100 Octane + 91: Driving Impression in RZ-34

[Chokinzoku]

So I’m stuck with 91 octane in California so I decided to try a blend of 100 octane + 91 octane to see if the Z would respond better acceleration-wise. I added 5 gallons of 100 plus about 11 gallons of 91, which probably gets me somewhere in the 94/95 range. The result is the Z is noticeably more responsive and pulls harder after 5K RPM. It already revs to redline super fast, but now it feels like it’s pulling there faster and harder. Interestingly the temperatures on the gauges stayed below 200 degrees F, except for the oil, which was at 206 F, and usually they are all above 200F.
The difference isn’t as big with 100 octane blend as it is in my ‘24 GT-R, which felt like the car took a dose of viagra, but it’s definitely restoring some lost horsepower that got deleted with the 91 octane in the Z. The car is running on Michelin PS4S and the tires were making more sounds than usual, telling me that more power is basically trying to make its way to the ground. The VR30 was designed to consume 93 octane, so the better the fuel blend you feed it, the better it responds. Kind of like eating a steak or eating lucky charms; one will give you higher quality protein and energy while the other just keeps you going…. 3-5 gallons of 100 octane with the remainder being 91 octane is my new go-to-fuel on this 23 Z.

 

[MHockey17]

So CA doesn’t sell 93AKI anywhere but some carry 100?? Not sure I understand the Cali logic there lol

I was surprised to find that the OM for new Z actually recommends 93AKI as preferred fuel, as it seems like most OEM max recommendation for performance vehicles is 91AKI (presumably cause 93 isn’t available everywhere); maybe it’s normal for FI motors though

 

[Brock]

Oklahoma doesn’t have 93 Octane as well, so I drive to Texas to get mine!

 

[trackratZ]

So CA doesn’t sell 93AKI anywhere but some carry 100?? Not sure I understand the Cali logic there lol

I was surprised to find that the OM for new Z actually recommends 93AKI as preferred fuel, as it seems like most OEM max recommendation for performance vehicles is 91AKI (presumably cause 93 isn’t available everywhere); maybe it’s normal for FI motors though

CA sells 100 at only a few stations for those who track. 100 is available at local tracks also, but much more expensive.

 

[MattJ2020]

I wonder what and how 98 Octane goes in Australia?

 

[Bert]

I wonder what and how 98 Octane goes in Australia?

I believe the US refer to octane as AKI whereas we use the European measurement RON. Basically add 4 points to the AKI figure to get the equivalent in RON and vice versa

 

[MattJ2020]

I believe the US refer to octane as AKI whereas we use the European measurement RON. Basically add 4 points to the AKI figure to get the equivalent in RON and vice versa

ohhhhh! Thanks!

 

[2in2out]

ohhhhh! Thanks!

Yea US 93 is like a no name servo version of our 98

 

[MHockey17]

CA sells 100 at only a few stations for those who track. 100 is available at local tracks also, but much more expensive.

Oh that’s nice atleast, tho still strange you can buy essentially race-grade gas in CA but not normal premium-grade

Wonder if that’s a state regulation or just a logistical issue of some kind for fuel stations?

 

[Hatoshi]

Oh that’s nice atleast, tho still strange you can buy essentially race-grade gas in CA but not normal premium-grade

Wonder if that’s a state regulation or just a logistical issue of some kind for fuel stations?

It's for emissions and junk like that. I'm in az and we share the same crappy 91 gas that California gets. The two states have a "special blend" although some parts of az don't use that iirc.

 

[Hatoshi]

So CA doesn’t sell 93AKI anywhere but some carry 100?? Not sure I understand the Cali logic there lol

I was surprised to find that the OM for new Z actually recommends 93AKI as preferred fuel, as it seems like most OEM max recommendation for performance vehicles is 91AKI (presumably cause 93 isn’t available everywhere); maybe it’s normal for FI motors though

Not just Fi motors wanting 93 for best performance. The BRZ/frs/gt86 motor also is rated/recommended with 93 octane but it's high compression motor. 91 is acceptable if 93 is not available.

 

[trackratZ]

Oh that’s nice atleast, tho still strange you can buy essentially race-grade gas in CA but not normal premium-grade

Wonder if that’s a state regulation or just a logistical issue of some kind for fuel stations?

It's more logistics, they're located at various race tracks around here. Although still some but very few in commercial areas.

 

[MHockey17]

Not just Fi motors wanting 93 for best performance. The BRZ/frs/gt86 motor also is rated/recommended with 93 octane but it's high compression motor. 91 is acceptable if 93 is not available.

Oh nice, would not have expected that for those motors. The VQ37 was considered high compression also n seems to run a bit better on 93 too, even though it’s rated for 91; Figured it was the standard rating for factory performance motors since it’s the more common high octane fuel.

I guess the even greater compression in modern engines warrants the higher rating though