Monday, August 25, 2008

The REAL lowdown on the "risk" of running E85 in a non-FFV

This is the best comment I've ever read:

My Take on E85 fuel system wear in Non FFV's.

In 1988 mandates require auto manufacturers to be safe with E10 (10% ethanol) which everyone has been running for years. At this time, the use of vunerable rubbers, eaisly corroded metals, etc was minimized to allow safe operation of vehicles on 10% ethanol. Furthermore, Ehanol is typically only corrsive to modern fuel systems when it is exposed to water (ethnol is, unfortunately attracted to water and readily absorbs water). This is part of the reason all fuel systems are closed, no outside air (minimal) or moisture can enter the system when the gas cap is closed.

An acceptable figure for damaging moisture contect of E85 would be approximately 1%(over a period of time), thats about 1 pint of water would have to be consistently added to every 12.5 gallon tank of gas to obtain any appriciable corrosion in a fuel system 1988 or newer (personally I use 1996 is a benchmark for converting vehicles to E85 without substantial fuel system upgrades, also when OBDII was implemented but this is another subject).

The long and short of it is, fuel system (modern) are very robust, running E85 in a modern engine can be safely done (in my opinion, based on information available to me). After coverting my personal vehicle, a 1998 Toyota Tacoma, and 2nd hand reports of Subaru's running E85 for periords of 2 - 5 years or so, I have seen no physical evidence that rapid deterioration of a fuel system occurs in late model vehicles. One could thorize that over a period of 10 to 20 years an issue could generate but I don't expect to have my Toyota until 2028, it would be 30 years old and by then I hope there will be some better alternatives. Or I will have completely overhauled it anyway.

My experience is based on a Mechanical Engineering Degree and 2 years working for an injection company (several years ago) engineering department conducting durability testing on injectors and pumps.

People expect manufacturers to come out and certify that their cars will be ok but this is never going to happen, no one will take that kind of liability or potential loss of sales etc etc. Converting a vehicle is a personal decision that each person should make based on thier own judgement (and take responsibility for). There is an abundance of mis-information on the web going in both directions and I encourage everyone to weight each source carefully.

Real negative's of running E85

1. reduced mileage per gallon, anywhere from 5-30%, people with turbocharged or supercharged engines have been able to take advantage of higher octane ratings and optimize system performance (mileage, torque and HP) retaining up to 95% of their original fuel economy. In my Toyota 4cyl, I have been getting 18 mpg as opposed to 21-22, but the fuel has been consistently $1 cheaper so it's a win win for me, plus I like more of my money staying in the States.

2. Initially, you will experience the need to change fuel filters several times until all the garbage in the regular gasoline is cleaned from the system. I personaly consider this a good thing. It's not that hard to change a $10 inline filter, I like to cut them open and double check that there is not debris from fuel system parts, so far just sludge from the 125000 miles worth of cheap gas. Some people have had a fuel pump failure from the increased sludge coming out of the take while the E85 is cleaning things out, not common but still a possiblity.

3. When switching between the gas types, you will notice the cars computer taking some time to gradually change parameters, some say about 20 miles or several run cycles. (engine cycles involve the car warming up from cold, not just turning it on and off)

How does a Flex Tek or Full Flex conversion work?

Well, they both work off the same principal per my understanding. In a nutshell oversimplified explanation, a cars computer reads unbonded 02 (from the O2 sensor, go figure). Based on this reading, it just reads O2, nothing else, it assumes that unused O2 means there's more oxygen than fuel and therefore inefficient combustion. The only parameter that the computer can change is the fuel injector duty cycle. Great, why do I need a piggy back computer if the computer can add more fuel by itself. From the factory, computers can usually only adjust fuel rates by +/- 15% to accomodate changes in elevation, fuel quality, etc. Well, it's a fact that E85 contains 25-30% less energy so it stands to reason that about 30% more fuel is required for efficient combustion. So, this piggy back computer simply adds a predetermined (about +15% for this example) to the injector duty cycle. Now, your cars computer can easily adjust from 0 to +30% fuel to accomodate a range from regular unleaded up to E85. People will notice the gradual change in performace as the computer adjusts parameters, thats why it is recommended to run 50/50 mix of E85 and regular unleaded in between regular gas and E85, as the cars computer (OBDII) adjusts parameters gradually and remembers the previous parameters at each startup.

These piggy back computers acheive settings that "gearheads" have been doing for years when modifying and tuning cars but it takes all the guess work, trial and error, dyno time, expensive sensors associated with an expensive ECU or fuel system controller that most of us couldn't handle programming or installing...

E85 is a step in a right direction, easily used in Late model vehicles and even better when included as an OEM feature. The option warrents careful consideration by anyone interested in supporting our local economies, reducing dependence on forign resources, sticking it ot the man (oil companies realize 100 million dollard each and every day in pure profits), reducing polution, 70% at the tailpipe and a modest 20-30% when the entire supply chain is considered.

Interesting Fact, our tax dollars (through subsidies) pay farmers not to farm over 40 million arcres of agricultural land in the United States. Using modern technology and coservative estimates this land alone could alleiviate approximately 50% of US importants on oil. Yeah, the cost of beef might increase a little, so what, at least that money would stay here and our childrens childrens childrens would stand a good chance of having some resources left.

3 comments:

Chris said...

Once the flex fuel kit has been installed for some time, the cars ECU will have negated the xtra injection time?
I dont understand whether it would make any difference except for intial First tank of e85.

If I refuel with a tank of regular fuel and drive it out the add E85 and the kit is installed the entire time how ould the engine readjust for E85 again?

Do these kits do anything if they are installed before the e85 is added?

My car goes great at high revs but is sluggish when i put my foot down at low revs and seems to go better if i only increase power slowly?
Also I seem to have an intermitent shudder or miss when cruising, like the engine is starving for fuel but if i put my foot down again it is ok. I was wondering if my cars EGR (exhaust recirculation is causing problems or if the Flex fuel Kit is causing problems at low power (cruise) becuse the engine ECU leans out the fuel mixture.

buzzcut said...

Chris, I thought that you had a flex fuel Caravan. You bought a Flex-tek? When did you do that, and what vehicle is it on?

Chris said...

Car is a Mazda 323 Astina 1600cc 4cyl.
I put a white lightning kit on it about 2 months ago. I am generally very happy with the results. Only issues are there are not enough E85 stations, cruise speed "feathering or missing" and some low revs power issues.
Saving 30% on trips and 20% around town. I my home town E85 is $1.05 per litre and ULP varies between $1.50 and $1.65. In the city the margin is smaller and I have to go further out of my way to get E85 for $1.15 p/L ULP is $1.42 to 1.52 p/L
per liter and ULP varies between $1.50 and $1.65. In the city the margin is smaller and i have to go further out of my way to get E85 for $1.15 p/L ULP is $1.42 to 1.52 p/L