i can’t be the only one who runs regular in a GT right?

[ice445]

Or if your in California and no matter what you do the bloody pump wont dispense so you assume the pump is broken and try another one and keep doing that until the cashier shouts over the tannoy you need to ensure the rubber vapor cover is fully engaged. The what now? Look down at pump handle and realize that the rubber boot around the nozzle is meant to cover the gas cap and when fully compressed releases the gas.

That happened to me when I went to California this summer. Was pretty embarassing once it was pointed out to me, lmao

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[bootlegger]

Off topic but I don't see how there can be a true equivalency chart like that.

The R in the US formula and RON in Euro ratings are "Research Octane Number".

There would be no point in doing motor (the M in the US formula) testing if you could just multiply the RON you already tested by .95x to get the same number as doing a completely different Motor test and then averaging them.

If such a ratio exists it only could if the fuels labeled by RON is refined in a common way that also resulted in the same M. But there is no doubt that different gas with a RON of x could have a different M. That was the entire reason for coming up with (R+N)/2! Therefore, there cannot be a true formula or even a table equating a RON value to a specific (R+M)/2 value.

So, I suspect those charts assume a common refining process that just happens to come close to a .95x ratio.

The chart uses an average that is generally understood in the industry. After decades of testing millions of samples of fuel, they have a pretty good feel on what relationship RON and MON have to each other. The point of testing MON is really to get more precision, but the + in every octane rating means that precision isn't as important. The oil companies use a factor of safety to make sure they aren't responsible for engines popping.

 

[sk47]

Hello; Interesting. If such never crosses the mind how do you know what fuel to use?

 

[331GT]

not sure about him, but it you're a bit suspicious ...

 

[FinitePrimus]

My question.. is there any benefit to running 94 on a stock Gen 3 vs. 91.
I've been putting 94 since I purchased but with the price of gas, I question if I should switch down to 91 (especially if it's just being wasted based on the stock tune)

 

[ICU812]

Perfectly fine with the Mustang, I'm tryna explain other things, that some here no comprende on.

No you are not, you just want to argue, nothing more.
Everyone understands when and if they track the car or are going to push it at an event that running 87 isn't ideal.
But to claim it'll harm the engine under normal use , even under the load of passing another car is well, ignorant .

 

[sk47]

My question.. is there any benefit to running 94 on a stock Gen 3 vs. 91.
I've been putting 94 since I purchased but with the price of gas, I question if I should switch down to 91 (especially if it's just being wasted based on the stock tune)

Hello; My take before getting involved in this thread is for ordinary non-racing or non-performance driving is you can use the lowest octane fuel mix your car is rated for. If you have a tune or some sort of boost or some other modification that will affect things, then you likely will need to up the octane.
I will add the potential for carbon build up in the combustion chamber over miles as a potential factor. The old carbs and port fuel injection would wash the intake valves with fuel and sort of keep them clean. With direct injection (DI) the intake valves only flow air.
Back in the carb engine days I did two things to help deal with carbon build up. One was to run the engine hard from time to time. The other was risky but seemed to work. With a warm engine running at fast idle I would drip water directly into the carb. Had to be careful to use only very small amounts of water. (by drips, I do mean drips a little at a time.) The idea is water expands to 1700 or so times its volume as it turns to steam (same thing that pops popcorn). The small amounts of steam was supposed to break off some carbon build up. I sometime just ran hard on a rainy day hoping the high humidity might help. Well, any excuse to run hard worked for me in my youth. Now there are carbon cleaners you can use that do the same thing.

I did not forget the question this time. So, at 91 octane you are well above the base 87 for a Mustang. Should be good. If you are still on the fence about it fill up from 1/2 a tank with 87 one time and next time do 1/2 a tank of 91. For normal driving with an engine rate for 87, you should be more than safe with 91 and safe with the 87.

 

[m3incorp]

I highly doubted there is any advantage if you are doing normal street driving and no engine mods.

For those that read over this too fast.....poster isn't asking anything about 87 vs 91.

My question.. is there any benefit to running 94 on a stock Gen 3 vs. 91.
I've been putting 94 since I purchased but with the price of gas, I question if I should switch down to 91 (especially if it's just being wasted based on the stock tune)

 

[sk47]

I highly doubted there is any advantage if you are doing normal street driving and no engine mods.

For those that read over this too fast.....poster isn't asking anything about 87 vs 91.

Hello; I understood. The extra comments are added at no charge.

 

[jwt]

I assumed that 94 would let timing advance further than 91 and thus give you potentially more power at high load high temperature applications. However given your location you probably mean PetroCanada 94 which gets most of its octane boost from additional ethanol so is the marginal increase in power on timing alone from 91 to 94 worth the marginal decrease in (per volume) loss in power from added ethanol?

I know you can get more power from ethanol but it presupposes you have mapped increased fuel delivery and I don't know if the Gen 3 recognizes added ethanol and adapts accordingly.

TL;DR I don't know, interested to hear opinions myself.

 

[ICU812]

Still ? Go home a fuq your wife instead of trying to mount me from behind all the time.

WTF.
Hit a nerve I see.

 

[velocityblue5.0]

Gentlemen, gentlemen…please! Didn’t think I’d start so much drama with my thread at least i put 89 in yesterday…..

 

[DougS550]

Top Tier ≠ Octane rating

Besides the engine being a high performance engine, higher octane usually means a cleaner burn, less carbon build up, increase in gas mileage, and I would assume higher RPM HP achieved due to the slower burn of the higher Octane. Yep, I do and always use the highest pump rated octane each time I filly car.

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