Phil_R

For those of you with a stock tune on your 4.6L V8's, what octane are you using when you put gas in your car?

87 89 91 92

Do you know what Ford recommends?

Thanks in advance for your replies

mrp5150

I put 91 in my Bullitt. I would use 93, but California for some reason doesn't have 93 at any gas stations I've ever seen.

Phil_R

Thanks Mark!

Do you remember what Ford recommends for the 05-10 V8's we have?

Thanks again,

Phil

stupidgenius36

If it's a GT...87 is what is recommended, and 87 is what you should use. The owners manual has this information.

I think the Bullitt may have been the first to start adjusting for different octanes, like the 5.0 does now. I'm sure Charlie will chime in, and can clear that up.

southern stang

Hi Phil, 07gt here I use bp 87 only. Irv

Paris MkVI

The stock 4.6L V8 with a stock tune is an 87 octane setup. You will not get any significant advantage from a higher octane, because the EEC will not dynamically change timing based on octane.

Octane is simply a measure of gasoline's resistance to ignition under heat and pressure. Higher octane gasoline is more resistant to ignition, allowing you to alter timing and use higher compression ratios to boost power output.

Think of regular 87 octane like kindling - burns fast and easy. 93 octane would be the 2-4" diameter wood that takes longer to burn steady. 95 Octane (Europe mostly) and up is the big logs - slow to burn.

NC14GT

While the '07 GT manual states 87 is fine I feel I have noticed a difference with 93 when driving a bit harder. What I usually do is use 87 with mostly highway non-shifting driving and then use the 89 or 93 when I know I will be driving a bit harder and shifting to higher revs. Never a ping or knock using this formula. Maybe it's a waste of a few bucks but I like having the good stuff in a 300 HP car when shifting past 4,000 RPM.
It's interesting to see the advancements being made. My Trans Am, which is just 6 years older with similar horsepower, will ping and knock like the engine will blow up if I used regular 87. Supposedly the computer adjusts but no way does it run the same. Night and day. Perhaps this is why I like to err on the side of caution and use 93 in the GT. It may not make noises with the 87 but what's really happening?? My GT just runs and accelerates superbly with the 93. It's up to each person. I don't mind spending a few bucks extra while gas is under $4 a gallon. Also there can be more additives in the 93 which is never a bad thing. I noticed at the BP stations that the premium 93 is now the only Amoco fuel left in their lineup. Amoco was always super gas before the merger.

Phil_R

Thanks everyone for the info. I thought 87 was recommended, however the salesman that I bought the car from put in 91 before a test drive and I wanted to be sure on this.

You all have been very helpful and again thanks a lot!

You all are the BEST!!!

Phil

cdynaco

FYI The 08/09 Bullitt's released Ford's new 'adaptive spark ignition' which carried over to the '10 GT (last year of the 4.6L3V). Your engine will adjust for 91 octane and add about 10#' of torque in the low-mid range.
I run 87 most of the time except for 'play days' when I'll run a few tanks of 91.

Joeywhat

I tried a tank of 93 in my V6, didn't notice any difference...didn't really expect one, either...but figured I'd try it.

With my Focus I ran either 90 or 93 exclusively. Engine ran sooo much better with it. Didn't really feel like more peak power, but it drove much better at lower RPMs.

tbear853

Our '08 GT 5 spd runs just about perfect with no ill affects on a diet of 87 octane "BP with Invigorate" .... nothing else.

Phil_R

Thanks very much for that info!

I would think a brand name gasoline rated at 87 octane will make my 07

happyas well

Regards,

Phil

Paris MkVI

Good information - thank you! I did not know this. I must correct my post to include the phrase "the 4.6L in my 2006 model".

lowblustang00

Before my tune I ran 93 octane in it always, unless it wasn't available then 91. Don't think it really had much of a change, I have just always ran premium in my cars. ( I have questions as to wether or not the "87" or other grade is always what they say it is.)

scramblerider5

I always run 93

Red Gt

95 here in europe.


Red Gt.

ford4v429

my 06 prefers 87 sunoco... dont run as good on cheap station gas. grogery store gas seems to make the accelerator 'soft' off idle, like its loading up a little or something.
Ive found if I run 89 sunoco, average MPG goes from 18(87) to 20(89) but it seems to stumble a little off idle, and idle is not smooth. running 91 or 93 its noticably sluggish, starting in cold weather seems to crank harder too- that seemed backwards to me, but Ive tried several times running different stuff/mixing, just to see what it 'liked' best.

my mom always ran hi test in her car, I tried to tell her it hurts performance unless timing is adjusted... she ran so much injector cleaner (every tank for yrs) that she was always having issues...last time we were in colorado, I filled her car (late impala) with 87, refused to put injector cleaner in it, she remarked how much smoother it ran... bet shes still running premium again though...hardheaded

high octane just burns slower/more stable- I need to get a tuner, I know these little motors can really wake up with a bit of advance and better fuel.

my wifes chevy avalanche (flexfuel) loves the cheepest grocery store 87 gas(18 mpg mixed hwy/city), best mpg it ever got was on 85 octane at high altitude in colorado(25 mpg highway)... put sunoco 87 in it, mpg is down (to 16 mixed), sunoco 89 it runs like crap and mpg drops to like 12mpg (mixed). all motors seem to have their favorites, but its all about the timing. that truck once averaged 24mpg on a 4000 mile trip, 21 to 25 the whole way, 25 was nearly 1000 miles at high elevation up in the mountains- my gut feeling is if the high altitude 85 octane was available like on kansas flatland, her truck woulda got over 27 but most cars would literally ping themselves to death on that crap...

I only run 89 in my 06 if going on the highway- it just runs better on 87 but gets 10% better mpg on 89... at the track, best it ever ran (13.78 @ 103) was with 1/4 tank, half 87, half 89... again, 89/91/93 each progressively degraded 1/4 times AND mpg... gotta have timing to lead that higher octane burn, else all it does is heat the exhaust up from the slower burn. my 2 cents anyways...

NC14GT

ford4v429, Hate to tell you this but you shouldn't be having idle issues with different octanes unless you are not 'stock'. My car starts the same and idles flawlessly whether 87 or 93 in hot or cold weather. I also don't get mpg variations. You sure it isn't just highway mileage??
As far as your 'Mom' I have never heard of an additive or premium harming performance. Never, in 40+ years of driving muscle and sports cars. If anything, the exact opposite, like STP in the 70's when it basically did nothing for your car. If these products were actually detrimental I think Chevron, LucasOil, etc.. would be in a world of hurt. I don't use them on every fill-up but I sure do monthly and I have never had an issue, from Porsche to Chevy to Ford.

stupidgenius36

I just find that hard to believe. You're talking some big mileage improvements from gas that should have zero effect. I'm not gonna argue with you, if that's what you found. But I won't believe that unless I see it in person, and I'm not gonna put 85 in my car. Hell, I don't think I've even seen 85 anywhere. Your findings are certainly not normal...

Millions of people run 87, as they should, with no issue. There's just a lot of people that are stuck in their ways, and even more that fall for the "premium"marketing label.

Just a note for this thread: There is nothing "premium" about 91 or 93. There are just different octanes, and you only need the octane that your car is tuned for.

NC14GT

I've seen 85 and 86 octanes in the mountains out west several times on our many treks. While I'm sure it is fine I also wouldn't put it my cars. I think the next step up was 88, if I remember correctly, and I used that. No problems.
I'm not cheap when it comes to cars. If I blow a few bucks extra each refill I just don't care. I err on the side of caution. When electric companies and insurance companies and local govt's raise fees, taxes and prices at the drop of a hat with absolutely no benefit for me every single year, I certainly can spend a few dollars on something for my own car and peace of mind. I also despise the sound of 'pinging'.