I have a stock GT (minus a K&N filter swap) but use 93 (premium) octane.
Anyone else experience any noticeable differences between prem vs regular? What if you use a higher octane booster? to yield something like 100 or so? what are the pros cons to that?

Also, to ween it off of prem. would one have to do it in increments?
i.e. Say I just burned through a tank on premium- would I fill it up half premium half medium? then burn through that and do all medium- then half medium half regular? then back to regular??? or is it as simple as going from 93 to 87 at any time, at any interval?

Also, I know in the S197 (at least some of them...) "Ford recommended British Petroleum (BP)"- I take it that was just a promotional thing, like ford got paid to say BP is better for the car? Or is it really that much better for the engine? Which brand do you find to most beneficial to the engine?

Just another thing then, what roll does the 10% ethanol play into it? Is 100% gasoline the way to go? In terms of performance, mpg, knocks, engine wear, etc... even tho 100% stations are few and far in between now a days...

Thanks!

 

i'm not an expert on the interal combustion engine but just get whatever the manual says to use. if you had something like forced induction then you would need 91-93, but it's stock so just buy whatever is recommended IMO.

oh & it doesn't matter what brand, it is all just marketing at that point.

 

I preferred the ethanol blended gasoline in my old 5.0. I always used it because it is the same price as regular 87, but it's like getting premium. I have heard that it gives slightly (3-5%) worse mileage than regular gasoline, but because it has a higher octane rating, I could bump my timing up which made a very noticeable difference in those cars.

I imagine with the 2010s it would offer the same benefit without having to manually adjust the timing. As far as changing from 87-93, I don't think you need to do it gradually. The engine management will adjust according to the octane of the fuel instantly.

 

Shell here and I do notice a difference between shell gas and speedway gas. Enough of a difference that I don't buy speedway gas anymore.

 

Time Out! First things first. You need to know the terms and the science. Take that and the financial side and make an educated decision.

1.) Octane is resistance to detonation. This allows for more timing without pre-detonation or "knock".

2.) More important than Octane is the BTU rating of a fuel. This will give a better idea of overall efficiency of a fuel.

You can do some searching on the internet to get some facts.

Simply, if you get a performance tune (which modifies timing) and use 93 or 91 (altitude) octance fuel, you can take advantage of the fuel and get better mileage.

Most vehicle factory programming doesn't allow the computer to take advantage of anything over 89 octane.

If you do an intake and 93 Octane tune, typically you get a greater percentage of mileage and power than the associated cost.

Examplefrom the MidWest) Mid Grade - $2.67 a gallon gets about 21 MPG, Premium $2.87 a gallon with an intake and tune gets 24 MPG.

(2.87-2.67)/2.67*100= 7.5% increase in fuel cost

(24-21)/21*100=13.6% increase in fuel economy

Figure you drive 10K miles, it will be about $100 cheaper to use the more expensive gas and tune. You do this for 3 years and the mods pay for themselves. In the meantime, you are burning a much cleaner fuel, you are physically stopping for fuel less, and you gain 25+ RWHP.

 

Chevron 91 here, would be 93 but they don't have it in Vegas. I don't know nearly as much about it as Shaun but have have several mechanics tell me Chevron is the best over the years.

 

We don't have a Chevron here anymore. I use Valero 93 as I was told Valero is a U.S. refiner that uses non-middle easter oil.



Sure beats using Citgo.

 

As a mechanical engineer who has studied combustion I approve of this post

Great way of explaining it

 

93 Octane Shell, occasionally Exxon 93. Anything else and my car knocks

 

I can't believe no one has mentioned the ethanol yet! This is NOT a flex fuel motor! You are not supposed to be using E85 or any mixture of gas and ethanol. Whether or not it does damage shouldn't matter necessarily. I wouldn't want to use my 'stang as a guinea pig.

 

My first choice is 76; my second choice is Chevron. They are the two top-tier fuels commonly available in my area. I use 87 octane with no knocking with a factory tune. I haven't noticed any difference in performance, though, when I have used off-brand gas in a pinch.

The reason I choose the above is that when I used to drive BMWs I did notice an improvement in performance using 76 over the other top-tiers. So it is just habit, I guess .

 

Ethanol up to 10% is fine and will not do any damage to your engine. All modern engines are built with ethanol in mind up to 10%.

 

After reading this post, I finally found a compelling reason to get a tune installed in my GT/CS ! I was a "fence-sitter" before this! Thanks for cutting down the fence!

 

Mach1s only are allowed to run premium...,Right from the Factory, Premium only car..

 

I'd just love to try some of that Oregone (dune area) 100% octane.

 

Just don't forget to always set it back to factory settings before you takecar in for service & check strategy number that it matches befofe uploading the tune back in. I always demand Never Touch the ECM or reflash it !

BTW 93 Race tune for the most runs sweet 2nd 91 per

 

Being a former petroleum distribution engineer, gas is gas. Shell, Texaco, BP, etc. can all share the same base gasoline. The difference is the additives and what they do. A Shell driver can pull up to a Texaco terminal and use their base gas and add in the Shell additive. Companies trade base gas all the time. Why pay money to travel to their terminal when they can trade for it someplace closer?

I typically fill up at either Shell, Hess, and Sunoco. I notice no difference in power or fuel economy from any of them.

Also, it is a good idea to use different brands of gasolines. The additives that are added to the gas help reduce buildup and keep things clean, but the additives themselves will also cause their own buildup. Using Shell for say 5,000 miles will have their additive causing their buildup. Changing to Mobil will help wash away Shell's buildup, but will leave Mobil's buildup. So it's always good to change maybe every 5,000 miles to help keep things cleaner, and stay with that one brand.

Remember Shell's ads when they said they could improve your engine performance with just 5 tankfulls? Using only their gas would help wash away the other companies deposits. But they fail to tell you they will leave behind their own.

So for me, brand names are pretty much all they same. It's only their additives are different and they clean differently. No-name stations could have anyones gas, or sub-par additives. Nothing wrong with using them, but use the 5K rule and switch to clean out the junk they leave behind.

 

I have used Union 76 exclusively for the 30,000 miles that I have on my car. So are you saying that I should change brands every 5000 miles to remove that companies deposits? Interesting. I guess I could run Shell and at each oil change which back to Union 76.

 

That's what I have read and heard. There are plenty of articles around on it if you do a search. I had injectors that were a little clogged in my previous DD and the dealership even mentioned swapping every few thousand miles. It's not a perfect method, but they said it does help. The current DD is at 70K and doing fine with nothing but brakes and oil changes!

 

So whats the best or safest way to add an additive for build up ? there is so much BS on a store shelf now a day that some retards even use NOS energy drink in thier gas tanks