Going from 87 to 93 octane

[Tremoring4fun]

Anyone try jet fuel yet!!!hahaha

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[Eskram]

Anyone try jet fuel yet!!!hahaha

I used to put 5g of toluene in the tank of my Subaru to raise octane.. ?‍

Paint thinner FTW!

 

[JExpedition07]

Anyone try jet fuel yet!!!hahaha

Chrysler made a turbine car in the 60’s, interesting concept is also a guy who Boeing swapped his Porsche!!

 

[dmac]

It's been beat like a dead horse on this forum, but I just filled my V8 up with e85 today (previous tank was 91 octane), and the torque + smoothness is so much better compared to 91.

Why?
E85 is effectively ~105 octane, which helps the NA high compression engines greatly, even on the stock tune. Kudos to Ford for that.

Here are some Dyno numbers by Livernois to show how going from 87 to e85 on just the factory 5.0 tune can be stronger (atleast in most of the rev range) than a 93 octane tune.

87 Octane Factory Tune
- 330 hp @ 6.19k, 358 lb/ft @ 4.13K

93 Octane Factory Tune
- 357 hp @ 6.56k , 374 lb/ft @ 4.18K

E85 Factory Tune
- 360 hp @ 5.14k, 414 lb/ft @ 3.97K

93 Livernois Tune
- 368 hp @ 6.91k, 403 lb/ft @ 4.03k

Notice how much lower peak power and torque are available with e85.

For high performance ecoboosts as well, octane does seem to make them happier per this C&D article https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/.

However, I usually just try to find the cheapest $/mile fuel which in some places for me is e85, some 87.

Moral of the the story (my unimportant opinion), octane does matter.

 

[JExpedition07]

@dmac thats the surprise most tuner shops have found, the torque the 5.0 makes on E-85. Most find the stock file to be in excess of 400 lb ft at the wheels…..that puts you at 454 lb ft of torque at the crank by a typical 12% loss factor (400X100/88), and most shops have found it to be closer to 410 lb ft at the wheel which is (410X100/88) ->465 lb ft. I was floored the first time I ran E-85. The truck spun all 4 wheels in 4-High. This is no tune bone stock. It takes some torque to spin all 4.

 

[gb7FRz26]

try not to mix 50/50

Here's a convenient button that does just that! hehe

 

[Tremoring4fun]

I am running some 91 thru now, but will try the e85 as well. Now I am going to have to go to Livernois's website to see the dyno sheets with the 3.5 EB motor!

 

[JExpedition07]

I am running some 91 thru now, but will try the e85 as well. Now I am going to have to go to Livernois's website to see the dyno sheets with the 3.5 EB motor!

With the 3.5 I believe you can mix up to about E30 or so? @Snakebitten is that correct? I do not believe you can run straight E-85 on the 3.5 EcoBoost without an injector swap. Sorry if we confused you with our ramblings. The 5.0 is Flex fuel and can run ethanol, the other engines are not. Snake bitten runs a cocktail he can share with you that puts down some juice.

 

[Snakebitten]

E20, if you are running factory calibration.

On a Powerboost with a 30 gallon tank, and depending on the TRUE ethanol content at the E85 pump, we are talking about 4-5gallons of E85 per tank. (mixed with 25-26 gallons of E10)

 

[Jeff1779]

Maybe I'm crazy but I have ran e85 all the way up to 100% in my 21 powerboost with no problems. It will set a code eventually claiming lean because the LTFT has to shift too far out of spec to make the lambda happy. The short term trim easily stays at near 0 and it runs fine. I don't push it real hard that way just in case and normally only run about a 25% ratio of e85 per tank and the truck loves that. If I watch my timing it will actually retard under boost on 87 oct. but with some e85 it's able to maintain some advance. I know it's not ideal but right now gas is over $5 a gallon in cali and I can get e85 for $2.99. Yes mileage goes down but not enough for a $2 per gallon difference. If I keep the LTFT from going over 20 It won't set a code. I believe it's over 24 for a code to set. This all on a stock tune.

 

[Gord0]

Maybe I'm crazy but I have ran e85 all the way up to 100% in my 21 powerboost with no problems. It will set a code eventually claiming lean because the LTFT has to shift too far out of spec to make the lambda happy. The short term trim easily stays at near 0 and it runs fine. I don't push it real hard that way just in case and normally only run about a 25% ratio of e85 per tank and the truck loves that. If I watch my timing it will actually retard under boost on 87 oct. but with some e85 it's able to maintain some advance. I know it's not ideal but right now gas is over $5 a gallon in cali and I can get e85 for $2.99. Yes mileage goes down but not enough for a $2 per gallon difference. If I keep the LTFT from going over 20 It won't set a code. I believe it's over 24 for a code to set. This all on a stock tune.

That's a great way to burn things up... And your LTFT already told you it's going to.

 

[Bossharp]

I have a 2024 on order with the 5.0 and unfortunately we don't have the option to use E85. I have decided to run 93 if I can find it on the trip back to Florida from Iowa. I haven't paid much attention in the last few years filling up my Honda Fit but 91 is what I see for the most part. A few stations sell Ethanol free (don't know what octane rating) at a very high price around me and in Daytona Beach I know you can find genuine 'high test' but at extremely high price.
Back in the late 60's early 70's all the cool kids used Sunoco 260 and I vaguely remember a dial on the pump. When I was shopping for my 2006 SRT-10 Quad cab (EPA 9-12) when gas prices REALLY spiked the prices on used trucks fell and on the forums folks were letting them go simply because it was so expensive to fill up. My first truck was a later 70's Super Cab with a 460 with and 'rebuilt' carburetor that only got 4-5 MPG at best..I got that one fixed quick.

 

[Jeff1779]

My understanding is if LTFT is able to shift to a point that STFT can keep up and stay near zero and the oxygen sensors are showing good afr then it should be fine. We’ll see I guess.

 

[Calson]

If you are towing a heavy trailer then add 93 octane rated gas to the tank. It matters not at all if you have residual 87 octane rated gas in the tank. The engine computer will adjust and retard the spark as much as is needed to prevent pre-ignition of the gas in the cylinders.

Octane is a measure of how inclined a fuel is to pre-ignition when it enters a hot engine's cylinders and nothing more. It is not a measure of btu's that it provides. If you mix 5 gallons of 87 octane rated gas with 5 gallons of 93 octane rated gas the resulting mix is going to provide closer to 91-92 octane and not 90 octane as one might think.

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