Thermostat temp rating effect on HP?

[damork]

Has anyone found a correlation between HP and thermostat temperature? It seems running with higher temp thermostats (195 vs 180) provides slightly better ecomomy. Maybe someone has already done so, but would be interesting to know.

[Bnave95]

Today was my Spring cooling system clean up.I have been running 180* Stats For the last 7 years. Now I have choosen to go back to the 195* Stats.
This will give me a ideal if my fuel MPG will get any better. I did make some power runs and power was as before. I did notice less black smoke. The temp gauge must really be off for it will read 210*.(could a new sending unit make a difference?)
Also a reason for me to change is I think the Eng. was running to cool because my CDR vavle and tube going to the turbo was full/clog with black grud like goo.Don't know what caused this other than running to cool.

[damork]

I've been running 180's going on 4 years but no goo yet, it's just that I saw a slight drop in economy with the 180's.

[Bnave95]

Back in 98 I installed the cooling Mod's and the push at that time seem to be using the 180* as a means of keeping the system cooler. Now through the years having read that there may be to much of a heat cycle going on that may not be good on the Eng.
When I was towing a TT I could see temps around 210* and would cool down to 180*. At one time even JK pushed the 180*, though through the years that thought has changed.
Not towing any more and would like to see my MPG go up somewhat.
When I was towing with the single stat(180*) the clutch fan would cycle. With the duel stats the fan has never had to lock up.
Some member wish they could get even higher Deg. Stats.Say around 210*
If I would say after the change I may feel as though the truck does have more power seeing how I am having a better burn. Course the air temps were also cool. The Eng. would have to get real hot before the fuel was pulled. The ECM can't pull my boost but could pull the fuel though I have never had a heat issue ever with the truck.Single Stats yes.
I was also one of the guys that thought cooler was better. After a couple of hard runs and a hour drive,back to the shop I pull the turbo boot off and could see where there was still some small water droplets in the CDR tube and oil fill tube.

[Doug Thom]

I just finished going through this with General Motors a few weeks back. Wasn't getting proper heat in the cab and turned out that after flushing the heater core all was well. Seeing as my 1995 and never had a thermostat change since new, I thought I should give it a new one at this time. I went to GM store and they gave me a new one which they said was a 185 degree thermo (they are not stampted on the housing plus the degree is not even on the box the thermo came in). I asked about whether I should use a 195 thermo and they didn't have a clue! I contacted the technical people at GM and they said NO, use the one that the parts dept. gave me as the 195's are too hot! Hope this helps!
Regards
Doug

[More Power]

The latest AC Delco t-stats I've seen were stamped in degrees Celcius.... (i.e. 88).

In the FYI category... Peninsular Diesel used 160-degree t-stats the last I heard. I ran a 160 in my 6.2L diesel for several years. Plenty of cabin heat during the winter here in Montana, and it would deliver 24-mpg when I did my part. :)

Jim

[Bnave95]

The latest AC Delco t-stats I've seen were stamped in degrees Celcius.... (i.e. 88).

In the FYI category... Peninsular Diesel used 160-degree t-stats the last I heard. I ran a 160 in my 6.2L diesel for several years. Plenty of cabin heat during the winter here in Montana, and it would deliver 24-mpg when I did my part. :)

Jim
Jim, thorugh out the year's the T'Stat has been a subject of what to run?
#1 Heat cycle
#2 Members preference
#3 JK recemendation(at first)cooling Mods.
#4 160*-210* T-Stats.
#5 Whats better, cool or hot.
Marine Boats are under a constant load,boost 90% of the time and this difference can not be compaired to trucks running down the road,towing is another subject.
After 7 years of running 180* T-stats. Installing 195*my truck todate,today Has power,cleaner burn than I have ever seen.
My truck had black smoke as long as I'v knowen.
Strange thing with the 6.5,there closes to being the same yet they seem to run different.
Where the fine line?
What to run T-stat*?
With the Diesel Page I've seen trends come and go,this is good. Keep's us up on or toe's,

[More Power]

The best thermostat temperature rating for your 6.5 is.......

I don't know... ;)

Some of this debate involves personal preference, some of it might be based in engineering intuition, but not much is based on thorough engine testing data for this particular engine in this particular application....

My preference for the electronic 6.5 is 180 degrees.... Based partly on the fact that many EFI failures (FSD, OES, ect.) are heat related or heat affected. Running 15 degrees cooler (than 195) makes sense - to me.

From a performance and fuel economy standpoint, I hope to get an opportunity to work with Peninsular in the next few months, where we put a fuel economy engineered 6.5 on an engine dyno, and run a variety of configuration tests - mostly for fuel economy. Thermostat rating could be one of those tests.... We'll be measuring bmsfc using various configurations, but with a 50-60 fwhp load at 1800 rpm primarily - both NA & TD. Perhaps the t-stats will tell us something... :)

Jim