E85Forum.com

CARS · Joined: 27 Jun 2005 Posts: 62 Location: Comfrey MN

Hello. I am new to this forum and have learned alot about what people are doing to use E85 in their gas-powered vehicles. Instead of getting a little info here and there could one (or more) of you spell out what is needed to convert engines to E85? Spell out the differences between F.I. and carb conversion setups, Fuel flow rates, computer re-flashing, compression rates for optumum performance ect.
I am also under the impression that unless the vehicle was built as a flex-fuel vehicle it is illegal to convert to E85 for emission reasons. What can a person do to convince a company like Holly or Edelbrock to make a 50-state legal conversion kit like they do for aftermarket performace products?
I am primarily interested in converting my older (pre-95) vehicles.
Thanks,
Chris
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hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

Chris --- sorry for the long delayed response !

Here is my 2c on this topic.

Converting engines to E85 raises some interesting questions. You actually have two different issues here. One is for a basic conversion by someone who only wants to make a conversion with largely existing equipment ( ie minimum investment in order to cut fuel costs, to get some of the benefits of a superior fuel or as a political/social statement regarding foreign oil independence or renewable fuel concerns) For those folks the conversion is really pretty simple.

If you are on the other hand looking at an "optimized conversion" where you are custom building a setup to get the most out of E85 --- than that is a whole different ball of worms.

For the "basic conversion" You only have a couple of issues to worry about.
1. Ignition timing changes are not necessary E85 and gasoline use almost identical ignition advance at both max power and max effeciency.
2. Fuel flow increase to adapt to the different fuel. In this case your most important concern is to increase fuel flow by about 27% give or take a bit so the engine is working with an ideal mixture.
3. Fuel system component compatibility ( modern rubber fuel lines are ethanol safe) Some fuel pumps, and gasket materials may have issues.

On modern OBDII electronic engine management systems, almost no changes of any kind are needed at fuel mixtures of 33% and below of E85. The modern ECU's have enough fuel trim authority to adapt to these mixtures. If the user is willing to live with some CEL's and a slight lean out under max power, you can push that up near 50% mixtures with no changes at all. For mixtures between 50% E85 and 100% E85 you need to increase the fuel system flow capacity by using larger injectors, increased fuel pressure etc.

On the EFI systems, if there is a user tuneable or (vendor tunable) ecu reflash or adjustable piggy back tuning solution, you can optimize the fuel mixture by using commonly understood tuning modifications.

Generally you richen the mixture about 27% across the board. At max power if performance is the goal you will want to run it even a bit richer as Ethanol based fuels continue to make more power at up to 25% rich of stoich mixture where gasoline reaches max power at about 15% rich of stoich. EDIT I have one source that says you can go up to 40% rich of stoich on E85 and still get increased torque. On carburator systems you may need to enlarge fuel inlet sizes and ensure the needle and seat material is compatable with ethanol fuels.

For max fuel economy the ethanol based fuels produce more torque at lower throttle openings and their higher fuel octane and cool burning characteristics will allow you to lean out the light throttle low load cruise portions of the fuel map father than you would dare on gasoline.

On an optomized carburator system, basically all the above applies but it is a bit more complicated to get there. For an average driver, only interested in getting the car to run well on the new fuel. Richen the primary jets about 27%, and the secondary jets a bit more. You will probably want to increase the accelerator pump shot and may need to modify the idle mixture sytem slightly to get good drivability. You may need more carburator heat, and or more agressive choke settings in cold weather.

Any tuner that is good with carburators should be able to dial in a setup with a bit of experimentation. There are a handful of shops that build custom carburators for racers that run methanol fuels and an E85 conversion carburator would be a pretty simple adaptation of their methanol carb design I would think. Call around and see who builds "alcohol carburators" for the racers and they should be able to get up to speed pretty quickly.

Once you get to trying to optimize the engine for a high ethanol fuel like E85, you would be making pretty much the same modification the methanol fuel class racers do to their engines with the exception that your fuel flow rates would be a bit lower. Due to the higher octane you would run a higher compression ratio ( up to 13:1 or so on NA engines).

Wet flow in the intake manifold of carburated systems is more critical due to the higher volume of fuel dropplets and strong charge air cooling of the alcohol fuels. Alcohol fueled engine tend to like heads and manifolds that have higher air flow capacity by about 10% ( actually ports shaped for slower mixture velocities but higher flow, bigger intake valves, more cam etc. ). The engine can make use of the higher volumetric effeciency where on gasoline it would have gone over the edge into detonation with the higher flow intake system. The increased torque and higher compression ratios, with the alcohol fuels largely gets rid of low speed drivability issues that the larger intake flow and more agressive cams would create on a gasoline engine. The Alcohol fueled engine may also prefer a larger header tube size for performance applications (ethanol produces more exhaust gas volume than gasoline does).

Fuel drop out is more of a concern for max power engines running alcohol fuels, as is keeping the mixture in suspension. Engines can run with slightly warmer thermostats to aid cold weather drivablility, and keep oil temp up high enough to keep from building up fuel in the oil due to the very rich mixtures racers run. Modern synthetic oils appear to work just fine with E85.

A smaller cooling system may be useable on the E85 setup than you could get away with on gasoline. In some cases you may want to intentionally lean the fuel mixture out a bit to get some heat in the engine. In carburated engines they my like more intake manifold heat in cold driving conditions.

Due to the lower exhaust gas temp, catalytic converters light off slower (or fail to light off) with alcohol fuels, so more attention should be made to keep heat in the exhaust system prior to the Cat.

Older vehicles (pre-1980's) may have some fuel system compatability issues with carburator floats, fuel hoses and seals. Cork based carburator gaskets have been known to cause problems on some cars as have Plastic foam carburator floats. Remove any magnesium or zinc in the fuel system, keep an eye on aluminum if it is constantly wetted by fuel and open to the air so it can absorb moisture ( ie carburator float bowls). Anodized aluminum is safe as is stainless steel, mild steel, nickle plated brass and bronze fuel fittings. Mixing many dissimilar metals in the same fuel system should be avoided. ( things like copper tubing, aluminum etc may set up electrolytic corrosion if in the same system. Much like underwater corrosion control in boats, highly reactive metals like Zinc and magnesium are to be avoided)

Some Plastic fuel tanks may have issues with E85, Older fuel tanks coated with "tern" metal ( a lead based coating) may slowly have the internal metal coating stripped off due to this sort of electorlytic action.

CARS · Joined: 27 Jun 2005 Posts: 62 Location: Comfrey MN

Thanks Larry. It was worth the wait.
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hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

Glad you found the post helpful.

You may also want to check out a couple of the following sources.

The necessary Components of a Dedicated Ethanol Vehical
www.westbioenergy.org/reports/55019/55019_final.htm

The Compatibility of Reformulated and Oxygenated Gasoline with Fuel System Materials
(DAI Informational Document # 970201, February 1997)
http://www.ethanolrfa.org/Final960501.pdf

Fuel Ethanol Industry Guidelines Specifications and Procedures
RFA Publication # 960501

http://www.pei.org/FRD/rfa_pub.pdf
http://www.ethanolrfa.org/Final960501.pdf <--- 2003 version

Driveability and Performance of Reformulated and Oxygenated Gasolines (PDF)
(April 1997), RFA Information Paper # 970302
http://www.ethanolrfa.org/pdf/DAI970302dri%20ability%20perfo.pdf

Properties of Alcohol Transportation fuels
U.S. Department of Energy
http://www.ethanolrfa.org/pdf/DAI970302dri%20ability%20perfo.pdf

Larry

CARS · Joined: 27 Jun 2005 Posts: 62 Location: Comfrey MN

I forgot to add this to my last post. In regards to the EPA not allowing conversion kits anymore, is it due to increased emisions that an optimized (specific buillt) engine would produce? I have read over the years that the reason for the reduction in compression ratios in the early 70's was due to the fact that lower compression lowered the emissions put out by the vehicle. Only untill the perfection (?) of efi and on board computers were the automobile mfgs able to increase the compression ratios to 10:1+ like we see as the norm today.
Am I correct in this assumption? Would a 14:1+ compression, specific-built engine be able to ever pass emission testing?
Any takers...
Thanks
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hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

The main issue with the EPA is that they force the manufactures to warrantee the emissions system will work as designed for 50,000 miles. They also prohibit modifications unless you jump through a very expensive hoop to prove that the modification does not compromise this 50,000 mile guarantee. Small shops and vendors simply do not want to buy into the problems unless it is a high volume system. In the case of CARB certifications you only see those on things the performance vendors can sell in huge quantities.

A high compression engine might have some issues if run lean. NOx emissions are a function of high temperatures and pressures in the cylinder. Due to ethanols cool burning characteristic as long as the mixture is lean enough to avoid the very high temps necessary to form NOx, you should be okay.

As I recall there were two major issues and a minor issue.

First, they began phasing out lead in fuels, that lowered the available fuel octane. They began blending fuel for the majority of cars that were light weight, small displacement economy cars rather than big block muscle cars.

When I was in highschool I worked in a Mobil gas station ( circa late 1960's) and at that time our pump premium was supposed to be about 102 -103 octane. Can't say for certain but that is what we were told. I had no problem running a 10.5:1 compression ratio in a 392 Chrysler Hemi on plain pump premium, in fact I could run it on regular if I did not push it hard. The small block chevy guys were running up to 12:1 compression ratios on the street at that time.

The second was, as they attempted to lower emissions without going to catalytic converters, high compression ratios and high cylinder pressures increased NOx emissions.

The third minor issue was that due to oil supply issues (oil embargo 1972-73 and very high prices up till early 1980) the oil companies began to try to blend the cheapest fuel they could and still meet the minimum octane requirements. This led to some high sensitivity fuels that had an adequate fuel octane according to the R + M/2 method but the motor octane was so low that they caused problems with detonation. At the same time, we were still using carburators on most cars (the first wide spread EFI system was the 1969 VW, even though Chrysler tried it in 1958.)

They were running silly lean mixtures on idle to try to get good gas milage in stop and go traffic, and the engines had problems with run-on when you shut them off. They would rattle and shake and sputter for several seconds in some cases, you even had to stall the engine by letting out the clutch in gear to get a hot engine to stop running on some cars.

In short, there were lots of factors involved, and each model year the manufactures tried something new. Look through an old motor manual of the period and you will see different tune up specs each year, different emissions systems, distributor, and ignition designs as well.

Larry

CARS · Joined: 27 Jun 2005 Posts: 62 Location: Comfrey MN

Dang... your good Hotrod. Hopefully we can get some other peoples opinions and insight.
Are there any engine builders or fuel specialists listening?
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chenely63 · Joined: 09 Aug 2005 Posts: 27

has any body tryed the flextek coversions?
www.abcesso.com
I sure would like to know how well it works befor buying
thanks
Leo

specialgreen · Posted: Wed Aug 10, 2005 4:10 pm Post subject:

The approach Hotrod and others have taken is to increase the fuel pump pressure, or increase the size of the injectors, to cause the car to flow fuel at a higher rate. The computer is left as-is.

It appears that this kit is a chip and sensor harness which doctors the sensor signals to the ECU. Their website mentions that they don't increase the fuel pressure, or the injectors.

My first thought is that there is no way that this kit will allow proper operation under wide-open-throttle. Without increased flow, there will just not be enough fuel flowing, and the mixture will be overly lean.

However, it could be sufficient for typical street cruising. The manufacturer claims that the device can be switched from active "E85 mode" to passive ("gasoline mode"), allowing you to switch back to gasoline, such as for car trips where E-85 may not be available.

Interesting...

stellar · Joined: 09 Aug 2005 Posts: 3 Location: Jönköping, Sweden

CARS · Joined: 27 Jun 2005 Posts: 62 Location: Comfrey MN

Well everyone, We did it!!! Ok, my brother actually did it I just stood there with a cold one in my hand most of the time Very Happy

.
We converted my bother's 1984 Mustang drag car over to E85 with the help from your advice.
It took a couple of weekends of testing at the track but we are as fast as we ever were and while everyone else was cooling thier cars off with fans and ice we actually had to leave it run! I think the max temp during the 20 runs we made was about 160!!
The downside was that we used more fuel than ever before. Guess we will have to buy a few extra gas cans next time.
My brother says he will write down every little thing he did so I can post it here for your viewing pleasure.
thank god one of our crazy ideas worked for once!!!
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hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

Great to hear it worked out okay.

You may have to run a hotter thermostat to get engine temps up. I have a 180 deg F thermostat in my car and according to my monitor at high engine rpms the coolant can drop to near 160 deg F.

For drag racing you may even be able to cut down your aero drag by blocking off part of the radiator inlet as well.

Larry

jachristner · Joined: 12 Oct 2005 Posts: 64 Location: Kokomo, IN

I'm interested in converting a vehicle to run on E85. However, I don't want to lose the ability to run on full gasoline, if needed.

I'm planning on getting a newer Wrangler, which would of course be fuel injected. Based on your "basic" conversion plan, it seems the only thing it should need is an increased fuel supply. I've seen suggestions on here of changing to larger injectors and increasing fuel pressure but neither of those seems well suited in my opinion.

I noticed that Hotrod has done a lot of tinkering with this and the problem seems to be the ECU. With the larger injectors, higher percentages of E85 are possible, but at the expense of compatibility with full gasoline.

Increasing the fuel pressure should work and the suggestion of an adjustable pressure regulator should allow compatibility with both full gasoline and full E85. However, I'm assuming this would require replacement or addition of some relatively expensive fuel system components and without an extensive control system, would still require manual changeover for each fuel. I'm sure it wouldn't be very much trouble, but with someone who is prone to forget things as I can be, it doesn't seem to be the best solution.

If the fuel pressure is increased to increase fuel flow to the cylinders, will the ECU adjust the pulse length down when running on full gasoline to prevent running too rich? If this is true, it seems that higher fuel pressure should solve the problem. Does increasing the fuel pressure promote better air/fuel mixing and improve combustion?

That leaves the approach of increasing the injector pulse length. From what I understand (and someone correct me if I'm wrong on this), the ECU adjusts the air/fuel mixture by varying the pulse length. Hotrod stated the problem with his Subaru is that the ECU can't adjust the length far enough in the rich direction to properly run on E85. The larger injectors fix this problem, but simply moves the range of adjustment up which sacrifices the lean end and causes trouble with full gasoline.

I've been wondering if the pulse length signal could be modifyed when it leaves the ECU to expand the range of adjustment possible. I think that if the pulse signal could be multiplied by some factor, the ECU would be able to adjust farther in the rich direction on it's own.

Does anyone else have any thoughts on this? I'm not sure if there would be other problems with this approach. If it has a base signal built-in, this would throw that off. Whether or not that causes problems with the electronics or causes the computer to think there's a problem, I don't know.

hotrod · Joined: 19 Apr 2005 Posts: 872 Location: Colorado

Each car is a little different regarding what is practical, what is doable and what is affordable.

As you say the simple answer is to increase the fuel flow but there are several ways to get there from here.

On fuel injected systems, ---

larger injectors (as you point out simply moves the available control authority up)

Increase fuel pressure --- with an adjustable fuel pressure regulator you can dial in the amount of increase / decrease you like.

Add an add on injector for example some cars may allow you to install a throttle body SPI on a direct port manifold and only use the throttle body injector when running E85.

Spoof the control system for fuel, by giving it a false single regarding air flow. ie. Tell it your flowing more air than you really are. After market systems like the SAFC do this by tweaking the MAF signal.

You can actually reduce the air flow rather than increase the fuel flow. It would reduce power slightly but the magic most affordable setup may be to do several tweaks each of which gets you part of the correction you want.

At some point some electronics hacker will come up with a useful way to use the GM sensor that detects the percentage of ethanol in the fuel. You may be able to do the same by simply developing a circuit that measures the electrical conductivity of the fuel.

Once you have a sensor input someone who is handy with a PIC controller could come up with a system to modify the fuel injector pulse width on the fly just like the manufacturers do but I suspect that is a few years away.

Not likely to happen before people figure out the basics of which cars are most user friendly with after market modifications for E85.

Larry

specialgreen · Posted: Thu Oct 13, 2005 12:31 pm Post subject: Re: Full Flex Conversion

Too bad there's not a FFV Jeep you could buy. If you could deal with a truck or SUV, you'd have lots of options.

It sounds like your goals are:
-Drive a Wrangler
-switch back and forth between gasoline and E-85
-not have to do anything maunal to switch

...basically a D-I-Y FFV kit. Pretty-much everything we've talked about has required some operator intervention to switch between gasoline or E-85.

The FlexTek may be a good compromise for you: you'd have to go under the hood and flip a switch to go from gasoline to E-85. I suspect that you could drive on up-to 50% E-85 with the FlexTek set to "gasoline"; and from 50% to 100% E-85 when set to "ethanol". But there may be a range right in the middle where operation is rough. Caveat: I don't own one, and only heard from the Swedes that the FlexTek works.

The slickest thing would be a combination of the FlexTek with a GM in-tank fuel sensor: the FlexTek would vary the pulse length based on ethanol content in the fuel. But that doesn't exist yet. And if you're going to go mucking with fuel system components, then maybe a variable-pressure fuel rail would be better than just lengthening the pulse, since it might let the car get to wide-open-throttle without fuel starvation.