E85 questions

[Eclipsed]

I searched and couldn't find any posts relating to E85. We got a new station in town and is selling E85 for 1.50 a gallon. I've heard E85 is around 105 octane and obviously cheaper then gas, but you do burn it twice as fast (and it burns much hotter then standard gas). But I've also heard you need to upgrade your fuel system to handle it. So I guess my question is, is it harmful to a stock engine to run E85?

 

[Honcho]

Most engines by the major manufacturers are tested to safely use up to 10% Ethanol (E10) in the gasoline blend. The major issue with higher blends like E85 is that the alcohol can damage rubber seals and certain aluminum alloys in the engine fuel system that were not designed for Ethanol. There was an earlier thread on Prime from a few months back that noted the NSX engine was designed prior to the widespread use of E85 or E10, so it is unknown what effect Ethanol will have on the fuel system internals. It's a pretty safe bet however that E85 will ruin the system. E10 may also have ill effects too, but it's just not really known how sensitive the fuel system is to Ethanol.

Edit: Also, using 105 octane probably won't do anything for you in terms of performance. To take advantage of the higher octane, you would have to increase your compression and/or re-tune your ECU to realize any meaningful gains.

 

[nsxotic911]

Ethanol (or at least E10) suxors..... you get an automatic 10% reduction in mpg, has resulted in thousands of not millions of people going to into starvation, contributed a lot more to global warming and is one of the dumbest, dumbest ideas that politicans and enviromental loonies have thought of - in a very long time.

Sadly, the industry and government is so married to it, that this will continue for quite some time.


Truly stupid.

 

[N Spec]

Ethanol (or at least E10) suxors..... you get an automatic 10% reduction in mpg, has resulted in thousands of not millions of people going to into starvation, contributed a lot more to global warming and is one of the dumbest, dumbest ideas that politicans and enviromental loonies have thought of - in a very long time.

Sadly, the industry and government is so married to it, that this will continue for quite some time.


Truly stupid.

Agreed, it's pretty sad.

 

[Eclipsed]

Thanks for the input guys, I'm getting most of my info on E85 from the domestic guys here at the track. They all swear by it. But cast iron push rod carbed V8's are completely different then the nsx.

Thanks again!

 

[greenberet]

I agree with everything Honcho wrote above and won't be putting E85 into my NSX for exactly those reasons. Here’s the thread he mentioned - “The official E85 thread”: http://www.nsxprime.com/forums/showthread.php?t=105362

Ethanol (or at least E10) suxors..... you get an automatic 10% reduction in mpg, has resulted in thousands of not millions of people going to into starvation, contributed a lot more to global warming and is one of the dumbest, dumbest ideas that politicans and enviromental loonies have thought of - in a very long time.

nsxotic911, man:

1) If a 10% ethanol blend (E10) gets you a 10% reduction in mpg, the ethanol in the fuel must not be contributing to combustion at all, right? The gasoline must be doing all the work and the 10% ethanol is just along for the ride, watering it down. However, that’s not the case. Ethanol is an alcohol that does burn. The energy content of ethanol is only 2/3 that of gasoline (21 MJ instead of 32 MJ per liter), so you will need more fuel to do the same amount of work. But a 10% ethanol blend will cause a 3.3% reduction in mpg, not 10%.

2) Ethanol has caused thousands or millions of people to go into starvation? Since 1961, the world’s population has increased by 113%. World agricultural production has increased by 180%. We are producing 32% more agricultural products per person today than we did in 1961. In 2007, about 1% of the world’s agricultural production went into biofuels. That still leaves 31% more food per person than there was in 1961. If people are starving, it’s because of bad distribution.

If it’s high prices causing people not to be able to afford food, there was a price spike in agricultural commodities in 1995 that was just as bad as the 2008 spike, and there were no significant volumes of biofuels on the market causing that. In 1973, the price spike was twice as high (in inflation-adjusted terms) and there were no biofuels back then, either. There have always been price spikes in agricultural commodities and blaming the most recent spike only on biofuels is ignoring the effect droughts, financial speculators trying to get out of mortgage-backed securities, etc. had in causing the 2008 spike.

3) Ethanol causes global warming? The ongoing production of ethanol reduces greenhouse gas emissions, regardless whether you make it from corn, wheat, sugar cane, etc. However, if you need to clear land to produce it, you will get a one-time CO2 release that may take years of ongoing savings to make up for again. In North America and even more so in Europe, we’ve cut down lots of forests and put the till to large areas of former prairie. Since we’ve been producing agricultural products on that land for a long time, we’ve made up for the one-time CO2 release. If we don’t allow third-world countries to do the same thing, we will be increasing global warming in the long run and more importantly, we will prevent them from developing as we have.

Edit: Regarding economics, it costs more to produce ethanol from American corn or European wheat than it does to produce gasoline from Middle Eastern crude. We’re so far away from the equator that it’s relatively cold and dark and plants just don’t grow that efficiently here. To have North American and European ethanol industries, you currently need subsidies and government regulation. In Brazil on the other hand, sugar cane grows so well that it’s cheaper to produce ethanol there than gasoline. If North America and Europe would allow Brazil to export its ethanol to our markets, not only would it not need any subsidies, it would actually reduce the price of gas at the pump. But government interference is preventing that from happening. Now whether our governments should be interfering in the hope that “next generation” North American and European biofuels will actually be cost competitive is a tough question to answer.

 

[David]

E85 makes LESS power than gasoline per unit. If you will not see a significant benefit from taking advantage of the increased octane (very high compression or boost) you will make less power. Period.

 

[greenberet]

If you will not see a significant benefit from taking advantage of the increased octane (very high compression or boost) you will make less power. Period.

Why? E85 has less energy per gallon than straight gasoline, so you need to inject more of it. If you inject enough of it, why will horsepower go down?

 

[Gman]

I have noticed a major drop in MPG in the past 3-4 years in all of my cars whenever they started adding Ethanol. As far as any "other" issues...I don't know and don't care, but my MPG loss is way more than 3.3%.

 

[N Spec]

I have noticed a major drop in MPG in the past 3-4 years in all of my cars whenever they started adding Ethanol. As far as any "other" issues...I don't know and don't care, but my MPG loss is way more than 3.3%.

Just a broad guess, but the 3.3% probably gets exponential for inner city driving or for lower gears?

Either way, it's a damn shame than ethanol is so fruitless given the measures to create it. I really would rather just see electric cars for daily commutes.

 

[David]

Why? E85 has less energy per gallon than straight gasoline, so you need to inject more of it. If you inject enough of it, why will horsepower go down?

If you just inject more gas do you make more power? Of course not.

 

[flyeyes]

My experience running E85 in a standard nonperformance vehicle was that it neted around the same, but not more on the mpg avg., as 87 octane gasoline. This was on a full tank in my '06 F150, traveling strictly highway with the cruise set at 70mph. This was on a trip from Chicago to St. Louis.

While I know that the mph avg was higher than a more desirable 60mph speed to help increase mpg. I found that once I refueled with regular 87 octane gasoline, that the mpg were nearly the same.

Not sure if this helped the discussion toward fueling an NSX with this fuel type. My $.02 on the matter, is that I would NOT consider this E85 for use in my NSX...... EVER.:tongue:

 

[theman1990]

I track my MPG religously, and I get about a 10% reduction in it when I use ethanol subsidized fuel.

While yes the "3.3% power difference" = 3.3% mpg difference sounds great on paper, the reality is it's worse... In the Apache you could go just a little bit faster at 100% power compared to 85% power. The 15% power difference did NOT = a 15% performance difference. I realize that in the bird it's an aerodynamic thing, but I'd venture to say that in cars there is a similar mechanism at work.

 

[greenberet]

If you look around, some people report slight increases in mpg with E10, some report no change (like flyeyes above - with E85 ) and most report decreases when they fuel their cars with ethanol blends.

Chemically, ethanol is a hydrocarbon with built-in oxygen. It’s like gasoline in which 1/3 of the molecular weight has been replaced with something that doesn’t burn. That’s the reason it has 1/3 less energy per gallon. If you burn 1 gallon of ethanol, it will produce 1/3 less heat than burning 1 gallon of gasoline would. Burning 1.5 gallons of ethanol gives off as much heat as burning 1 gallon of gasoline.

The oxygen in ethanol isn’t just dead weight, though. The oxygen content means that ethanol doesn’t need to get as much oxygen from the atmosphere for it to burn. The ideal air/fuel ratio with ethanol is around 9:1 – about 40% less than with gasoline. If your engine is inhaling a given amount of air, you should inject more ethanol than you would gasoline for it to burn efficiently. The engine needs to run richer on ethanol.

Since the stoichiometric ratio is about 40% lower with ethanol but the energy content is only about 33% lower, for a given amount of air your engine is inhaling, you can make a bit more power if you inject enough ethanol. For that to work though, you need to reprogram your targeted air/fuel ratio, your fuel injection system needs to be capable of delivering the increased flow, and your engine shouldn’t corrode or leak when exposed to ethanol. In addition, since ethanol has a higher octane rating than gasoline, you can make mechanical changes to the engine as well. You can run a higher compression ratio and thereby convert a larger proportion of the energy in the fuel into horsepower. Those factors together allow Koenigsegg’s ethanol-powered CCXR to produce 26% more horsepower than its gasoline-powered CCX but also cause it to use about 30% more fuel.

At pumps, you can get E10 a lot more often than E85 or E100. With E10, you’re reducing the energy value of the fuel by 3.3% per gallon by increasing the oxygen content. If you don’t reprogram your engine management computer to take the different properties of E10 into account, you will effectively be leaning out your air/fuel ratio a bit. Maybe that’s why some cars react favorably to E10 and others don’t. Maybe it depends how exactly the engine management computer was programmed in the first place.

In addition to the different energy content and corrosive properties of ethanol, it’s a better solvent than gasoline. If there’s crud in the gas tank, ethanol will do a good job flushing it out. If you’ve been running straight gasoline for a while and then switch to an ethanol mix, that may flush crud into your fuel filter or injectors, also impacting fuel economy.

In summary, E10 should reduce an engine’s fuel efficiency by 3.3% if the engine management computer was programmed perfectly for straight gasoline before and was then perfectly reprogrammed for E10. If the engine management computer wasn’t programmed perfectly to begin with, results may vary.

 

[Vega$ NSX]

If your car is boosted, you can take advantage of the high octane rating of E85 and go to boost levels unattainable with standard 91 or 93 octane. Many performance racers are switching to E85 and cranking out huge boost and power levels. The E85 also seems to have a very slight cooling effect, similar to water/meth injection. However, they also have to increase the size of their fuel injectors to rediculous levels and the resulting fuel consumption goes up insanely. Basically they are just flooding the crap out of the cylinder. They also have to tune the bejesus out of the ECU to manage the system to take advantage of the fuel system.

However, this has no bearing if you have a standard NA NSX and E85 will not benefit you in any way. It probably won't destroy the engine for a couple takes or two, but it's not something I would recommend running on for an extended amount of time.