Which gas to use

[Hikerdogs]

Originally Posted by Magumba

Something to watch out go if you will be on the west. In some states they sell 86 octane as regular gas and 88 octane is the next step up for 10-20 cents more power gallon. I use 88 in my motorhome even though it's more costly.

Another "phenomenon" in the world of alternative fuels is that in almost every little town across Iowa there's at least 1 gas station that sells NO Ethanol regular grade gasoline. Ironic in that Iowa is the largest producer and promoter of ethanol and ethanol blended fuels. It seems they love to produce and sell it but not necessarily use it themselves.

[TDI-Minnie]

No marinas sell ethanol laced gas.
It is awful stuff for your engine.

[twinboat]

There are many marinas that dispense ethanol gas, but are now offering non ethanol.

It has been a battle, all along the east coast, to change the laws about ethanol gas. It cost owners of older boats, millions in repairs, before it happened.

Problem with marina gas is getting your RV out, on the dock.

[rideandslide]

If you are in a marine area, there is usually a gas station or two that offer alcohol free.

[BrianGlenn]

Originally Posted by sincky64

Hi everyone, my wife and I are getting ready to leave on our vacation soon. My wife asked me if we were going to use premium gas while towing? I never thought about that. Has anyone here seen a difference while towing using premium? I don't believe I'm going to get better gas mileage, but what about better performance from the tow vehicle. We have a 2015 GMC Sierra 1500 4X4 with the Z71 tow package.

You will not see any improved performance with higher octane fuel IF the engine does not de-power on regular graded fuel. The only way to know if the engine computer (ECU or ECM) is de-powering to control knock is to monitor ignition timing through some OBDII monitoring program. If knock occurs the ECU/ECM cuts back on timing, and reduces power output. Secondarily some engines will reduce fuel injector pulse width to reduce fuel but that is pretty rare.

Your specific tow/driving scenario will affect how the engine performs - everyone else has a different set up. Weight, gearing, cooling capacity, road conditions, etc, etc. Too many variables.

I recommend you read your owners manual, if they recommend premium fuel for towing situations, then I would buy the premium if you feel that is warranted. As mentioned the engine will run fine, and be protected running regular grade fuel.

My thoughts,
Brian

[mel s]

Originally Posted by sincky64

Hi everyone, my wife and I are getting ready to leave on our vacation soon. My wife asked me if we were going to use premium gas while towing? I never thought about that. Has anyone here seen a difference while towing using premium? I don't believe I'm going to get better gas mileage, but what about better performance from the tow vehicle. We have a 2015 GMC Sierra 1500 4X4 with the Z71 tow package.

sincky64
I would use whatever gasoline the owners manual recommends.
(IMO nobody knows your GMC better than GMC).
Mel
'96 Safari

[ampmtnbkr2]

Just did that experiment. Ran a full tank of 90 octane no-ethanol gas through my tow vehicle (2015 Jeep Cherokee Trailhawk w/ V6 and factory tow pkg.). $1.05/gal. more than 87 octane regular. Was pulling TT that as loaded, was probably right near, if not a bit over, the max. towing recommendation (4500#). I got a whopping 2.5% better mileage, and could not feel a difference at the pedal. That minor of a difference in mileage could easily be chalked up to driving/road conditions (different route than 87 octane comparison tank).

For the difference seen, I will keep the extra $15 spent for premium fuel in my pocket now on.....

[twinboat]

I did some searching, when this post started. Edmunds, Bob the EPA and other organizations, all said if your car is designed to run on 87, you will get no gain on higher octane.

I was surprised. I thought you would get better mileage, but not enough to offset the cost.

[pasdad1]

Read another thread on the same topic...

http://www.ford-trucks.com/forums/50...le-towing.html

People are forgetting that an engine with mileage is different than one which is new.
The older engine will have soot and deposits on the top of the piston which will increase the compression ratio. Higher compression, and higher than normal heat (from towing -especially climbing grades) will raise the octane requirements. If knocking starts under load, engine damage could be occurring. Better to have the higher octane fuel, which gives a buffer zone, than to risk damaging spark knock. IMHO

[schrederman]

There's a reason that "out west" they sell 86 instead of 87. The altitudes are higher, and the air is thinner. 86 will do just fine at higher altitudes in engines designed for 87.

Higher mileage engines will not benefit from a higher octane rating. If the engine and ECU and operating as they should, you'll not see a difference in performance or mileage. The detergents that help get rid of deposits are present in regular unleaded, usually in the same quantities as premium. If there is more in premium, then there's less gasoline per gallon, and your mileage will actually suffer. Gasoline is gasoline, and premium will not make more BTUs of energy than regular in an engine designed to use regular.

Diesel, on the other hand....... oops... different subject.

[shepd]

There is no point in using premium fuel when your manual tells you regular fuel is all the vehicle needs. You'll get absolutely no benefit. The exception is the occasional vehicle that supports regular OR premium fuel, and the engine computer uses the knock sensors to figure out just how far it can advance the spark timing. However, if your vehicle is like that, the manual will tell you. If you have the choice, I personally like having the extra power on tap, so I'd pump in premium. But in the end, that's all that you'll get with premium fuel (when supported): More horsepower/torque. Not better mpg.

The best proof of higher octane being completely pointless unless the engine is designed for it is to drive a propane powered vehicle. Propane offers incredibly high octane numbers (100+, often 110). Yet, due to lower BTU and a detuned (as far as octane goes) engine, propane powered conversion vehicles tend to be more sluggish on propane. Of course, tuned properly, it'd offer performance rivaling gasoline engines, but that never happens.

What you want is ethanol-free fuel if you need top performance. You can get ethanol free fuel in any grade, however, most commonly its sold only in premium octane levels (and many stations have octane in all grades of fuel). If you're not trying to eke a tad more performance from your vehicle, then work out how much power (and thus efficiency, and therefore mpg) you're being robbed of. As mentioned earlier, it will likely be about 4%. If ethanol blended fuel saves you more than 4% over non-ethanol fuel and you don't need the extra power, then pump in E10/E15 fuel (just be certain your owners manual says your vehicle is safe for that much ethanol). If, somehow, you're in an area where both are the same price, the math is easy: Pump in the non-ethanol fuel.

Ethanol is to gasoline as bread is to dinner: Filler.

[Magumba]

I just realized there is a station that sells non ethanol gas where were staying, it's 10 cents more per gallon, I'll try using that fuel in my Jeep for awhile.
I'd love it if we could get ethanol out of our fuel, it makes food more expensive and lowers fuel mileage.

[Onstar20]

I run E85 in my flex fuel Quadvan. The station pump displays a sign that says E85 is 100-105 octane. I understand there is less btu, but I definitely have more power pulling the TT. Without doing all of the scientific analysis, at $.40 - $1.00 per gallon LESS cost than regular gas I would surmise E85 is more cost effective with more power.
More:

https://www.youtube.com/watch?v=Udfcf7qP3m8

Happy Travels!

[Mr_D]

Originally Posted by Magumba

Something to watch out go if you will be on the west. In some states they sell 86 octane as regular gas and 88 octane is the next step up for 10-20 cents more power gallon. I use 88 in my motorhome even though it's more costly.

At higher altitudes they can use lower octane so they sell 86 octane there. The engines adjust for the difference.