Guys, anyone know why the new breed diesels get less fuel economy than past diesels? More rpm's and more performance requiring more rpm's I suppose? I would like to see some lighter weight diesels making their way into smaller vehicles....with the price of fuel I would asume our automakers are looking into this.
Gary

 

Emisions are a majore part of it. That and the fact that my current Cummins has over twice the horspower of the original ones in 1989. I am not sure but I balive they where rated at 160HP and mine is 325HP. But most of the milage went down the tubes due to emisions. For example an 03-04 truck identicle to mine with the 305HP engine would get 20-22 mpg down the highway resnoble easaly. Then in 04.5 when they released the 325HP 600ft/lb version that I have they tightened up the emisions and milage dropped off 3-5 mpg. They added a Cat to the exaughst and added a 3rd injection event amoungst other things.

 

new diesel get worse because of emission, morepower, trucks weigh more now than before.

I didn't think they put more than one injector in them? I thought each injector just fired 3 times. starting with a small shot of fuel first then little bigger and then the big one. Guess i'm wrong.

 

Yes the trucks are heavy. I weighed my 03 F250 crew cab long bed and it was 7620lb. That was on a guaranteed scale at a truck stop with a full 38 gallon tank and me in it and I don't weigh but about a buck fifty!!

 

My brother has a Dodge cummins and I think it is a early 90's or so and he can get 24.5mpg with his. Now the power with his older Dodge is nothing compared to mine so I can understand the better mpg. Also his old Dodge rides like a covered wagon and is so loud you can't talk back and forth. I guess we sacrificed mpg for power. I will take it after riding in that old Dodge.[img]i/expressions/face-icon-small-happy.gif[/img]

 

You are correct. If you re-read what I said you will see that I said 3rd injection event, not 3rd injector. The pre 03 cummins trucks(hte ones that sounded like real diesels) had 1 big shot of fuel and then the 03-04 305HP trucks had that shot cut into 2 smaller ones and the 04.5 325HP trucks that they refere to as the "600" and now "610" engines cut it again into 3 shots of fuel per ignition stroke to improve on emisions and help quiet it down.

 

oooops sorry about that..........

 

Dont take this wrong .............but shoulda bought a FORD. Chevy's get notoriously bad mileage. I have some buddies who are diehard chevy guys and all they complain about is the mileage. My Ford 4x4 f350 dually gets 19 in town.

 

my 99 F350 CC dually has 4:10's and 60 HP chip . horrible mileage, but i 'm always pulling big loads at around 70MPH, lotsa hills. bottom line, truck costs 50-60K. we wanna get everywhere NOW or sooner. so how can any of us possibly justify whining about our fuel mileage?? now the moving target price of diesel is a totally fair complaint....

AND, i always thot the Cummins had the others beat on mileage. my uncle has '90 or '92, regular cab, SRW, Cummins, standard tranny. NEVER goes over 50-55 with it. he says he gets 27-28 mpg. (Imperial gallon is 4.55 litres, US gallon is 3.78 litres, so figures will be distorted a little). my last trip up fairly high mountain hwy and then an hour in 4low as we crawled into camp, saw me get 9-10mpg (US gallon). but i got there fast, and that must have nmeant more than saving $10-20 in fuel.

 

All of the current diesels are within a mile or two of each other but worse than previous generation. Ford's 6.0 however is notorious for always being in the service bay at your local Ford dealer. Ford already has plans to drop the 6.0 by 2007 model year. I wonder why????