Bad Premiun Gas During Winter Months

[Astro14]

EPA Comments on the Gasoline Additive MMT | US EPA

EPA Comments on the Gasoline Additive Methylcyclopentadienyl manganese tricarbonyl (MMT)

www.epa.gov

MMT is allowed in U.S. gasoline at a level equivalent to 1/32 grams per gallon manganese (gpg Mn).

Since a gallon is about 3KG (close enough), 1/32g is about one part per 100,000...give or take...so, far lower concentration than TEL...

 

[Andrew1972]

I owned premium running vehicles for first 25 years of driving and never had fuel issues in 25 years.

 

[gathermewool]

I would venture a guess that most cars that recommend mid or premium grade are operated solely on 87/regular. Why? Because people are cheap and most are utterly clueless about cars. If a person buys a car new they’re likely to maintain it well and use the appropriate fuel. Subsequent owners, much less so.

Plenty of relatively mundane cars recommend mid/premium fuel (my ‘96 Maxima and ‘07 Pacifica are two examples), so this is not just the type of vehicles (BMW, Jaguars and the like) owned by folks with lots of money to burn. I highly doubt lots of premium is getting run through the cheaper cars.

Modern powertrain controls can cope with the varying octane available at our pumps quite well.

Many can, but some can't. My owner's manual says that my '14 FXT can use regular fuel, but I might experiencing knocking. No offense to anyone who wants to baby their turbo Subie to prevent detonation, but that just sounds ridiculous. Subaru can't be the only one with a relatively aggressive tune for their turbo vehicles.

With that said, Subaru has obviously figured out a way to make the FA24DIT run on regular, though I'd love to see a log of that engine on a dyno pull.

Finally, most knock schemes I would guess are always adding timing to the point of knock and then backing down. I'd hate to gun in just when that specific table has a more aggressive timing applied. Again, with that said, I also figure that modern knock sensors and predictive tuning prevent any damage from occurring, even if it sounds bad to say that an ECM is riding the knock curve.

 

[gathermewool]

EPA Comments on the Gasoline Additive MMT | US EPA

EPA Comments on the Gasoline Additive Methylcyclopentadienyl manganese tricarbonyl (MMT)

www.epa.gov

MMT is allowed in U.S. gasoline at a level equivalent to 1/32 grams per gallon manganese (gpg Mn).

Since a gallon is about 3KG (close enough), 1/32g is about one part per 100,000...give or take...so, far lower concentration than TEL...

I wonder how much of an octane boost that amount of MMT actually produces.

How much effective MMT is in Boostane? Why is anyone using race gas if this stuff is so cheap (for reasonable increases in octane, not vs straight race gas)?

Is the stuff safe, though? Why would it be limited if it's apparently so cost-effective to use? Fouling issues, pollution, etc.?

You guys can use it all you want. There are too many questions outstanding for me to ever consider it, regardless of whether their claims are true.

 

[Astro14]

I’m not certain that we have a choice in the use of MMT. It’s used by various blenders, and I couldn’t tell you which brands, or which stations, do, or do not, have it.

 

[The Critic]

Many can, but some can't. My owner's manual says that my '14 FXT can use regular fuel, but I might experiencing knocking. No offense to anyone who wants to baby their turbo Subie to prevent detonation, but that just sounds ridiculous. Subaru can't be the only one with a relatively aggressive tune for their turbo vehicles.

With that said, Subaru has obviously figured out a way to make the FA24DIT run on regular, though I'd love to see a log of that engine on a dyno pull.

Finally, most knock schemes I would guess are always adding timing to the point of knock and then backing down. I'd hate to gun in just when that specific table has a more aggressive timing applied. Again, with that said, I also figure that modern knock sensors and predictive tuning prevent any damage from occurring, even if it sounds bad to say that an ECM is riding the knock curve.

Exactly. I think one thing that folks seem to forget is that performance and economy often go hand-in-hand. If the timing is being retarded to accomodate for 87, you can expect efficiency to be compromised as well.

 

[DGXR]

As others said, I get premium from busy stations and try to use brands known for quality (mainly Chevron).
Only the Tacoma runs 87 and it happily burns just about anything.

 

[bonjo]

As far as i know modern cars have knock sensor and those running high octane (98+ RON over here) can safely run on regular (95). The discussion is about temporarily switching RON.

There are many sensors in the car other than knock sensors which provide the ECU with info which in turns controls the engine running and performance.
knocking can be caused by overheating, carbon deposits amongst other causes which includes too low octane Fuel. But we are digressing.

if one is concerned about water in the fuel, conditioners are on the market to help with this. Or so they claim. Of course if you accidentally put water in the tank, then i would drain it fully.

 

[Odd_Ball]

I miss the days of Amoco Premium Gas. 97 octane even in the lead-free era. 100+ octane in the leaded era.

 

[antonmnster]

If I'm on a road trip, I'll go with 87. I really don't trust higher octane on the interstate, and the prem price just isn't worth it. Somehow I get better mpg on 87...

 

[Shel_B]

Yes. I can’t think of a component that would add so much knock resistance with so little added. Think about how much half an ounce is, mixed with a gal of gas. That’s like 500:1 or something close.

A gallon is 128 ounces, ergo, the ratio is 256:1

 

[gathermewool]

A gallon is 128 ounces, ergo, the ratio is 256:1

Thanks for the correction

 

[wolfox03SS]

I've got a premium required road beast. Other than seasonal variations in blends, I've never realized problems.

Fueling her on regular gas is a false economy. The PCM pulls timing and overfuels the bores for thermal quenching all in the sake of preventing knock. I tried it once.

...Once.

Mileage and power completely tanked. If I continued to fuel up on regular pump gas, it would cost 1/3 more than if I just dropped 91+ gasoline in her maw.

But I can attest to customing high traffic stations. My sister unfortunately tanked up at a nowheresville station because they had lowest premium fuel prices on a gas finder app on her smarty-phone. She blasted for home in her late model Jeep Cherokee Limited HEMI and barely made it into the driveway. A tow and very expensive trip through her local FCI shop later?

More than 1/3 of her fuel tank was very intert, non-flammable H2O. A third...W.T.In.The.Actual.F?

I recommended that if she wants to drive a power dense model, just go get gas where I do 'cause mine's a super, seroiusly picky factory tune. We both now fuel up by a highway-side, high volume Shell station on V-power Nitro+.

(Not a sponsor)