That's normal when you first start using it. After you've used it for a while, it won't matter which way you do it. Trust me, I've used it for over 50k miles and I've tried every combo possible.Is there a de facto standard on how to fill the ACES IV in the gas tank?
Last time I did it ACES IV first, then filled up. Seemed like the car picked up on this right away.
This time, I filled up first (completely) and then filled the ACES IV. This time the car seemed to lose pep right away, pulling out of the gas station and driving home. How's that possible...does the computer pick up on the gas octane/quality that quickly?
I use the same Chevron gas station I always use. Also, I'm on my 3rd treatment. First treatment didn't seem that much different (added ACES IV after gas fillup), the 2nd treatment I added CAI, exhaust and Johan tune (he was informed of ACES IV). Car felt really powerful.
It has a lot to do with the residual lubricant in the cylinders. You haven't used it long enough for it to smooth things out so that it won't matter how you add it. I stopped adding it before filling when I had all the pumps fail on me at a gas station due to a computer glitch when only halfway through adding fuel. The car wasn't happy about running on double aces for the few miles until I got to another station.