ocorral20

i just received my xcal2 with 87,89, and 91 tunes... i currently have 1/2 of gas of 87 so i installed the 87 tune and wow its awesome!!!.. my question. is... i want to use the 91 tune.. but as i read here before i have to use about 2 tanks of 91 first..
so am i going to be using the 87 tube with the 2 tanks of 91 octane then change the tune to 91 after that..... also when im ready to change the tune to the 91...do i repeat the process of installing the 87 tune???
is switching tunes any different on the xcal2???? i appreciate all the help i canget thanks

Nuke

If you have about 1/2 tank of 87 and you want to use the 91 tune, run it down more and fill-up with at least 10.7 gallons of 93 octane. That ratio will get you to 91. If you don't have 93, run the 87 as low as you feel comfortable with then fill-up with 91and run that tank down and refill. You shouldn't have to run the2ndtank of 91 down too low.

Swapping tunes is a snap and takes maybe 2 minutes, if that. Just plug in the tuner like you did when you downloaded the 87 tune. When prompted to choose a tune, select the one you want. I often travel long distance and can't always get the octane to match my installed tune. I just pull the tuner out of the trunk and I'm back on the road in a few minutes with the different tune.

ocorral20

what about changing the tune from 87 to 91 once im on the 2nd tank of 91?
do i load it with the xcal just like i loaded the 87 for the first time?
or is it a diff. procedure?

Nuke

Same procedure. I edited my previous post. Read up. It's really simple. Just try it and you'll see. You can even load the 91 tune right now, then reload the 87 without driving.

Argonaut

Same procedure, just plug it in and follow the on screen instructions to loadthe 93tune.

Regards the conventional wisdom that its required to run 2 tanks of the higher octane gas before switching tunes. I realize its the "safe" way to do it but I question its necessity. The car has knock sensors and adaptive learning. If you run the tank to empty and then fill up with the higher octane and then re-tune,I would think you'd be fine...i.e. the car would retard the timing if it detected any detonation in the slightly lower octane gas (~14 gals of 93 octane mixed with 2 gallons of 87). I'm not giving advice, I'm just wondering. Maybe one of our master mechanics will pipe in.

ocorral20

wow thanks for the fast reply guys.. i really appreciate it and yes it does look like a snap...
any one else have any input on the necessity of going with the 2 tanks of higher octane gas to reload the tune??

Nuke

I agree with argonaut but my recommendation erred on the conservative side. If you drive enough to run the tank downoften AND you have a little patience, do 2 tanks.

ocorral20

yea i think ill do the 2 tank thing just to be on the safe side.. but then that brings me to the final question... is there a problem if im gona still be running the 87 tune.. and ill be using the 2 tanks of 91?

dbspcl

There is never a problem with running higher octane gas on a tune designed for a lower octane. You're just not taking advantage of the higher octane (to advance timing, etc). Won't hurt anything except your pocketbook.

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dbspcl
2007 GT tungsten-grey coupe stick, IUP, etc.

move: JLT CAI, Brenspeed 91 tune
grip: Eibach springs + adj. panhard, 20" Foose black nitrous
look: Roush quarter louvers, Webelectric sequentials
feel: Steeda tri-ax

Corsa Crew Member