ok i have HKS air intake ,Carbon ti exaust ,Bov,and a Boost controler i curently run on 91 octane how do u swap to 93 octane

 

You get re-tuned..that's ideal..

 

Are you specifically tuned for 91?

If not, then just pump the 93 in the tank and you're good to go. Your EVO will like the 93 even better than it likes 91.

If you are tuned for 91, then, yes, you will need a re-tune on 93.

EDIT: Simon is correct below. I should have said: If you are tuned for 91, then, yes, you will need a re-tune on 93 to realize the benefit of upgrading your fuel. But, your EVO will run just fine on 93 with a 91 tune. IIRC, the EVO comes from the factory tuned for 94, so if your EVO has never been tuned it will run even better on the 93 than on the 91.

 

The car will run perfectly fine on 93 octane using your 91 tune. However, to take advantage of the higher octane, you need a re-tune. If you don't retune, just a waste of $$, unless you need some added knock resistance at let's say a track day for example.

 

thank u guys going to the club soon pick up some *****es in the evo