Quote:
Originally Posted by gsxr
It takes a pretty substantial axle ratio change to move an engine far enough out of the optimum efficiency window to make a big change in fuel economy. It also makes a difference if you are talking about pure city, mixed, or pure highway economy; and how much of a lead foot you have.
That said... when you figure out the difference in MPG, also calculate the current cost of fuel per gallon, along with the miles driven per year. I find it comical that many people freak out over MPG when the car in question gets driven under ~10kmi per year. I went through this calculation when we switched out my wife's 300D 2.5T (30mpg average, mixed driving) with an E420 (20mpg average, mixed driving). Even with the massive difference... the 300D got 50% better economy compared to the gas guzzler... the actual DOLLARS PER YEAR difference was far less than expected. With fuel around $4/gal and ~10kmi annually, it was ~$500. Nothing to sneeze at, but having nearly triple the horsepower on tap was worth every penny.
Now if you drive a huge amount of miles per year... say, 30k-50k per year... then every MPG can make a big difference in the wallet. If it was going to cost us a couple thousand dollars extra per year to drive the funner car, we probably wouldn't have done it.
 |
For me, never having to deal with smog check or any sort of inspection in California was the main reason to switch from a gasser to a diesel. I had no desire to own a diesel until last year when smog check became an even bigger pain in the ass for old pre OBD2 cars. Going from 15c/mile to 9.7c/mile was just icing on the cake. I drive ~15k miles a year.
Quote:
Originally Posted by partsman225
Thanks everyone I just got back on the site . I decided am going to sell the car now due to a got laid off. Its halfway through body work. Just needs paint. I really dont have the money to finsh car now. May just list it here.
I have a 1991 560SEL with 2.47s , I get 12to14 mpg city and 18to19 hwy.
Like someone else here said I had a 1984 500SEL that got 24to26 mpg hwy.
I was told it was because of decell shutoff the EHA dumps fuel to cool the cats so it dumps fuel everytime you let off the gas is this right?
|
I doubt that. You would be spewing massive amounts of unburned HC if that were true.