farmtruc

[kerrige]

Two tables exist. Low and high. Timing is better in the high table. It is more aggressive resulting in more power. If you have a single Oct tune both are the same. With a dual tune the low timing makes as Erica said roughly 7hp less. If your truck happens to think you have 89 if will have 7hp less. Even if you have 91 in the tank the pcm may think you have 89 and you will make less power. The single while using 91 all the time you make all the power all the time. With the dual tune it will and can change and make less power at times.

[mopower440]

Two tables exist. Low and high. Timing is better in the high table. It is more aggressive resulting in more power. If you have a single Oct tune both are the same. With a dual tune the low timing makes as Erica said roughly 7hp less. If your truck happens to think you have 89 if will have 7hp less. Even if you have 91 in the tank the pcm may think you have 89 and you will make less power. The single while using 91 all the time you make all the power all the time. With the dual tune it will and can change and make less power at times.

Understandable. But as long as it does have good gas and doesn't detect any knock, will the dual tune run on the 91 table and put out the same power as the single 91 tune?

[Erica@NP]

Understandable. But as long as it does have good gas and doesn't detect any knock, will the dual tune run on the 91 table and put out the same power as the single 91 tune?

That is correct.

[mopower440]

That is correct.

Hmmm, ok, Allen acted like it still would not perform as good as the single tune even with good gas and no knock, that's why I didn't know

[kerrige]

Understandable. But as long as it does have good gas and doesn't detect any knock, will the dual tune run on the 91 table and put out the same power as the single 91 tune?

Yes however any false knock can send it into low octane.

[mopower440]

Yes however any false knock can send it into low octane.

I see. That makes sense. If I have a straight 91 tune and it detects false knock, what does it do?

[GMCwantsLS1]

I see. That makes sense. If I have a straight 91 tune and it detects false knock, what does it do?

It will reduce timing during that knock event but will remain on the same timing tables. That is what is best about single tune, it will still correct for spark knock on the fly but still try to add as much timing as possible.