Because of availability issues I'm thinking of running Sunoco 110 leaded, instead of my current VP 103 unleaded. My question is how will this effect the current tune I have on 103? Will I need, or would you recommend, to go back and retune? Thanks

 

Would you retune if you went from 87 to 93?

 

Running leaded gas is gonna kill your O2/wideband.

 

I realize it'll kill the O2 but i don't run one, only have one I use to tune then plug the O2 bung when I'm done. Just wanted to know if the change in leaded/unleaded octane will be drastic. I know a couple guys have their engines tuned on 93, but once in a while will run 110. I'm not a tuner so just wanted the info before I make the change. My tuner says we might need an adjustment but on his personal engine he can go back and forth between 93/110 no problems.

 

From what I know, you can go back and forth but if your engine isn't tuned to take advantage of the extra octane (usually a more aggressive timing map), it makes no sense to use more than 93 octane if it was tuned for 93.

 

Exactly. You may even lose power and fuel economy using a higher octane fuel...assuming you are actually tuned for 93.

 

Never actually heard that before....

But...you'd DEFINITELY be wasting money by running Pump premium in a car that doesn't need it.

Will the fact that the gas is LEADED have anything to do w/ anything BESIDES killing the Wideband?