Kennedy
04-04-2005, 10:24
This is something I hear quite a bit of negative feedback about, and for the life of me cannot understand where the problem is. We did another one of our "marathon" trips to MI to drive my daughter home this weekend with the overall average being 19.425 mpg. Hard to knock that.
Loyal WI to Manistee MI:
Outbound was using the VA Smart Box LLY and burning Amoco #2 winterized diesel fuel (as labeled on pump) from Brenner Oil in Loyal with 8 oz of my FPPF additive cocktail added. We left in the 5:00 AM hour CST arrived Manistee MI approx 10.5 hrs later (2 food/snack stops and a driver swap) logging 582.5 miles on 29.2 gallons calculating to approx 19.95mpg. DIC calculated 23.5mpg and 24.7 gallons used. The DIC inaccuracy can be attributed to the VA box.
Manistee MI to Loyal WI:
Return trip was using the Edge LLY EZ and burning Amoco Premier (as labeled on pump) fuel from a BP station on the south end of Manistee MI with 8oz of additive also. We left Manistee in the 4:00 PM hour CST and arrived home about 10 hrs later (one food stop and a couple of driver swaps) logging 584.1 miles on 30.9 gallons calculating to 18.9mpg. The DIC calculated 18.9mpg and 30.9 gallons on the head.
Vehicle specs/standards:
2005 3500SRW truck with open bed and 6-7k on the clock. Oil is Mobil Delvac 1 15w40 with KD bypass filtration. All other fluids original. Tires are 265 (std size) Michelin LTX MS at 70 psi front and 60 psi rear. KD 4-5 exhaust, Uni foam filter in stock box and non functional EGR. Fuel filter was fresh at 3,000 miles. Filtermag RA 450 on fuel filter, RA 365 on oil filter and 300 series on Allison spin on. Bilstein shocks on all 4 corners since new.
Background:
Historically, we see our best mpg going out and a solid decrease on the return as was apparent here. My LB7 truck logged 20.2 on a similar run but it has a bed cover, more miles, and the weather conditions had us going a bit slower at times.
Driving Habits and the DIC:
What becomes VERY apparent is the influence of speed on MPG. While engine speed is definitely a factor, I believe that wind resistance is the key contributor here. On the return trip, the DIC was working upwards from 20.4 mpg when we hit the interstate which was a good 70 miles into the return if memory serves. When we left the interstate (Mackinac bridge) it was down to 17.5mpg. By the time we hit the interstate at Bonduel WI it had crept back up to 19.4 I believe. Interstate travel in MI was at 75mph with posted speed of 70mph. Interstate speed in WI was at 71mph with posted speed of 65mph. All non interstate was run at 60-62 mph. I believe the MPG calc was at 23.8 when we hit the MI Interstate and it took less of a hit then recovered a bit on the slower roads.
Even if the DIC is rendered inaccurate by a power module, it still is a VERY useful tool. It becomes quite obvious what inputs and conditions can influence mpg in both positive and negative ways. It is particularly obvious that starting out cold will drop it substantially with the loss of efficiency on a cold engine. That and the influences/number of stopping and acceleration cycles....
[ 04-05-2005, 04:23 AM: Message edited by: kennedy ]
Loyal WI to Manistee MI:
Outbound was using the VA Smart Box LLY and burning Amoco #2 winterized diesel fuel (as labeled on pump) from Brenner Oil in Loyal with 8 oz of my FPPF additive cocktail added. We left in the 5:00 AM hour CST arrived Manistee MI approx 10.5 hrs later (2 food/snack stops and a driver swap) logging 582.5 miles on 29.2 gallons calculating to approx 19.95mpg. DIC calculated 23.5mpg and 24.7 gallons used. The DIC inaccuracy can be attributed to the VA box.
Manistee MI to Loyal WI:
Return trip was using the Edge LLY EZ and burning Amoco Premier (as labeled on pump) fuel from a BP station on the south end of Manistee MI with 8oz of additive also. We left Manistee in the 4:00 PM hour CST and arrived home about 10 hrs later (one food stop and a couple of driver swaps) logging 584.1 miles on 30.9 gallons calculating to 18.9mpg. The DIC calculated 18.9mpg and 30.9 gallons on the head.
Vehicle specs/standards:
2005 3500SRW truck with open bed and 6-7k on the clock. Oil is Mobil Delvac 1 15w40 with KD bypass filtration. All other fluids original. Tires are 265 (std size) Michelin LTX MS at 70 psi front and 60 psi rear. KD 4-5 exhaust, Uni foam filter in stock box and non functional EGR. Fuel filter was fresh at 3,000 miles. Filtermag RA 450 on fuel filter, RA 365 on oil filter and 300 series on Allison spin on. Bilstein shocks on all 4 corners since new.
Background:
Historically, we see our best mpg going out and a solid decrease on the return as was apparent here. My LB7 truck logged 20.2 on a similar run but it has a bed cover, more miles, and the weather conditions had us going a bit slower at times.
Driving Habits and the DIC:
What becomes VERY apparent is the influence of speed on MPG. While engine speed is definitely a factor, I believe that wind resistance is the key contributor here. On the return trip, the DIC was working upwards from 20.4 mpg when we hit the interstate which was a good 70 miles into the return if memory serves. When we left the interstate (Mackinac bridge) it was down to 17.5mpg. By the time we hit the interstate at Bonduel WI it had crept back up to 19.4 I believe. Interstate travel in MI was at 75mph with posted speed of 70mph. Interstate speed in WI was at 71mph with posted speed of 65mph. All non interstate was run at 60-62 mph. I believe the MPG calc was at 23.8 when we hit the MI Interstate and it took less of a hit then recovered a bit on the slower roads.
Even if the DIC is rendered inaccurate by a power module, it still is a VERY useful tool. It becomes quite obvious what inputs and conditions can influence mpg in both positive and negative ways. It is particularly obvious that starting out cold will drop it substantially with the loss of efficiency on a cold engine. That and the influences/number of stopping and acceleration cycles....
[ 04-05-2005, 04:23 AM: Message edited by: kennedy ]