Hi guys, I have a question, would our cars benefit from gasoline rated higher than 93 octane or would be a not worth the additional cost. Sunoco use to have 94 octane. There are some fuel sellers who have 100 octane fuel, which is expensive. Your thoughts please.
Thanks

 

Waste of money.

 

+1. The compression ratio isn't high enough to warrant anything more than 93.

 

The engine achieves full rated performance on 91 octane so don't even bother with 93.

 

If you could afford an F-Type, pump that baby with the best fuel! Just saying. Other than that, nope won't get any better benefits with higher octane than 93.

 

93 octane it is.

 

I use 91 non ethonal, to avoid gummy issues, real or imagined. I have access to 93 but don't use it for that reason.

 

I hope it's not the placaebo effect; I went from running a tankful of standard pump 95 RON (UK) to 99 RON and have been running it on the more expensive fuel exclusively.

The only noticeable difference that I felt, was on acceleration. It felt more responsive.

Apart form that I didn't notice anything. I know some claim better MPG, but fuel economy isn't exactly top of the list with a car like this anyway.
It deserves the best you can put in it.

 

Those numbers are equivalent to about 89 and 93 Pump Octane in the US ([RON + MON]/2). There is usually about a 12 point difference between research and motor octane numbers depending on the blend stocks.There should be a noticeable difference between the use of standard and premium grades of fuel, but there are rapidly diminishing returns from fuels with higher octane than premium grade, unless the engine and tune are tweaked to require more octane. (higher boost, higher compression ratio, etc.)

 

I though it was an 8 point spread for Euro fuels. No? I thought the Euro owner's manual required 95RON, having based their HP claims on that fuel.

 

Could well be depending on the typical blend components coming from the local refineries. I am not familiar with the blending practices in the EU. In the U.S., the spread will be in the 10-12 point range. That spread is particularly high when using oxygenated blend components (ethanol, ethers) like we do here in the States.

 

HMmm. I'm confused now.

Having always been told and believed that N. Am fuel had an 8 point RON-MON spread which means that our 91AKI is equal to 95RON. All modern Jags have a recommendation to run on 95RON, having being were certified on this fuel.

If you are correct that our fuels have a 10-12 point spread, then Jag is saying that 89AKI is adequate. (??)

 

RON is not the only important number. If the MON is too low you will experience detonation at lower RPM high torque conditions. Here in the US, I would recommend a minimum of 93 pump octane at sea level and 91 octane at altitude (~4000+ ft). The reason Jaguar specifies RON is because that is the only number typically specified at European pumps. Keep in mind, my information is based on my experience in the industry in the early 90s. It may be dated.

 

There is a great benefit to using petrol with octane ratings higher than 93. It just that the benefit is to the retailer and oil company, not the Jag owner.

 

In checking again, all available sources indicate that the MON/RON split today is around 8 points. I believe it was formerly the 10-12 you mention.

 

Thanks for the update.