87 Octane

[robvas]

Here's a gen 1 coyote for shits and giggles

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[Farmer Fran]

Dyno pulls do not tell the entire story

 

[kinelisch]

Why would anyone fill up with regular instead of 93 on a $60,000 Mustang? Its like $19 PER TANK difference. Not worth filling with cheap gas.

 

[89Trooper]

I love these threads. Nobody will ever change anybody else's opinion.

Here is my opinion: I run on 87 all the time and never have a single issue. If I heard even the slightest bit of pinging or pre-detonation, I'd worry, but I don't... not even when getting on it. Why? It's tuned for 87. Otherwise it would say 91 or 93 in the manual.

Now my 1989 Fox Body? It's carbureted and I built the engine and tuned it for 93... so I use 93.

 

[Alan Applegate]

The reason you don't hear knocks is simply the fact the engine is equipped with knock sensors. After all, that is the exact reason they're used.

When knock is detected, the EEC reduces ignition timing, which in turn reduces power. That is the main reason we buy these cars!

From the Owners Manual: For best overall vehicle and engine performance, premium fuel with an octane rating of 91 or higher is recommended. The performance gained by using premium fuel is most noticeable in hot weather as well as other conditions, for example when towing a trailer.

 

[highvoltage]

Rofl. I love the omg how why you cheap out on fuel in a GT. Blah blah. Does it work? Yes. Does it hurt the vehicle? No. Does it have a tad less hp/tq? Yes. Will your but dyno notice it? Doubtful. Did you get better mpg? No despite you thinking so. It’s been proven you don’t get no better than a hopeful .5 mpg.

 

[robvas]

Dyno pulls do not tell the entire story

What's missing? It makes less power with lower octane gas.

 

[Q6543]

You won’t hear it, the
Computer will pull timing and retard the cams.

But it will show in the bearings over time.

 

[smurfslayer]

I love these threads. Nobody will ever change anybody else's opinion.

I sorta did after I bought the Raptor. I was kind of stoked it could burn regular; at the time it was my only vehicle that didn’t require 91+. Then I got one of these threads and was sent to the manual to ... you know, READ one of the 535 pages. I did read and skim a good deal of it, but I did not pay enough attention to the octane section, missing the key wording “for best performance”...
I migrated over to super because as most people here have suggested, I spent 3 score & 8 thousand dollars on the truck, why not get the best performance out of it?

Did you get better mpg? No despite you thinking so. It’s been proven you don’t get no better than a hopeful .5 mpg.

I’ve only tried this with the Rap w/ 3.5TT but I ran several tanks of 87, then cut over to 93 and several tanks and with mixed driving - no difference. The one time I tried it in/around OBX NC, I actually got better mpg with 93 than with 90 octane & no ethanol. This is “island time”, probably a max speed of 60mph. Not enough to be conclusive, but in mixed driving I didn’t see a difference and one back to back with near identical conditions where 93 did better.

 

[young at heart]

What's missing? It makes less power with lower octane gas.

Yeah this is all anybody is saying far as I can tell. Nobody thinks 87 will harm the engine, it just makes less power. The cost difference is meaningless to me.

I personally want every scintilla of power the car can give, all the time. Otherwise I’d have bought something else.

It ain’t rocket surgery.

 

[JimC]

Yeah this is all anybody is saying far as I can tell. Nobody thinks 87 will harm the engine, it just makes less power. The cost difference is meaningless to me.

I personally want every scintilla of power the car can give, all the time. Otherwise I’d have bought something else.

It ain’t rocket surgery.

Your location though says 'deep south' so I assume no snow and ice to deal with. Around here in SE Michigan I don't need the extra power and torque when dealing with snow covered or icy roads, so why spend the extra $10- $15 for the power I can't use in December/January/February when the car will run fine on 87 octane is all. Warmer months, of course I get the 93 octane because "I want the power!"

 

[fishinrich]

It's not a race car. Most of my driving is <60 MPH. 87 works fine and Ford says it is.

 

[RaceRedder]

In Europe we don't have 87AKI aka 91RON. Our gasoline starts from 91aki aka 95RON.

I never thought the American 87 is equivalent to the European 91.

The only downside of the European 95RON is that they mix it nowadays with a lot of ethanol. So the safest way to go ois 98RON aka 93AKI

 

[Eurasianman]

You won’t hear it, the
Computer will pull timing and retard the cams.

But it will show in the bearings over time.

And what are the long terms effects? How many miles until this is a high enough of concern that it needs to be addressed?

 

[Farmer Fran]

And what are the long terms effects? How many miles until this is a high enough of concern that it needs to be addressed?

Cannot say for the 5.0 but in the Hemi pretty fast.

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