Low octane table to high octane

[teal99camaro]

I was messing around on my laptop with the hptuners vcm suite and I took one of my bins that I messed around with and copied the values from the high octane table to the low octane table.. Should I be hesitant to flash this bin to my pcm?

I thought that I heard of people doing this, doesnt it increase the burn rate of the fuel by increasing the spark?

[98Camaro3.8]

Tune by the high octane spark table, copy high octane to low octane spark table, subtract 5° or so. Running the high octane table all the time is dangerous.

[teal99camaro]

how is it dangerous? and can you elaborate on where I need to subtract five degrees?

[arthansen]

Copying the high octane table to the low octane table can be a valuable tool for tuning. However, do not do it for normal driving. The reason you copy it is to make sure that you know what the commanded spark advance is while you are tuning. If you have them different, the commanded spark will be somewhere inbetween.

The proper methode is to copy the high to the low. Tune your car, changing both the high and low. Once you are happy with the tune, both tables should be the same. Then select every cell in the low octane table and ADD minus 5 (-5). For those of you who do not have a Ph.D. in math, adding a negitive is the same as subtracting.

It is not "Unsafe" to run the tables the same (as long as you have not messed with the knock retard), knock retard (KR) will protest the engine. However, KR is more agressive then the low octane table. If you have some bad gas and rely on KR to keep knock down, your car will run like crap. By having the low table 5 degrees less then the high table, you allow the car to use the low octane table with bad gas and it eliminates the KR which seriously robs power. Once you get some good gas back in the car, the PCM will move back to the high octane table.

Hope that makes sence.