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 Post subject: Welcome to the E85 forum
 Post Posted: Wed Oct 27, 2010 2:52 pm 
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My intention is to explore how best to make E85 work in the race engines that will handle it, and carb mods needed to get the most out of it. A lot of relevant info has been put out there. What we will try to do is put it in a way that everyone understands, and can possibly use to improve the tune of their E85 engines. As this is newer territory, it will be both a teaching and learning experience for me.


So what do we know about E85? First is that E85 isn't always 85%. Watching the fuel mix will be key, and you will need to learn what changes you will need to make accordingly. I live in Florida, and as a result of the warmer climate year round I don't expect some of the drastic changes you might see in the more northern states. My first buy of E85 locally looks to be right at 84-85%, I'll try to monitor the changes as we get closer to winter.

Another from the E85 850 thread is that the viscosity and density of E85 are different than gas or methanol, so mainwell, angle channel and booster passages need to have transitions that keep the fuel flow as smooth as possible to maintain laminar flow as long as possible. In addition to this is the booster design itself, it needs to be such that it creates minimal restriction to fuel flow yet still allow sufficient preparation of the fuel to help it vaporize a sufficient amount prior to the combustion chamber. The emulsion used to correct the fuel curve is a factor as well, the more you use the sooner the fuel goes turbulent as it lowers the viscosity and as a result makes it go transitional to turbulent sooner. And one thing more to consider, the viscosity of the fuel is affected by temperature, which will affect the fuel curve as fuel temps go up. Keeping the fuel cooler at least through the carb may have a benefit. Balancing and maintaining the fuel temp, engine temp, and spark plug heat range will be a key in consistency and performance.

Also a factor is the vaporization point and latent heat of vaporization of ethanol. Ethanol vaporizes at around 173˚ compared to around 148˚ for Methanol, however the latent heat of vaporization for ethanol is 364 BTU/lb, methanol is 473 BTU/lb. This means while the temp is higher for ethanol the total energy to vaporize it is lower. Not sure at the moment how to correlate the two or if it can be done, maybe Shrinker can help in that department. The addition of gas to make up E85 will improve vaporization to help start the fuel burning, and will improve cold weather starts.

Last is mixing fuel, be aware that ethanol does not like the addition of metallic ant-knock additives, they will lower the octane rating. This means if you mix E-98 with race fuel, be sure you are using UN-leaded fuel. The first link below discusses this, the other is more on the effects of Ethanol at different blends and compression ratios. I’ll set up another thread on my 1150 build and how I progress with it, at the moment I need to add O2 bungs to my headers and wire up the RPM converter on the FAST system I have so I can download data.


http://www.innovatemotorsports.com/foru ... php?t=7690


http://delphi.com/pdf/techpapers/2010-01-0619.pdf


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 Post Posted: Wed Oct 27, 2010 4:37 pm 
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Currently (october 2010) E85 fuel is not legal for sale in Australia. It is however being sold at some outlets. So there is hardly anyone here using it so my experience with it practically is zero. So I can only provide theoretical support at this stage. I have however researched Ethanol blend sufficiently over the years because I know it is coming, but when is the question.

There are very good points brought up in that Innovate motorsports forum thread. The basic run down is this.
1-Octane additives that contain metallic structures, basically all of them, have to be avoided with any alcohol fuel. DO NOT MIX IN OCTANE BOOSTERS.

2- If changing an engine from leaded gasolines or from previous fuels that used octane boosters set the timing low to reduce the possibility of detonation caused by residual metals on the chamber walls. Chamber deposits take a long time to clear. I consistantly notice changes in combustion with just normal gasoline when retuning engines. The changes are brought about from wall deposit alterations. The changes take weeks of normal driving.

3- The vapor pressure of ethanol when its mixed with gasoline becomes higher than either fuel on its own. That is a trap for unwary people. Vapor pressure has far more influence other than just how much evaporates from your tank in the sun.
The vapor pressure determines how many molecules are available in gaseous form at the ignition timing point. When you mix ethanol with gasoline you get more gaseous state Hydrocarbons during the compression stroke than on straight ethanol. These HC's will be taken in greater percentage from the gasoline components. The lighter chemicals of gasoline are high octane first stage reaction ones and therefor the most valuable in money terms to the oil companies. Releasing them into the gas state earlier in the compression stroke places those molecules under increasing pressure for a longer time. Once a molecule is in gas state and its heated by compression its becomes very critical as to what the temperature difference between its gas state energy level is and its detonation state energy level.
Do not assume that releasing high octane chemicals early will give you more octane. ITS OPPOSITE. Detonation occurs from gas state molecules being too high in energy level and the way to get them to that point is to compress them long enough. Knock occurs AFTER ignition, and it occurs in the furthest reaches of the chamber at around TDC and it occurs in the coldest reaches of the chamber first. The reason why it occurs in the cold is because it's warm enough there to gas the light chemicals but not hot enough to gas the heavy ones so the environment is Oxygen excess and the gas state fuel molecules are taking all the compression energy, so they overheat. Its the Oxygen excess thats the problem it alters the detonation resistance of the chemicals.
Its the advancing pressure wave from the combustion front that travels at speed of sound in the mixture that compresses the highly stressed light gas chemicals sitting in the cold, and that wave does it with a shock, just what you need to detonate things, just think like a detonator for explosives and you will get the idea. The situation in an engine is piston compression then wave compression then flame deflagration. All that creates even more energy input to the last vestiges of fuel residing on the walls so when those fuel molecules are stuck in an exhaust filled area because the chamber or cam etc is junk then they cant combust due to lack of oxygen so they hang around for the next cycle. Then they get moved etc and their already hot at the start of the compression so eventually they detonate.


Remember how you cant compress a liquid? Thats true but what it means is that the energy input into molecules existing in the liquid state has to be input via convection, collisions on the surface of the liquid then thermally transmitted via lesser collisions and vibration a slow method of kinetic transfer, whereas gas state structures receive it via individual collisions(Fast, straight to the point kinetic energy).

So anytime you blend gasoline with ethanol you just create a difficult situation worse. With Ethanol blends its much more important to eradicate design/detonation issues with combustion chamber shapes and porting than what it is with either 100% Ethanol or 100% gasoline. Unless you want to accept performance compromise that is.


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 Post Posted: Wed Oct 27, 2010 7:54 pm 
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I am curious about the buildup of lead, mine was cleaned and rebuilt with only two races on it. Heads were completely stripped, new valves and guides, pistons cleaned up. No way to drive it around either, however cooler weather this time of year may help prevent detonation. I can easily cut timing a couple degrees with the Digital 7, what are your thoughts of retarding timing in the lower RPM a few degrees and advancing it back as RPM climbs?


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 Post Posted: Wed Oct 27, 2010 8:17 pm 
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jmarkaudio wrote:
I am curious about the buildup of lead, mine was cleaned and rebuilt with only two races on it. Heads were completely stripped, new valves and guides, pistons cleaned up. No way to drive it around either, however cooler weather this time of year may help prevent detonation. I can easily cut timing a couple degrees with the Digital 7, what are your thoughts of retarding timing in the lower RPM a few degrees and advancing it back as RPM climbs?


Not saying that this isn't or can't be a problem but I've switched back and forth between methanol and c12 a couple of times and had no issues to date???

I do know that MMT, AV gas and methanol DO NOT MIX. I originally had a gas primer system on my car and first time out I had a siphon problem on that primer and one quart of MMT mixed AV gas mixed with methanol and beat a set of bearings out of my engine first time out. That primer system was removed the next week.

While I've heard that the deposits left in the combustion chamber "could" present a problem, it's not been an issue on my engine since that first episode.

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 Post Posted: Thu Oct 28, 2010 1:22 am 
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Ken; what we are saying is only evident when you push the edges of the envelope of safety. For instance, racers think that say 13 to 1 compression ratio with maybe 240 psi cranking pressure would need a 106 octane fuel or more. Im just saying that as an example to the next bit. However the octane requirement of an engine is extremely related to the fuel vaporization you achieve. I can make an engine detonate by having the compression TOO LOW for av-gas then increase compression and do nothing else and it will stop detonation. Ive done exactly that.
How engines perform, is not to a simple rule.
I see no point in me posting the normal responses that people can read anywhere on the net. You know stuff like -- run it at 12.8AFR, advance it up until it knocks then back it off 2, put the biggest carby you can afford on it, use big valves, long stroke makes torque, You know all that stuff. Its all junk. I talk about the details that are not talked about, but they are details that I have experienced. I always seek to figure out what it is that creates the problem and to correct it without detriment to other factors.
With the issue of metals and alcohols the stuff thats deposited on the walls doesnt activate much because the walls are normally protected by the boundary layer gases. However if your tune is causing even a slight detonation close to a wall, the boundary layer is stripped and the heat from the detonation impinges upon the metals impregnated in the material. Thats when you have a big problem. So a small error becomes a big one.


Last edited by shrinker on Thu Oct 28, 2010 2:54 am, edited 1 time in total.

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 Post Posted: Thu Oct 28, 2010 2:01 am 
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jmarkaudio wrote:
I am curious about the buildup of lead,

Lead doesnt build up as lead it becomes lead oxide, It's converted to lead oxybromide by scavenge chemicals in gasoline and its cleared away in the exhaust. This is how that process is done.
Ethylene dibromide (C2H4Br2) is used as the scavenging agent in aviation gasoline. Because racing gasolines are base stock of old avgas its likely this chemical is used in racing gasolines. Av-gas is only allowed to be 6 months old and then it gets recycled by the race gas makers. Some possibly make their own stock from scratch, its doesnt matter as they all have to deal with the lead deposits in the same way.
The desired result of the scavenging reaction is the formation of a volatile lead bromide (PbBr2) instead of lead oxide. The volatile lead bromide is removed from the combustion chamber with the exhaust gases.
It has been recognised that bromine remaining after the scavenge reaction can corrode engine components. The addition of ethylene dibromide to aviation gasoline is controlled so that only the right amount is added to react completely with the lead oxides formed. The ratio of ethylene dibromide to tetraethyl lead is termed a 1-T mix27
(one times theoretical).
The formation of lead oxybromides has a bad side, they cause deposit induced preignition. the formation of these chemicals is linked to the fuel–air charge temperature in the combustion chamber just prior to the passing of the flame front. So what that means in simple speak is the scavenging chemicals create lead oxybromide, but they create it just before visible flame temperature in a very small temperature window of opportunity. they are mainly the result of preflame reactions and as such they are affected severely by the vaporization level ahead of the flame front. The preflame reaction zone is very critical of the gas concentrations, get it wrong and you dont get rid of the lead. The burn rate has to be just right for the ethylene dibromide to be produced. So a correct engine burn stays clean, whereas a poor one doesnt. Its not just carbons that you look at on your heads.
See how I always talk about vaporization. Thats because it dam well is the whole key to so many of the processes BUT how to control it is not understood by tuners. Partly because they have no tools to control it. Thats why I designed my own carby to control these functions and learn about this. Thats why I say a lot of thing different to the mainstream ideas because I have been there and done that and possibly no one else has.
jmarkaudio wrote:
I can easily cut timing a couple degrees with the Digital 7, what are your thoughts of retarding timing in the lower RPM a few degrees and advancing it back as RPM climbs?

Yeah experimentation is needed, the ET slip will tell you. Controlling timing in that way to gain advantage is actually indication of vaporization issues. Correctly vaporized doesn't need timing changes. So if it goes better with more top end advance then its telling you to fix the fueling issues.


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 Post Posted: Thu Oct 28, 2010 7:43 am 
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Prior to using E-85 I'll need to make sure my fuel system is clear of lead. My engine was designed to use commonly available 93 octane fuel. It was dynoed on 93. I've been mixing it with 20% 110 octane just because I have the 110. My thinking here is that I can "flush" the system of lead by just using 93 from here on out.

Bandied about on the web is the view that it's not really cost effective to run E-85 on a engine with 10.2:1 such as mine. Or that there would be no real performance advantage to do so. I'd like to explore that. I just so happen to have an available Dominator (9377 converted to two circuit) to use with E-85.

Additionally, there is now a new E-85 pump about 5 miles away. When I get back from Vegas I'll have to purchase some and see how it tests and compare that to Mark's sample.


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 Post Posted: Thu Oct 28, 2010 12:57 pm 
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I'm looking forward to the info sharing in this section of the Board. I'm starting work on my conversion and I appreciate everyone's willingness to share info. I've talked to mark via PM the last few weeks and looking forward to his results. I found this Board last year and have been incredibly impressed with the open knowledge sharing. I hope someday to have half the knowledge as most here.

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 Post Posted: Thu Oct 28, 2010 2:15 pm 
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Years ago when I first started running methanol I had run a mix of AV gas and 93 pump gas in that "junk" 434 SBC 10.5 to 1 engine. After a couple of years of methanol I pulled that thing down for a freshen up and most all the deposits in the combustion chamber were gone. It was almost as if I had cleaned it before I took it apart. Since then every methanol engine I've ever pulled down was pretty much free of deposits also.

Does ethanol do this also? :-k

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 Post Posted: Thu Oct 28, 2010 5:02 pm 
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Here is an AFR chart that was posted over on YB. It shows E85 AFR when using an O2 with a gas scale. As my FAST is on a gas scale, I'll look at is as a guide for the time being.


Avoid the italics

Lambda E85 AFR Gas AFR
0.500 4.880 7.350
0.510 4.978 7.497
0.520 5.075 7.644
0.530 5.173 7.791
0.540 5.270 7.938
0.550 5.368 8.085
0.560 5.466 8.232
0.570 5.563 8.379
0.580 5.661 8.526
0.590 5.758 8.673
0.600 5.856 8.820
0.610 5.954 8.967
0.620 6.051 9.114
0.630 6.149 9.261
0.640 6.246 9.408
0.650 6.344 9.555
0.660 6.442 9.702
0.670 6.539 9.849
0.680 6.637 9.996
0.690 6.734 10.143

0.700 6.832 10.290
0.710 6.930 10.437
0.720 7.027 10.584
0.730 7.125 10.731 @ Max Power Multi Turbo
0.740 7.222 10.878
0.750 7.320 11.025 @ Supercharged/Turbo
0.760 7.418 11.172
0.770 7.515 11.319 @ Max Power NA
0.780 7.613 11.466
0.790 7.710 11.613
0.800 7.808 11.760 @ Consistant Race
0.810 7.906 11.907
0.820 8.003 12.054
0.830 8.101 12.201
0.840 8.198 12.348 @ Part throttle RACE
0.850 8.296 12.495
0.860 8.394 12.642
0.870 8.491 12.789 @ Idle
0.880 8.589 12.936
0.890 8.686 13.083
0.900 8.784 13.230
0.910 8.882 13.377 @ Part throttle STREET (economy)
0.920 8.979 13.524
0.930 9.077 13.671
0.940 9.174 13.818
0.950 9.272 13.965
0.960 9.370 14.112
0.970 9.467 14.259
0.980 9.565 14.406
0.990 9.662 14.553
1.000 9.760 14.700
1.010 9.858 14.847
1.020 9.955 14.994
1.030 10.053 15.141
1.040 10.150 15.288
1.050 10.248 15.435
1.060 10.346 15.582
1.070 10.443 15.729
1.080 10.541 15.876
1.090 10.638 16.023
1.100 10.736 16.170
1.110 10.834 16.317
1.120 10.931 16.464
1.130 11.029 16.611
1.140 11.126 16.758
1.150 11.224 16.905
1.160 11.322 17.052
1.170 11.419 17.199
1.180 11.517 17.346
1.190 11.614 17.493
1.200 11.712 17.640


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 Post Posted: Thu Oct 28, 2010 6:03 pm 
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Ken0069 wrote:
Years ago when I first started running methanol I had run a mix of AV gas and 93 pump gas in that "junk" 434 SBC 10.5 to 1 engine. After a couple of years of methanol I pulled that thing down for a freshen up and most all the deposits in the combustion chamber were gone. It was almost as if I had cleaned it before I took it apart. Since then every methanol engine I've ever pulled down was pretty much free of deposits also.

Does ethanol do this also? :-k

Methanol is a simpler molecule than Ethanol so the combinations that can be produced during combustion are far less for Methanol. Methanol cant be much else other than CO gas on a low temperature burn where as Ethanol can be quite a few substances. Not that thats any reason for it to not be as clean etc but what actually happens is because Ethanol has to break down a larger molecule in more steps to completion its more likely to not complete the pathways in some areas on the chamber walls, thus the chance of carbon deposition is higher than with Methanol. Methanol still deposits carbon if the temperature is enough to break the CO apart. then you get carbon deposited in areas of oxygen deficiency. Methanol still tans the plugs the same as gasoline if the gas levels are high enough around the plug area. The problem with alcohol fuels is getting enough energy to do that everywhere in the chamber. Sparkplugs are hotter than elsewhere and they have the arc energy too and the arc energy affects the combustion for a zone that's approx 6mm radius. The combustion for that radius is a higher energy than beyond that, so thats why you get tan plugs and clean pistons etc. The plug heat and the arc energy radiance achieve higher gasification levels that the rest of the chamber.
Methanol can handle massive boost like 55 to 70psi easily so why dont you shove 22 to 1 compression in it; well the reason for that is the wall area to volume space ratio goes up with 22 to 1 so there is too much cooling and it snuffs out. Whereas blowing lots of air into a reasonable space works. Its not until you sqeeze alcohols that hard that you start to gas them correctly in the entire chamber, then they make heaps of power and very good BSFC's provided your chamber materials have sufficient temperature handing.

if you dont compress ethanol or methanol enough then all you get is a hydrogen burn and thats just clean water. But water is only 60% of the power released compared to a burn of H and C. So your old clunker stayed clean whereas if you achieved some level of carbon dioxide burn from any alcohol you will get carbon. As always a perfect complete burn will have no solid deposits.
So most racers are on the low energy poor combustion side of the reaction process with alcohol fuels.


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 Post Posted: Thu Oct 28, 2010 7:05 pm 
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Some more info, although a little older here.
http://speedtalk.com/forum/viewtopic.php?t=12064

A couple things I saw interesting, was comparing the BTU for the volume of air consumed for different fuels, and zeolite molecular sieve material to dry the ethanol of water. I'll have to see if that is a cost effective way to ensure there is little water in the fuel.


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 Post Posted: Thu Oct 28, 2010 8:44 pm 
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jmarkaudio wrote:
My first buy of E85 locally looks to be right at 84-85%, I'll try to monitor the changes as we get closer to winter.

How are you measuring the % ethanol?

Rick


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 Post Posted: Thu Oct 28, 2010 9:49 pm 
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Real easy.

http://www.quickfueltechnology.com/spec ... -tube.html
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 Post Posted: Thu Oct 28, 2010 10:18 pm 
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jmarkaudio wrote:

that tool is a really good obvious indication of how much water Ethanol absorbs.


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