Improving Fuel Mileage

spfish · December 14, 2007

Gents. I'm new here but I've been reading this board for two weeks since I got my new Suburban. To say the least, I'm VERY disappointed in the fuel mileage. My '99 with 164k miles on it did over 15 and this one is only doing 14! Maybe I should have read this web site before purchasing or maybe I should have just set much lower expectations, but I really thought a newer truck with 9 years newer technology would get BETTER mileage than an old truck with a ton of miles on it. Reading all the posts here about this topic, most seem to point to a Diablo or Edge tuner, but that only gives minimal improvement. Has anyone "studied" or tested ethanol-laced fuel vs non-ethanol? I was surprised that my new truck came with an additional window sticker showing how "FlexFuel" would kill the gas mileage. I guess like the rest of the brain-washed, politically correct public, I just thought that ethanol was supposed to save the world. Now I find out that it actually takes a lot more E10 to go the same distance as normal gasoline.

I bought the truck with more options than I thought I would and I've purchased a lockpick to unlock my nav system, so I can't afford to put too much more into add-ons. I'm hoping that driving an extra five miles to fill up at a station with NON-ethanol fuel will actually save me some $ and improve the mileage.

Thoughts?

wellinghurst · December 14, 2007

Newer cars don't get better gas mileage, they have fewer emissions and in many cases more power. My old 97 V6 Malibu gets over 30 mpg just like the 4 bangers do nowadays, but it has 155 HP, which is what the 4 bangers get now too. It's a buch of BS, but they act like they can't make cars with better fuel mileage and more power while still meeting EPA standards for emissions. My 03 has 300 HP supposedly, which is nearly double what you got out of a stock 350 years ago, and gets about the same gas mileage and burns much cleaner. I love how they brag about having so many cars that get over 30 mpgs now, and my 97 Malibu has been getting that kind of mileage for 10 years now.

davzog · December 14, 2007

Welcome and congrats on your new Suburban...

My best friend had a 1990 Suburban with a 350 V8 and got over 20 mpg on the road...now has a 2005 Avalanche and gets 15 mpg on the road....go figure.

My last 3/4 ton truck had a V10 and got 16+ on the hiway, but my new Silverado with a 6.0 V8 gets a mere 14 at absolute best...usually 12-13 hiway, and 11 in town....dismal for sure.

I did a Flowmaster muffler (I love the sound) and got no increase in performance and might have dropped 1/2 mpg due to loss of back pressure. Added an AFE Brute Force intake and got great sound at WOT, but that's it...

Two weeks ago, I installed a Diable Predator, put in the 87 octane "performance tune", turned off the torque management, lowered the shift points to get into high gear sooner, and the final result is 14.2 mpg hiway, and a little more power that seems to almost overcome the loss of power due to oversize tires...

I have said before I did all of this "stuff" because of aesthetics, sound, looks, etc....never really expected much in the way of performance or mpg....I sure was not disappointed. The design engineers have done a pretty good job of getting performance and mileage out of today's trucks....

If gas mileage is you goal, you can do like I did....spend over $1,000 and gain almost nothing...but is looks cool!!

OR

You can put your money in your pocket so you'll have it when you buy gas....ha.

The ethanol does affect mileage, and 10% ethanol is all we have around here. From reports I have read, it would probably not be worth the wear and tear on your truck to drive several miles out of your way to get non-ethanol fuel.

I drive from St Louis to Baltimore a few times a year, and have never noticed any fuel giving me any better mileage than others....

I have wondered the same as you...why don't the newer trucks get better mileage than the older ones, since we have all the new technology....I dunno

A co-worker bought a Tundra with a V8 and does not get much better mileage than you and I do....Toyota has been an economy king for many years, and their truck get crummy mpg....maybe guys who drive trucks just romp the throttle too damm much...ha

For what it is worth, to get the "great" mileage I do get, I rarely drive over 65 and I never do jack rabbit starts....folks pass me all the time, right into the next gas station....

Enjoy your truck and let us know if you come up with a magic bullet for mpg....

justin95 · December 14, 2007

The only thing you can do is a tune. Ofcourse go with a custom PCM tune, not handheld.

Zembonez · December 14, 2007

Unfortunately, these are not vehicles that you can expect much fuel economy out of.

I get 16 flat out of my RCSB truck. My dad gets about 16 in his Suburban. Next door neighbor gets 15 in his Tahoe. Every fleet GM truck we have gets about 14-16. Not sure where these magic high MPG figures are coming from but I don't believe they are realistic... at least not on a regular basis. On one long trip with little wind, I did get 18 but never saw it again.

I know a few people who claim they get over 20 in their new trucks but they are just claims. NONE of them have any proof. There is always that guy that claims he gets 25 MPG with his big block while pulling his house loaded with bricks... blah blah blah.

For the comfort level and the safety of a big vehicle, I think they do just fine myself.

davzog · December 14, 2007

The cost of vehicles and fuel is relative....and one has to consider the time value of money.

My dad made $10,000 a year in 1967, drove a new Coupe de Ville (9 mpg) that cost $3900, and I was working in a gas station when gas went to $.30 a gallon, and minimum wage was $.90 per hour.

Today, he makes $100,000 a year, his new Town Car cost $44,000 (22 mpg) , gas is $2.90 a gallon and minimum wage here is $7.50 per hour.

So, salaries went up by a factor of 10, cars went up by a factor of 11, but gas went up by a factor of 9. So, when adjusting for inflation, gas is cheaper than it was in 1967, and we typically use less of it....the only thing lagging is minimum wage...ugh!

I agree with the above that I enjoy and can afford a full size truck....the cost is relatively the same as it has always been, it just seems like a lot more since most of us are used to paying less than $2 a gallon until just a couple of years ago...gee, gas was really cheap then?!?!?!?!

#8trx450r · December 14, 2007

The cost of vehicles and fuel is relative....and one has to consider the time value of money.

My dad made $10,000 a year in 1967, drove a new Coupe de Ville (9 mpg) that cost $3900, and I was working in a gas station when gas went to $.30 a gallon, and minimum wage was $.90 per hour.

Today, he makes $100,000 a year, his new Town Car cost $44,000 (22 mpg) , gas is $2.90 a gallon and minimum wage here is $7.50 per hour.

So, salaries went up by a factor of 10, cars went up by a factor of 11, but gas went up by a factor of 9. So, when adjusting for inflation, gas is cheaper than it was in 1967, and we typically use less of it....the only thing lagging is minimum wage...ugh!

I agree with the above that I enjoy and can afford a full size truck....the cost is relatively the same as it has always been, it just seems like a lot more since most of us are used to paying less than $2 a gallon until just a couple of years ago...gee, gas was really cheap then?!?!?!?!

Nice post

cm5 · December 14, 2007

Gents. I'm new here but I've been reading this board for two weeks since I got my new Suburban. To say the least, I'm VERY disappointed in the fuel mileage. My '99 with 164k miles on it did over 15 and this one is only doing 14! Maybe I should have read this web site before purchasing or maybe I should have just set much lower expectations, but I really thought a newer truck with 9 years newer technology would get BETTER mileage than an old truck with a ton of miles on it. Reading all the posts here about this topic, most seem to point to a Diablo or Edge tuner, but that only gives minimal improvement. Has anyone "studied" or tested ethanol-laced fuel vs non-ethanol? I was surprised that my new truck came with an additional window sticker showing how "FlexFuel" would kill the gas mileage. I guess like the rest of the brain-washed, politically correct public, I just thought that ethanol was supposed to save the world. Now I find out that it actually takes a lot more E10 to go the same distance as normal gasoline.

I bought the truck with more options than I thought I would and I've purchased a lockpick to unlock my nav system, so I can't afford to put too much more into add-ons. I'm hoping that driving an extra five miles to fill up at a station with NON-ethanol fuel will actually save me some $ and improve the mileage.

Thoughts?

how many miles on the 'burb?

your engine realy isnt 'broken in' until 15k. its very possibel that u will see slihgtly better mileage after that mark. i have in all my trucks. after abotu 10-15k better mileage.

if you wanna see some better mileage i would suggest a diablo predator handheld tuner. altho you dont wanna spend any more money, the predator will pay for itself (someday!). you can tune it for 87 or 93 octane fuel and will usually give you 2-3 mpg more. CAI also may help.

spfish · December 15, 2007

These are great responses. Thanks to all. I'll be keeping up with this - I'm pretty attentive to this mileage thing. This is my third Suburban (haven't owned a PU yet, but would love to have an HD diesel...). First Suburban, a '94 C1500 would get 23-24 on the highway, 18 in town - never towed anything with it. Next was the '99 K1500 and would always get 15 in town and once I got 21 on the hiway, usually 18-20 depending on the load. That truck would do 8-10 when towing a 6000 lb boat. Dang, I loved that truck. Just got scared something big was going to let go at 164,000 miles!

This truck is two weeks old and has about 700 miles so far - just two full tanks of gas. Yeah, I know - its a bit early to start worrying about the mileage. But numerous guys have said the engine needs to "break in." I'll stop sweating this so much until then. But I am going to fill up with NON-E10 Monday and see if that does anything different.

justin95 - you said "go with a custom PCM tune, not a handheld." Why is that? Where could someone get that done? Cost?

davzog - you didn't get much out of the diablo predator. Have you tweaked it any or just used the pre-packaged programs?

cm5 - what is "CAI?" Sorry, not familiar with that term.

Thanks again for all the responses. This is a great forum - I'm learning a lot.

justin95 · December 15, 2007

These are great responses. Thanks to all. I'll be keeping up with this - I'm pretty attentive to this mileage thing. This is my third Suburban (haven't owned a PU yet, but would love to have an HD diesel...). First Suburban, a '94 C1500 would get 23-24 on the highway, 18 in town - never towed anything with it. Next was the '99 K1500 and would always get 15 in town and once I got 21 on the hiway, usually 18-20 depending on the load. That truck would do 8-10 when towing a 6000 lb boat. Dang, I loved that truck. Just got scared something big was going to let go at 164,000 miles!

This truck is two weeks old and has about 700 miles so far - just two full tanks of gas. Yeah, I know - its a bit early to start worrying about the mileage. But numerous guys have said the engine needs to "break in." I'll stop sweating this so much until then. But I am going to fill up with NON-E10 Monday and see if that does anything different.

justin95 - you said "go with a custom PCM tune, not a handheld." Why is that? Where could someone get that done? Cost?

davzog - you didn't get much out of the diablo predator. Have you tweaked it any or just used the pre-packaged programs?

cm5 - what is "CAI?" Sorry, not familiar with that term.

Thanks again for all the responses. This is a great forum - I'm learning a lot.

Check out www.blackbearperformance.com , Im on my second tune. Or check out www.gmfullsize.com where he is a preferred vendor with plenty of fead back. Cost is about $150.

#8trx450r · December 15, 2007

If it makes you feel any better, My 99 DRW Crew Cab 4x4 with a 7.4 just got a whopping 7 mpg, yup you read right, 7 mpg. I thought it was doing good as the first half of the tank went rather well butt he second half just vanished !!!! 240 miles is what i got on that tank which is the first tank i have ran through it since buying it a couple weeks ago. I didn't buy it in hopes of getting good mileage so I can't bitch I guess lol.

justin95 · December 15, 2007

If it makes you feel any better, My 99 DRW Crew Cab 4x4 with a 7.4 just got a whopping 7 mpg, yup you read right, 7 mpg. I thought it was doing good as the first half of the tank went rather well butt he second half just vanished !!!! 240 miles is what i got on that tank which is the first tank i have ran through it since buying it a couple weeks ago. I didn't buy it in hopes of getting good mileage so I can't bitch I guess lol.

Is that the 26 gallon tank or 32?

#8trx450r · December 15, 2007

If it makes you feel any better, My 99 DRW Crew Cab 4x4 with a 7.4 just got a whopping 7 mpg, yup you read right, 7 mpg. I thought it was doing good as the first half of the tank went rather well butt he second half just vanished !!!! 240 miles is what i got on that tank which is the first tank i have ran through it since buying it a couple weeks ago. I didn't buy it in hopes of getting good mileage so I can't bitch I guess lol.

Is that the 26 gallon tank or 32?

I am pretty sure it is actually 34 gallons

justin95 · December 16, 2007

If it makes you feel any better, My 99 DRW Crew Cab 4x4 with a 7.4 just got a whopping 7 mpg, yup you read right, 7 mpg. I thought it was doing good as the first half of the tank went rather well butt he second half just vanished !!!! 240 miles is what i got on that tank which is the first tank i have ran through it since buying it a couple weeks ago. I didn't buy it in hopes of getting good mileage so I can't bitch I guess lol.

Is that the 26 gallon tank or 32?

I am pretty sure it is actually 34 gallons

If its a long bed its 34 and short are 26. My MPG sucks too. like 9 or so.

#8trx450r · December 16, 2007

If it makes you feel any better, My 99 DRW Crew Cab 4x4 with a 7.4 just got a whopping 7 mpg, yup you read right, 7 mpg. I thought it was doing good as the first half of the tank went rather well butt he second half just vanished !!!! 240 miles is what i got on that tank which is the first tank i have ran through it since buying it a couple weeks ago. I didn't buy it in hopes of getting good mileage so I can't bitch I guess lol.

Is that the 26 gallon tank or 32?

I am pretty sure it is actually 34 gallons

If its a long bed its 34 and short are 26. My MPG sucks too. like 9 or so.

Yup she's a long bed......................................