[1 DEMON]

Had my dealer install the crate PCM and high octane button. When I put 100 octane in or 93 octane in, it shows up in blue light that 840 high octane activated. Why would it show that with only 93 octane?

 

[THEONE]

Have you ran all of the 100 octane out? It could still be reading the mixture as being 100 octane.

 

[1 DEMON]

Have you ran all of the 100 octane out? It could still be reading the mixture as being 100 octane.

Yes. I ran the 93 octane down to empty, then filled up a full tank of 100 octane. Could there be something wrong with the crate PCM?

 

[THEONE]

If it doesn’t have 100 octane it should run through the checks to verify the octane and then go to 808 because the fuel isn’t 100 octane. I would probably take it in to the dealership to get checked.

 

[dragrcr]

Had my dealer install the crate PCM and high octane button. When I put 100 octane in or 93 octane in, it shows up in blue light that 840 high octane activated. Why would it show that with only 93 octane?

The HO button only ENABLES the 840 HP tune. It's up to YOU to make sure the octane is sufficient. If you enable the 840 tune and then you only have 93 octane in the car, nothing will happen if you drive normal or close to normal. Once you go full throttle the car will experience knock and then the car will drop out of the 840 tune and it will tell you in the DIC. And, yes the engine will no longer be Blue in the Display. You will have to cycle the ignition to be able to enable the 840 tune again. It states in the Owners Manual that this can damage the Engine but I know of some that have tried all kinds of stuff and tested repeatedly to see if it would stay in the 840 mode. So this is very conservative and engine damage must be rare. But still........

 

[MJS73]

I was going to say, these cars can't detect octane since it's a calculation, not a detectable characteristic.

 

[hc797]

.... and once the ECU detects it, the damage could be done

 

[2048 Demon]

.... and once the ECU detects it, the damage could be done

Knock sensors , exhaust gas temperatures, and O2 sensors protect the engine from operating with detonation. You will need about 8 gallons of MS109 race fuel to 2 gallons of 93 octane unleaded to keep the knock sensors from kicking you out of the high octane mode on the Demon. This has been my experience with my Demon.