samk

Are Porshes built to Flexible Fuel Standards? What are the long term effects on non FFV standard Porsches?

Also from CR:

"FFVs use special fuel tanks, lines, and pumps designed to be more corrosion resistant. Their emissions systems are also specially designed to recognize and compensate for higher blends of ethanol. Making cars E85-compatible costs automakers about $200 per car, according to some estimates. Therefore, engineering a car to run on E85 costs much less than building it to operate on other alternative fuels, such as diesel. "

Also:

"This chart shows how our 2007 FFV Chevrolet Tahoe performed while running on E85 and gasoline in three fuel-economy tests and overall, in four acceleration tests, and in three emissions tests for gasoline vehicles.

E85 GASOLINE
Fuel economy, mpg
City 7 9
Highway 15 21
150-mile trip 13 18
Overall 10 14"

Ubermensch

Sam, I think you're confusing E85 which is used in FFV and gasoline with ethanol added which is sold at nearly all gas stations. One is 85% ethanol and the other is 10%. The statements you're quoting from CR all refer to E85 (85% mixtures). While it's certainly your choice if you want to ensure no ethanol gets into your car, from a technical standpoint I don't think you have anything to worry about.

samk

I stand corrected, but I am only concerned with the long term effects, whether 10% or 15%, on my fuel system.

Sam

No HTwo O

I buy 93 octane pure gas (no ethanol) very easily at many spots in Wisconsin (Janesville), and a few in north central Illinois (LaSalle Peru).

BruceP

Jealous. Nobody sells ethanol-free gasoline above 91 octane around here.

I avoid ethanol like the plague, even in my truck.

Macster

Not sure there is any residue. I have at my feet a fuel pump out of my 02 Boxster that was in the fuel tank and immersed in gasoline (most of the time) with most of the time with some ethanol in it for over 200K miles and save the housing plastic of the old pump is a bit yellower than the new fuel pump's housing, the pump shows no signs of having been affected by anything in the gas.

Ethanol in gas is only going to increase -- EPA I believe just approved higher levels of ethanol in gas for cars from 2001 to 2006 cars with levels up to 15% up from the current limit of 10%.

Last fall the EPA approved 15% ethanol for cars made in 2007 and newer.

Gotta love the corn lobby!

Anyhow, buy a name brand premium gasoline, ethanol free if you can find it but regardless a name brand premium gasoline, from a busy station and worry about about something else besides ethanol residue.

Sincerely,

Macster.

tgt40

I thought the hygroscopic nature of ethanol was the major concern?

RollingArt

You're right tgt. Ethanol's hygroscopic property, and thus corrosion in the fuel system, is the concern. Residue is a non issue.

I'm hearing of a possible increase in fuel injector issues in recent months. Leaky injectors. Not a lot of them, but a few.. This is just my own hypothesis at work. Hearing of injection issues and thinking,, could it be the ethanol? Has anyone else seen injectors gone bad recently?




Phil

Macster

Maybe if the tank is filled with gas with ethanol and the car allowed to sit unused for God only knows how long.

The gas tank is not vented to atmosphere in any case thus the exposure to humidty and moisture is limited. Then the primary issue is not moisture build up but stratification of the ethanol and gasoline.

My 02 Boxster with 238K miles (assuming 25mpg on average fuel consumption) has been through roughly 9520 gallons of gasoline almost all of it with either MTBE or ethanol blended gasoline and the only fuel system component that has needed any attention is the fuel pump which quit working at some miles over 200K.

Original injectors, fuel lines, tank, etc are working just fine.

BTW, this 02 Boxster is 1st MY that does not have an inline fuel filter either.

The fuel filter is a very fine mesh part of the fuel pump's housing. The pump attaches to the bottom of the tank and the mesh that is the fuel pump intake is just a tiny distance above the tank's bottom.

The Porsche tech that handled the fuel pump R&R told me he saw no signs of any water in the tank, the tank bottom was quite clean. The fuel pump filter mesh had some debris in it but not much and there was plenty of mesh left free of any debris to allow unrestricted fuel flow.

As an aside, the mandate to use ethanol in gasoline is primarily a wealth re-distribution program to take money from the high gasoline consumption states (mainly located on the coasts) and distribute this money to some mid-western states.

Ethanol is not a good replacement for gasoline for several reasons but its attraction for water is not a sufficient enough problem to spend any time worrying about it.

Might add fuel system components like any other in the car, can quit working at any time, but for many owners these component failures occur early in the car's life rather than later, unless the car is owned/operated for a long long time.

I'm sure sometimes the blame gets assigned to the fuel, its load of ethanol, when almost certainly the real reason is just the natural occurence of infant death, that is a new part/component has a higher chance of failure shortly after it is put into service than later on.

Once an item/component has been in service for a while and the weak/marginal components have been eliminated through well this infant death syndrome then the remaining ones can and do last for a long long time.

At some point, of course, if the car is kept in service, old age then starts to extract its toll on these components.

Wear from abrasives (particles) in the fuel, or another type of wear that arises from deposits that form from time to time and then come loose which in doing so almost always has the deposit taking a bit of the base metal/material to which it was attached away with it.

Then there is corrosion which weakens the injectors' base material and makes abrasive wear more likely, or contributes to the wear from deposits forming and coming loose, to just the wear that comes from the violence of the fuel flowing past the injector tip/nozzle and the action of the fuel injector pintle that opens/closes each injector pulse.

This corrosion arises from of course any corrosive effects of the fuel, its refinery added additives, or aftermarket (driver/operator added) additives, or the break down of the fuel additives intended to fight corrosion which allow other things in the fuel to attack the fuel system components.

But by using a name brand gasoline, buying from a busy station, and treating the car to reasonable and regular use ethanol just doesn't seem to be a factor in young (or mature) fuel system component failure.

But if someone is intending to let the car sit longs periods of time between uses and subject the car to short trips (which subjects the injectors to increased deposit formation from the heat soak cycles that are followed by too brief periods of running that do not remove these deposits) then it might be worthwhile seeking to avoid using gas with ethanol in it (still mainly due to stratification issues). But in this case treating the gas to some aftermarket additive that has been proven to forestall the breakdown of gasoline over time and lessen the impact this has on the fuel system conponents, might help.

Or arranging to just drive the car more often might help too. And be a lot more fun than playing automobile garage chemist.

Sincerely,

Macster.

RollingArt

A filled gas tank has no air in it. Air is where the moisture comes from. A tank with two gallons in it and a large quantity of air is the problem scenario. Keep your stored cars' gas tank full to avoid moisture in the tank.

Never, ever, heard of a problem of the ethanol and gas separating. If it did I imagine that it would be remixed in about 100 yds. of driving.

The hygroscopic properties and possible non compatibility with fuel system components is the problem, not stratification. Stratification could possibly be a problem if you allow the car to sit idle for months on end. We're talking about daily drivers here, not unused garage queens.




Phil