Sorry, ignore the prior post, hopefully this captured the intended article.
Lawrence

Provided by Consumer Reports Location and price drive gasoline sales, according to a new survey by the American Automobile Association. But an extensive study also conducted by AAA, reveals that consumers would be wise to factor the quality of the gasoline in their purchase decision.
Using an independent engine testing lab that specializes in fuel analysis, AAA sought to answer the question: Is “Top Tier” gasoline worth the price? The short answer is yes.
What is Top Tier Gas?
Gasoline is essentially a shared commodity, often stored in common containers until it is purchased by a major retailer. After that, the retailer treats the gas with a specific additive, thereby giving the fuel its brand identity. But are these additives just a dosage of marketing hype?
Top Tier gasoline was developed in 2004 to go beyond the minimum standard for detergent additives to better protect increasingly sophisticated engines from carbon buildup and deposits on the intake valves—which can result in a rough idle, acceleration hesitation, knocking/pinging, and reduced fuel economy.
Interesting read on MSN Autos: Goof of the month: You put gas in my diesel!
Over the past 20 years, engines have become far more precise, operating under tighter tolerances and at higher compression ratios, while targeting cleaner emissions and improved fuel economy.
© Provided by Consumer Reports To achieve these goals, eight automakers—Audi, BMW, Fiat Chrysler Automobiles, General Motors, Honda, Mercedes-Benz, Toyota, and Volkswagen—have united in support of Top Tier gas, specifically recommending it to their owners with the goal of preserving their engines’ original performance and emissions over time.
Interesting read on MSN Autos: Which car additives are worth the money?
Top Tier retailers include corporate giants BP, Chevron, Exxon-Mobil, and Shell, as well a wide range of regional brands. (See a complete list of Top Tier fuel brands and retailers.)
© Provided by Consumer Reports
Gas Test Findings
For its test, the lab operated an engine continuously for 100 hours on a cycle to represent 6,400 kilometres of use. The engine was then disassembled, photographed, and its key components weighed and measured to determine the thickness of carbon deposits. Six fuels were used, randomly selected and split among three basic gasoline sources and three Top Tier.
Interesting read on MSN Autos: Want to boost your fuel economy? Stop turning left
The results showed that on average, Top Tier gasoline had 19 times fewer carbon deposits on injectors, intake valves, and in the combustion chamber when compared to regular gasoline.
AAA also found Top Tier gasoline can have a cleansing effect, reducing intake valve deposits by 45 to 72 percent when used over a 8,000-km interval. Variation in the results is attributed to the detergents used by different brands.
Further, analyzing gas prices over a 12-month period found just a three cent price difference between non-Top Tier and Top Tier gasoline.
Bottom line: For the nominal investment, this study shows that motorists would benefit from using Top Tier gasoline as their primary fuel.
Given the technological trend toward more sophisticated engines, we think the EPA should consider raising the minimum detergent standards to ensure all drivers benefit from the type of performance and longevity promised by Top Tier fuels.
Trending on MSN Autos: Imagining the cars of the future | A must-read section for car enthusiasts
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How to buy long-lasting tires
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Consumer Reports has no relationship with any advertisers on this website. Copyright © 2006-2016 Consumers

 

I would have hoped that they specify if the engine was direct injection or not and it seems they have not.
Lawrence.

 

Already thrashed in another post

https://www.jaguarforums.com/forum/s...8/#post1497416

in the S-type section but here's my 'the devil's in the detail' analysis of their findings:

That's an interesting study, thanks for posting it. I hope everyone takes the time to read it in full and then re-reads it to ensure that the essential findings are understood.

If not, here's the key points:

Long term usage of non Top Tier gas containing only the minimum amount of additives, might, in some cars, reduce mileage and power by 2-4%.

Switching to Top Tier gas might help recover some of the lost power and mileage but it will take 5000 mile of continuous use to do so, and drivers should expect only 50-75% recovery.

What this means:

Anybody who claims to note instant changes when switching to a top tier fuel has got a very active imagination.

Even long term, if we are to take the study's result as absolute proof, a typical S-type that sees nothing but top tier fuel from day 1 and averages 20 mpg would still get around 19.4 mpg if it had been fed so-called garbage fuel since day 1.

If a car was to switch from long term use of garbage fuel to long term use of top tier, the eventual difference in mpg pre/post would narrow to only .3 mpg.

Such minor changes would be virtually impossible for the average motorist to notice as typical variations from one tank to another without the owner making any changes can be as much a 2-3 mpg.

All of the above pre-supposes that there actually is garbage fuel readily available. Here in Canada, only a few retailers are Top Tier, none of which are handy to me. Am I to assume that all/some of the other brands are selling garbage? Or do they see through all the fuss and expense of the top tier scheme and just sell gas with enough additives for today's cars?

I find it interesting that Jaguar/Ford back in the day or JLR today does NOT require top tier fuels, unlike some of it's rivals. Guess they must have hired design engineers that knew what they were doing. Top tier engineers?

 

I've used Top Tier exclusively for at least 10 years now, and for port injection engines, I think the test data are compelling that the additional detergent additives in Top Tier do a better job of keeping intake and exhaust valves free of deposits. In traditional port fuel injection engines, the injectors spray fuel on the valves, which "washes" them, and the more detergent-heavy Top Tier fuels wash better.

Direct injection (DI) is a different animal, with the fuel injected directly into the cylinder, bypassing the valves, which
are not bathed in the injector fuel mist as they were previously. That coupled w/ the known valve coking issue in DI engines suggests that Top Tier is not as effective for DI engines.

There's a new standard being developed (Top Tier 3), and one of the reasons cited is the DI valve deposit problem. New oil standards are also in the works for DI engines. My fingers are crossed that they soon get handle on the issue.

 

But the data above concluded that the valve deposits from minimum additive gas only made a .6 mpg difference compared to to top tier.

There is also the point that a huge assumption is made that non-top tier fuels have inadequate levels of additives.

 

Same here, I use Shell V-Power Premium (it has no ethanol here) on all my cars - classics, Jag, even winter beater.

 

Top Tier also, fortunetly also cheapest at Costco.

 

Correct, non-Top Tier (TT) fuels may have equally effective additive packages, but the consumer doesn't necessarily know that. It just means they have not submitted their fuel to TT for testing. I'm sure many, if not most, brand-name, non-TT fuels have pretty good detergent additive packages.

Supposedly, the whole concept of TT was to provide a way for the consumer to obtain fuel they know was approved by manufacturers.

 

Just because it's a Top Tier (TT) fuel doesn't mean it doesn't have ethanol. It's virtually impossible to buy non-ethanol fuel in any major metropolitan area of the U.S. If you can find it, it won't be a TT fuel.

 

Correct. There's no connection between top tier and ethanol content at all.

 

In Canada its a lot easier to obtain non-ethanol fuel, for instance the previously mentioned Shell 91 advertises no ethanol. Some others do too, for instance I believe Ultramar does, yet they don't seem to be Top Tier.

Anyway, I thought the article was interesting in that at least an apparently reputable testing outfit went through a procedure to test the difference. If the car owner wants to be sure and use the 'apparent' best that is available, at least the testing shows some advantage... although the issue of a direct injection engine was not covered from what I read.

Your note concerning a new and higher level of Top Tier will be interesting to see what advantage it may have, if any and your comment on the oil would seem to indicate the best hope yet for direct injection.
Lawrence

 

Relatively few retailers in Canada (and obviously none outside of North America are Top Tier). Yet our cars run marvellously well.

There's little reason for a retailer to go cheap on additives given that it's pennies per litre. If a brand were to cut corners and someone 'spilled the beans' or if motorists started having trouble, the company would be dead in short order with no possibility of recovery.

I think that in general we're too attuned to believing advertising hype and mistaking for hard technical fact. I've sampled just about every beer on the market and find that there's little correlation with how many half-naked super models show up at my pool parties. This flies in the face of the TV adverts.

 

This could translate to millions when you consider how much they move.


Long history of various oil spills, most of them due to negligence, doesn't support your theory.

 

Dead birds in the ocean is very different than Joe Average's car not running well.

 

Just in case there is interest here is a list of top tier. note costco is top tier this was raised in the past. Retailers

 

In las vegas ethanol year round, just more or less by season.