What gas are you using?

[AvoidTheBoyd]

There is a lot of information in this thread, unfortunately half of it is wrong. 87 octane will work fine if you are in a cooler climate and using the truck lightly, say for your daily commute. If you are in a warmer climate or are thrashing the thing, it would be to your advantage to run a higher octane. This would be for engine safety, knock creates extra heat, and so the knock sensor doesn't cut your timing and hence power. The higher the octane the slower the flame front travels. Premium fuel has more additives, none of which burn as well as gas or have the BTUs of gas. Those 2 reasons are why you won't get higher gas mileage (or more power) running an octane number higher than which the engine is designed for. Racers don't just put 110 octane race fuel in and call it good. They blend the 110 with a lower octane to find where knock occurs and then run just above that to avoid ruining the engine. That method has been dyno proven.

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[xxaarraa]

There is a lot of information in this thread, unfortunately half of it is wrong. 87 octane will work fine if you are in a cooler climate and using the truck lightly, say for your daily commute. If you are in a warmer climate or are thrashing the thing, it would be to your advantage to run a higher octane. This would be for engine safety, knock creates extra heat, and so the knock sensor doesn't cut your timing and hence power. The higher the octane the slower the flame front travels. Premium fuel has more additives, none of which burn as well as gas or have the BTUs of gas. Those 2 reasons are why you will never get higher gas mileage running an octane number higher than which the engine is designed for. Racers don't just put 110 octane race fuel in and call it good. They blend the 110 with a lower octane to find where knock occurs and then run just above that to avoid ruining the engine. That method has been dyno proven.

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Yup. I race Ducatis/Aprilias in CCS and racers most commonly run a 50-50 blend of race gas and pump gas for this reason.

 

[xrocket21]

I find 91 nowhere in sight. Just 87, 89, 93. But I still mix my special brew of 91 by a little alchemy. Takes a bit longer at the pump though, and I bet people are wondering what I am doing.

Octane Mixture Calculator

Maine went through a weird thing where, we used to always have 93, and then something changed, and they got rid of 93 everywhere and it was only 91, and now for the past few years 93 has started trickling back in. Annoying for sure, as my last car was specifically tuned for 93, and I plan to get a 93 tune for the raptor.

 

[AvoidTheBoyd]

Here is a link to a good (short) read from a SAE whitepaper. The test was done on F150 Ecoboost. This is PROOF that higher octane cannot increase power or mileage without an accompanied increase in compression. Higher compression is also higher efficiency. So as some have stated correctly, higher octane is useless in an engine not tuned for it. Adding E30 to your Raptor does nothing over regular gas with sufficient octane to prevent the knock sensor from retarding the timing. If an engine has VVT and a sensor that measures ethanol content you may see a lot more benefit. The real debate should be if Ford tuned the Raptor for 91 octane, but is relying on the knock sensor to keep things in check while not deterring buyers by requiring premium fuel.

Link
Effects of Fuel Octane Rating and Ethanol Content on Knock, Fuel Economy, and CO2 for a Turbocharged DI Engine

 

[Wilson]

I find 91 nowhere in sight. Just 87, 89, 93. But I still mix my special brew of 91 by a little alchemy. Takes a bit longer at the pump though, and I bet people are wondering what I am doing.

Octane Mixture Calculator

e-30 is about 95 octane

 

[Jeff-Ohio]

Makes sense to me. Looks like I'll just run 93. Like someone else said, spend all the money on a performance truck and some people won't put good gas in it. Doesn't make much sense. Thanks for the reassurance of using 93!

I had issues with uneven acceleration (surging) on 87 and started running 93 to get rid of the issue. I recently switched to 89 and everything appears to be working the same as 93.

 

[ogdobber]

Here is a link to a good (short) read from a SAE whitepaper. The test was done on F150 Ecoboost. This is PROOF that higher octane cannot increase power or mileage without an accompanied increase in compression. Higher compression is also higher efficiency. So as some have stated correctly, higher octane is useless in an engine not tuned for it. Adding E30 to your Raptor does nothing over regular gas with sufficient octane to prevent the knock sensor from retarding the timing. If an engine has VVT and a sensor that measures ethanol content you may see a lot more benefit. The real debate should be if Ford tuned the Raptor for 91 octane, but is relying on the knock sensor to keep things in check while not deterring buyers by requiring premium fuel.

Link
Effects of Fuel Octane Rating and Ethanol Content on Knock, Fuel Economy, and CO2 for a Turbocharged DI Engine

1) the 17 raptor is tuned for 87 octane minimum. However running a higher octane you WILL see an increase in power (and milage) however it probably tops out at 93 octane, to see a benefit from higher octane than that, a custom tune will be needed
2) power and milage are the result of engine efficiency. Take away timing and/or compression (boost) and your engine is less efficient
3)regarding this test, doing dyno pulls vs real world you get dramatically different results. So let's say you had an extremely low octane gas. The computer would have to pull timing as not to knock. The end result is less power and thus to do the same task vs higher octane and higher timing you get worse milage (and that's not touching the compression)
For example,
Let's say you are pulling a trailer up a hill, you have put a low octane fuel in. The ecu will back off timing (and boost) as to not detonate. To maintain your speed, you will have to open the throttle more whereas with full timing and boost it will take less throttle resulting in better milage.
Another example is something they did on top gear. Watch this, it's fantastic
https://youtu.be/eKIryzmF-VM

4) turbo engines have the unique ability to increase compression... By increasing boost

5)an efficient engine is only efficient if you drive it efficiently.


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[AvoidTheBoyd]

Boost is not compression. A turbo increases the density of the air mixture and does increase cylinder pressure, but that is not compression. The compression ratio is mechanically set with the engine design. You would need to change piston or head dimensions to change compression ratio. I agree with the towing scenario and the efficiency comments. The point is however, if an engine does not have pre-detonation with 87 octane, you can't gain power or mileage by going to 93. Like i said earlier, I'm a bit skeptical if Ford actually tuned for 87 or if they tuned for something slightly higher and are relying on the knock sensor.

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[Supertuner700]

Someone hook up a laptop and datalog
Then just watch timing and boost with 87 and then 93

 

[ogdobber]

Boost is not compression. A turbo increases the density of the air mixture and does increase cylinder pressure, but that is not compression. The compression ratio is mechanically set with the engine design. You would need to change piston or head dimensions to change compression ratio. I agree with the towing scenario and the efficiency comments. The point is however, if an engine does not have pre-detonation with 87 octane, you can't gain power or mileage by going to 93. Like i said earlier, I'm a bit skeptical if Ford actually tuned for 87 or if they tuned for something slightly higher and are relying on the knock sensor.

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Boost is compression not mechanical obviously. Two formulas "boosted compression ratio" and "effective boosted compression ratio"
For example 11:1 compression with 20psi boost is 26:1 boosted compression and 16.9:1 effective boosted compression
And yes you can gain power going from 87 to 93. Older dumb cars no. But 17 raptor...100% yes

Edit*
"The Raptor Supplement Manual for the gen 1's even stated the 6.2L produces 401hp on 87 and 411hp on premium."

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