20mpg average possible?

[Sierkonblazer]

Has anyone here achieved a 20mpg average (highway/city)? Normally Im all about HP with most of my vehicles, but after trading in a 22mpg, 400hp G8 GT for our Yukon, I miss the great mileage and power combo. Im thinking of doing the following mods in pursuit of a 500 mile tank of gas:
Intake, exhaust, LT headers, 2/3 drop, Comp 401-13 VVT cam, and some tuning.
My wife commutes almost 75 miles a day, mostly on the interstate, but Texas just raised the I-35 speed limit to 75, which was awesome for the G8, not so awesome for that brick Yukon. Some aerodynamic mods would be nice, like maybe removing the roof rack, but not sure how to go about doing that..

 

[Faceplant]

I feel ya when it comes to the mileage crunch. I have a 750+hp Cobra that gets around 20mpg on the highway (assuming I am not putting my foot up its ass), but my Tahoe is my DD and I would love to get 20mpg out of it. To be honest, I am not sure of the ROI of the mods you listed. Cams and LTs are not cheap, unless of course you do the labor yourself. Not sure how they would help in the MPG department anyway. Might want to talk to the Black Bear tuning peeps about a gas saver tune. That's what I was going to do.....

 

[Awakened]

My buddy rented a Suburban while visiting Denver, he got an avg. of 19 mpg supposedly...

 

[Goodinblack]

I am getting that now according to my vehicle computer.

I can double check and report back after i fill up in a day or so.

 

[soulsea]

I'm afraid you're asking for too much considering the nature of the vehicle you own ...

Even the Hybrids don't average 20mpg unless someone is driving 90% highway. I get between 22-24mpg on the highway and 15-18 city depending on how I'm driving. On a 50-50 split city-highway I average around 18-19mpg. That's weighing about 500lbs less than regular Tahoes and with improved aerodynamics (no rack, air dam, etc).

So, given that expectations are always the building blocks of disappointment, expecting 20mpg average out of your truck is setting you up for the latter.

 

[Sierkonblazer]

I thought the Hybrids weighed more that the regular Tahoes.

 

[soulsea]

Actually I just checked and they seem to be pretty much identical these days ... it used to be that the Hybrid weighed less, or at least that's what I remember.

Still, you can see the official mpg ratings here: http://www.fueleconomy.gov/FEG/bymodel/2012_Chevrolet_Tahoe.shtml and it's about 5mpg difference combined mpg with the hybrid rated at the mileage you are looking to get.

I'm not sure if the vehicle you're trying to get 20mpg from is the Denali mentioned in your sig, but I just can't imagine of any minor modifications getting you there. http://www.fueleconomy.gov/FEG/bymodel/2012_GMC_Yukon.shtml

Like I said, I'm happy if I get 18-19 mpg combined out of 50-50 city/highway driving.

 

[jdpber]

one word...

DIESEL.......

 

[edgaranah1]

yeah I drive 74 miles one way to work on 98% highway and average 17.4 MPG. 14.5 when im on the streets. this is with the 5.3l FFE.


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[Jerden]

13.8 mpg

I thought getting 15 would be awesome.

 

[domin8]

Don't feel too bad. My Cobalt SS was tuned, pullied, etc and I was seeing 40 mpg highway when I wasn't slaying Corvettes. Now I'm averaging 16.7 combined in the Tahoe.

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[Sierkonblazer]

one word...

DIESEL.......

Wrong... Diesel isnt even worth it these day. My Sierra gets about 16.5mpg average, and it costs $90 to fill up, where as if I fill up the Denali with 89 it costs me $73 and I get about 15mpg average. The oil companies basically phucked us in the rear for using diesel as a viable source of fuel and economy. If I still had my 99 dodge, then it would be worth it. That sweet little Cummins would average 23mpg and I managed 29mpg on a trip from Tx to Ca once with it.. My next truck is probably not going to be a diesel. Yea, I'll miss the power and torque, but if fuel prices keep going the way they are, and the oil companies keep ****** us by overpricing by-products like diesel, then I have no other choice..

---------- Post added at 03:35 PM ---------- Previous post was at 03:32 PM ----------

But back on topic, I think a cam swap would open up alot of potential for efficiency with these VVT motors. Gas technology is following the diesel trend, more power equates to better mileage to a certain extent. More power = less time accelerating, and less time accelerating means better mileage. Changing a cam to more efficient valve events with some conservative tuning may help..

 

[KimberHDII]

I know this is going to be a giant gas bomb around a bunch of torch holding flamers but here we go:


My Tahoe:
2010 5.3 w/ DOD and 3.08 rear gear and RWD only.
LT3 w/ no NAV
Stock 17's on stock Rubber at 45 psi
Bone Stock Tahoe w/ 3rd row remove.

This is my DD in Savannah,GA (Read FLAT LAND W/ MINOR elevation chagnes +/- 50 ft.)
I have 2 stop lights and 2 stop signs each way to work ( M-F) and do most rural driving on the weekends. I follow the speeds limits which is predominately 45 and 55 mph. Yes I drive SLOW and use cruise control as much as possible, and accelerate like a grandma...what ever. I will consistently get 22.8-23.8 MPG Week in and Week Out... On the dash display for mpg and calculating from my gas receipts they both agree to .1 mpg, and I will consistantly get well over 600+ miles per tank...

Now driving on the high way i have noticed somethign very intersting.

@ 60-70 mph i will average 20-21 mpg. I wont get over 21.1 mpg. It doesn't matter 60 or 70 mpg, but I've noticed the DOD doesn't hardly go to V4 mode, and when it does it kicks back to V8 and drops mpg and then levels out.

@ 75 mph i will get 21-22 mpg. Very consistently 21. mpg. I've noticed it NEVER uses V4 mode and stays in V8 mode and is very light on the throttle.

I know it's a very particualr case on how I use the vehicle, but needless to say. Since I bought this vehicle, my drving style has changed. It's BIG, COMFY, ROOMY, QUIET(almost too quiet), Heavy, and I drive it accordingly. It gets me and whatever/who ever I can cram in it there in style and comfort. I'm thrilled and love it... And will definately be buying another one.

 

[Goodinblack]

I just got 19.58 MPG on 80% Highway.

 

[sumo]

ive got 22 mpg once, 90% Highway, no ac use, BB tune and 17 rims. Driving 10% in town dropped it to 17.8

 

[CHOO CHOO]

Can we trade everyone...Hell, I'm lucky to get 300 miles to a tank of gas. The avg on the dash says 13.0 constantly. I recently started to drive about 45 mins away 2-3 times a week.( all highway) I cruise control at about 70-75 mph and get around 320 miles to a tank.
But....I do city driving and its stop and go almost the whole way there. Probably 10 stop lights and signs together with a max speed of 35. If I were getting 15 mpgs, I would probably be like a teenage boy when he dreams of SuperchargedSS's supposed wife pic......(mrs. cuthbert if you don't know who I'm talking about)

 

[soulsea]

The Denali doesn't get the same mpg as the HyHoe ...

Ley's put it this way ... the other day I forgot to turn off the engine whilst filling up and I was there for 37 hours, AND I had less gas when I left.

 

[stevek]

I drove 2 hours on a highway no-stopping going 70, no elevation changes. Just flat. Got a whopping 17.1mpg

 

[edgaranah1]

The Denali doesn't get the same mpg as the HyHoe ...

Ley's put it this way ... the other day I forgot to turn off the engine whilst filling up and I was there for 37 hours, AND I had less gas when I left.

Hahahaha

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[AR2007denali]

I drove down I-40 to Oklahoma pulling a 5x10 flat bed trailer in my 07 denali and I was averaging 10.3 mpg. The 6.2 really loves the gas. It was the first time I pulled anything with it and needless to say I was ready to trade it in before I crossed the state line. Ha.