build ideas to improve fuel economy?
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build ideas to improve fuel economy?
2003 savana 3500 6.0 215k 4sp trans
Looking for ideas to improve fuel economy. Mainly used for family transport on trips, minimal towing but full when traveling, is in great shape for the age, no mechanical issues,
considerations:
1) covert to diesel
2) change transmission
3) rear diff gear swap
Other ideas? Thoughts on these? link to other threads on this?
Thanks
Looking for ideas to improve fuel economy. Mainly used for family transport on trips, minimal towing but full when traveling, is in great shape for the age, no mechanical issues,
considerations:
1) covert to diesel
2) change transmission
3) rear diff gear swap
Other ideas? Thoughts on these? link to other threads on this?
Thanks
Last edited by GM_Van03; Apr 11, 2022 at 10:28 AM.
CF Junior Member
Joined: Aug 2021
Posts: 51
Likes: 17
1. The thousands of dollars you'll spend converting to a diesel can buy years worth of gasoline. You're not replacing just the engine, but electrical harnesses, computers, fuel tank, exhaust, etc. All for a few additional MPG?
2. Changing the transmission to a 6L80 or 6L90 will provide two more overdrive gears, but the final ratio will be close to the same as the four speed. Computers will need to be changed. Will aid mileage slightly. Again, cost effectiveness is the determining factor.
3. Rear axle ratio will help add maybe 1-2 MPG to your highway mileage but may decrease in town or city mileage. Speedometer and ABS will need to be reprogrammed. GM Dealers will not do it. You'll need to find a shop that performs custom programming.
I did this with my Silverado only in reverse. Went from 3:23 to a 3:73 ratio. Highway mileage dropped from 21 to 19.5 MPG. Towing mileage (7300 lb trailer) actually increased from 9.5 to 11.
IMHO unless any of the three items listed above need repair or replacement it is not cost effective to modify them. The most effective low cost solution is to use your Cruise Control and set it to a comfortable speed.
Remember, you're driving a 6500 lb brick down the highway. Aerodynamics isn't a strong point.
2. Changing the transmission to a 6L80 or 6L90 will provide two more overdrive gears, but the final ratio will be close to the same as the four speed. Computers will need to be changed. Will aid mileage slightly. Again, cost effectiveness is the determining factor.
3. Rear axle ratio will help add maybe 1-2 MPG to your highway mileage but may decrease in town or city mileage. Speedometer and ABS will need to be reprogrammed. GM Dealers will not do it. You'll need to find a shop that performs custom programming.
I did this with my Silverado only in reverse. Went from 3:23 to a 3:73 ratio. Highway mileage dropped from 21 to 19.5 MPG. Towing mileage (7300 lb trailer) actually increased from 9.5 to 11.
IMHO unless any of the three items listed above need repair or replacement it is not cost effective to modify them. The most effective low cost solution is to use your Cruise Control and set it to a comfortable speed.
Remember, you're driving a 6500 lb brick down the highway. Aerodynamics isn't a strong point.
Last edited by og52; Apr 11, 2022 at 12:54 PM.
CF Pro Member
Joined: Aug 2013
Posts: 607
Likes: 80
diesel costs so much more a gallon that you will see no cost savings over gas.
These were built with a diesel option, so you would just go buy one of those and sell this one.
My suggestion would be to lower it at least in the front and make some kind of air dam to direct air around rather than under the van, or add some tin panels to smooth out the undercarriage. This would give you some MPG although it will make things a pain to work on.
These were built with a diesel option, so you would just go buy one of those and sell this one.
My suggestion would be to lower it at least in the front and make some kind of air dam to direct air around rather than under the van, or add some tin panels to smooth out the undercarriage. This would give you some MPG although it will make things a pain to work on.
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