Fuel Octane rating

[Mudnut]

I have a spec question.

Why does the US specs state octane rating for the V8 at lower than the Ecoboost? Here in Australia the Ecoboost has octane rating of 91 RON, and the V8 uses 98 RON?

Not only more fuel, but on average $.10 more per litre.

Cheers,

Ken

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[5Boss]

Filled mine up while in Los Angeles last weekend and 91 was their premium.
Makes no sense to need 98 other than tuners can put a heap more timing in with the higher octane.
I run all our 2008 Super snake in Perth on 98 only as gas is a lot cheaper than an engine.

 

[Evolvd]

Possibly due to the compression ratio? Without looking up the number for both a turbocharged car requires a higher octane to reduce pre-ignition due to heat and pressure from the turbocharger.

 

[Mudnut]

Possibly due to the compression ratio? Without looking up the number for both a turbocharged car requires a higher octane to reduce pre-ignition due to heat and pressure from the turbocharger.

That is my point. Our (Australian) Ford web page states that the Ecoboost requires 91, where the V8 requires 98. Should be opposite in my opinion.

cheers,

Ken

 

[G RUSH]

That is my point. Our (Australian) Ford web page states that the Ecoboost requires 91, where the V8 requires 98. Should be opposite in my opinion.

cheers,

Ken

I don't think I'd be sticking Oz 91 fuel in these engines at all.

95 minimum in the country if 98 was unavailable, otherwise 98 all the way.

Keep the modern engines clean and happy.

 

[WILDB]

The US measures their octane rating differently to everywhere else in the world.

93 RON US = 98 RON in Australia.

 

[G RUSH]

The US measures their octane rating differently to everywhere else in the world.

93 RON US = 98 RON in Australia.

Yes and in the US 87 octane is recommended according to the manual, which is our 91.

It also states "to provide improved performance, we recommend premium fuel for severe duty usage such as trailer tow"

Or my driving lol

In any case, i'll be putting in 98.

 

[Rex Chan]

Yes and in the US 87 octane is recommended according to the manual, which is our 91.

It also states "to provide improved performance, we recommend premium fuel for severe duty usage such as trailer tow"

Or my driving lol

In any case, i'll be putting in 98.

Hi all,

Not sure if my info is current, but the Ford US Mustangs require 87 octane, which is our 91 RON.

Ford AU brochure says 95RON for EB and 98RON for 5.0 GT.

Is this due to a RHD/export/hot Australian climate engine calibration that our cars have?

I care becuase I plan on daily driving my 5.0 GT and currently do 40,000 kms per year I care a lot more about the sound of the V8 than the power it makes

 

[noboot]

Yes and in the US 87 octane is recommended according to the manual, which is our 91.

It also states "to provide improved performance, we recommend premium fuel for severe duty usage such as trailer tow"

Or my driving lol

In any case, i'll be putting in 98.

My last car was a VE SS and my current drive is a VF SS Redline and both were/are exclusively BP Ultimate 98 octane. You pay a little more but it's worth it. If you can afford to buy a V8 Mustang there's no excuse to then skimp on the fuel you use.

 

[garage34]

esso japan sale 100 octane gas ;) maybe in future nitro

 

[MC]

98 all the way. When I bought my XR6T someone told me, if you can't fill it up with 98, put in only as much 95 as you need to get to somewhere where they sell 98.

 

[Rex Chan]

My last car was a VE SS and my current drive is a VF SS Redline and both were/are exclusively BP Ultimate 98 octane. You pay a little more but it's worth it. If you can afford to buy a V8 Mustang there's no excuse to then skimp on the fuel you use.

Hi nobot,

Thanks for the feedback, but I am after any knowledge around why the US 5.0 GT can run fine (according to the manual) on 87 octane (our 91RON). I realise the max. torqur/power ratings are with 93 octane (98 RON).

As stated above, I do not require 435hp (or whatever the max is) in daily driving, so I'll just be throwing away money.

The way I see it, modern engines are equipped with knock sensors, and will have a base expectation of fuel quality (maybe in the US it's 91RON and in AU its 98RON), and then retard based on knock sensor feedback. If there is a different engine calibration for US vs. RHD/export, then so be it, and then we should be running the 95 or 98RON.

BTW - I am pretty sure the 98RON "BP Ultimate" is exactly the same RON as any other 98RON fuel sold in Australia. There may be an additives package added that make it "BP Ultimate" (i.e. detergents, etc), but it won't affect the octane rating (unless some chemists know different - I'm a mech eng).

 

[Rex Chan]

esso japan sale 100 octane gas ;) maybe in future nitro

Pure ethanol is 100+ RON already ANd you get the lovely smell too

 

[noboot]

Hi nobot,

Thanks for the feedback, but I am after any knowledge around why the US 5.0 GT can run fine (according to the manual) on 87 octane (our 91RON). I realise the max. torqur/power ratings are with 93 octane (98 RON).

As stated above, I do not require 435hp (or whatever the max is) in daily driving, so I'll just be throwing away money.

The way I see it, modern engines are equipped with knock sensors, and will have a base expectation of fuel quality (maybe in the US it's 91RON and in AU its 98RON), and then retard based on knock sensor feedback. If there is a different engine calibration for US vs. RHD/export, then so be it, and then we should be running the 95 or 98RON.

BTW - I am pretty sure the 98RON "BP Ultimate" is exactly the same RON as any other 98RON fuel sold in Australia. There may be an additives package added that make it "BP Ultimate" (i.e. detergents, etc), but it won't affect the octane rating (unless some chemists know different - I'm a mech eng).

Don't know why the octane ratings are different so I can't help you their.

Not requiring the 435hp as you say is fair enough but being a mech eng you should know that the higher octane fuel is cleaner and better for your engine and its internals. If you plan on keeping the car for a long time then does it not make sense to look after it with the best fuel you can give it rather than the lower octane stuff?

Yes the octane ratings on our fuels here are the same but I've spoken to many people including mechanics and people in the automotive industry and seen many articles and the general consensus is that in Australia BP and Mobil fuels in 98 are the ones to go for above Shell and Caltex. They're all basically the same fuel but each company adds in their own stuff as you said. In saying all that though trying them out and seeing for yourself couldn't hurt.

 

[car]

merican posts largely use the lower rating for the
GT so I will be as well (using 91)

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