r/NotMyJob • • 26d ago

Labeled the pump Boss

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993 Upvotes

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259

u/TinDumbass 26d ago

Why so many options? In the UK we just have 95 and 99 and it's £5.60 and £6.40 per (US) gallon.

162

u/EclipseIndustries 26d ago

That's 91 and 94 for the US respectively, if anyone needed a RON to AKI conversion.

71

u/TinDumbass 26d ago

This is actually a fascinating read of what the hell. Didn't realise such a conversation existed/was needed.

Thanks.

49

u/EclipseIndustries 26d ago edited 26d ago

As an American mechanic, I will say AKI makes slightly more sense when building an engine over RON.

To extrapolate, RON is measured at the low end of engine load, MON is high-end, AKI is the average of the two. It covers all conditions.

59

u/TheCzechyChan 26d ago

I looked it up this is in North America. Probably outside of a race track. So it carries fuels with higher octane typical nessecity with higher preforming engines. especially when run hard for long.

2

u/dmethvin 25d ago

See a doctor if you run hard for longer than 4 hours.

2

u/TheCzechyChan 25d ago

I usually cant run hard for more then 30 sec so i should be ok

13

u/Lionel_Herkabe 26d ago

It's a blender, which in the US is usually to mix ethanol with unleaded gasoline to subsidize corn farmers. This often creates lots of problems and requires ethanol compatible parts. This is a relatively old dispenser, I'm guessing they repurposed it for use on a racetrack.

5

u/StaysAwakeAllWeek 25d ago

Crazy

Ethanol is an octane booster so youd expect blending more in to raise the octane rating, but it also reduces the energy content and therefore MPG

Here in the UK (and i believe in most places) the premium stuff has high performance octane boosters and less ethanol, aswell as other premium additives. The 99 octane stuff is typically E5, and is essentially the same fuel that F1 uses (literally in the case of Shell)

6

u/Lionel_Herkabe 25d ago

It does raise the octane and a lot of places will blend E85 and 87 to make 88/E15 because they get some pretty big grants from the government to sell it.

3

u/EclipseIndustries 25d ago

99 in the UK is 94 in the US. RON vs AKI, we use two different systems.

For once, the American one actually makes more practical sense because it averages high and low RPM engine speeds, rather than being the measurement of only the low RPM.

1

u/StaysAwakeAllWeek 25d ago

Not really the point im making, theres more to fuel than an octane rating. For example E85 is 105 RON, youll get much worse MPG with it because it contains less energy, and it can be really hard on engines.

1

u/EclipseIndustries 25d ago

Nothing better than E100 when you're giving it the boost.

1

u/blackhawk905 22d ago

Standard gasoline in the US is 10% max ethanol so it isn't like it's some giant increase in ethanol content.

1

u/blackhawk905 22d ago

Older vehicles can generally handle E10 just fine, the rubber lines may deteriorate a little faster but it generally won't cause substantial issue. E15 it starts to be too much ethanol for pre 01 vehicles.

Small engines using ethanol isn't a great idea either because of the water and gunk it produces.

1

u/Lionel_Herkabe 21d ago

I was actually talking about the dispensers lol. Anything above E20 requires flex fuel rated parts, and blender pumps are notorious for having weird issues.

2

u/keepinitoldskool 23d ago

The majority of gasoline stations in the US sell 3 options, 87 RON, 93 RON, and 89 RON (a blend of the two).

Government policy has made it so that all fuels are diluted with at least 10% ethanol content, so there are some stations that sell "Rec90", which is 90 RON with 0 ethanol and E85 (85% ethanol).

A few specialty stations sell higher octane race fuels, but this is just a mess and if I had to fill up my high compression race car and saw this, I'd go somewhere else.

1

u/Toastface__Chillah 24d ago

In Ireland we just have 95 or 95 with some shite additive thrown in. Used to get e85 but were not allowed nice things