For those getting their cars professionally tuned, are you only getting tunes for pump gas? What if you want optimal tuning on pump gas (for street) and also optimal tuning for race gas (for race)? Seems like if there is pump gas in the tank during the tuning process, then you obviously can't turn up the boost and tune for race gas. And if there is race gas in the tank, you can't effectively dial in timing for pump gas because the knock monitoring will be useless with the race gas in the tank.

Thanks,
RichJ

 

If you are planning to tune for both pump and race gas, it is wise to head toothe dyno with very little pump in the tank (1/8th tank). Then you can fill up with race gas. A lot of dyno shops will have it on hand or you can buy a cannister and bring your own. That way you can add the race gas in after your pump runs are done. If there is only a small anount in the tank then it won't lower the octane of the race gas very much. If you still have too much pump in the tank you can just drain it out first.

 

I like to pull the oil return lin off the fuel rail and turn the car on, it will drain out the tank very rapidly, after its dry you may still have another gallon or 1.5 gallons of pump in the tank, but mixed with 5 gallons of 110 octane you will probably be fine, its pretty difficult to tune to the the ragged edge of 110 octane anyways.

 

you meant fuel return right, not oil

 

Heh, I just blew someones engine!