Tips for maximizing fuel economy

[hapyspaz]

Maximizing Fuel Economy/Minimizing Costs

I know we are all concerned about mileage with these big heavy SUVs we choose to drive, so here are some gas saving tips.

The best fuel economy possible is the direct result of proper maintenance and good driving habits. Listed below are GM's recommendations to achieve the best mileage possible. The first group are things to consider for your vehicle, while the second are tips relating to your driving habits.

Vehicle Considerations:

Tire Pressure - One of the major contributors to poor fuel economy are under inflated tires. Tires low on pressure create drag that the vehicle's powertrain must overcome, wasting dollars in fuel. Always keep your tires inflated to the proper pressure as shown on the vehicle placard. This not only serves to increase gas mileage but cuts down on tire wear, further decreasing your costs per mile.

Air Filter - A vehicle that has a dirty air filter can't efficiently draw air into the engine. This restriction forces the engine to expend energy to "breathe" wasting fuel in the process. Change recommendations are found in your vehicle Owner's Manual.

Proper Viscosity "Starburst" Rated Oil - Always use the proper viscosity oil in your engine. Oil that has a higher than required viscosity will create more drag on the internal components of the engine, causing more work for it, especially when cold. Each Owner's Manual contains information on the proper type of oil for your vehicle. Look for the "starburst" symbol on the front of the bottle, and the SM rating on the API circle on the back label. If you are in doubt, stop by your dealer for an oil change, and any other services required. Most current GM vehicles are equipped with oil life monitors to further assist on the "when" to change your oil. (Aveo/Wave/Optra/Epica currently do not have oil life monitors).

Note: GM Vehicles DO NOT require additional engine oil additives. Some additives may cause harmful effects to the internal seals and additionally void the terms of your vehicles New Car Warranty.

Top Tier Fuels - Some fuel manufacturers provide gasoline advertised as TOP TIER DETERGENT GASOLINE (Chevron, Conoco, Phillips 66, Shell, Entec Stations, MFA, 76, Somerset Oil, QuikTrip, and Kwik Trip in the U.S. and Chevron in Canada. These fuels are preferable when and where available. They help to keep your fuel injectors and intake valves free of deposits. Clean engines provide optimal fuel economy, performance and reduced emissions. When Top Tier fuels are not available, consider a bottle of GM Fuel System treatment PLUS, P/N# 88861011 (in Canada, # 88861012), at oil change time which will remove intake system and injector deposits. GM does not recommend any other fuel system cleaner.

Important: DO NOT confuse Top Tier Fuels with Higher Octane (Plus/Premium Grade Fuel) commonly sold at most all gas stations. Plus and Premium fuels are required in some high performance GM vehicles. However, they do not necessarily represent higher detergency present in TOP TIER Detergent Gasoline.

Note: E85 FUELS: Only vehicles designated for use with E85 should use E85 blended fuel. E85 compatibility is designated for vehicles that are certified to run on up to 85% ethanol and 15% gasoline. All other gasoline engines are designed to run on fuel that contains no more than 10% ethanol. Use of fuel containing greater than 10% ethanol in non-E85 designated vehicles can cause driveability issues, service engine soon indicators as well as increased fuel system corrosion.

Use the Recommended Grade (Octane) Fuel-
Purchasing higher than required octane fuel is a waste of money. Using higher octane fuels in a vehicle that only required regular unleaded fuel will neither increase performance nor improve gas mileage. In all cases refer to your owners manual and ONLY use the octane rated fuel recommended for your vehicle.

Important: In high performance GM vehicles that DO require Premium (91 octane or higher) fuel, you MUST use fuels of at least this octane. Use of lower octane fuel may result in reduced performance, knocking, and/or permanent engine damage not covered under the terms of the New Vehicle Warranty.

Check Engine/Service Engine Soon Light - Is the Check Engine/SES light on? When this light is on, the vehicles On-Board diagnostics computer has noticed that something is wrong. GM vehicles have many sensors that the computer uses to both control and sense actual fuel usage. When the computer lights the Check Engine/SES light it has lost some ability to run efficiently. This may result in increased fuel consumption, increased emissions, and/or driveability concerns.

Spark Plugs - Even though current GM vehicles have 160,000km (100,000 mi) service intervals for spark plugs if your vehicle is at that point in it's life, have the spark plugs changed to assure proper running and continued efficient, trouble free operation.


Changes In Driving Habits:

Slow Down, Drive Smoothly - Avoid quick/full throttle acceleration from a standstill in town and high cruising speeds on the interstates. While the optimum MPG for highway cruising speed varies from vehicle to vehicle, faster is almost always worse. If your vehicle is equipped with a Driver Information Center that displays Instant Fuel Economy, select that read out and vary your cruising speed while on the highway. The display will change continuously with uphill and downhill sections but you should quickly be able to identify on level ground the speed range that your vehicle does the best in.

Empty Your Trunk - Avoid leaving unnecessary items in your trunk. It takes power to move increased weight and that means more gasoline consumption and reduced performance. While the change may be slight, multiplied by thousands of miles, it all adds up.

Avoid Extended Idling - There is no need to idle your engine till it reaches operating temperature. Idling wastes fuel.

Combine Trips - Your vehicle uses much more fuel when the engine is cold. This is especially true in the winter months when the engine will take the longest to warm up. Combine errands or trips so that the vehicle only needs to warm up once to encompass many different stops.

Chalk one up for JK

 

[3blackchevys]

top tier fuel....SHELL

 

[foreverfalcon40]

Modding your truck too helps MPG!

Basic Bolts-Ons to help your truck breathe better such as Intake and Exhuast (cat-back, even better Full Exhuast incl. Headers) Also anything that will help in combustion such as MSD Ignition Upgrade (People stated an extra 50miles to the tank) and The Big 3!

Right now I just have CAI, TB SPACER, Cat 3in Exhuast and a tank lasts me a full week. I drive 50 miles a day M-F. Weekend if it I keep it local it will last too. When I'm highway driving my Cruise Control is set to 55mph.

If it helps my truck is lowered so maybe less drag?

Right now I'm using my 99 Jeep Grand Cheokee Limited with 4.7L. Stock too just swallows gas faster then the HOE.

 

[LSCALADE]

From a vehicle maintnenance stand point new air filter and injector cleaner with PEA should help bring back what eficiency was there and got lost due to reduced spray pattern and air flow. Cleaning the MAF is free.

The other biggest thing you can do to see MPG increase is reducing rolling resistance so if you go from 35psi on your tories to 40psi you will see some difference but you will also feel more of the road in the driver seat.

 

[Eman85]

We're dealing with 30 yo dinosaurs that weigh 2 tons+ with big tires and 4wd in most cases.
On these old Vortecs I'd say one thing few check or adjust is the distributor offset and replacing the distributor gear or the whole worn out plastic distributor.

 

[Marky Dissod]

Exhaust mods are better at improving both MpG & horsepower, vs intake.
Not saying that intake mods don't work at all, but the MpG improvement from intake mods are far from exhaust mods in terms of bang for the buck.
It is incredibly difficult to improve Helmholtz resonance under 2400 engine RpMs and improve peak torque or power at the same time.
In fact most intake mods move the power curve 'to the right', away from the RpMs where most engines spend most of their time.
(*Opening one's nostrils and/or mouth wider cannot make anyone a better runner or swimmer without better lungs, circulation, nutrient uptake, etc.)

Long-tube headers & cat back exhaust systems, properly selected, can noticeably improve MpG by improving scavenging,
if the improvement occurs anywhere between 1500RpM-2500RpM, where most engines live most of the time, and where MpG gains are best noticed.

*Best hope for improving highway MpG for our bricks on wheels include:
Improving airflow under the vehicle - depending on how you do it, a side benefit might be slowing corrosion
Lowering, up to a point, as well as using front air damns to prevent some air from getting under the vehicle in the first place also helps
(just 'cause the latest GM suvs overdo it in terms of active frontal aero mgmt, doesn't mean we can't learn anything from them)
So far as I know, keeping one's normal cruising speed under 70MpH (& more TCC lock time / less unnecessary downshifts from 4th) helps too.
If you want to learn about hypermiling techinques, they work as well as you learn how to use them, until someone else kills you for hypermiling.

*If your suv has a 4L60E or 4L80E, best way to improve city MpG is 3.73, 4.10, 4.30, or 4.56, depending on your tire size & usage cases.
If you take a small highway MpG hit, it will be defrayed by the 4-speed spending more time with the TCC locked in 3rd & 4th, so it'll last longer between rebuilds.
Highway MpG can also be improved by a competent tuner who is aware of how to fully take advantage of an Australian operating system's idiosyncracies.

*If your suv has a 6L80E/90E, 3.42, 3.73, or very rarely 4.10 or 4.30, depending on your tire size & usage cases.
Again, a small highway MpG hit will pay off by helping your 6-speed spend more time with the TCC locked in 4th 5th & 6th, so it'll last longer between rebuilds.
Tuning of a 6L80/90E yields less MpG improvement than tuning a 4-speed, but also yields several other benefits, some more immediately obvious, some less so.

 

[LSCALADE]

Exhaust mods are better at improving both MpG & horsepower, vs intake.
Not saying that intake mods don't work at all, but the MpG improvement from intake mods are far from exhaust mods in terms of bang for the buck.
It is incredibly difficult to improve Helmholtz resonance under 2400 engine RpMs and improve peak torque or power at the same time.
In fact most intake mods move the power curve 'to the right', away from the RpMs where most engines spend most of their time.
(*Opening one's nostrils and/or mouth wider cannot make anyone a better runner or swimmer without better lungs, circulation, nutrient uptake, etc.)

Long-tube headers & cat back exhaust systems, properly selected, can noticeably improve MpG by improving scavenging,
if the improvement occurs anywhere between 1500RpM-2500RpM, where most engines live most of the time, and where MpG gains are best noticed.

*Best hope for improving highway MpG for our bricks on wheels include:
Improving airflow under the vehicle - depending on how you do it, a side benefit might be slowing corrosion
Lowering, up to a point, as well as using front air damns to prevent some air from getting under the vehicle in the first place also helps
(just 'cause the latest GM suvs overdo it in terms of active frontal aero mgmt, doesn't mean we can't learn anything from them)
So far as I know, keeping one's normal cruising speed under 70MpH (& more TCC lock time / less unnecessary downshifts from 4th) helps too.
If you want to learn about hypermiling techinques, they work as well as you learn how to use them, until someone else kills you for hypermiling.

*If your suv has a 4L60E or 4L80E, best way to improve city MpG is 3.73, 4.10, 4.30, or 4.56, depending on your tire size & usage cases.
If you take a small highway MpG hit, it will be defrayed by the 4-speed spending more time with the TCC locked in 3rd & 4th, so it'll last longer between rebuilds.
Highway MpG can also be improved by a competent tuner who is aware of how to fully take advantage of an Australian operating system's idiosyncracies.

*If your suv has a 6L80E/90E, 3.42, 3.73, or very rarely 4.10 or 4.30, depending on your tire size & usage cases.
Again, a small highway MpG hit will pay off by helping your 6-speed spend more time with the TCC locked in 4th 5th & 6th, so it'll last longer between rebuilds.
Tuning of a 6L80/90E yields less MpG improvement than tuning a 4-speed, but also yields several other benefits, some more immediately obvious, some less so.

Mine has 3.08 gears and 5.3L it seems to do extremely well on highway at 75mph it’s right at 1700rpm and gets over 20mpg. On a few trips I’ve seen 23 and even 24mpg on V8 only mode. Bigger gears seem to make it run higher RPM which depending on the BSFC it may be a good thing. I can run in 5th gear and not get past 2000rpm and still get 20mpg but have power to climb hills.

So what’s your thoughts on a 3.08 set up in 2WD?

 

[Marky Dissod]

... what’s your thoughts on a 3.08 set up in 2WD?

I fully appreciate that different people buy 'the same' vehicle for different reasons & different use cases, but very generally speaking,
CAFE MpG test scenarios are not realistic enough (I'm aware they were altered to be somewhat more realistic in the late 90s / early 2000s, but not by enough).

To me, it seems as if 3.08 was the gear that GM had been influenced into concluding was adequate.
I'd be willing to bet that with 3.42 instead of 3.08:
the real-world MpG difference would be barely detectable for the vast majority of people
any MpG penalty would be offset by making the transmission more long-lived / durable
the tow rating improvement with better axle gears literally means that (even if the engine is not more powerful) more power is being put thru the tires to the ground

The 2012 Yukon XL I used to drive in NYC had 3.08, which was enough, I guess, to get the job done,
but it'd've been so much more fun-to-drive and more capable with 3.42 or 3.73.
Think about how much more time it could've spent with the TCC locked with better gears.

 

[LSCALADE]

I fully appreciate that different people buy 'the same' vehicle for different reasons & different use cases, but very generally speaking,
CAFE MpG test scenarios are not realistic enough (I'm aware they were altered to be somewhat more realistic in the late 90s / early 2000s, but not by enough).

To me, it seems as if 3.08 was the gear that GM had been influenced into concluding was adequate.
I'd be willing to bet that with 3.42 instead of 3.08:
the real-world MpG difference would be barely detectable for the vast majority of people
any MpG penalty would be offset by making the transmission more long-lived / durable
the tow rating improvement with better axle gears literally means that (even if the engine is not more powerful) more power is being put thru the tires to the ground

The 2012 Yukon XL I used to drive in NYC had 3.08, which was enough, I guess, to get the job done,
but it'd've been so much more fun-to-drive and more capable with 3.42 or 3.73.
Think about how much more time it could've spent with the TCC locked with better gears.

So side question for re-gearing, what all would need to be done? Escalade rear axle and maybe front diff swap? I have 2 Escalades at home both 3.42s, perhaps the parts can be swapped over, but they seem to be more peppy even off the line with the same 6L80 but both hold higher RPMs although not by much on highway speeds. Thats maybe something to consider if the diff gives up the replacement would be an upgraded one.

 

[Marky Dissod]

Simplest way to improve axle gears would be to find a used rear axle / front differential assembly in good shape with 3.42 or 3.73
(or 4.10 if you want a 2500/3500-type axle, but then there's a bit of suspension labour involved in making a 2500/3500 axle a 1500 axle (not much, but some).

Taking apart & rebuilding an axle is a deferred investment (in terms of money) that you won't get back til your next trans rebuild which got delayed by better gearing,
unless you can do the labours yourself, or your friend gives you some kind of discount, or something like that.
OR, you can wait until you can justify the upgrade to coincide with maintenance.
I updated-upgraded my front brakes when I first bought my Tahoe Z71, since the seller already told me it would soon be time to replace front rotors & pads anyway.
But in the case of axle gearing, waiting means you're effectively rushing your next transmission rebuild.

Looking at your sig, if your ESVs both have 6.2L-6L80E-3.42, I'd prioritize 3.73 in the Suburban over 3.73 in the ESVs.
Just think about how less often your 6L80 would need to downshift with better gears.