Getting a tune and switching gas?
 

So I am going to order a tuner for my 06 v6 auto from American Muscle. Besides taking off the annoying limiter and who not, I want to tune it for 93 octane which is what I hear read gets you a good gain. Now if I was to switch over to using 93 octane, what would be the best way to switch? Would it be best to wait until there is basically no gas left or does it not matter?

Thanks.

Yes, run it down to very low gas, then fill up with 93. After you've filled up then drive for a mile or so that way you get all the lower octane gas out of the lines and filter. Then tune the car.

you don't have to make sure all of the low octane is out of the lines just don't fill up all the way with regular and then tune it for premium. Before your about to tune it or if you fill up recently before you receive it just throw premium in it

thanks for asking this question always wanted to no that

I just waited till I got down to an 1/8 of a tank, filled up, and tuned the car. When I started it and drove away, there was some extreme detonation. It sounded like someone threw some marbles in a tin can and was shaking them around.

I then took the tune off, realized that I would still have fuel in the lines, drove around a little bit, put the tune back on and everything was fine.

So yes, you do need to make sure you don't have a bunch of 87 octane gas in the lines.

what you could do is start using 93 now (on your next fill up) and then when the tuner comes in you will already be runing 93 Octane!

Yeah thats what I figured, I will just go ahead and switch over now.

yup thats exactly what i did.

dont mean to steal the thread but I have a question:
Is there any harm to the engine if switching back to 87 after driving with 93 for a while? just curious.

If you have a tune for 87, you should be running 87. If you have a tune for 93, then you should be running 93. Switching between tunes doesn't do any harm, but make sure you're running the right gas for your tune.