Gear Vendor and MPG

[wsurf]

b737jets, I have an 03 CA model, bone stock dually with the 48RE, 4. 10's and GV unit. Have had the GV unit for about a year. It is great for towing! As towards mileage I think its a wash (friction, etc. ). While I do not have specific quantifiable numbers I do not think there is a mileage gain with the unit, maybe slight but negleable. I commute 25 freeway miles one way every day. At 70 mph my rpm's are 1650 double over. One of the best benefits is engine noise reduction, considerable difference between 2000 rpm and 1650. At the cost of a GV unit, I agree with the comments, it would probably take 150K miles to break even.

 

[djbobo]

Won't taller tires increase wind resistance. The only time you would see any fuel savings is when your running empty in double overdrive. I would choose to keep the truck as low as possible & get the unit. Besides that it would be fun!

I know that the GV unit is the same in every application for every Dodge truck & have been told that it only would cost around $400 to get the different adapters to change it to whatever truck you might have in the future. So I would look at it as only "looseing" $400 instead of $3000 if you always plan on haveing a truck.

I think your gear ratio in double overdrive would be in the 3:20 range. If I had 4:10s I would get get them and enjoy the best of both worlds.



dj

 

[b737jets]

Thanks wsurf





were you able to hold mpg..... ?



I guess what I'm asking is were your mpg numbers still the same at 70 mph with or without the G/V on or off... .....

 

[Jeremiah]

Standard deviations

Originally posted by John - K5AWO

I just did a quick little spreadsheet to see how this would effect me. This is how it played out.





Fuel at $2. 09 per gallon avg

Gear Vendor estimate_____________Cost/Mile___Cost/yr 20k miles

Current MPG at 60 mph_______16_____0. 13_____$2612

Hoped for improvement_______19_____0. 11_____$2200

Gain (lucky toss of coin)_______3_____0. 02_____$412___<--Savings/yr



Cost of Gear Vendor unit

$2,695. 00______________130,667___<-- Miles required to break even.



Obviously, if the mpg improvement fell short of 3 mpg, this scenario would have a lot of holes in it fast.



I made the break even computation by dividing the Gear Vendor cost by the savings per mile accurate to six places. I only showed two places for display.



This means I would have to keep my 6 year old truck another 6 years before I could even break even on the cost of the unit. The up side though would be my 2000 rpm economy cruise just might get me a few extra MPH before wind resistance took too heavy of a toll.



Now if I made my living traveling a lot of miles, this would be shortened IF the load was light enough to pull in OD. I doubt that would ever be the case, most likely the improvement would only be realized when dead heading.



I think the hoped for improvement previously mentioned of $900+ for 20,000 is optimistic IMO.



Can someone tell me how to make this web site display TABS correctly?? I had to space everything out with those underscore characters.





John

It played out fine. The only thing you didn't do was take your figures out to the third standard deviation, which would guarantee, oh, maybe 99. 9 percent accuracy or so.