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Rich: 105 octane E85
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Posted by: XRpredator

Have you played around with any of this stuff yet? Should I run it in Vic? Will it blow the head off the cylinder?

Just wondering. I've heard of a few guys running it in their quads (the workhorses, not the quadbillies) with decent results, but we're not talking about high performance. I've also read stories about lower fuel economy, but that's a push with the cost savings.

What's the word, Thunderbird?

Posted by: Rich Rohrich

Well there are a few issues you would have to contend with to make it workable Pred.

The first is jetting. You need approximately 1.5 times more fuel for the same amount of air when comparing E85 to pump gas. That's like going from a 175 to a 260 main jet on the hex head Mikuni jets. Mains and pilot jets aren't that much of an issue , but getting the needle and needle jet sorted so you'd have good transitional response would take a lot of work. Along with that is the issue of getting enough bulk flow out of the petcock to feed the additional requirement.

Which brings up the issue of the distillation curve and basic characteristics of E85.

Ethanol has a single point of evaporation; where as normal gasoline is made up of hundreds of different components that evaporate from temperatures well below 90 F to temps above 400F on pump fules. The tendency of a fuel to evaporate {to change from a liquid to a gas state} is one of the most fundamentally important qualities of fuel in carburated engines because it has a major influence on the vapor-air ratio in the cylinders at the time of ignition.

In a normal engine nearly all the fuel needs to be evaporated before ignition. So for any Engine/Air Temperature combination there is a minimum volatility that is required for proper throttle response and high speed running.

Gasoline is normally designed with a specific vaporization/distillation curve (or volatility curve) to match the running conditions of the engine that looks something like this:

10% Evaporation 157
50% Evaporation 205
90% Evaporation 217
End point Evaporation 230

The point of all this? 85% of E85 evaporates at the same temperature (172 F), most of the other 15% of the fuel is there to try and lower the front end vaporization temperatures to help spread the curve out a bit and make it easier to start when cold. What makes ethanol (and methanol) tricky is it's Latent Heat of Vaporization, or the heat absorbed when it changes phase from liquid to vapor.

Even though the temperature of 172F doesn't seem all that high the amount of additional heat required to make that phase change to vapor absorbs an enormous amount of heat from the surrounding surfaces and cools them down to the point where some of the fuel stays in the liquid state. When fuel manages to stay in the liquid form all the way through the combustion cycle it will eventually end up diluting the oil.

When you have hot intake runners, low rpm, and high water temperatures like automotive engines see along with high pressure EFI you can engineer around these issues. We have short isolated intake runners that run relatively cool and are fed by a simple slide carb, so it's a poor environment for this type of fuel. In short, on a carburated engine it just doesn't work and it leaves a big hole in the distillation curve that makes throttle response non-existent. Tuners call this the "alcohol flat spot"

The funny part is, all these “negatives” are part of the value of alcohol as a race fuel. This cooling effect lowers intake temps and increases air density to the engine giving the same basic effects as supercharging. It just comes at a cost in terms of dealing with the rather bizzare after effects of all this physics and chemistry fun.

Let's not forget that ethanol attracts water and forms what is called an azeotrope. Once the water and ethanol join in this way you can't isolate ethanol without using some sort of drying agent that can soak up the water.

All the above points hold true for ethanol added to standard pump fuels even when the percentage is lower (in the 10-20% ethanol range), they just occur to a lesser degree. Along with this comes a lot of potential issues with corrosion, partly from the solvent effects of ethanol, and partly from the water it will eventually attract.

So I'd say, be nice to Vic and put decent fuel in his tank, and maybe buy him some new grips to show you really care.

Posted by: IndyMX

I had heard that Ethanol fuels weren't good for a bike, but no one has ever explained it some completely to me before..

I had figured they were just hatin on Ethanol.

I have only one question, I have read a lot of what you have written on Jetting, Plug reading, and Fuel, plus that nice bio thats floating around on here. But, I don't recall reading where you got so damned smart about this stuff?

Thanks again for the great read.. Should make this a sticky somewhere...

Posted by: XRpredator

Quote:

Originally Posted by IndyYZ85

. . . I have only one question, I don't recall reading where you got so damned smart about this stuff?

wikipedia.

Posted by: IndyMX

Quote:

Originally Posted by XRpredator

wikipedia.

HA! You ain't right man!

Posted by: Rich Rohrich

Indy, this is where I learned about fuels.

Lots of time spent trying to understand fuel and combustion a 1/4 mile at a time.

If you aren't totally bored hearing about alcohol, here's an old post on it : http://www.dirtrider.net/forums3/sh...ad.php?t=115212

Posted by: IndyMX

Another good read, not that I understood all of it.. But, I have a few things to read up on, and hopefully will understand it all sometime soon.

Posted by: biglou

Quote:

Originally Posted by IndyYZ85

Another good read, not that I understood all of it...

That Rich, he's not only smart, he's Fluffy!

Posted by: GPracer2500

The dyno testing I've seen of E85 in a 450cc Honda Unicam engine showed it to be on par with VP's U4 in terms of power. The same engine was also tested with methanol and a 44mm Lectron carb (the E85 and U4 were using a 40mm FCR). The methanol setup showed larger gains than either U4 or E85. An alcohol specific FCR jet needle was required for E85. If memory serves, no custom Keihin mains were needed (i.e. no bigger than #230).

Other reports I've been given about E85 in motorsport applications indicate that basically, E85 is a viable fuel choice with carburetor requirements similar to--but not exactly--what you'd find for a methanol setup. In other words, if you're prepared to go through the steps necessary to make methanol work for you then E85 might be worth looking at. If you're looking for a "pour-it-in-and-make-some-minor-jetting-adjustments-and-go" fuel then E85 isn't the right thing.

I'd be tempted to experiment with E85 but 1) I'm not aware of an E85 source in my area and 2) I'm uncertain of the real-world effects of E85's corrosiveness. I've "heard" some say they've experienced no adverse effects from regular use of E85 in engines/carbs originally intended for gasoline while others insist E85 should require draining draining after each use.

R3Concpets in Tuscon AZ did the dyno testing that I mentioned.

$0.02

Posted by: Jaybird

Dyno runs are great, but they don't say much about the throttle response each set-up produced. And IMO, TR is much more important to the majority of riders (and racers) than top speed HP is.

Posted by: mideastrider

I can say from my kart racing days using methanol that it does (as Rich said) take about 1.5 times as much. We ran oval tracks and was at wide open throttle 95% of the time, not a big problem. Off idle and low end throttle responce is where I think you'll have a problem coming up with a setup you can live with, especially in the woods.

Posted by: Rich Rohrich

Quote:

Originally Posted by mideastrider

Off idle and low end throttle responce is where I think you'll have a problem coming up with a setup you can live with, especially in the woods.

That's the crux of the problem with E85. On the dragstrip or a kart track you can make it work well, but with all the throttle transitions we encounter with MX and woods applications that alcohol flat in the middle of the distillation curve is a huge problem to overcome using a carb like an FCR.

EFI bikes with engine management systems that have wide ranging control over the ignition curve will be much more likely to handle this assuming someone builds a proper map for the specifics of E85. I for one won't be holding my breath waiting for that to happen.

Posted by: mkelly04

Quote:

Originally Posted by IndyYZ85

I had heard that Ethanol fuels weren't good for a bike, but no one has ever explained it some completely to me before..

I had figured they were just hatin on Ethanol.

I have only one question, I have read a lot of what you have written on Jetting, Plug reading, and Fuel, plus that nice bio thats floating around on here. But, I don't recall reading where you got so damned smart about this stuff?

Thanks again for the great read.. Should make this a sticky somewhere...

From what I understand, in addition to the carb not being set up to run e-85, the alcohol is corrosive to rubber that is not designed for it and can cause damage to the carb.

Posted by: YZ165

Great explanation as usual Rich. Thanks...

Posted by: oilguy

we have a retired 03 KX 65 that, just for fun, we rejetted to burn E85 last summer. Can't remember the jets #'s we used, but I think we were about 1.6 X the volume on the main to begin with. The racer boys said it definately had more power than on TT111 fuel it had always used. we mixed the fuel with benol. here's what we concluded

+ the little engine rips on that stuff, no transition issues observed
- hard to read the plug when jetting (fuel doesnt leave deposit on plug)
- fuel/oil separation issue with Amsoil Dominator
- gummy crud in float bowl if castor premix is left in there for any amount of time
- HARD to start in warm temps VERY HARD to start in cold temps
+ inexpensive high octane fuel with a very clean burn

we have since replace the alky setup with gasoline jets to make it easier
for the visiting little people to start. back to 1 kick

Posted by: 2strok4fun

Quote:

Originally Posted by IndyYZ85

From info I had gathered from reading a SAE paper that dealt with Chinese motorcycles, sediment in the carbs were noted and piston scrape on the 2strokes was evident. The tests were done using E10.

That was enough for me to avoid it.

Posted by: PAULRY

I can add the following regarding alcohol fuels, although not relating to E85.

I have run methanol fuel in 2 stroke mx bikes for track use.

The power gains are impressive. The lack of throttle response is minimal, but having said that I have never had the chance to run a race fuel, so I am comparing to pump fuel on a stock motor. As previously mentioned, this is not a fuel you put in your bike and go, it take plenty of development to get it running right, and should always be done from the rich end of the fueling curve, as this fuel has a low tolerance for running lean.

As for the difficulties of starting and the corrosive qualities, sticking to the following procedure avoids all the problems:

1) The easy way to start a bike on alcohol is to have someone blow through one of the vent tubes on the carburettor and then give it 2 or three kicks and away you go. If the weather is warm this usually only has to be done first thing in the morning, there after the start procedure is as normal. On a cold day you will have to follow the morning start procedure mentioned above.

2) In all the years of running methanol I have never had a problem with the fuel corroding parts or aging seals, o'rings etc, but after each days ride the bike must be flushed with pump gas. I have a lawnmower petrol tank filled with pump gas and oil ( more on the oil later), which I connect to the carb. The bike starts easy enough because the float bowl still has alcohol in it. I run the bike until it begins to splutter, this is the point at which all the alcohol in the carb has been consumed and the bike is now running on pump fuel. At this point it is important to use alot of throttle other wise the bike will stall and you will find it difficult to restart on the pump fuel. The reason for this is that the bike is now running in an extremely rich condition (remember the bike is jetted way richer than it would be if it were running pump gas). From the moment it is running on the pump fuel I run the bike for 2 to 3 mins to make sure the bike is flushed. Also pour all fuel out of the petrol tank. Never use old fuel always mis fresh, if you ride on a weekly basis.

A final point concerning the 2 stroke oil. Use a castor oil or a castor/synthetic mix. Straight castors offer good lubrication, but they tend to clog the motor especially the powervalves. I have been using a castor/synthetic oil, of late, and have found that the powervalves can go longer with out cleaning. An important note, the castor/synthetic oil separates out if left to stand during the days riding, so always give the fuel drum a good shake before putting the fuel into your b

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Rich: 105 octane E85

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