCM to use all the timing in the stock tables, or the tuner to add more.

All above will make you a little more HP.

Cons: None

 

Thanks appreciate the info. Harry

 

What he said , ttt

 

There is one minor CON - You're heater will put out cooler air.

 

To create an even more cooling CON you may want to have someone set up your fan cycle.

 

On my C5 it didn't. Stayed nice and toasty even when it was 20 degrees outside. Haven't needed the heater yet with my C6, but I doubt it will be a problem here either.

 

OK it may have but it's all in the heat exchange in the heater coil. 160 deg water vice 180-200 deg water. You tell me.

 

There is one con. While you gain full throttle HP by running more timing/avoiding knock retard due to lower combustion chamber temps, you lose part throttle efficiency (lower MPG) due to the exact same reason. People don't realize HP is heat...1 HP=746 watts, for a demonstration of that concept, grab a 60 watt light bulb. For every gallon of gas burned, there is a certain heat content released during the combustion process. A very rough estimate (for demonstration purposes only) has about 1/4 of the heat going out the exhaust, 1/4 going to friction, 1/4 going to the cooling system, and 1/4 going to the rear wheels to drive the car. Changing the t-stat to a lower temp means there is a higher difference in temperature between the combustion chamber temps and coolant temps. This causes a greater amount of heat to go to the cooling system and with the friction and exhaust components a constant, this reduces the amount available to drive the wheels. Since the HP to go a constant speed doesn't change, more gas has to be burned to compensate for the extra heat rejected to the cooling system. This is simple thermodynamics but you'll see it as a reduction in MPG...something your tuner might not tell you. That leaves you wondering where your fantastic MPG went to that you use to get. There are no free lunches, every design element on the car is a compromise between EPA (emissions, MPG, and noise)/safety standards/reliability/costs/drivability/consumer desires and performance that GM has to walk the fine line on. Any mods will skew that compromise and may result in an undesirable side effect to the consumer...you are smart to ask what the negative side is to a mod before blindly buying into the positive side.

EDIT: This post is just to identify the pros/cons, it's not a recommendation for or against a 160 degree T-stat. Are the gains in HP worth the loss in MPG? That's for the individual car owner to decide.

 

Of course. Always have been, always will be.

 

no lost of gas mileage here. avg 28-29 on 800 miles road trip.

 

Also saw on loss in MPG in my C5 when I changed the thermostat. Now when I changed the rear gears from 3.42's to 3.73's I sure did.

Your point is valid from an engineering point of view, but considering how little HP it takes to cruise at part throttle the difference in gas usage from 20 degree cooler ECT's is very little, even less when you add in the fact that with more timing your BSFC goes down so you don't have to push the gas pedal as much to get that same cruise speed under part throttle.

 

I've run 160 stats in all my LS type motors since 1999 and never suffered any Gas milage loss. If anything I gained. My C5 made over 400rwhp and got 28mpg. My C6 Ls2 motor at the end of modding was making 461rwhp and got 28-29 mpg. BTW wth over 50,000 miles on the clock with that LS2, I put it in my son's C5. Before it went in, we pulled the pan and saw nothing that would indicate any build up due to running a cooler temp, (ie not getting the oil hot enough) as some people say on this forum. This isn't here say I looked for myself. It was clean as the day it was new. So much for that theory. Finally my 427 stroker L92 motor making 525rwhp gets 26.5 mpg at 70-75 mph highway. My motor runs between 178-183 highway, and in traffic at the longest traffic light it never gets over 200.
Although I will admit I do have a large direct fit radiator now with the big inch motor. But even with the old radiator , with my LS2 motor driving in Las Vegas in july in traffic it never went over 208. Now as for the EPA people, and Emmissions,well, I've never had much in common with TREE HUGGERS. Anyway that's my input on 160 stats.