Difference 91 vs 93 Octane
Thread Starter
Burning Brakes
Joined: Jul 2007
Posts: 753
Likes: 47
From: Clearfield Utah
Difference 91 vs 93 Octane
What if any difference is there between 91 and 93 octane fuel? What can I expect in performance between the two? Just curious what others have experienced. Thanks
Safety Car
Joined: Sep 2005
Posts: 4,222
Likes: 643
From: Orange County Ca
Here in commiefornia, 93 is very rare, so I couldn't swear to anything. But, 91 seems to run just fine. Even my neighbors zr1 runs well on it.
I don't have any technical info, but, I wonder if it's the same as the issue of running 91 in a car that calls for 87? Usually no additional performance in this case.
I don't have any technical info, but, I wonder if it's the same as the issue of running 91 in a car that calls for 87? Usually no additional performance in this case.
Race Director
Joined: May 2001
Posts: 15,323
Likes: 2,077
From: Guelph, Ontario
I know that in my 2018 I get light pinging at part throttle between 1500 to 2000 rpm if I run 91 octane in the warm weather and if I run 93 or 94 I get no pinging at all. It doesn't detonate at full throttle with 91 though, but I suspect it's probably pulling out some timing and I could potentially be losing 5-10hp vs 93.
Burning Brakes
Joined: Jun 2023
Posts: 952
Likes: 440
From: FL
Is Canadian gas different than US gas?
91 vs 93 should not matter in performance or function. The car has sensors to de-tune a bit if the right octane is not used. 91 may net you .2 or .3 mpg worse. That should be the only difference.
91 vs 93 should not matter in performance or function. The car has sensors to de-tune a bit if the right octane is not used. 91 may net you .2 or .3 mpg worse. That should be the only difference.
Team Owner
Joined: Jul 2004
Posts: 28,432
Likes: 3,285
From: Hartford WI
Instead of asking the forum to guess what will work at the conditions you have, maybe the best thing is to ask the ECM? I would have to accept that air quality plays a big role. So maybe we can hook up a scanner to see whether 93 has less knock or whether it doesn't matter? What you hear doesn't count for squat since the ECM will retard timing faster than you can process it unless it is so far out that the ECM cannot adjust. I would run 91 till it is very low, scan midrange to WOT and see what you get for 91 and then fill up with 93 and see what you get. I don't believe anyone is really that good that they can hear the slight ping before the ECM shuts it down and it could be a placebo effect. On my 91 C4 that was doing 420 RWHP, it didn't seem to make much of a difference.
