Not very happy right now.

[grizz]

No one was arguing that, they were arguing the verbiage of which fuel you should be allowed to run in the truck. May want to go back and review.

Some people were making the claim octane has no impact. I'm specifically responding to them.

You guys are so darn hilarious arguing about fuel. My truck has had 87 octane for 1500 miles. I also did some testing with a VBOX and saw ZERO difference in times between 87 and 91 octane. I took my truck to the track with 87 octane and it performed perfectly fine.

So you put in 91 and immediately tested times afterwards? It takes some time for the ECU to adjust to the increased octane levels.

does it really matter what octane or gas someone uses, its what you believe works for you. now tampons are a different story, sure they all absorb blood but it all comes down to applicator and comfort. its all about the user....

This isn't about belief. This is about science.

 

[AvoidTheBoyd]

OK, since this turned into a fuel and octane thread, I'll take the bait.

There is not a fuel composition sensor on the Raptor. It can not adjust for octane. It can only retard the timing when it senses knock. So the comment made by Grizz about ecu needs time to adjust is just stupid.

Under the right circumstances, it is true that increasing the octane will have no benefit. Most of the time you will see a benefit because these trucks are tuned to run off the knock sensor. So the higher octane will keep it from retarding the ignition timing. Running octane above the point where the knock sensor is no longer retarding the timing in theory actually produces less power and worse mileage. For an extreme example, go blow some coin on 110 octane and test it out for yourself. Race engine builders don't just run 110 octane. They dyno an engine with the lowest octane that doesn't cause knock. 106 octane and no knock is more power than 110 octane and 104 octane might blow the engine. You can apply these same principles to the Raptor octane discussion.

---------- Post added at 09:00 PM ---------- Previous post was at 08:47 PM ----------

Most vehicles rated to run E85 (obviously not Raptors or Ecoboosts) will have a fuel composition sensor. This sensor acts like a switch, on or off, not an analog signal like a rheostat. So if the sensor detects E85 it activates and the ECU can advance the timing to take advantage of the higher octane of the E85.

 

[grizz]

OK, since this turned into a fuel and octane thread, I'll take the bait.

There is not a fuel composition sensor on the Raptor. It can not adjust for octane. It can only retard the timing when it senses knock. So the comment made by Grizz about ecu needs time to adjust is just stupid.

Under the right circumstances, it is true that increasing the octane will have no benefit. Most of the time you will see a benefit because these trucks are tuned to run off the knock sensor. So the higher octane will keep it from retarding the ignition timing. Running octane above the point where the knock sensor is no longer retarding the timing in theory actually produces less power and worse mileage. For an extreme example, go blow some coin on 110 octane and test it out for yourself. Race engine builders don't just run 110 octane. They dyno an engine with the lowest octane that doesn't cause knock. 106 octane and no knock is more power than 110 octane and 104 octane might blow the engine. You can apply these same principles to the Raptor octane discussion.

---------- Post added at 09:00 PM ---------- Previous post was at 08:47 PM ----------

Most vehicles rated to run E85 (obviously not Raptors or Ecoboosts) will have a fuel composition sensor. This sensor acts like a switch, on or off, not an analog signal like a rheostat. So if the sensor detects E85 it activates and the ECU can advance the timing to take advantage of the higher octane of the E85.

I never said that the raptor has a "fuel composition" sensor. The ECU won't instantly detect higher octane and immediately start raising timing back to its base line tune. I understand very well that most if not all production cars have a base line tune rated for a certain octane, and can only decrease timing based on knock. However, once higher octane fuels are added, the ECU will start to increase timing until it reaches its base line tune. This is not done instantly.

Also, I don't know about the raptor, but some German cars I've owned made after the year 2000 can advance timing up to a 95 octane base line.

You are wrong about E85 sensors acting like a "on/off" switch. This is not true at all. My wife's Q5 is flexfuel and has an ethanol content sensor that can detect a +-1% change in ethanol and adjust timing accordingly.

 

[gwpfan]

The other thing if it acted as a switch....what happens with mixed fuel...last place didn't have E85, this one does and I'll fill up but still have a half tank.....

 

[AvoidTheBoyd]

You are wrong about E85 sensors acting like a "on/off" switch. This is not true at all. My wife's Q5 is flexfuel and has an ethanol content sensor that can detect a +-1% change in ethanol and adjust timing accordingly.

Yeah, I wasn't 100% correct. It is a discrete signal (on/off) but the processor measures pulses from the sensor and then calculates the approximate alcohol content. Interesting, but irrelevant to our trucks. I looked for a sensor on the truck and for part numbers and can't find either. So unless someone knows better, the truck can adjust timing for increased octane, just retard the timing from the base map when knock is sensed. Besides, these sensors detect alcohol, not octane. To my knowledge there is no such thing as an "octane sensor". It requires lab analysis. So any vehicle wouldn't know the difference between 87 or 91 ethanol-free except for the presence of knock on the lower octane.

 

[Crashking]

Yeah, that wasn't 100% correct. It is a discrete signal (on/off) but the processor measures pulses from the sensor and then calculates the approximate alcohol content. Interesting, but irrelevant to our trucks. I looked for a sensor on the truck and for part numbers and can't find either. So unless someone knows better, the truck can adjust timing for increased octane, just retard the timing from the base map when knock is sensed. Besides, these sensors detect alcohol, not octane. To my knowledge there is no such thing as an "octane sensor". It requires lab analysis. So any vehicle wouldn't know the difference between 87 or 91 ethanol-free except for the presence of knock on the lower octane.

Welllll... he's actually right... for his wife's Q5 atleast on the ethanol subject. I'd imagine most other companies are probably using the same or similar sensors since there are only so many manufactures in the world for automotive sensors.

 

[AvoidTheBoyd]

Welllll... he's actually right... for his wife's Q5 atleast on the ethanol subject. I'd imagine most other companies are probably using the same or similar sensors since there are only so many manufactures in the world for automotive sensors.

My apologies, I was actually admitting my original statement wasn't 100% correct.

 

[Crashking]

I do have some slight curiousity though. Over the weekend I drove from west palm beach to Orlando, and then back the next day, at about 9 at night starting both trips. I filled with ethanol free 90 going to Orlando, cruise set at 74mph and averaged 19mpg using the cruise the whole way up i95 over to 528 to I4.

On the way back I filled with 89 ethanol free and Took the turnpike back. Cruise set at 74 and only averaged 16.4mpg resetting the trip meter both times after getting on the highway. I'm super curious if I got a bad batch of the 89 or a higher than advertised 90.
Though I did notice, when I went from the turnpike to 95 on the way back, my mpg jumped about 1mpg just due to the difference in the road. No drifting of semis or major differences in traffic either.