Hey peeps....

Getting my 2007 Tahoe in a few weeks (its being shipped) and I was wondering what everyones opinions were on running Regular Unleaded 87 or 89 Vs. E85....

I have both fuels available for me to use and would like peoples opinion on which way I should go.... I know that E85 is around $.50 Cheaper per gallon, but the manual says the performance is less because the fuel doesnt have the same energy released as 87 or 89.

I usually drive in town 1-3 miles a day, with a trip everyother week thats around 100 miles.

Feel free to voice opinions... as that's what Im looking for!!

What are some of your results?

Thanks-

Freer-Love

 

Welcome to the forum.

E85 will decrease your mpg 25%-30% so if it isn't that much cheaper then you're losing money. No benefit in going to a higher octane either. Just run 87 unless you've reprogrammed the ECM. You'll probably get 12-14 in town and 17-21 on the hwy. YMMV. BTW the DIC mpg is a little optimistic usually.

 

Thanks for your input.

Reading your descriptions of your Tahoes.... Would you mind shooting me over a few pictures??

Also, I wanted to ask people about Mods they've made for their Tahoes.... Any Tread already started that you might be able to point me to?

Thanks again-

Freer-Love

 

hmmm, got same feeling about DIC mpg, but its real and accurate

 

lol, so what your saying is that you trust the OIL pressure guage, the Tachometer, the Speedometer, the gas guage, the temp guage, the voltage guage, the tranny temp guage, the odometer, and you trust that the fuel injector's accurately measure fuel in the thousandths of a gallon, hundreds of times a minute, yet... darn it, somehow that silly MPG guage is off...

yea man, I don't know... I'd much prefer an abacus and some 1 gallon milk jugs to measure the gas usage. Then we can drop string out the window and see how far we went . We can count the knots


Sorry, it's just funny...

the DIC MPG can't lie. it's a machine. the ECM measures fuel very, very accurately... and it knows how far you drove... it even knows you rolled that stop sign 2 miles back leaving your home...


Also, don't use E85, I hate it so much, there isn't enough room here for me to explain how bad it is...

 

use 87 octane and be done with it
we have a '07 2wd with the 3.42 rear end. we get 14 - 15 with all city and 19 - 21 all highway (60 mph is best for mpg but who drives that fast on the highway anyway?)
I always hand calculate at every fill up and the computer is really pretty close, less than 1 mpg off so while not perfect it is close enough if you reset at every fill up.

 

Like I said, the DIC is usually off a little (~0.5 to 1.0 mpg) on the optimistic side. I've owned several GM vehicles w/ a DIC and they were all the same. I calculate every fill-up.

I agree re: E85. Biggest scam since Social Security. Only reason it's even close to competitive is a Federal subsidy and a big tariff on importing sugar and sugar based ethanol. That and the fact that it takes about as much energy to produce corn-based alcohol as you get back.

 

i guess nobody saw the mythbuster where they tested undoing your windows vs. air conditioning, they used ford expeditions (yea i know it is ford) they ran the trucks out of gas and put the exact same amount of gas in each of 2 trucks 1 with the a/c on and the windows rolled up, the other with a/c off and windows down they both displayed the exact milage but the a/c on truck ran out of gas 2 laps before the tuck with the windows down truck died, eplain that scenario, maybe fords dont account for the a/c on. i would sugest doing a test on your trucks to see if it is accurate, driving your truck on a flat stretch of ground drive the same speed in 2 tests 1 with a/c off and 1 with it on, we all know a/c sucks gas (aparently myth busters didnt) note the milage the computer gets with it on and off, then the acuracy of the comp will be known. my daily driver is 30 years old so needless to say i dont have the milage comp (or a/c for that matter), try it, what have you got to lose (except the sence of security in your comp)

 

As I remember that episode, the difference of two laps on a whole tank of gas could be attributed to state of tune, etc. The conventional thinking was drag w/ windows down and A/C off would offset the power needed to run the A/C w/ the windows up and reduced drag. Bottom line, to save gas, windows up and A/C off. Personally I'll just buy a little extra gas.

 

AC vs. Windows Down
Adam and Jamie tackle not so much a myth as what they call an "urban puzzle". The debate arises because both methods of cooling influence a car's fuel efficiency—air conditioning requires a lot of power to run, but at the same time, open windows create drag.

Revisited in MythBusters Revisited, Season 3, episode 38
Myth statement Status Notes
Running a car with air conditioning on is more fuel efficient than running with the windows down. Partly Busted Tests were performed under varying conditions (55 miles per hour (89 km/h) versus 45 miles per hour (72 km/h)). Also, the 55 mph test was using a computer to estimate fuel efficiency based on air intake, not actual fuel consumption, and showed A/C was more efficient. The 45 mph test consisted of running the tank until it was empty, and showed open windows were more efficient. This experiment—or one like it—is sometimes cited by the Magliozzi Brothers on Car Talk when presented with this question.


http://en.wikipedia.org/wiki/MythBusters_(2004_season)

Part2:

AC vs. Windows Down
Myth statement Status Notes
Running a car with air conditioning on is more fuel efficient than running with the windows down. (From AC vs. Windows Down) Partly Re-Busted/Partly Confirmed The fundamental flaw in the MythBusters' test was that the point where the drag becomes powerful enough to inhibit a car's performance with windows down was inside their 45–55mph margin at 50mph. Going less than 50mph it is more efficient to leave the windows down, but going greater than 50mph it is more efficient to use the A/C.

http://en.wikipedia.org/wiki/MythBus...._Windows_Down

(Air Drag is exponential, while the A/C compressor is a constant load)