Have you read anything the others have posted? LOL...... Completely the opposite of what is said. RMS8 is dead on with what he said. If it isn't tuned for the octane, or have enough compression to need it, then it is pointless. Higher octane= less boom, it's that simple.

 

Yup, most are spot on here. I always laugh when someone tells me that their old beater won't run on anything but the "Expensive Gas."

 

To be honest (and play devils advocate….) there may be some truth to that, just a bit though.

For example, if that old beater was made in the 60’s, it’s possible that it might have a higher compression engine. Also, (and more importantly), if an engine is old and has a lot of carbon build up on the pistons (or even the valves for that matter), it’s possible that this excess build up could create “hot spots” and be the source of pre-ignition, requiring the use of a higher octane fuel to prevent ping. This scenario is simply masking the bigger problem of a worn out engine though.

 

The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. Lower-octane gas can handle the least amount of compression before igniting spontaneously. When fuel ignites because of compression rather than spark, it causes detonation which is the engine "knock" or "ping" that you hear. This can lead to engine damage.

87 octane fuel is 13% heptane and 87% octane. Heptane will spontaneously ignite under high compression. Not suitable for high compression engines. Octane on the other hand can withstand significantly more compression and is thus required for high compression engines. In those engines that have extreme compression, like alcohol top fuel dragsters, ETOH (ethanol) is used because this fuel can withstand tremendous compression without spontaneous ignition.

The compression of your engine is predetermined from the engine manufacturer and can only be modified by changing out internal engine components or adjustment to the engine's management software through a tuner (aka advancing the timing). If neither of these modifications have been done, using higher octane rated fuel will have zero net gain.

Can you use mid-grade or premium fuel in your engine, which is rated for regular? Yes, but it will be a waste of money. Even though the oil companies might try to make you believe otherwise, your car will not run cleaner, more efficiently or produce any additional power.

 

So someone summarize this for us.

If we're running a tuner, such as the Edge at level 3, which says you must run 91 octane at that level, is that not nessecary true? So I could go back to the cheap stuff and still stay at level 3 performance?

 

they are advancing the spark which adds more heat... which could lead to ping

 

Yes as long as their is no ping in your motor which you cant always hear in new quiet vehicles so you data log it under heavy load it prove this and that why you paid Edge to do it for you

 

In my opinion, no. 91+ octane should be used to maximize the performance of the tuner. I wouldn't recommended using 87 octane in this situation. FWIW I'm also using the Edge Evo and enjoy level 3 performance but not the price tag of 93 octane. Here in Houston 93 is about .35 cents more than 87. I filled up on Thursday with regular and it cost me $75.00.

When you advance the timing, as is done with the Edge Evo on level 3, the intake valves are opened slightly longer allowing more fuel into the cylinder. More fuel in the cylinder creates more compression. A lower grade fuel might detonate under this compression before the piston enters the power stoke. This would mean that the ignition of the fuel would occur during the compression stroke, while the piston is in an upward motion. The results could be bent valves or even spun crank bearings.

Its my understanding that these engines have a "knock sensor" that detect detonation and relay this condition to the PCM. The PCM in turn will automatically retard the timing to correct the situation. So this would negate the level 3 tune by the Edge Evo and possibly prevent engine damage.

 

Sorry for the hijack, but 07HD, do you have any pics of your HD with the Magnaflow? ...nice truck!

 

Run the lowest octane fuel you can get away with.

 

Mr. Oxlander, what you've just said is one of the most insanely idiotic things I have ever heard. At no point in your rambling, incoherent response were you even close to anything that could be considered a rational thought. Everyone in this room is now dumber for having listened to it. I award you no points, and may God have mercy on your soul.

 

hahaha sorry but i have to agree with suzuki, in no way is the timeing have anything to do with how long the valves are open, that is a set variable that the only way to change is with different cams or rockers, also there is no way these engines produce anywhere near the compresion to ignite the fuel on compresion only.....

 

What's not rational about this?

 

i.ride.suzuki is just calling him out it was mostly wrong

 

I think we all would agree that when we say “timing” we mean the location of the piston relative to TDC and the position of the intake and exhaust valves when the spark plug delivers the spark. While I agree that my fundamentals in this area may be weak, you are also wrong when you say that the only way to change the duration of valves opening and closing is by changing cam and/or rockers. VVT (Variable Valve Timing) which all of the newer F150s are equipped, allows the lift (duration) or timing of the intake or exhaust valves (or both) to be changed while the engine is in operation. This is controlled by the cam phasers. In fact Ford engineered this engine with variable valve timing via the cam phasers that offer up to 50° of adjustment on each bank of valves. While the engine is running.

Variable Cam Phaser (VCP) replaces the standard pulley, sprocket or gear in a gasoline engine's valve train. It enables the cam lobe (lift event) timing to crank shaft timing to be changed while the engine is operating, based on the parameters of the engine. The parameters are determined by the PCM which gathers its information from engine sensors like the knock sensor I mentioned in a previous post. Variable cam phasing changes the timing of the valve lift event. It can be used to shift the intake cam, the exhaust cam, or both on dual overhead cam engines. Which the F150 is so equipped. This helps increase engine efficiency, improving idle stability while delivering more torque and horsepower.

Hummm, how is that possible? Making more torque and horsepower by adjusting the duration of lift event? Could it have anything to do with filling the cylinder with more fuel and then compressing this fuel? Thus requiring a higher octane rating.

According to Edge’s information taken from Jeggs webside take a look at the following:

Your Edge EEF2400 Evolution monitor allows you to monitor the performance of your engine’s vital engine components and output values. The following parameters can be displayed on the main Evolution screen (maximum 4 at one time):
• RPM
• MPH
• Engine Coolant Temp
• Engine Oil Temp
• Transmission Fluid Temp
• Cylinder Head Temp
• Air Intake Temp
• Line Pressure Control Desired
• Fuel Rail Pressure
• Output Shaft Speed
• Turbine Shaft Speed
• Manifold Air Flow
• Manifold Air Flow Sensor Voltage
• Variable Cam Timing Actual Advance
• Spark Advance
• Torque fuel/spark Limiting Status
• Fuel Economy
• Engine Load
• Accelerator Pedal Position
• Battery Voltage

http://www.jegs.com/webapp/wcs/store...0002_396851_-1

Why would the Edge Evo monitor the Variable Cam Timing Actual Advance? Maybe because the program that it uploads to the F150’s PCM alters this parameter.

Look, all-in-all I may be completely wrong here. I’m no engineer. I am educated, consider myself to be partially intelligent and certainly don’t want to make cyber enemies with anyone. If I am way off base on this, then educate me on the reason why level 3 on the Evo requires 91+ octane, because as I understand it the only benefit of having a higher octane rating is to withstand higher compression without premature ignition.

Happy Holidays Everybody :santa: