Dual tune question?

[Mark_in_Tulsa]

So how does the truck know there is a different octane in the tank? And how long does it take for it to know it, and adjust the fuel and timing....etc.

And can you get an economy 87 tune and an aggressive 91 tune? Or do they both have to be the same?

If you can get an 87econ/91hot would the 91 hot be as aggressive if it was just a 91 hot tune?

[Wingnut]

I believe the two modes are commonly referred to as "sip" and "wheelie".

 

[jaslo]

I have been told by wester's that you can only get a hot tune for that specific octane. You can get a 87/91 dual tune or 89/91, but you wont have the performance gains as the hot tune.

[Butch 02 Denali]

I have been told by wester's that you can only get a hot tune for that specific octane. You can get a 87/91 dual tune or 89/91, but you wont have the performance gains as the hot tune.

 

<{POST_SNAPBACK}>

 

 

 

The dual hot tunes are hotter than the straight octane tunes. We hardly ever do straight octane tunes anymore, only on pre 99's and race only vehicles.

 

The dual hot tunes will have more timing on the upper table than the straight tunes. This can be done since the PCM will set the tune just below knock level with it's knock detect cycle at every fillup. This will optimise the tune for the gas that you put in the tank, anywhere between the two tuned dual tables, and down to the lower table. Gas quality and octane vary, the dual tunes tune will always be at their best and highest level because of the adjustability.

Straight octane tunes do not have the ability to adjust the tune level. The high and low tables are the same, therefor no adjustability. Since these tunes have to work without pinging on various levels of gas quality they must be backed down a bit.

[Mark_in_Tulsa]

I have been told by wester's that you can only get a hot tune for that specific octane. You can get a 87/91 dual tune or 89/91, but you wont have the performance gains as the hot tune.

 

<{POST_SNAPBACK}>

 

 

 

The dual hot tunes are hotter than the straight octane tunes. We hardly ever do straight octane tunes anymore, only on pre 99's and race only vehicles.

 

The dual hot tunes will have more timing on the upper table than the straight tunes. This can be done since the PCM will set the tune just below knock level with it's knock detect cycle at every fillup. This will optimise the tune for the gas that you put in the tank, anywhere between the two tuned dual tables, and down to the lower table. Gas quality and octane vary, the dual tunes tune will always be at their best and highest level because of the adjustability.

Straight octane tunes do not have the ability to adjust the tune level. The high and low tables are the same, therefor no adjustability. Since these tunes have to work without pinging on various levels of gas quality they must be backed down a bit.

 

<{POST_SNAPBACK}>

 

 

 

 

So if I get a 87/91. Can the 87 be an econo tune and the 91 be a hot tune? Or do they both have to be hot.

 

Also how long does it take for it to notice there is a different octane in the tank?