Thread: Simple question's about octane

Let's say you had a pretty much stock all motor setup tuned on 87 octane........If I was to get a retune on 93 octane, approx..... how much more power can be expected/squeezed from the motor just from the switch of octanes? What if the octane was changed to 110....how much power then could be squeezed from the motor. I know the answers are going to vary but I am just trying to get some ideas... need some solid answers , please no guesses.

You're not looking at too much of a gain.. Maybe 10whp just from running higher octane and getting a tune for that octane but thats honestly pushing it

When you say 10hp is that 10 hp from 87-93........or 87-110 octane?

An octane rating just means that it is harder to ignite i would expect any gains by just switching different octanes. The reason people run high octane in there cars is because they have extra heat added like forced induction or higher compression which builds up lots more heat than being stock.

-dave

Imo there are good gains to be found after switching to a minimum 93 octane fuel. This is because it allows you to run a much more aggresive tune or timing.

That was sort of the basis of this question as well... and why I used a all motor car for a example.....if 93 octane is that resistant to heat and not completely burning in the cylinder and the rest of the mixture is being pushed out the tailpipe the isn't power being lost by moving to a higher octane in a way? Does this mean that a 93 octane setup needs to be tuned slightly richer than those with lower octane to achieve the same results as using a low octane fuel? How did I come up with this well I was switching back in forth between octanes and I noticed my car was sluggish with the 93 octane while on the other hand 89 octane felt like it was a better fit, 87 octane was detonating.

No if anything you could lean it out a tiny bit like i did with mine.

The higher the octane number the higher it's resistance to detonation. That's all, nothing more.

Well said.

My best guess would be that on 87 octane a stock DE is knock limited at about 130WHP with tuning. With 93 octane I think around 150WHP is the knock limit. And on 110 I don't think you'd be knock limited anymore, and you might be able to squeeze 160WHP out of it would be my guess. 93 octane gets you pretty close to MBT I think.