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mpg discusion

vaicase said:
yes the 6.5 with 4.10 gears and being a 4x4. will get you about 13.5 stop and go. to about 16.2 is the best i got once. ive had the truck for almost a year and a half. power service does not help. 2cycle oil does not help. it does quiet the engine though. after market exhaust and air filter . no help. at least not for me. even summer fuel here in kansas. no change. no miracles out there. dont beleive the snake oil salesman. dont drive a diesel unless you have too. and slow down. that helps a lot. thanks for your intrest.
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Power service does suck. and 2-cycle was never intended to increase MPG, its like a maintenance item to prevent 0mpg from a dead IP. The exhaust and filter are meant to improve highway and loaded MPG with better airflow, that wont really help stop and go, except better power.

My feeling is that keeping them hot is the best way to make then run efficient. If there was a 205* t-stat available I'd be willing to try it when not towing anything.

Around town the gearing should not matter much and too high of gearing could detract from stop and go mileage, requiring more fuel to get up to speed and off the line. Low idle and putting the truck in neutral at stop lights would help, since thats 0mpg, and it takes almost twice as much fuel when the tranny loads the engine at 600rpm.

So with 4.10s, I think the tires are another big factor for highway mileage, should have at least 235/85/16s which are at least 31.5" tall. The 3.73s can tow just as much as the 4.10s, just depends on the tire height when towing. Throw some 28" tires on 3.73s and it can spin the tires all day, putting lots of power to the ground. And it also lowers the ride height for better aerodynamics on the highway and lower unsprung weight for in town stop and go. But use the stock 245/75/16 tires at about 30.25" tall and on the 3.73s and you have nice compromise in towing power and highway efficiency.
 
Hey buddy, I agree on keeping hot, but below 210. Have you confirmed on a scanner that engine requires more fuel while stopped and in gear? I have always thought that the lower the rpm the better , so I would turn on the a/c and keep in in gear to drop it as low as possible. Maybe on the DS4 the PCM will flow more fuel in that condition? compaired to DB2 or carbed gasser?
 
I always feel that the truck is lugging when at a stop light in gear and I try to throw it in N if it is a known slow light. I also consider the AC to be lugging the engine and I usually have the windows down in town. Thats just what I do, I haven't paid much attention to the fuel rates and my computer with GMTD crashed.
 
Yes higher fuel rates when in gear or with AC on another slight increase. With the DS4 it compensates with more fuel to maintain programmed RPM. Even with the mechanical its more load and even at lower RPM it will use more fuel. Since diesels run very "lean" at idle, there is adequate air pulled in to use much more fuel even at the same idle RPM
 
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