Chris(MA)

Hey folks, so it looks like next year whether we like it or not US gasoline will be 15% ethanol. Will our 996's run ok on this or is there something we can do to prepare them for it?

wyovino

You gotta keep the lobbyists happy.

strathconaman

Charles at LN has an article where he recommends running "fuel treatment" every 2nd tank (!) for cars pre-2006. Otherwise he recommends upgrading the fuel system (injectors, fuel lines) for parts that are engineered for E10 or E15. Other than that he recommends running non-ethanol blended fuel. I personally try to use unicorn blood whenever I can get my hands on it.

I have thought of changing my injectors. Warehouse33.net has them at a very reasonable price, but are they rated for E10 or E15? Who knows? And then there is this:

https://www.bellperformance.com/blog...ector-problems

I am 90% sure that I could to a Tesla swap easier than sorting out all the issues with these motors.

e90steve

Would it be better to run ethanol free 90 or ethanol 10% 93?

peterp

I'm not an expert, but my understanding is that ethanol free is ALWAYS better than ethanol blend. Ethanol produces less power and less efficiency, so you typically get slightly worse performance and slightly worse gas mileage when ethanol blend is used. Sadly, ethanol free is practically unobtanium in NJ.

e90steve

Yeah the question is it better to run a lower octane that is ethanol free or a higher octane that has ethanol. I have access to the ethanol free but only at 90 octane. I believe the manual recommends 91 or higher.

peterp

Sorry -- missed the "90" in your question. My gut opinion is that 90 pure gas would run better since it's so close to the 91 required, but I guess you'd have to make sure the 996 knock sensor works well enough to ensure there is no early detonation (pinging) since that could be damaging to the engine over time.

jhbrennan

Ethanol blend will increase the octane
which may increase performance but you're right, it is much less efficient when it comes to gas mileage. I had an E85 truck that ran extremely will using E85 except gas mileage was at least 25% less (18 mpg to 13 mpg)

Splitting Atoms

Ethanol has almost exactly two thirds the BTUs of energy that gasoline has. There are two problems with burning it. The first is that the blended fuel with a higher percentage of ethanol will run leaner given an equal volume. The second is that ethanol can degrade plastic and rubber parts, such as the o-rings in fuel injectors.

I should also add that burning corn ethanol is one of the most stupid policies we have. We are basically burning food in a process that is a net energy loss. If I was king of the US of A, it would be the first thing I would change, although I would probably have to change out a bunch of senators and representatives to be able to do it.

peterp

Agreed that Ethanol increases octane, but as long as you have enough octane for a particular car, excess octane doesn't really help it run any better. You just need enough octane to prevent early detonation, beyond that the car runs the same no matter how high the octane is. In theory, lower octane should actually run "better" in cars that don't require high octane because low octane fuel is easier to combust than high octane fuel, though you probably wouldn't feel much/any difference in actual application.

-- that's a hell of a drop!

Good to know we are all making some corn farmers happy. That's what really matters .

Splitting Atoms

[QUOTE=peterp;15349033]Agreed that Ethanol increases octane, but as long as you have enough octane for a particular car, excess octane doesn't really help it run any better. You just need enough octane to prevent early detonation, beyond that the car runs the same no matter how high the octane is. In theory, lower octane should actually run "better" in cars that don't require high octane because low octane fuel is easier to combust than high octane fuel, though you probably wouldn't feel much/any difference in actual application.

Ethanol molecules contain more oxygen atoms, therefore you can have higher octane while also running leaner for a given volume. I remember reading that some of the Indy car teams were upset at first when they were told they would be running "green" ethanol fuel. They quickly realized they could get more power when running ethanol, they just needed to burn more of it. Larger fuel injectors, higher capacity fuel pumps, bigger fuel lines, etc. It's kind of like a junior version of nitromethane. We could get more power out of our 996s running pure ethanol, but it would take a lot of modifications to be able to do it.

docmirror

A few thoughts, most important stuff has already been covered well.

Ethanol adapting for 15% from the 0% which these cars were designed for has to take into account the entire fuel system. From the gas cap seal, all the way to the cats. Ethanol isn't 'good' for any part of it(for lack of a more scientific POV). Because component parts of a car are made from many vendors, and are subject to interpretation of the requirements of the mfg materials, it's possible to have a failure due to Ethanol anywhere along the way. I have seen several Bosch fuel pumps with the internal plastic impellers softened or ballooned out due to Ethanol blending with one or more of the natural rubbers used in the chemistry of the parts. I've also seen lines fail, and like I mentioned the gas cap seal has come in for some failure too. This is not to mention the AOS which is misnamed as an 'air - OIL separator' when it is really a crankcase vapor - crankcase fluid separator, where some of the constituents of the crankcase products of combustion contain elements of the fuel that has gotten past the rings, and valve seals. So, the products of combustion that go back into the crankcase are a mix of oil and fuel, and then the fuel is boiled off as long as the car is driven long enough.

I try to avoid Ethanol in older cars. and 15% mix is something I would avoid whenever possible. The cars have a knock detector that will change the engine parameters to avoid knock due to lower octane.

Quaz

Strictly speaking from a performance car perspective E15, could increase the performance of a 996 given a proper tune. Yes plastic and rubber parts not intended for it could fail prematurely. Blah Blah Blah That being said, E10 is what we already use in most parts of the country and it hasn't killed any cars yet. E10 was introduced in the early 90s in the highest smog areas. The 996 was produced at a time when this fuel was a requirement for the US market, so everything in it should function just fine. If a tuner could create a tune to take advantage of the higher octane and oxygen content there is probably another 10% of power in there, but gas mileage will suffer. All of the 1/4 mile guys have known about this for years and usually put a 1/8 tank of E85 in to a full tank of E10 for a E20ish blend. In a turbo charged car it allows the car to maintain higher boost longer even with a heat soaked intercooler. In most cases it can gain a couple tenths without any tuning at all. If you are worried about your 996 it will be fine, but probably just get worse gas mileage with no tune. On a warm day it will also run a little cooler with less chance of knock. Downside is it just costs us all more money :-(

sasilverbullet

Just curious, where do you get the data to support this?

Splitting Atoms

It's on the front page of Yahoo News right now. Actually, it would allow retailers to sell E15 gas, but there is apparently a tax incentive for the major retailers to do so.