E85 & 91 octane gas engine build.

[ScubaSteve]

E85 & 91 octane gas engine build.

I'm looking to build a modest 454 BBC that will run E85 for my 18ft Tahiti Jet Boat. The river area I frequent in Arizona has E85 readily available, and while it may or may not be cost effective to run it at times I think it would be interesting to do a build. Because E85 may not always be where I am, I would like to achieve this in a way that I can also run 91 when E85 is not available. As I understand Ethyl Alcohol, its burns slower and doesn't product as much power as petroleum gas but under the right compression and timing it can be made to run equivocally. My main reason for this post is to get a compression recommendation and build suggestions for this engine. I expect I'll have some carb / jet questions at some point as well.

I've been told 91 can be run on in a 12:1 compression without any issue. I've also read that E85 being a high octane gas (105 i think) the higher the compression the better. So assuming and E85 only engine would do better at say 14:1, would it even be worth trying to run it at 12:1? From a performance stand point is there anything to gain from E85 if I'm not going to go up to a compression that just wouldn't suit normal gas?

Outside of compression, is there anything about the bottom / top end I should worry about? I know alcohol affects plastics differently then gas, are there any concerns with the types of seals, etc?

Does production E85 contain water (Anhydrous I believe its called), and if so to what percentage and does anything need to be done to address this? Will a water separate benefits this, as I intended to run one regardless given this is a boat and there is potential for water to wind up in the gas.

Thanks in advance for the input.

 

[FAST FRED]

Might it not be easiest to vary the compression peaks by using a waste gate turbo?

Simply dial up the most boost the engine can take , with minor detonation.

The ethanol is a disaster for most boats , simplest is to simply drain the tank to empty after a days fun.



FF

 

[robherc]

Hmmm...I agree with FF that some form of turbo/supercharger would be a good idea. Doesn't have to be huge, just enough to make up the difference between the 12:1 @ 14:1 ratios. Run the blower when you're burning E85, disconnect it when you're burning 91 octane.

Problem 1: E85 burns best with a 10% richer mix than gasoline. Because there's oxygen built into the ethanol compound, it doesn't consume as much oxygen when burning, thus it functions better (and keeps your engine cooler) in a richer mix. With fuel-injected engines this is as easy to solve as running 2 diff. fuel maps...just "flip the switch" when you fill up with 91 octane & you're fine. I don't think it'll be that easy with your carburated engine.

Problem 2: E85 (even anhydrous) DOES contain some water, AND it can wreak havok on natural rubber. In modern gasoline engines where nat. rubber is never used anywise this is almost never a problem, so make sure all your fule lines are metallic or synthetic. As far as the water in it, it's a max. of 5% of the ethanol (so a little over 4% of the fuel)...most engines very quickly tolerate this amount in gasoline, and no, it's NOT easily seperable from the ethanol...which is why most "fuel drier" additives contain ethanol. I don't think the water will be you main problem.

Benefits: E85, when used properly, burns cleaner & cooler than gasoline in your engine. And, under optimal conditions, will reward your 10% richer mix (thus 10% less fuel economy) with 10% (or more) more horsepower & torque from the improved efficiency. Also, IMHO, it'll prob. reduce your maintenance costs by 10% or more, because it burns SOOOO much cleaner. E85 doesn't fould engines/valves/fuel pumps/etc. in any comparable way to what gasoline does.

Afterthought: You can also advance your ignition timing with E85 as it is soo much less prone to detonation/dieseling reactions. This is another way you could realize efficiency gains with it, but you'd have to adjust the timing back if you wanted to run 91 octane.

 

[robherc]

Also, if you do some web searches, I actually found a vid. where a lab tore apart the engine & fuel system of a (I think 200/2001 bronco) SUV that had been run on almost ONLY E85 with no conversion kit, and on a comparable SUV that'd been run on gasoline...turns out the E85 engine was in better condition for every part examined!

Not exactly a scientific study, but it was informative & encouraging!

 

[pistnbroke]

you dont want to put that E85 anywhere near a boat ..it absorbs water and will be a pain in the *** ...Its 15% ethanol ......100 -15 = 85 ....No mods neccessary you get 5% less power ....

Personally I wouldnt even put the stuff in a car ......

 

[robherc]

Wrong again, E85=85% ethanol...you know, that's kinda how it was named!
Most E85 blends are TECHNICALLY somewhere between:
84.9% ethanol, 10% gasoline, 4.1% water
and
85% ethanol, 15% gaoline, 0% water

Although I think the second option is a pipe dream, you can get close by using chemical "drying" processes to rid yourself ot the wather content. The expense is extreme though, so those processes are usually only used for making alcohol for laboratory use where 100% purity is FAR more important.

Interestingly, "normal" gasoline from the pump in most states in the US, at least, is now actually E10 (90% gasoline, 10% ethanol from the refinery...closer to 88% gasoline, 10% ethanol, and 2% water by time you pump it into your car or boat, though), and I know of NO way (besides filling up at the refinery, under controlled laboratory conditions) to keep ANY gasoline, OR ethanol-based fuel 100% free of water by time it gets into your vehicle! Therefore, go for the method that has the higher tolerance for water content, and that's Ethanol (check the ingredients label on any commercially-available "fuel dryer" additive if you don't believe me).

 

[robherc]

P.S. (To ALL) Before you consider someone's opinion, check their "Rep" you automatically start with 10 "Rep Points" when you join the forum. If someone has <0 rep, they've either started a LOT of fights, or posted a lot of WRONG information (or both). If someone has a Rep of, say, >100 (not me, but I wish), they've put a LOT of effort into giving people useful information on the site!

 

[pistnbroke]

did you do a mistype ...85% ethanol.....err we would have no food and very small oil imports ...the only place that as that kind of ratio is Brazil/cuba ..its called poor peoples petrol and the fuel consumption is dreadfull...

I agree some states have legislated for maditory 10% ethanol...its a con...consumption increases by more than 10% so we import more oil...great for the oil companies .....

As for this rep caper ...I am on other sites and have many people by pass the site and e mail me direct for electrical guidance ...your rep only relates to the ability of the reader to understand right from wrong.

 

[robherc]

No, I didn't make a mistake there, it is 85% Ethanol, that's how they designated it as E85.

E10 doesn't reduce your efficiency by "more than 10%" unless you're running an early flex-fuel vehicle; they had an issue with the fuel O2 monitors in them & it caused too much fuel to be dumped in anytime there was ethanol in the mix. In a properly tuned engine, you should only notice a 2%-3% drop in fuel economy when using E10. Also, the E10 was mandated not to reduce our reliance on oil, but instead to combat pollution output in colder weather, by adding Oxygen to the fuel (in the ethanol molecule) to make it burn more cleanly. The ironic thing here, however, is that it takes more fuel to START a car in cold weather when using Ethanol; as the Ethanol has lower volatility than gasoline at low temperatures....thus is the efficiency of our government.

E85, when burned properly, increases your fuel usage (i.e. Liters/100KM) by about 10%, but yields 10% better horsepower, and runs cooler at the same time (which is why they use Methanol [cheaper than ethanol to produce] in top-fuel drag racing).

As far as us running out of food, they are actually now distilling the Ethanol from feed corn, during a fermentation process that was already being used to add protein to the corn for feed purposes (the yeast & mold used are digestible as SCP by livestock), so the Ethanol was simply evaporating away before, but now is being used. If you'd like to talk at more length about Ethanol production, feel free to e-mail me & I can give you almost any info. you want there...including the new methods being developed (one of them by me) to harvest Ethanol from wood, switchgrass, and (my favorite) corn husks/soybean stems/other agricultural waste, using new processes that will actually boost the production of livestock feed, by producing SCP-feed from these plant-fibre stocks.

As far as Brazil/cuba, Brazil is now using up to 95% Ethanol fuel (pure, except for the water content) in almost all of their vehicles, which has brought their dependence on foreign oil down to almost nothing.

As for the rep caper, I am also an "expert" here, and know that some of your statements were, in fact, wrong...though you would never have had the negative feedback posted had you not been so blatantly rude and so disrespectful of others' opinions and information presented.

 

[TollyWally]

While I have had a terrible time with my local govt. adding alcohol to my gasoline the drag boat guys are pretty enthusiastic about e85. They think of it as dirt cheap race fuel. Try this link: http://www.performanceboats.com/html/forums/showthread.php?t=26696

These guys are real knowledgeable about the finer points of motor head minutia.

Shorter version, less energy, more octane, more compression, more hp.

 

[robherc]

Tolly, that's about the right way to look at it too...plus it burns nice'n cool & clean, so it's better for your engine in the long run...once you have it set up to burn the stuff efficiently

 

[StianM]

I got a emerald injection system.
It can be programed with 3 different programs and it can controll a waste gate trough a bleed valve.
http://www.emeraldm3d.com/
It's made in the UK and the £ is quite low now.
You can have a selector switch in a panel chosing betwen two programs, one for 91 and one for E85.

Elcohol burns colder witch also make you able to increase the compresion more than what the octane level normaly would allow.

 

[robherc]

Elcohol burns colder witch also make you able to increase the compresion more than what the octane level normaly would allow.

Also worthy of note is that it burns SLOWER...also allowing higher compression, as it won't over-pressurize the cylinder as easily. Be careful though, as its properties of burning cooler & absorbing more heat when vaporizing will already increase your EFFECTIVE compression ratio by keeping the intake air cooler. You can still blow an engine if you don't take that into account!

 

[gonzo]

Alcohol for high performance engines where economy is not an issue works great. It allows for higher boost pressure. However, it is an advantage because they are injecting a lot of fuel. Alcohol has less calories than gas, which means you need a larger volume to produce the same power.