What octane is everyone using?

[neeqness]

I can't see any reason to use less than 93 octane (91 where that's the max available) for a performance car like this. It gets decent gas mileage, and why buy a high-performance car but hinder it from reaching the maximum performance it's capable of to save a little on gas? I'm savings tons on gas even using 93 compared to my previous 11 mpg V-8.

That said, I do think Ford creates confusion by the way it deals with octane in the ST Supplemental Manual. On p.10 it clearly says 87 is recommended, with premium rec'd for severe duty such as trailer towing. On p.7, buried unhelpfully in a stack of engine specs, it shows the maximum hp and torque figures "on 93 octane." As some others have noted, "recommending" the lower octane fuel lets Ford make people think they will spend less on gas. To me, it would be a lot simpler and more honest if they would just recommend premium, and note that you can use regular but it will diminish performance.

+1

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[Truth in Ruin]

According to razorlab's posts, it IS an actual, measurable amount, and it feels like a discernible difference, but then I am still not pushing this car to the max yet, even accelerating on an empty, LEO-free road (it only has ~3K miles on it now).
http://www.fiestastforum.com/forum/threads/10046-Second-FiST-2016-Fiesta-ST

Still, even at lesser throttle angles, it does feel more potent (can't wait to get the cp-e IC in, and Strat Flash tune loaded).

Yeah, that's a good thread. I tried it myself. I had 1/4 tank of 91 E10, put 1.6 gallons of E85 in (it could've been E70 at the time; I didn't have my tester, because it was in my other car), filled the rest of the way with 91 E0, and couldn't feel a performance difference. I might have to use more E85 since the petrol pump next to it is E0?

I bet you can't wait for the tune. You might as well add the E30 tune with it!

 

[M-Sport fan]

You might as well add the E30 tune with it!

I am SERIOUSLY considering it, now that I found an E85 station closer than 50 miles away!

 

[Truth in Ruin]

I am SERIOUSLY considering it, now that I found an E85 station closer than 50 miles away!

You should do it! When I get Strats tune I'm going to add the E30 tune as well. I honestly think I'd be content power wise running an E30 tune w/ a bigger intercooler.

 

[WAM]

I wish more people would run accel tests on their cars. The one guy earlier who ran a 2500rpm to redline timed test got kind of bad-mouthed. Something like hey, what do tests prove, anyway? I would agree they have to be run right, and run consistently -- but if a stopwatch couldn't tell the difference between 87 and 93 on my car, I wouldn't be spending the extra money. We don't race dynos and don't race on the seat of our pants.

 

[ForeverZero89]

i can't get 93 where i am, but i can get 93ish by doing a few gallons of race gas(100 oct) and the rest is 91.

 

[M-Sport fan]

i can't get 93 where i am, but i can get 93ish by doing a few gallons of race gas(100 oct) and the rest is 91.

How much do they get for that 100 unleaded?

There is a Sunoco around here that gets $10.00/gallon for their 100 GT at the pump.

 

[ForeverZero89]

How much do they get for that 100 unleaded?

There is a Sunoco around here that gets $10.00/gallon for their 100 GT at the pump.

it's cenex and it's 5.29

 

[kivnul]

Closest E-85 station to me is over 300 miles. Wish some company would take the plunge and enter the market.

 

[Hardline]

Sunoco 100 octane here is 5.79 a gallon.

 

[M-Sport fan]

Sunoco 100 octane here is 5.79 a gallon.

That's only a little more than some Cali stations are getting for their 91!!

 

[neeqness]

Sunoco 100 octane here is 5.79 a gallon.

Now that sounds pretty reasonable. If it were priced like that in my area, I'd go much more often.

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[neeqness]

That's only a little more than some Cali stations are getting for their 91!!

Yup, Cali prices are higher for less octane. Cross the Arizona border and you can see up to a dollar drop for 87.

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[M-Sport fan]

Now that sounds pretty reasonable. If it were priced like that in my area, I'd go much more often.

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WAY better than merely "reasonable"!!

That is a good deal less than the drag strips around here were getting for it 20 YEARS AGO!!

 

[Truth in Ruin]

WAY better than merely "reasonable"!!

That is a good deal less than the drag strips around here were getting for it 20 YEARS AGO!!

Maybe we've covered this before, but how many gallons of E85 do you run on your stock tune?

 

[jmrtsus]

Just filled up with 93 Octane NON-Ethanol for $2.43 a gal. in E. TN.

 

[M-Sport fan]

Maybe we've covered this before, but how many gallons of E85 do you run on your stock tune?

For a full tank, with the balance being Shell, Sunoco, or BP 93E10, I use 3 gallons of E85.

 

[Truth in Ruin]

For a full tank, with the balance being Shell, Sunoco, or BP 93E10, I use 3 gallons of E85.

Dang, so about E28, or so. How does it run? And how noticeable is the power bump?

 

[M-Sport fan]

Dang, so about E28, or so. How does it run? And how noticeable is the power bump?

It's hard to tell (about the actual power) since I have not logged it at all, and I will not run any more than this until I get a proper E30 tune.
It seems to run fine, smooth idle, clean pulls in gear, and that slight 'moonshine/corn likker' smell to the exhaust. LOL

I was just trusting in razorlab's results doing this, and using it as a 'headroom precautionary' type deal against hot summer weather detonation more so than an actual power adder mod.

 

[Truth in Ruin]

It's hard to tell (about the actual power) since I have not logged it at all, and I will not run any more than this until I get a proper E30 tune.
It seems to run fine, smooth idle, clean pulls in gear, and that slight 'moonshine/corn likker' smell to the exhaust. LOL

I was just trusting in razorlab's results doing this, and using it as a 'headroom precautionary' type deal against hot summer weather detonation more so than an actual power adder mod.

Thanks; I'm going to give it try.