Any tips to improve fuel mileage?

xSHIFTxNASTYx · May 29, 2019

Hi everyone. I'm new to GM with a "new-to-me" 2017 Silverado LT Z71 Midnight Edition truck.

I've been lurking for a while before and after my purchase. I've been reading a lot of threads (keyword here is "a lot") and I haven't really been able to collect enough information of my own so here I am with some questions for this community. Preface; I'm coming from a 2012 Dodge Charger that had a 3.6L Pentastar V6 engine (averaged 27-28mpg) to this truck with a 5.3L V8 engine. I'm not looking for "if you wanted good gas mileage, you should have bought a car" answers. I'm ok with the significantly lower mileage but I'm new to GM so I'm still learning about these sexy trucks.

What has everyone done to improve their gas mileage, if anything at all?

I've read that Black Bear suggests 89 Octane due to our high compression ratio, what are people running fuel-wise to maintain MPG?

Should I be sticking with 87, or switching to 89 or even 93?

Any tips or tricks with these trucks to maintain good MPG without being a Gordon Lightfoot?

I started with 87 Octane and probably averaged 18-21 city/highway. I added a K&N cold air intake and the mileage didn't change. I switched to 89 Octane after reading up a lot on Black Bear Performance and my mileage seems to have dropped. This is even on my 2nd full tank of 89 Octane. Now I'm struggling to break 16.5 in the city and 20 on the highway. Do I need a tune for just adding a CAI? I'm planning on an exhaust by the end of the year or at least early next year so I don't feel like tuning yet, especially with an extended warranty right now. Need to read up more on maybe buying a separate ECM core for dealership work to keep my flash counter at zero.

My Charger had a ton of engine mods and a custom Diablo tune so that is why I'm wondering what are we all doing to our trucks for this.

Thanks and looking forward to chatting with you all in the years to come.

Jacoby · May 29, 2019

The MPGs are what they are. Unless you "Gordon Lightfoot" it as you say they wont get any better. Octane wont change anything and adding an intake, exhaust and tune sure as hell wont make it better. The tune will sacrifice MPGs for performance.

You want good gas mileage then put it completely back to stock and get some good highway tires like Michelin Defenders and have at it.

And BlackBear sucks a fat one

m3n00b · May 29, 2019

Use cruise control whenever you can. My 6.2 would get anywhere from 25-30 flat hwy at 65-70 using cruise... when it was stock

xSHIFTxNASTYx · May 29, 2019

1 hour ago, Jacoby said:

You want good gas mileage then put it completely back to stock and get some good highway tires like Michelin Defenders and have at it.

Yeah, I figured that these Duratrac’s aren’t helping me at all! I know I will pay for playing by adding stuff like I mentioned and that’s ok.

1 hour ago, m3n00b said:

Use cruise control whenever you can. My 6.2 would get anywhere from 25-30 flat hwy at 65-70 using cruise... when it was stock

I have been doing that but I am also slowly trying to retrain myself to drive a little bit slower just to let it run more efficiently.

Edited May 29, 2019 by xSHIFTxNASTYx

aseibel · May 29, 2019

Keep everything stock. Run highway tires. Drive the speed limit. Those are the only things you can do to get the best fuel economy possible. Anything else you change will likely cause worse results. Due to EPA requirements the motor companies are already squeezing every possible MPG out of the vehicle, so nothing you do will make it better.

You are only fighting friction and wind resistance when moving, so avoid anything that changes the way air flows around your truck. (larger tires, lift, level, adding lights, etc.)

I also agree that tuning won't net any better mileage. The point of it is for performance under high throttle. To get good fuel economy, you want to be cruising at like 10% of throttle.

Racindave · May 29, 2019

1 hour ago, Jacoby said:

The MPGs are what they are. Unless you "Gordon Lightfoot" it as you say they wont get any better. Octane wont change anything and adding an intake, exhaust and tune sure as hell wont make it better. The tune will sacrifice MPGs for performance.

You want good gas mileage then put it completely back to stock and get some good highway tires like Michelin Defenders and have at it.

And BlackBear sucks a fat one

What’s the negative with Blackbear? Was thinking about a tune... wanna make sure it’s not a waste.

garagerog · May 29, 2019

Ditch the K&N filter and go back to stock intake. If you over-oiled the K&N filter the MAF and MAP sensors are getting dirty resulting in reduced mpg. Clean the intake and go back to stock intake.

xSHIFTxNASTYx · May 29, 2019

7 minutes ago, garagerog said:

Ditch the K&N filter and go back to stock intake. If you over-oiled the K&N filter the MAF and MAP sensors are getting dirty resulting in reduced mpg. Clean the intake and go back to stock intake.

It has a dry filter so I know that isn't the issue. but thanks for chiming in. I thought about switching back maybe next week just to see if I notice any difference after running the K&N for a week.

Wiggums · May 29, 2019

Going 55 on a flat surface, my 5.3 V8 gets me 26 to 27 mpg. Going 65, it drops to around 22 to 23.

But I have a 2019. Slowing down makes a big difference, sucks, I know, but that's one way I did it.

Sierra Dan · May 29, 2019

Atmospheric conditions play a huge role in MPG especially with our trucks.

Another note to mention is the switch over from Winter Blend Fuels.

Maybe you recently filled up at a station that had leftover or last remaining winter blend fuel before the summer switch.

That will take away at least a couple MGPs.

xSHIFTxNASTYx · May 29, 2019

Another note to mention is the switch over from Winter Blend Fuels.
Maybe you recently filled up at a station that had leftover or last remaining winter blend fuel before the summer switch.

You know what... you have a very valid point there. I completely forgot about that. I did go fill up at a station that I don’t really go to and isn’t usually very busy either.

Hmm. Thanks!

ammoaddict · May 29, 2019

Hi everyone. I'm new to GM with a "new-to-me" 2017 Silverado LT Z71 Midnight Edition truck.

I've been lurking for a while before and after my purchase. I've been reading a lot of threads (keyword here is "a lot") and I haven't really been able to collect enough information of my own so here I am with some questions for this community. Preface; I'm coming from a 2012 Dodge Charger that had a 3.6L Pentastar V6 engine (averaged 27-28mpg) to this truck with a 5.3L V8 engine. I'm not looking for "if you wanted good gas mileage, you should have bought a car" answers. I'm ok with the significantly lower mileage but I'm new to GM so I'm still learning about these sexy trucks.

What has everyone done to improve their gas mileage, if anything at all?
I've read that Black Bear suggests 89 Octane due to our high compression ratio, what are people running fuel-wise to maintain MPG?
Should I be sticking with 87, or switching to 89 or even 93?
Any tips or tricks with these trucks to maintain good MPG without being a Gordon Lightfoot?

I started with 87 Octane and probably averaged 18-21 city/highway. I added a K&N cold air intake and the mileage didn't change. I switched to 89 Octane after reading up a lot on Black Bear Performance and my mileage seems to have dropped. This is even on my 2nd full tank of 89 Octane. Now I'm struggling to break 16.5 in the city and 20 on the highway. Do I need a tune for just adding a CAI? I'm planning on an exhaust by the end of the year or at least early next year so I don't feel like tuning yet, especially with an extended warranty right now. Need to read up more on maybe buying a separate ECM core for dealership work to keep my flash counter at zero.

My Charger had a ton of engine mods and a custom Diablo tune so that is why I'm wondering what are we all doing to our trucks for this.

Thanks and looking forward to chatting with you all in the years to come.

Octane is the resistance to pressure or compression. Higher octane fuel is a complete waste of money unless you are experiencing spark knock or dieseling.
Like others said, keep it stock. If any of these add ons would get a fraction more mpg, you would probably never recoup the cost of it. I have an older f150 that gets 12 mpg. I looked at a dual exhaust system that they guaranteed 1 mpg more. I calculated the cost of the system against the fuel savings and it would have taken 68,000 miles just to break even.

Sent from my Moto G (4) using Tapatalk

Grumpy Bear · May 29, 2019

Think 'resistance' and reduce it. A few suggestions in the previous replies go to this end.

1.) Alignment

Having an alignment that is in spec and having one optimized can be quite different. This one could still improve on the thrust angle.

2.) Tires. Street tires and weight matters. The factory General and Bridgestone HT work well. Continental Cross Contact LX20. A place to start. Be OCD about maintaining pressures. 35 psi cold. Factory sizes for the WT1 was 255 -70-17. The Generals are the lightest. Bridgestone the longest wearing, Continental the quietest and most comfortable. Nothing wrong with the others suggestions of Michelin but about $25 a tire more money and really don't work any better.

3.) Use 0W30 instead of 5W20 but use a good one. My personal preference is Red Line. The large moly add is a real friction killer. Red Line or AMSOIL in the diff's. Ditto transmission.

4.) Use the 195* thermostat from the Camaro/Corvette and delete the trans thermal bypass valve. Or install IPSCO thermostat housing and run the earlier SBC stats like the 180F. If you get to the 170F to 180F range then the 0W20 oil will reap some incremental gains. Don't get 3 and 4 confused. Oil choice is temperature selected. Operating temperature.

5.) Lower the truck slightly and keep the front air dam and the rear wheel well opening winglets. Best way to achieve the lower is the drop spindle. 2" is plenty. This will retain the factory geometry and alignment ranges. In the back loose the 1.25" spacer, use the 2" drop shackle and the McGaughy's lower shock extenders. That will let you lower the rear that much and keep your factory shocks.

You do this drop other ways if you like but the idea is lowering frontal area.

6.) Bed Cover. Soft roll up like a LUND.

7.) Loose the idea you can tell anything about mileage in a tank or two. Averages made from hand calculations over say 5,000 miles and in like season tell the story. Yes that takes patients. Data is your friend.

8.) Get a monitoring device like the Autometer Ecometer or Linear Logic Scan Gauge II. Eyes on what is happening is a great 'feed back' trainer.

9.) Tighten that loose nut behind the wheel. Not one of the above will yield monumental improvements (except driving habits) but combine it can be quite the game changer. Mind set is everything. Your driving habits have more to do with mileage than anything on this list and it has to be your HABIT not what your do once in awhile.

A word on fuel. Think in terms of cost per mile instead of MPG when making that choice. 87 is fine. Your truck as a KR sensor.

Normally the above list yields a nice return for any vehicle. When motors have AFM it can be substantial and little reductions in resistance have a pronounced effect on how long the AFM is active. Think of it as a MPG multiplier.

You may reject it entirely. Some will disagree with some of the suggestions. What they cannot disagree with are the results it has had in use in my truck but, it's your truck, explore it and enjoy it.

xSHIFTxNASTYx · May 29, 2019

11 minutes ago, Grumpy Bear said:

You may reject it entirely. Some will disagree with some of the suggestions. What they cannot disagree with are the results it has had in use in my truck but, it's your truck, explore it and enjoy it.

Grumpy, thank you so much for chiming in. I've read alot of your posts, especially your posts about your experiences with Redline. You seem very knowledgable and thanks for giving me quite the list to consider! They're all valid points and I won't reject any of it as it all has merit and I will investigate all of it further... appreciate it.

Sierra Dan · May 29, 2019

42 minutes ago, xSHIFTxNASTYx said:

You know what... you have a very valid point there. I completely forgot about that. I did go fill up at a station that I don’t really go to and isn’t usually very busy either.

Hmm. Thanks!