mit Erlaubnis des Autors: (wenn ich ein wenig Zeit finde uebersetz ich das auch noch falls Bedarf besteht!)
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Converting your car to use E85
During the last few years a lot of so called "flexi-fuel" cars has seen the light of day. They are ordinary cars with the capability of running ordinary gasoline, E85 or E100 (ethanol) and a blend between the two. This is developed in response to the high fuel prices and to try to take care of our environment. In theory or in a controlled lab, ethanol only leaves behind the rest-products of water and carbon dioxide after a complete burn. When burning ethanol in real life it is easy to get very close to this as well.
I and many others have converted their gasoline car to run on E85 (ethanol fuel). This is a guide on how to do the same thing. I will try not to get too technical and I will try to keep it simple for everyone to understand.
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First of all, what is E85?:
E85 consists of 85% ethanol and 15% additives. The additives vary a lot depending on where you live and time of the year. But roughly, the 15% additives is mostly made up of gasoline, additives that helps the engine to make a complete burn, additives that helps the engine start when it´s cold and additives to color the fuel and the flame (so you know what substance it is, and also to help you see that it is really burning).
(Positive) facts about E85:
1. It is
not corrosive to the fuel system or the engine. This is a myth and ethanol is often confused with methanol, which actually have corrosive properties. Some models before 1988 on the other hand may have some parts that is not ethanol resistant. If we are talking Volvo´s, then this mainly applies to the non-electronically injection systems such as K-jet etc. Most cars with electronical fuel injection (EFI) should be resistant to ethanol.
2. It is not as harmful to the nature/environment as gasoline or any other petroleum products for that matter. Ethanol is made out of renewable energy resources such as crops and trees to name a few things. The carbon dioxide that an ethanol powered car emits is not contributing to the greenhouse effect, but is taken up by the plants and is being "re-used". The carbon dioxide then goes around in a closed loop. Gasoline on the other hand is made from oil that comes from old dinosaurs, plants and other stuff 100 000 of years ago, and it doesn´t take part in the closed loop but only adds to the amount of greenhouse gasses. Ethanol is also easily bio-degradeable if it should leak into our environment.
3. E85 is 104-105 octane and therefore it´s more knock-resistent and can tolerate more boost or a higher CR.
4. E85 cools the intake charge more and therefore it´s more knock-resistent and can tolerate more boost or a higher CR. And it also makes the engine run cooler and to some degree, even safer.
5. E85 is in most cases at least 5% more effícient than gasoline at the same lambda value (up to 25% more efficient on some cars optimized soley for E85).
6. Since E85 has very good cleaning properties as well as leaving behind a rest-product of water, it is cleaning the fuel system and it will keep the injectors nice and clean. The combustion chambers, valves, ports and the exhaust will also be clean(er), almost like the car had water injection.
7. In most cases it will cost less $/mile to run on E85.
(Negative) facts about E85:
1. Cars running on E85 have some trouble starting when the engine temperature drops below +5*C. Cars running E100 (not very common) have some trouble starting when the intake (the air) temperature is below +15*C. This is easily solved by using an engine heater in the winter, electrical or fuel-heated (this is recommended on all cars regardless of fuel to get better mileage, less wear on the engine and less impact on the environment etc., but that is another matter to discuss and will not be brought up here...). Some people also adds a little extra gasoline to the tank of E85 to help with cold-starts.
2. Since cars running E85 requires roughly 30% more fuel, a tank of E85 will not get you as far as a tank of gasoline and you will have to refuel more often. This is often disregarded by E85 users who learn to live with it because of the economical gains.
Technical facts about the mentioned fuels:
E85 requires 39% more fuel to reach stoich even if that is not what you may come up with when doing calculations based on the table below. This is because the injector flow is slightly different when using E85 among many other things I can´t really think of at this time (will be added at a later time).
Fuel ........................
AFRst ........
FARst .......
Equivalence Ratio ...
Lambda
Gas stoich ................ 14.7 .......... 0.068 ................ 1 ................... 1
Gas max power rich .... 12.5 .......... 0.08 ................. 1.176 .............. 0.8503
Gas max power lean .... 13.23 ........ 0.0755 .............. 1.111 ............. 0.900
E85 stoich .................. 9.765 ....... 0.10235 ............ 1 ................... 1
E85 max power rich ...... 6.975 ....... 0.1434 .............. 1.40 ............... 0.7143
E85 max power lean ..... 8.4687 ...... 0.118 ............... 1.153 .............. 0.8673
E100 stoich ................ 9.0078 ...... 0.111 ............... 1 .................... 1
E100 max power rich .... 6.429 ........ 0.155 .............. 1.4 .................. 0.714
E100 max power lean .... 7.8 .... ...... 0.128 .............. 1.15 ................ 0.870
The term AFRst refers to the Air Fuel Ratio under stoichiometric, or ideal air fuel ratio mixture conditions. FARst refers to the Fuel Air Ratio under stoichiometric conditions, and is simply the reciprocal of AFRst.
Equivalence Ratio is the ratio of actual Fuel Air Ratio to Stoichiometric Fuel Air Ratio; it provides an intuitive way to express richer mixtures. Lambda is the ratio of actual Air Fuel Ratio to Stoichiometric Air Fuel Ratio; it provides an intuitive way to express leanness conditions (i.e., less fuel, less rich) mixtures of fuel and air.
When driving purely on E85 you can blend it with up to 25% gasoline in case you want to raise the AFR number used to produce max. power. In that case you can raise the boost even further since the volume of fuel needed to reach the desired lambda is decreased.
Performance application and fuel needed:
Performance application:
Let´s pretend for a while that the ECU´s in our cars are pretty good at their jobs. On gasoline it will try to keep an AFR of 14.7 (lambda=1) all the time at idle, cruise and light load. It will also try to keep a good AFR at WOT/boost of 13.2-12.5, sometimes even lower than that, probably closer to 11.x.
Why? Because the fuel has a cooling effect on the intake charge and the space in which the combustion occurs.
As you can see from the table shown above this section, the ideal target AFR´s under boost for both gasoline and E85 are listed. For gasoline it´s 13.23-12.5, and for E85 it´s 8.47-6.975. However, with E85 you will not need to richen the mixture under WOT/boost as far as 6.975 or beyond. It does not need to be proportionally richer when compared to gasoline.
Why? Again, Because the fuel has a cooling effect on the intake charge and the space in which the combustion occurs. And at such a low AFR as 9.765 (lambda=1 on E85) or lower the fuel cools pretty good, don´t you think so?
Many people with some experience in mapping an ECU for use with E85 says that as high AFR as 8.5 or lambda=0.80-0.85 works well. No need to go to the extreme end of the useable scale to get safe power. It only uses a lot of fuel without giving any benefits.
Since you don´t have to richen the mixture as many percent (proportionally) as you have to on gasoline, you can make more power without having to use as much fuel. Instead you can keep the AFR´s leaner across the board and by doing so you can make room for higher boost without maxing out the injectors.
Fuel needed:
As you will see, both in my article as well as other places on the internet, different fuel requirements are listed. What numbers will you see and why?
1. A car converted, but not specifically mapped for E85 will consume ~30% more fuel.
2. A car running E85 will require ~42% more fuel.
3. According to your own calculations (if you have bothered to look in to it), it will not quite add up. Most people scratch their head.
Let me show you a table again:
Mode ...........
Gas ....
E85 ......
extra % (mass) ...
extra % (flow)
Stoich .......... 14.7 .... 9.765 ........ +50.5% ................ +42%
Lean power ... 13.2 .... 8.47 .......... +55.8% ................ +47%
Rich power .... 12.5 .... 6.975 ........ +79.2% ................ +69%
E85 has a higher density than gasoline. The change in AFR from 14.7 (lambda=1 for gasoline) to 9.765 (lambda=1 for E85) is 50.5%. But the resulting flow needed is only 42% greater.
Explanations to this: E85 will need a fuel flow that is 42% greater than the flow needed for gasoline. However, it will not use 42% more fuel since it will actually be more efficient. Generally, the engine will consume ~30% more fuel.
I am using 46.7lb/hr injectors (45% larger than stock) and my AFR´s should theoretically look like this:
*At idle, cruise and low load (closed loop) the AFR will be 9.56, the O2-sensor sees this and will correct it to 9.765.
*When at WOT/boost (open loop) the AFR will be between 8.58-8.13. This looks a little lean according to the AFR table, doesn´t it? It isn´t even in the "rich" area according to the table. No worries, the cooling properties of E85 are pretty good. But in reality I will actually get an AFR of around 8-7.5 since my ECU wants to run a slightly richer mixture than 12.5 on gasoline. It obviously does not know that it is running E85...
Economical gains:
I can´t compare to other cars, users or driving styles but myself and my own Volvo 945 Turbo.
So let me tell you guys about the fuel prices here in Sweden.
98 octane gasoline cost 12sek/L = $1.68/L = $6.36/gallon.
And 104 octane E85 cost 8sek/L = $1.12/L = $4.24/gallon.
My car usually use 12.5L (average) of gasoline per 100km of driving (mixed, pretty normal driving). E85 is supposed to use up 30% more fuel, so my consumption should be 16.25L of E85 per 100km of normal driving.
I have driven the car a lot on E85, and I am going through 65L of E85 in 400km. WOW! That is exactly 16.25L per 100km, just like calculated.
I am impressed!
This also means that my usual cost of 150sek/100km has gone down to 130sek/100km, even though I drive like a maniac.
And of course, the power and driveability is much better.
My experience with E85:
1. Better power (cooler intake charge, higher octane and the fact that it is cleaning the engine pretty good).
2. Smoother power and better stability at part-load.
3. I don´t want to go any higher than 16psi on the stock 13c piece of **** turbo, but it pulls harder and harder all the way to redline.
4. After only 50 miles the tail-pipe began to get a lighter color. It was black inside before, now it´s brown and very transparent. My pipe is chromed and now you can see the chrome on the inside as well. When I have driven the car for a couple of 100 miles more I will tell you if it has got any cleaner inside.
5. The sound from the engine is different. It sounds more powerful.
6. The smell from the exhaust is much nicer.
Thoughts about E85 for those who like to go one step further:
Since E85 is more knock-resistent you can modify your engine to make better use of the properties of the fuel and thereby gain both power and mileage at the same time. You can benefit from:
* Advancing the timing (statically or dynamically).
* Raising the compression ratio by milling the head down.
* Still maintain a high boost level in conjuction with high CR.
* In some cases you can run a slightly leaner mixture under part-load or WOT that will benefit the mileage and give head-room for more boost.
* If you have an aftermarket EMS you can get a lot out of E85 with careful mapping.
* For those of you that have looked in to Somender Singh´s groove theory, this may be very interesting for you (think: 12:1 CR, very advanced timing and high boost...).
* And yes... My chips clearly makes a larger (positive) impact on performance when used with E85 (better AFR´s and more advanced timing).
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And now: How to convert to E85
There is one advanced, and three simple and different ways to convert to E85:
1. The advanced way,
tuning and re-flashing the ECU to optimize it for E85.
Advantages:
* The car will be optimized for E85.
* It will be very fuel-efficient.
* More power at the same boost level.
Disadvantages:
* So far, extremely expensive (many hundred up to several thousand dollars).
* You can´t easily go back to gasoline if you want to, unless you feel comfortable with opening the ECU now and then.
* An optimization for E85 causes the injectors to use most of the "overhead" potential they have. Forget being able turn the boost up at all.
* To be able to get any bigger performance gains out of this setup you will need even more performance parts like injectors etc.
* Not the Turbobricks way...
2. An
electronical device (piggyback device) that you plug in between the injector wires and the injectors. It will expand the injector pulsewidths by approximately 30% and it will have the possibility of both running on gasoline and E85 by flicking a switch.
Advantages:
* Easy to install and use.
* Has the capability of both gasoline and E85.
Disadvantages:
* Expensive ($350+).
* When running in E85 mode it causes the injectors to use most of the "overhead" potential they have. Forget being able turn the boost up at all.
* To be able to get any bigger performance gains out of this setup (when running E85) you will need even more performance parts like injectors etc.
* Not the Turbobricks way...
3. An
adjustable fuel pressure regulator.
Advantages:
* Easy to install.
* The car ECU will adapt to the changes (if it is equipped with an O2-sensor).
* Cheap (~$100 including hoses and clamps).
* You can still do (most of) the performance mods listed on Turbobricks.
* Can be used if you want to blend gasoline and E85. You will always have to keep track of the percentual blend of gas/E85 though. If you want to run a blend of gas/E85, for simplicity, decide a percentual blend and stick to it.
* Can benefit from being used in conjuction with conversion alternative #4.
* This looks more like the turbobricks way...
Disadvantages:
* Too high fuel pressure will put unneccesary strain on the fuel pump or kill it.
* Too high fuel pressure will alter the spray pattern and/or hinder the injectors from opening properly.
* You have to set the fuel pressure differently for different blends between gasoline and E85 (doesn´t take more than a few minutes but can be irritating to some).
4.
Bigger injectors.
Advantages:
* Easy to install
* The car ECU will adapt to the changes (if it is equipped with an O2-sensor).
* Cheap (at least if you buy some used ones from a junk-yard or pick-n-pull).
* You can still do all the performance mods listed on Turbobricks.
* Can be used if you want to blend gasoline and E85 (to some degree, more about this further down the page).
* Can benefit from being used in conjuction with conversion alternative #3.
* This looks more like the turbobricks way...
Disadvantages:
* You can´t run on a high percentage of gasoline (will run too rich).
* If you have to run gasoline, you will have to swap back to a set of smaller injectors.
So, we will be looking at the two easiest/cheapest ways which most people think are the best ways of doing it.
Installing a fuel pressure regulator (FPR):
You will need a fuel flow that is roughly 30% (39% or more is preferred) higher than stock. Up to 60% more flow can be used for performance purposes. A good target is 35-40% increase in flow to start with.
Here is an example of increase in flow, and as you can see below, this will yield a very high pressure. Some injectors can take it and some can´t. The fuel pump will also have to work harder. Very good results can be had on a stock car, but if you want to get some performance as well the fuel pump may not support the needed pressure and flow. For performance, an adjustable FPR is best used in conjuction with larger injectors:
* Going from 3bar (43.5psi) of fuel pressure to 4bar (58psi) you will gain ~15% of flow.
* Going from 3bar (43.5psi) of fuel pressure to 5bar (72.5psi) you will gain ~29% of flow.
* To get a satisfying injector flow on stock injectors, you will probably have to go to 5.5bar (80psi) or more...
What you need:
* An adjustable FPR.
* A mounting bracket.
* 30-35" of soft fuel-lines (rubber hose?).
* 20-25" of vacuum-hose.
* A T-junction.
* 4 hose-clamps.
* A fuel pressure gauge is highly recommended.
How to install:
* Run the car until you only have a gallon or so left in the tank.
* De-pressurize the fuel system by pulling fuse #11 (or #1 in some cases) while the car is running.
* Find the stock FPR.
* Connect a fuel-hose between the outlet of the stock FPR and the inlet of the adjustable FPR.
* Connect a fuel-hose between the outlet of the adjustable FPR and the fuel return-line.
* Cut the vacuum hose that connects to the stock FPR and put the T-junction in the middle.
* Connect a new vacuum hose between the T-junction and the vacuum inlet of the adjustable FPR.
* Secure all fuel hoses with hose clamps and make sure there are no leaks (you should be two persons for this, one operating the car and one looking at the connections).
* Fill up with E85.
* Disconnect the vacuum hoses to both FPR´s and set the base fuel pressure to the desired value.
* Connect the vacuum hoses again.
This is what it may look like when it is installed:
There is also an alternative FPR that will fit in the stock location, replacing the original FPR.
It is the
Holley HLY-512-503-5 and that can be found here:
Summit racing, direct link
It is adjustable between 2.4-4.5bar (35-65psi) of base fuel pressure.
(Thanks to
adam_c for finding it.)
Installing bigger injectors:
The easiest way that gives the best results.
Highly recommended!!!
You will need 39% bigger injectors. I use ~50% bigger injectors than stock though, and that works perfect. I also chose a little bigger step up than 39% because of my performance goals.
Example:
* If you are using stock injectors, then look for 42lb/hr injectors or use 37lb/hr injectors (browntops) in conjuntion with an adjustable FPR.
* If you are using 37lb/hr (browntops), then look for 48-52lb/hr injectors, 42-46lb/hr injectors + an adjustable FPR, or just raise the fuel pressure if your fuel pump can handle it.
Calculating useable injector size:
(CURRENT INJECTOR SIZE x 1.39) up to
(CURRENT INJECTOR SIZE x 1.6)
945T man has done an excellent article on how to swap injectors:
How to install Brown Tops on LH 2.2!
Everything that is said about swapping injectors in that article also goes for E85 on both LH2.2 and LH2.4.
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READ THIS:
An air/fuel-ratio gauge is always recommended when doing any of the two mentioned upgrades. On some vehicles that doesn´t adapt well, you may have to set the base idle and lambda again. You don´t want to run too lean and destroy your engine. LH2.4 will auto-adapt and needs no further adjustments :) .
Good luck and happy driving
,
Fredrik
