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fleebut

Non-FFV

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So, the discussions of running E-85 in non FFV always sway to the cautions of lean burn damage? If I understand correctly ethanol has more oxygen molecules within the fuel or what is referred to as naturally oxygenated. An E-85 fuel burn requires a different air fuel ratio as compared to unleaded. An engine under same operating conditions (fuel ratios) as unleaded; E-85 will cause engine damage produced by lean burn combustion. Right?

 

So, E-85 fuel requires more fuel in mix or if some how the engine can limit its own oxygen mix the same result. One or the other required for correct burn and efficient hp engine. Most I.C engines can't  change their air supply unless someone figures out how to dump more EGR gases in combustion chamber instead of fresh air.  Has anyone tried that? This would be produce less horsepower, but during low hp requirements wouldn't this be good? Under high hp conditions dumping in correct ethanol with fresh air should produce more hp than unleaded as more E-85 can be burned with comparable charges of air as compared to unleaded. Maybe the reason so many experience power. The high O2 reading from oxygen sensor pumps more E-85 fuel developing more hp. Good for high torque need, bad for light cruising.

 

Do the auto companies try this trick with variable valve timing? Or Fords Atkinson cycle engine? When operating in the Atkinson mode the IC could just push out more fresh air to minimize cubic inch displacement. A temporary small CI engine with less squirt of E-85.

 

Anyways, was just thinking....my question. Are we hurting engines by running straight E-85 in NFFV? During summer I like straight E-85 in GM pickup 3.7 six cyl or close. Trips to KC (600 miles) will lose only 1-2 mpg. Engine runs for long time under hot conditions. Seems sweat, but am I lean burning engine? This used to burn valve seats prematurely for cycles and small engines. If I put in a flex fuel kit, it would get more power and avoid lean burn....but my mpg would go south right? Am I hurting a NFFV engine with E-85? 

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"Are we hurting engines by running straight E-85 in NFFV?"

  After a certain mix there can be damage from running lean.  Thats why there is a market for conversion kits and why the solve the problem.  Our kits work by adding the extra fuel so there is no running lean.  Non Flex Fuel vehicle computers have a limit to how much fuel they will add before basically saying...  That's it, my program won't let me add anymore and the engine is running lean.  With the extra 15% (give or take) from our kits the vehicles computer actually stays within the limits of its program while adding the right fuel mixture.

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Fleebut- that was a lot of question there ;D

*I will not delve into the EGR issue other than to say in general most apps it is in is merely for emission control though you pose an interesting question.

*Adding a kit can take care of a few issues;

1) keeping the check engine light by keeping fuel trims in line - if the CEL has been on.

2) the biggest risk you take w/o the kit is that there is a good chance your ECU does not have, or does not have enough learn capabilities in open loop- thus if you are towing a heavy load up a hill or nail it to pass and go into wide open throttle (open loop) then the ECU is going by it's old gasoline map rather than the O2 sensor-- this is danger zone. A good kit will be adding fuel on top of the ECU map command. At that point with the kit the danger would come only if your fuel pump is too small, injectors are out of room (or partially plugged), a fuel filter is starting to restrict flow because it is plugging, or you have some performance mods pushing the limit already.

 

A kit will not necessarily cause you to use more fuel- remember that if you have more power available you can do one of two things- use it with more speed and faster accel OR you will use less throttle than w/o the kit. It takes only so much HP (fuel) to go down the road at steady cruise so you need a bit less throttle.

 

One other choice is to install larger fuel injectors if you are wrench happy.

 

Will you damage your engine running E85 full strength with no mods or kit? -- cant say. A few local guys do it and a couple of them even tow that way. One Ford pickup owner litterally run the back axle out of his pickup pulling used farm equip all over the Midwest- yet his engine was good as new, Do I recommend it- NO. Have I towed with 60%--yes.

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Ok, in order:

 

"E-85 will cause engine damage produced by lean burn combustion. Right?"

 

Ethanol naturally burns at a cooler temperature than gasoline.  The likelihood of engine damage from running lean is reduced with ethanol.  Also consider that ethanol cools things down more than gasoline when it vaporizes.  That also helps.  I've ran perhaps too many engines lean on E85 and never noticed a problem.  I think that the big problem with running lean on gasoline is that it pings more easily, and that causes engine damage.  Ethanol, in a standard naturally aspirated gasoline engine, simply doesn't ping, regardless of the fuel / air mixture, so you're somewhat safe running lean.  Not that I recommend it.  ;)

 

You could limit the amount of fresh air entering the engine, using EGR, in order to fool the computer into injecting the required amount of fuel.  But WOT power would be way down.

 

Essentially, if you don't notice a loss of power running E85 in a non-FFV, at WOT, then the computer is compensating and you're not running lean.  If you were, you would know it.

 

Also, the oxygen in the fuel does not  contribute to combustion.  It's just along for the ride.  It doesn't affect the oxygen sensor either, since that detects free oxygen, not that bound to something else, like carbon dioxide.

 

Does that make any sense?

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So, if I understand WOT the most dangerous condition or high hp towing. Maybe, I am in a low risk category. No engine fault light, except a couple times when making quick transition and stop to soon. I drive for mpg, no towing, tonneau cover, 62 mph, high psi tire pressure, and 23+ mpg mileage. Yes, a full size 1/2t truck. This will drop to 22+mpg with E-85. Usually a couple times a year 1,200 mile round trip on E-85 and yes Minnesota loaded with ethanol. The truck never experienced WOT, not even if in passing lane. Lots of coasting, but no delay, just avoid hard braking. Doesn't make sense to me to race to a red light. I will keep up with traffic if congested and troublesome to be in slow lane. I don't play that game. But, yes most semi's pass me. Knock on wood, but that pickup has almost 200k miles and looks runs good, no problems and no oil burning. It's high geared or low? About 1,200 at 50mph. Cruise at 1,500 rpm. The pickup is not aero, like pushing a piece of plywood.  High speed really takes hp.

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I'm blending e10 and e85 in my 1999 lumina sedan, 3.1 l v6.  With my 14 gallon tank, I can put 7 gallons of each fuel in with no CEL whatsoever.  If I bump it up to 8:6, I get the CEL some times, but not every time.  Seems to me that I get the light on this mixture more when it is drier out.  Even in cold winter driving (now), when it is overcast and very humid/wet, I don't get the CEL.  If on the next commute, it is bright and sunny, with little moisture in the air, the light will come on.

 

Or maybe I'm just way over analysing this seemingly random CEL pattern.

 

Anyways, 7:7 e10:e85 ratio and there are no lights ever.  I've never noticed any problems either in the way she runs or sounds. 

 

This 7:7 ratio causes my mpg to drop from 22-23, down to 20-21... so I'm pretty happy with that.  With the 19% spread I'm currently getting (thanks Kum & Go  ;D) this has been working very well for me for the past 2 years.

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What kind of truck you got there fleebut?

 

I noticed on my old Explorer, when stock, that WOT power would be affected above about E30.  Not very noticable at E30, but you could tell it just wasn't making the power that it used to.  But still, no CEL and it drove fine if you didn't depress the gas pedal more than about 2/3.  That would continue up until it was full strength E85.  At that point, the computer would give up trying to adjust, turn on the CEL, and drivability would be affected.  It would hesitate, and forget about accelerating quickly.

 

Larger injectors solved the problem nicely, and I was running full strength E85 in it for quite a while before I pulled the engine and went for high compression.

 

Here's my motor build thread from a long time ago, and on a different forum:

 

http://www.ford-trucks.com/forums/529041-i-got-me-a-motor.html

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My wife is doing taxes now on quick-books...  and she is not too happy about having to code and enter 2 entries every time I gas up at Kum&Go.  Would be great if they had blender pumps... one charge for 14 gallons of e50... rather then 7 gallons of e10 and 7 gallons of e85...

 

or I could pony up and get the white lightning kit...  :-[

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