Jokeurmnd

so i got myself a cai and a tune but i still had a full tank of 87 in the car so i got an 87 tune and a 91 tune. i was wondering when is it ok for me to fill up on 91. i'm pretty much at a 1/4 tank now.thanks

hammeron

well you can fill up with 91, 92 or 93 anytime you choose,
but the main concern is, when are you going to switch to
the 91 tune.

you will want to make sure all of the 87 octane
fuel is consumed (or as much as possible), before switching
to the 91 tune.

moreover, you can run the 87 tune with higher octane gas for a tank
or two, it won't hurt anything. What you don't want to ever
do, is run low octane fuel in the tank, while running a higher
octane tune.

Jokeurmnd

thanks for the info,i'll just wait till my light goes on then i'll fill it with 91 and change the tune

Aziraphale

When the light goes on, you still have 1.5+ gallons. Wait until it is really low and you'd probably be fine.

If I remember right, most people wait till it is really low, throw in the 91 but keep the 87 tune. The next tank of 91 is when they put the 91 tune in.

acascianelli

Wait until its very low on gas, fill up with 91/93, then wait till you burn a little bit of the 91/93 then flash.

I'm glad I didn't have this problem, I have always filled up with 93.

howarmat

+1....run a tank of 93 even if you want....it wont hurt anything but it will get the car ready

Jokeurmnd

makes sense enough thaks for the help