Engine/Transmission (1998.5 - 2002) 180° thermostat increased mileage

[hammersley]

showerhead injectors?

Showerhead Injectors - what are these beasts????

 

[Mark_Kendrick]

I got them from Quadzilla here in FT worth... HUGE!!!!!!!!!



I can suck the lift pump dry on occasion



they are hand matched injectors given a lot of TLC. . not cheap but worth it

 

[mocummins]

I have noticed that I get better mileage during warmer weather. Even with the A/C running which should lower gas mileage. I usually get 18. 5 winter and 19. 7 in the summer. With that said I must admit strange things can and do happen in the real world. I don't want to spout out a bunch of engineering jargon so I will use the K. I. S. S. principle. Well, I will have to use some.



The average diesel cycle is:

• 29% heat loss to coolant system
  
• 32% heat loss to exhaust system
  
• 32% heat used for power
  
• 7% heat loss to radiation
  

The system, in theory is adiabatic/isentropic, meaning no heat is lost to the heat reservoirs during compression and expansion strokes. Which means that there should be no real mileage difference with either thermostat on a theoretical model. The only real difference that can be made on a model diesel cycle is raising the compression ratio. Which is exactly what Cummins did with the H. O. motor. They increased the compression ratio which only improved the efficiency by less than 1% but they gained 10 hp & 45 ft lbs of torque. I speculate that the lower emission engine(with 190 thermostat) is more efficient.



The diesel cycle is approximately 15% more efficient than the Brayton power cycle.



In the real world and using my bulletized list you can see that if the coolant system takes less heat from the system there should be more heat available to do work. Or it could be lost in the exhaust. Has anyone noticed an increase in EGT with the 180 degree thermostat compared to the 190? If EGT's stay the same with either thermostat then more work is possible. That could increase the motor efficiency slightly and improve mileage slightly.



Has anyone noticed that good hp gains are made when the EGT goes down. That is because you are taking lost heat from the exhaust and turning it in to usable hp. Does anyone know what the ratio is for hp gains and lowering EGT? It almost seems 1:1

 

[Mingoglia]

I think I'm going to start producing 185 degree t-stats for the ISB and settle this matter once and for all.

 

[Mark_Kendrick]

Originally posted by Mingoglia

I think I'm going to start producing 185 degree t-stats for the ISB and settle this matter once and for all.

hehehehe!

 

[Mark_Kendrick]

mocummins,



the mpg is probably from the fan not running like stated earlier. as long as the engine is not working too hard the air coming through the radiator is just cool enough to keep the fan from engaging.



The engine may run cleaner at the higher temp but loose the gained efficiency to the fan.

 

[mocummins]

Mark



I think it's a thermodynamic issue vs. the fan load. I noted that I get better mileage during the summer with the A/C on almost all of the time. However, I still get better mileage based on "thermodynamic principles". I'm not saying that the fan doesn't contribute but the main reason is purely thermodynamic. Try a search for diesel cycles and look at how it works. I thought the bulletized list explained it all? All engines work based on thermodynamic principles and can be used to describe why certain things happen. In fact these cycles existed long before engines did.



Hey we could just go with the 185 degree thermostat and move on.

 

[GeneralMachine]

T Stat

Ok Guy's I couldn't stand it, Today i installed a 180 Part# 354194. We will be testing the outcome,The 190 had came apart im glad I changed it. Harv:--)

 

[GeneralMachine]

T stat

Im up loading a pic of the busted 190 T stat. Harv