As many of you know I am approaching my (hopefully) final tune on my build. Things happened and I couldn't get to it at the time and I let the car sit for 6-8 months now. At that time I drained and filled my tank with our best option here (91 oct. Shell V-power) in preparation to take the car in for tuning at that time. So the fuel isn't crazy old, but it did sit with no kind of stabilizer for what I think is 6-8 months now. I know the fuel's various molecules start to break down pretty quickly, even as soon as 30 days. Do you think the fuel is fine for tuning, or would it be stupid no to drain and fill again? Or what about adding in an octane booster?

The only reason for my worry is that we are talking about a dyno tune on a 800ish whp turbo build. If it were a normal situation where some car just sat, I'd drive it and not worry because the fuel it not that old. But is it too old to go put the engine through hell on the dyno? This is that one time where things need to be especially perfect right? Or am I thinking to far into this?

 

I'd drain and refill. Even the fuel is "mostly okay" your tune could be suboptimized as a result.

As someone that has had to drain fuel more frequently than many, a good hack is to remove your return line from your FPR and attach you a hose there that runs to your fuel can to let your pump empty the tank.

 

Ya I decided to drain and fill what I could. Used the fuel in my other cars. Still works fine for them. Re-topped off with our Cali-crappy 91 oct. Should be fine. The fuel wasn't even to crazy old. Just trying to optimize the situation. I'm tripping because I have 12 or 13 G's more into the the build this time that I'll have to watch get pounded on the dyno. Has me worried .