170 or 180 thermostat for my 99 5.3
06-20-2011, 01:54 PM
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Generally speeking, a cool engine (160-170deg) will develop more horsepower because the IAT is lower and a more dense air mass fills the cylinders, that is why drag racers will try to keep the engine and intake a cool as possible.
On the LS based engines, they prerform more efficiently at 210-220deg F and gas mileage will increase as a result. That being said the VE/MAF tuning is also critical to the efficiency of an engine.
On the LS based engines, they prerform more efficiently at 210-220deg F and gas mileage will increase as a result. That being said the VE/MAF tuning is also critical to the efficiency of an engine.
06-20-2011, 08:39 PM
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The only difference I could ever see was the water neck itself that the thermostat fits into and the 04+ style is readily available for free (old leaky water pumps) so its no big deal there.
With the stock thermostat it runs right around 195 so why would you ever want to get it hotter than that? 210-220 is nuts. If you like running it that hot you must like going slow too.
With the stock thermostat it runs right around 195 so why would you ever want to get it hotter than that? 210-220 is nuts. If you like running it that hot you must like going slow too.
07-01-2011, 12:05 AM
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There was a lengthy thread about a year ago, and what I learned from that thread is that the LS engines seem to like to operate between 185-200* IIRC. I've been running a 160* stat in this truck for years though and it has worked well for me. Heat in the winter is not an issue, as 175ish degrees is more than enough to keep your booty warm lol. (I've noticed that that's about where this engine would operate before I had my fans adjusted to come on at a higher temp, and back when I had the clutch fan) Actually, I always ran 160* stats in my carbureted sbc's prior to this truck, and what I really like about them is that the heat comes up quicker since the t-stat opens sooner 
Just so you know, 160* is the temp that the the stat starts to open, it isn't fully open until it's over 170*.
I've read different things about the stock stat temp, with folks stating it to be a 180, 187, 192, and 195...I don't think that 180* is correct, but I know that 180* stats are offered out there. BTW, if you still have your original water pump, or a direct replacement, $20 sounds cheap for your stat, as your stat is the one that comes with the housing, not just the stat element. IIRC, 04 is when they switched to the separate stat/housing
Just so you know, 160* is the temp that the the stat starts to open, it isn't fully open until it's over 170*. I've read different things about the stock stat temp, with folks stating it to be a 180, 187, 192, and 195...I don't think that 180* is correct, but I know that 180* stats are offered out there. BTW, if you still have your original water pump, or a direct replacement, $20 sounds cheap for your stat, as your stat is the one that comes with the housing, not just the stat element. IIRC, 04 is when they switched to the separate stat/housing
my tstat i run is a 180* with the serperate housing a new waterpump. I mean my vmax is a 05, I had to figure out that change when I was doing my swap. But my Tahoe is also tuned for my 180* tstat as well. Temps are perfect too me.
a stock tstat is 195*
07-01-2011, 10:37 PM
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I may just leave it alone and accept the fact its about at its max considering its 105 degrees everyday and its mostly stock. Its running pretty well considering what it is.
07-02-2011, 01:07 PM
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the GM engineers are pretty good at what they do, and they used the 195* stat for a reason.
Thermal efficiency is proportional to engine heat. so as long as you can maintain good IAT, then there is benefits to running at slightly higher temperature. Of course there are a lot of other factors that play part in this.
On the safe side thou~ if in doubt, stick to stock
Thermal efficiency is proportional to engine heat. so as long as you can maintain good IAT, then there is benefits to running at slightly higher temperature. Of course there are a lot of other factors that play part in this.
On the safe side thou~ if in doubt, stick to stock
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