BC

E10 will have no or little effect on the fuel system of the 928 over the long range time frame. There is no Fuel in the united states that I have seen in all my travels is all E10 at least.

The result from E10 will be a 40% reduction in the gas mileage for that 10% of the fuel. I can't/won't do that math for that, but there it is.

928 at last

Who you callin' impudent?

RKD in OKC

Had a 76 914 2.0 back in 1988. Local Texaco had an ethanol gas, used one tank and had to replace ALL FOUR injectors. The seals were ate up by the ethanol. After I sold the car the new owner ran the Texaco gas, within 3 months the car had a fire from a fuel leak and burned to the ground. I personally try NOT to use any ethanol in my older cars if possible. Rubber seals disappearing can cause more than just a maintenance issue.

My question is that if ethanol has better emissions, but in a mix with gasoline gets less mileage, isn't the overall bad emissions the same?

Vilhuer

Same thing in Finland. 95E10 replaced earlier 95E5 in January 1st. Many people moved to use 98E5 which is still available and its consumption more than doubled. Doesn't make much difference in late MY 928 as they need 98 anyway. E10 and E5 are upper limits so no one really knows actual mix at the pump. Considering minimal price difference and slightly better fuel economy of 98 there really is no point in using 95 in any car.

BC

Again. Ethanol is not an acid, it does not rob your pantry, it is not methanol, and it does not cause warts on your *****. It SOFTENS natural rubber and similar materials like most plastics. At that point, the seals may not work as well as intended. It does not dissolve anything but will soften and remove some resins (such as the resins in JB weld for instance).

It would be helpful for those that actually wish to learn the difference between fact and lore to read the technical papers on what GM and Ford HAD to chance to run E85 and what they did not have to change.

RKD in OKC

Wouldn't have done me a bit of good to read any reports or technical data as I have no idea what material those green rings sealing the Bosch injectors on my 914 were. In fact, I have no idea what any of the materials used were and or even if those same materials are used in later than 76 or after gasohol was introduced. All I do know is at that time the use of the old Texaco "Gasohol", as they called it, caused the Bosch injectors to start leaking. The local Porsche mechanics also warned their customers off the stuff as they saw a huge increase in injector leaks after the gasohol was introduced. And they were recommending pre-gasohol Texaco as a quality gas to try when owners complained of loss of power and hesitation. I didn't have any other ill effects the 2 years after that incident that I owned the car. Could have been the new Bosch injectors, replaced some 12 years after the car was made had a different material o-ring. However, I still avoided using gasahol.

I work for a company that makes pumps and valves used in petroleum production and in the last 20-30 years there have been a lot of materials changes for seals, gaskets, diaphragms, and o-rings. Some of the materials that were used 20 years ago are no longer even available.

GlenL

This is wrong. It also depends on the vehicle. The fact is that ethanol has, per unit volume, 1/2 the power content of pure gasoline. So a 10% mixture still has 95% of the energy and you should expect a 5% drop in economy.

People may report huge variances but most people don't do good science. It'll be something like "I measured my economy with a tank of ethanol and I'm 40% down from the EPA rating." Never mind they were driving cross-country at 75 MPH and hadn't benchmarked with a tank of straight gas.


Oh. I'm a logical engineer when I'm getting paid and chronically illogical about my 928.

Leon Speed

I didn't do any research into all this, but if Porsche says it's all models as of MY 1997 can use E10, I'm staying on the safe side and will not use it.

Fabio421

Brendan, how long did you have your fuel tank filled with E85? I have had a piece of fuel tank submerged in E85 for 1 1/2 months so far and it has not softened or lost any color to the E85. It is still as it was when I put it in the E85.

Fabio421

Another month has gone by and my test fuel tank is still intact. It has not softened one little bit. With gasoline prices skyrocketing, E85 may be a viable alternative for more people.

wildguy

just my 1.5 cents
The rubber fuel lines on the 928 are the problem. They should be replaced with Ethanol compliant rubber or hard lines.
I've tuned many street and race cars with E85-E100. Mostly all turbo cars. On the turbo cars there was an increase of 25-30% fuel trims. Again, all the rubber lines were replaced with proper rubber lines.
ATL fuel cell company states to not use any more than 10% in their fuel cells unless they are specifically for ALKY.

Fabio421

Yes, the flexible fuel lines need to be replaced with Viton lined hoses with a suitable pressure rating. The big question was whether or not our stock fuel tanks would be OK when using the E85. Some of the 951 ( 944 Turbo ) guys have been using E85 for as long as 2 years so far with no ill effects but I wanted to test our tanks seperately to be safe. So far, so good after 2 1/2 months.

dr bob

The original tanks are high density, high molecular weight linear polyethylene, and should be fine with ethanol blends. That's the tank itself. No telling how well the fitting o-rings and hose connections will do.

Truth is that most 'test cases' for what works with ethanol are forensic investigations into burned-down vehicles. Deciding what leaked first, what caught fire first, all from a pile of smoldering scrap and melted aluminum, must be some mystical art. In the meanwhile, what they put in the fuel in Cali is more than what I like to see in the car. "Up to 10%" is giving way to "up to 15%" thanks to the lobbying efforts of the big corn processors like ADM. I can see a pretty linear reduction in fuel consumption with the incraese in ethanol content, so while it might make emissions sense on a per-gallon basis or maybe even a per-pound basis, no way is it justified on a per-mile basis.

BC

I did not see this post, so I apologize for the late response. The Tank that I tested was from my 78. I will have to find my posts from then, but I also had conversations with people in private emails. The effect that the E-85 had on the tank was to soften area around the outlet pipe so much so that it caused the threads to come out very easily when I attempted to remove the strainer.

Now - this is one test, and indeed sort of an incomplete one. I mean, who the hell am I, where the hell did the tank come from, and were there proceeding issues that should cause anyone reading this to disregard the test? Probably.

I feel as though it was tested proof that the ethanol will SOFTEN the plastic. Meaning it will not hold its shape in the currently stiff manner. So pressure or vacuum will deform it more. I do not believe I made any statements that it would dissolve the plastic - if I did, I do not recall that. I will have to recheck my notes.

I DO know, without having to "feel" it, that ethanol dissolves most any glue, resin, or multi-part chemically activated substrate. So if the plastic was not structurally affected by the ethanol, anything that is keeping the threads in the plastic will dissolve if the ethanol gets in there - if there is glue.

I have also tested ethanol on aluminum, paint (unhardened), JB weld, and un-coated steel, and rubber hose.

I have also done what now amounts to years of research on this wonderful fuel. What does that mean? That I know very little, but a hell of a lot more than I did originally. My fuel system is the outcome of this - as is my engine parameters. The fuel lines are SS hardline, the aluminum is anodized, and the softline is teflon coated. The fuel pumps are Fuelab, and the filters are SS.

Maybe I have helped, maybe I haven't.

BC

I hope so. I hope my test was an anomaly. And I am completely pro- ethanol, and it would be nice to just hook up an ethanol friendly FP and FF and run-what-you-brung.

I have questions about the coating on the inside of the aluminum fuel lines under the car.