mike.warrenws6

you dont need 93 octane on these motors, u can run 91 and i perosonlly see much better performance on 91 octane as 93, and its cheaper.

82cetuner

iTrader: (9)

yeah 93 is a little over kill for 10.1 compression

have you been back to the track to see what your times are now?

did you actually figure out exactly what the problem was i would say maf or 02s

WhiteKnight '01

91 is better than 93?

Where I'm at, 91 isn't even available...93 is the only choice. Curious why you think 91 gives better performance?

RPM WS6

iTrader: (3)

The lowest octane possibile that still 100% prevents detonation will ultimately give the best overall performance.

If your setup produces 0 KR on 91 octane, then there is absolutely no benefit to using 93.

DarkFox118

iTrader: (7)

my car produces ~7.2 deg. KR on 93 right now.


it's not the fuel that's causing this however. It's cos I'm running out.

nice insight tho rpm, hadn't thought of that. We only have 87,89, and 93 here though.

WhiteKnight '01

So people who say, "well I used 100 octane, racing gas on my car, that made it faster. Or I used Jet fuel, 110 octane...it was a lot quicker" That's not true? I always did kind of doubt it.

RPM WS6

iTrader: (3)

If they have a setup that requires 100 or 110 octane to keep detonation away and allow maximum ideal timing advance, then yes the higher octane would make the car faster (these would usually be very high compression/heavily boosted applications). Sometimes people will run more octane than necessary for engine safety purposes (max effort forced induction/N2O engines can't afford to have detonation, so they will usually run a bit more octane than they really need, just in case conditions change you don't want to be right on the edge of adequate octane).

On the other hand, if their setup allows full ideal timing advance with 0 detonation/KR on 93 or even 91, then using 100 or 110 will actually reduce power output and gas mileage.

The higher the octane, the more resistance to detonation and the slower the burn. Lower octane will combust more easily and burn faster, thus making more power so long as it doesn't detonate.

There is a lot of misunderstanding in the world in regards to octane and what it does. More octane does not automatically equal more power, more octane equals more resistance to detonation.

Zlow28

iTrader: (11)

op, have you done a compression test? on a cold start, check your radiator and see if any bubbles come out. When idle, does it smell like fuel all over the place? Any smoke from exhaust? ses lights??