Wound back the timing on my svt tune

Wound back the timing on my svc tune

I have a 91 tune in my truck. The price of 91 fuel has been pissing me off so i thought id try 87. I took the timing to -1 . I believe the svc 91 is -4 on the global spark setting ? Anyway maybe its my imagination but it feels much more sluggish. 80-140 kph i lost a second.

are you referring to the SVC tune?

Less timing and lower octane fuel, yes it should feel more sluggish.

If it wasn't pinging on 0 (default) Global Spark, there is no reason to change it.

Gsteve said:

I have a 91 tune in my truck. The price of 91 fuel has been pissing me off so i thought id try 87. I took the timing to -1 . I believe the svc 91 is -4 on the global spark setting ? Anyway maybe its my imagination but it feels much more sluggish. 80-140 kph i lost a second.

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By default the SVC is set for 91 or higher, which global spark is set at 0, not -4. If you want to use 89, then set it for -2. If you started to use 87 as you said then you need to set it to -4.

You can be at something lower like -4 and use any octane higher without issues. But you don't want to be higher on global spark and use octane lower. So at -1, you need to be running 91 again or reflash at -4 and you will see if makes a difference.