The OBS pickups were 215hp from the factory, my 2000 is 20 horsepower more that that at 235. I don't know where you're getting the 250 for a 99.5 but that didn't happen until 2001. Regardless of that fact, I guess we can only expect the OBS trucks that are chipped to start dropping like files any day now because of too much heat, is that correct?

It's also a scientific fact that too low of temperature may cause accelerated wear rates, but you don't want to talk about that now I'll bet.

 

So if I take my intercooler off, my egt's will be cooler and I'm ok to install a 203*?
Is that scientific fact?

 

Talking to Eugene is like

love you!

Barney

 

I read it as +60*c to an unknown base temp. I did not use the 200*C as a base. So my math and logic is correct as well as yours. 60*C = 140*F.
200*C to 260*C is a 108*F swing.

What is the TRR on a powerstroke? (80% Full load)
What is the exhaust to coolant ratio in a stock tuned powerstroke?(80% Full load)
What is the % of energy converted into heat in the psd?

My .02 is its more about egt control.
TRR has more to do with load and fuel.
The psd is dam efficient. To cold is as bad as to hot.(coolant)

Bill

 

I was just passing along some sound advice on stats ...and I see that several agree with me! Some of the other issues you raise will be covered here... https://www.ford-trucks.com/forums/9...tock-7-3l.html

 

Agree with what?
At 260*C the wear comes from a lube problem!
The temp has surpassed the flashpoint of most lubes.
All though the flashpoint might rise with pressure. (unknown)
Just cannot see how your statement of remove your 203 stat and your top ring
will be happy. This opposed to a 195 stat.

.02
Bill

 

I remember just over 2 years ago when I had just bought my late '99 all the talk about switching to the DIESELSITE 203* Tstat and their billet housing which I did and really haven't noticed any change in how my engine runs or a difference in coolant temp.
So, IF we want to now return to a "stock" Tstat which temp do we need to seek out? the 192* or 195*?? what came in it originally?? what brand should we get? Ford?
I sure don't want to "damage" my engine!!

 

Stick with the 203 ,.... won't hurt it a bit , may get better mileage

 

Well let's review the bidding... I said...

...and then these were posted...


..which to me sounds like agreement with my advice!


If you go from a stock 192*F/195*F stat to a 203*F stat how many more crankshaft degrees per revolution does the piston spend in the wear-inducing regime of mixed or boundary lubrication? What effect does the temperature increase have on abrasive wear ...and on corrosive wear? Well keep reading my engine-wear thread because I'll be trying to figure out the answers to these and many other questions as well!

As a general principle ...I think that anyone who advises members to modify the OEM Ford design also has a burden of proof to justify that their suggested mod isn't harmful to the long term like expectancy of the engine ...so I'd like to see your analysis that using a 203*F stat won't shorten the engine's like expectancy.

For what it's worth ...the normal coolant temperature as specified by Cat for my 7.2L C7 is between 180*F and 205*F ...and at 205*F the ECM activates the air-clutch and turns on a huge radiator fan which quickly reduces the temperature below 200*F. Cat is so concerned with a hot running engine that if the temperature somehow manages to reach 215*F the ECM de-rates the fueling until the temperature is below 205*F again ...and if the de-rate is ineffective and the temperature keeps increasing past 215*F the ECM gives a warning to pull to the side of the road ...and the ECM shuts off the engine! Cat also uses 2 thermostats in parallel to guard against running hot and recommends that they be replaced every 3 years even if no overheating has been encountered.

The paper work from when I changed my C7 stats is buried somewhere in the truck ...and when I did a search all I could find were comments like below ...which tells me these engines should'nt be run any hotter than is necessary...

I have a Silverleaf engine monitor which is much more accurate that the dash gauge and my C7 quickly reaches 180 degrees and then ranges between 180 and 190.

My C-7 runs at 195.

I have a 400 Cummins that runs at 185 all day long. On a hill climb on a hot day ( climbing from Phoenix to Flagstaff ) it will only come up 5 degrees.

 

Pulled my 203 stat and threw it in the trash... it was junk.

 

I always wondered what would happen if you ran lower temps and thinner oil.....

 

Eugene;

What are you're thoughts on heating intake air from exhaust pipe and switching to normal intercooled air once it hits 2-5 lbs of boost?

I'm thinking it might help to warm up, and combust fuel better while driving lightly......

 

Coke or pepsi.


The reduction of the T-Stat's opening temp in the psd was done for emission reasons!

You have your work cutout for you!
Pressures and temps are allways changing in the bore along with rpm's
per mile of the piston.
It also has to do with how quick the coolant can absorb heat from the
cylinder wall. Example: 50% water and 50% ethylene glycol vrs 60% water
and 40% ethylene glycol. The 60/40 is more efficient at extracting the heat
from the cylinder. 100% water beats them both! NPG is another route.


Its not apples to apples here with a C7!
The C7 has forged steel pistons (2 piece welded) and thin rings!
Its a ACERT T emission reduction motor.
Completely different animal to a powerstroke.

Bill

 

This is what i've been asking for a while too. What temp thermostat was the engine DESIGNED for??? I've also read that ford put the 195 in there for emissions reasons, which makes sense. Lower combustion temps means lower NOx, but less efficient fuel burn.

Who knows what temp it was designed to have in it??

 

The tune on a T444e is not the same as the PSD.
It produces less hp/tq, and peak rpm is less.

Besides the emission reason for the change of the stat was
the start of the diesel hp/tq wars. It was the old run it cooler
so you can extract more power from it. This reduces its lifespan.

Bill