Difference between flex fuel model and non flex fuel model 3.0 engine.

[Brain75]

the way the guys who did superchargers at bandimere (1/4 mi race track) explained it to me. Supercharging is just like raising compression ratio, you need a higher octane gas after a certain point. My buddy who took his silverardo with the LS block swapped heads, lowered compression and then added a eaton supercharger - so he could still make it work with available 104 octane street gas and not AVgas aka LL-166 (Low Lead 166 - 166 octane)

 

[stmitch]

Now, if I were to run regular low grade gas in my truck I might not be reaching that horsepower? And I’m assuming that the reason for the extra horsepower is because of the different head size?

Not sure how a supercharger requires a better grade of fuel, after all gas is gas, but the grade is determined by the amount of pure gasoline right?

The different heads don't really have any impact. You can see that they have the same compression ratio for gas and FFV Vulcan engines. And Ford stopped using the special FFV heads after a couple of years and used the same heads for both gas and FFV Vulcans because it wasn't worth it to deal with two cylinder head designs that had no meaningful difference in performance.

E85 has much higher octane than regular unleaded. Octane = knock resistance. So, the higher the octane, the more you can increase timing (hp) without knocking/detonation. In a Flex fuel vehicle, the PCM can actually change timing based on the octane that's being picked up by the sensors which leads to higher hp.

Boosted vehicles make more heat in the combustion chamber (increasing pressure adds heat). Without higher octane, that heat causes detonation or spark knock. Unchecked, that causes things to explode, so modern engines use knock sensors that detect knock, and then tell the PCM to scale back timing to a safe level. That results in lower power until the knock stops. Running Premium unleaded (or E85) is often required in naturally aspirated engines with high compression ratios, or engines with forced induction for that reason.

 

[AK Ranger]

akranger also has a 99 I believe, and he definitely does have the sensor - we worked together to go through a stalling issue...

We definitely worked through some issues and Brian was a big help, it sure runs better than it did.
Still fighting Fuel Mixture Imbalance and Cylinder 5 Misfire Detected issues. It has new plugs, plug wires, coil IAC Motor, all three O2 Sensors and a new cylinder 5 injector. I have smoke tested the intake and the exhaust, which yielded no leaks. I still need to run a compression test, but get distracted by other projects and duties . We'll eventually get it, but is is at least drivable.

 

[Brain75]

I was hoping at some point you would check back and tell us everything was smooth sailing... guess not just yet eh.... bummer

 

[AK Ranger]

I was hoping at some point you would check back and tell us everything was smooth sailing... guess not just yet eh.... bummer

Slowly getting closer. With my job, working to sell a different truck and my son starting a summer job, time to work on the Ranger is limited. Just surprised with the parts we’ve put on, that it’s still throwing the same codes. It is running better, so I’ll take that win.

I hope the OP gets his issue resolved.