How to Blend Your Own Fuel, and Why You Should
 

There is increasing evidence that E10, or gas with 10% ethanol is the worst possible blend for your car. The 10% is just enough to mess with the fuel, but not enough to get the sensors to "adjust" properly. ( or the reverse, the 10% messes with the sensors to a much greater degree than is called for )

3 recent studies, one by Volvo, one by the University of North Dakota, and one by Minnesota State University all point to a "sweet spot" MPG in most cars using E30, or 30% ethanol.

In the case of the I4 2.3L Ford Fusion, this car got better MPG with 30% than with 100% gasoline. The Ford Fusion did worse than gasoline, but better than predictions based only on btu content, with 20% ethanol.
The Ford Fusion did worse than predictions at 10% ethanol, and blends over 45% ethanol.

The 2.4L Toyota Camry also did better than pure gasoline with 30% ethanol.
The 3.5L Chevy Impala did best on 40% ethanol, nearly as good as pure gas, but not quite.

It seems in modern, newer cars ( the 3 cars tested were all 2007's ) the air/fuel sensors, and fuel injectors adjust "properly" ( or at least to your advantage... the lean side of things ) at about 30-40% ethanol.

NONE of the cars tested got a "check engine" or warning lamp with less than 50% ethanol. Some "regular" cars can run on up to 65% ethanol before getting a check engine lamp. All cars "run" on E85 ( just poorly ).

So myself and some others at work are going to give this a shot.
( most people I know do not drive hybrids though )
We are going to mix our own 30% and 40% ethanol fuel.
It is easy to do if you live in an area where you can get E85.
Just "dilute" the E85 with regular gas.
( or "enrich" your gas with some E85 )

The tables below tell you exactly how to do this.
Table 1 is for E85 and plain gas.
Table 2 is for E85 and E10 gas.

If possible, allow 3 tanks for your car to fully "learn" the new mix, and to average out weather and traffic concerns that affect MPG.
However most researchers feel this adjustment period only takes 30 minutes / miles. Please report your findings. Thank You. -John

Re: How to Blend Your Own Fuel, and Why You Should
 

Cool!

I look forward to your results. However, I would probably approach it from a slightly different tack. I would prefer to mix the gas in spare cans rather than try to mix in the tank. Our variable sized bladder Prius is not the best 'mixing' container.

Bob Wilson

Re: How to Blend Your Own Fuel, and Why You Should
 

Can't you just mix the gas in your tank in the proper ratios, intentionally not filling the tank several times. Then after several iterations of doing this, top it off with a slightly out of balance ratio, if required, to get a "full" tank to calculate mileage based on the totals added.

Obviously this will have to be a manual calculation, but it should work to see the effects of Ethanol mix vs. straight gasoline :)

Re: How to Blend Your Own Fuel, and Why You Should
 

That's one reason why I made the table in post #1.

At first tank, I can make a 30% mix based on 15 gallons.

On second tank, I will have to "estimate" based on gauges how much "empty space" I have in my tank, and make a 30% mix based on the predicted "empty space". But not knowing exactly, I will say, need to make a mix of 13.5 gallons the second time.

If I'm about to enter an area / state where E85 is hard to find, and my tank is not "empty" there may come a time when I need just 5 gallons of 30% mix to "top off".

I have 30% in my car now, and have gone 25 miles with no caution lamps or any drivability issues. Purrs like a kitten ( so far ).

Any reason to doubt the accuracy of the ScanGauge or On-board display for MPG? ( knowing each has +/- 2 MPG error on regular gas )

Re: How to Blend Your Own Fuel, and Why You Should
 

I just ordered my Scangauge and still waiting for it yet, so I'm just going by what's advertised on their website for this. But isn't one of the trip data parameters you can track "fuel used"? Is that accurate enough to know very precisely how much room is left in your tank?

I'm thinking that if I can use that "fuel used" parameter data to keep accurate measurements of my fuel usage on each tank, I can use that to get the proportions right. Then I can just keep a couple of 5 gallon fuel cans of E85 at home so that when I get to empty I know exactly how much to put in at the station and then come home and top it off with the E85. It's a bit of a trip to get to the nearest station with E85 (about 7 miles from home in the wrong direction from my trip to work), so it'd work better for me to stock up on it and mix it at homethan to go to that station each time to fill up.

Re: How to Blend Your Own Fuel, and Why You Should
 

There are ways to adjust the SG... but I know mine always under-reports just a touch.... it is usually within 0.5 gal out of a 15 gallon tank.

Sounds like you have a really good idea.
Use the E85 for one tank while you are there,
and then take some home with you for next time!
I think they sell yellow cans for E85, but I think it is "legal" to put E85 in a red gas can.... but it may not work well in lawn-mowers, etc. so you may wish to get a yellow gas can. I think blue cans are for kerosine. IIRC.

( I put E50 in a gas generator at a construction site and it ran fine. )

I think you will find ethanol costs about 1 cent more per mile to use in your non-flex-fuel cars. Is one cent per mile worth it to you to use a home-grown, made in the U.S.A. product?

( It's cheaper price, but lower FE will still result in 1 cent extra cost, likely, but that is my guess... and each experiment will help prove/disprove this. )

It costs more per kWh to get your power from a windmill also, about 30 cents more per day, just as a comparison.
:angel: -John

Re: How to Blend Your Own Fuel, and Why You Should
 

Chuck, I like your idea too. The SGII-xgauge is very accurate when the tank fill, refill procedures in the manual are followed. If you move your SG to other vehicles, the tank values will be skewed. That's just another GOOD argument to Santa to have one for each vehicle :)

Re: How to Blend Your Own Fuel, and Why You Should
 

The fractionation system designed by Applied Milling Systems will separate the corn into bran (combusted as an energy source to save the ethanol plant an estimated 40 percent of its natural gas costs), germ, and endosperm (starch for ethanol) as well as other food products like corn meal. ( Word on the street is Frito Lay will buy corn meal from "food grade" ethanol plants. )

http://grainnet.com/photo_gallery/im...e/13_large.jpg

Re: How to Blend Your Own Fuel, and Why You Should
 

interesting. There is an E85 station about 30 minutes from the office....

Re: How to Blend Your Own Fuel, and Why You Should
 

I wanted to drop a line and say thanks :D as this is terrific information. I only wish the local fuel stations would sell anything ethanol (other than Casey's General Stores 10% blend).

Your research showed exactly what I found out a few years ago - that vehicles run poorly on a 10% ethanol mix. I found out the hard way that the fuel was 10% ethanol in the first place (didn't notice the sticker on the pump) - my Toyota 4x4 ran like it was ingesting wet gas (fuel with some water content). It took all kinds of additives off the shelf (octane booster, heet, etc.) to get the poor little 2.4L EFI motor to suck that stuff even partially through. Once it got 1/4 tank down, I topped off with Super Unleaded (93 octane out here) and it started improving. Turns out that my 3,800 pound 4 cylinder truck really did need all of it's available power to climb the hills out here.

I'm going to keep my eyes open in the near future for E85 and hope for the best. In the meantime, I hope they find a more suitable source than edible corn to produce fuel. Imagine the backwards world we live in - with people starving with little food in some areas - and the rest of us wanting to turn food into fuel for our vehicles. :confused:

Re: How to Blend Your Own Fuel, and Why You Should
 

#1 Did you know that "HEET" is mostly alcohol? Alcohol is what removes water from gas tanks / gas lines.

#2 Ethanol (alcohol) fuel is not made from "food corn" directly, as humans only eat a small % of the corn produced in any year, but it can be argued that the ethanol corn is animal food, and the animals ( cattle, pigs ) are used to feed humans, but there are many people who say the U.S. in particular eats too much red meat anyway.

( for the record, I eat more than my fair share of red meat... )
:angel:

So far, in my car I get:

About 31 MPG Highway (Winter) on pure gas.
About 27 MPG Highway (Winter) on 10% ethanol.
About 27.5 MPG Highway (Winter) on 30% ethanol.

Re: How to Blend Your Own Fuel, and Why You Should
 

The 27.5 is an important result but somewhat difficult to measure. Could you go over how you measure it? What sort of driving terrain?

Do you have instrumentation to look at the ICE rpm, torque and fuel flow? This would make it easier to read out the efficiency.

I live in North Alabama. Would you have a recommended URL that might point me at regional sources of E85?

Thanks,
Bob Wilson

Re: How to Blend Your Own Fuel, and Why You Should
 

Bob: http://www.e85refueling.com/

I found an E85 station that's only a few miles from my house, near the Pentagan. I tried the mix ~E30, but still only about 120 miles into the first tank. So far I'm about 1.5mpg below my long term average average :( ... I do see the car learning already the new mix. My first day driving I was down 5mpg below average driving the same. I'm going to give it 2 tanks to see what the results will be to see if it's worth the hassle.

Re: How to Blend Your Own Fuel, and Why You Should
 

It looks like the nearest is Nashville TN. If I pickup 5 gallons of E85, I can brew up 14.1 gallons of E30. That would be enough for a tank and a half. I would just need three, 5 gallon cans and they run about $10/each. For $30, I could test the mixture.

What I'm more interested in is why E30 vs. E10, E15 or E85? What is the 'theory' behind this ratio versus any other?

Thanks,
Bob Wilson

Re: How to Blend Your Own Fuel, and Why You Should
 

here is the study that a lot of people are refering to: http://www.ethanol.org/pdf/contentmg...inal_12507.pdf

30% seems to be a sweet spot for most vehicles tested. E85 gas is about 15% cheaper, so I figured I had nothing to lose by testing it myself. The only variable here is the human one as outside of a lab, 30% in the tank is hard to get accuratly. but if things are going to improve on the car, i doubt if it's not 30% exactly; ie 25-35%, it will matter much. I'm mixing in tank, so I know i'm a little off, but like i said, doubt it will alter testing outside of a lab much with all the other variable: weather, driving condition changes, etc.

How i mix: My first tank I know I've been using E10 for a few weeks, and know that's at the pump. So I added to the 13gl tank about 3gl of E85, and topped it off with regular. As soon as this tank is low (I'm going to wait until the gauge has 2 bars on it which is about 10gl low) I'll add ~2.25gl of E85, and top off with regular. This will maintain the ~30% mix taking account the 30% mix that's already in there.

Re: How to Blend Your Own Fuel, and Why You Should
 

Thanks for the info. I've got a full plate of things to test: (1) next transaxle oil flush and change, (2) exhaust mods, (3) battery experiments, and (4) tire experiments. However, I may be able to squeeze in an ethanol test in the spring. I need 'standard days' and that is at least four months away.

What I can measure is the speed, fuel trim, air flow, injector timing, ICE rpm and ICE torque while the car is running. I have a standard hill that I climb at 55 miles per hour to get reproducible energy data. In the spring, I can do the fuel tests just after my spring oil change and maintenance.

Thanks,
Bob Wilson

Re: How to Blend Your Own Fuel, and Why You Should
 

Bob- I used cruise control repeatedly over a ~100 mile section of interstate at 65 miles per hour. All days were cold, in the teens and 20's outside. No significant wind... not enough wind to bump the car around that I was aware of. Winds were light, and a cross-breeze.

E10 Sold for $2.899
E85 Sold for $2.169 during one tank of testing.

That makes E85 about 25% cheaper cost in my town.

3.5 x $2.169 = $7.59
11.5 x $2.899 = $33.34

15 gallons of E30 fuel cost $40.93 or $2.728 per gallon.
A savings of $2.565 per tank

15gal x 27.5 MPG = 412.5 miles traveled at 65 MPH cruise control, E30.
15gal x 31.0 MPG = 465.0 miles traveled at 65 MPH cruise control, gas only.

52.5 extra miles, if from pure gas would equal 1.7 gallons and if from E30 would be 1.9 gallons.

So really, E30 is costing me more than gas I think.

But the whole point is, E10, which is what most people are forced to use will cost more extra per tank, when compared to gas only. :angry:

This is a "premium" fuel with a premium price. E30 is about 97 octane, and has a large effect on cleaning up emissions, and you will also use 30% less gasoline, which equals about 10% less foreign oil use, since some foreign oil is used to manufacture the ethanol, of course. E10 is only saving about 3% oil, and costs more per mile than E30.

I just mixed 3.5 gal of E85 with 11.5 gal of E10, since all gas in MN is 'supposed' to be E10. The Ford Escape reads "empty" at about 14 gallons, but really holds about 17 gallons.

To use, or not to use E30 is a personal, and complex question.
However, I think E10 is currently a bad choice.
My personal choice is to use 30% if possible, as there are more benefits to it than E10.
-John

P.S. I'm visting So. Cal. and "regular" gas here has 6% ethanol and costs $3.359 near my folks house. :omg:

Less foreign oil and better emissions - reason for me
 

I'd like to again say thanks to everyone for their info on Ethanol enhanced fuel. I will be mixing my own as soon as I can - to see for myself, and the nearest station that sells E85 is still 40 miles from here.

I posted earlier about the horrible effects 10% ethanol had on my 86 EFI Toyota 4x4. I forgot to mention that this engine already had a number of mods to get some HP out of an archaic 2.4L 4 cylinder.
A huge number, actually :P including a custom cylinder head (not a Toyota casting), camshaft, header, injectors, a decked block and milled head to increase compression, custom pistons, flywheel, K&N filter element, 2.5" exhaust system, etc. And while all this means I have enough power to move the truck well, it gets horrible mpg and won't run on anything that isn't good ole' full oil unleaded. Maybe I'll try testing it again someday soon - I kinda broke the rear axle awhile back LOL.

So readers - please don't think that your stock 22RE equipped 4 cylinder Toyota truck won't run on ethanol blends - they probably will. I think we owe it to ourselves to try this, even by guess-timating a mix level at the pump. Maybe sometime soon we'll be able to push an E30 or E40 button on the pump and help our economy and our air quality. I'd buy it today if it was 5 bucks a gallon ;) .

Re: Less foreign oil and better emissions - reason for me
 

These exist today in the states of Kansas, Minnesota, and S. Dakota ( and perhaps Iowa ). They are called "blender pumps". ( but there's not very many in service yet )

You can choose E10, E20, E30, E50, E85.

The station owner has just two tanks of gas, E10, and E85. The pump does the rest.

Actually, almost every gas station on the planet has blender pumps.
The station owner only buys High Octane and low Octane. The mid-grade is usually a 50/50 mix of the two. :angel:

Re: How to Blend Your Own Fuel, and Why You Should
 

Hmm. I drove through out the mid-west this past summer (S.D., Ia, Wisc., Michigan, Ill, Ind., Ok) and I found my '06 Prius averaged over 50 mpg. A lot of that driving was on local, county, state and US roads.

Ethanol blender pumps at every gas station
 

The previous posting about ethanol blender pumps in some states cemented what I had known as well - blender pumps have been in use for years, as there are only 2 "standard" types of fuel out there. High test for finicky motors and regular unleaded for the rest =- anything else is a mix of those 2.

And while it would be difficult to get new equipment installed at gas stations across the nation, can you imagine how much harder it would be to roll out another fuel source (e.g. Hydrogen - anyone ever see the Hindenburg footage? someone please stop these fools - or fuel cells HAHAHAHAHA, scientists are so happy at getting grant money - NEXT.)

I, for one, would be more than happy to give up the unleaded premium at the local pumps for an Ethanol mix (of suitable quality - such as 30% or better). This would be very easy to accomplish, as long as supply can meet demand.

The only vehicles that currently require super unleaded are supercharged, turbo-charged, or high compression (higher than say 11:1) equipped. I am almost positive that these vehicles could be run on the higher octane, but lower btu ethanol enhanced fuel. In my past experiences, most of these configurations should not be required to run high octane fuel - the manufacturer places this demand on the fuel quality in a preference to the highest performance. With some simple reprogramming, I would think even the earliest models of these cars could be adapted to run an ethanol mix.

Case in point, some fuel stations out here have 4 levels of unleaded fuel. You can stand there for 5 minutes deciding between 87, 89, 91, or 93 octane. The truth of the matter is this - if the vehicle states super or premium only, then it requires 91 - otherwise just throw some 87 octane in the tank and get on with life's real decisions (for instance, is it time to buy something that gets decent gas mileage yet? LOL). I have NO IDEA whose braincramp it was to offer 4 choices of fuel. As if Joe Q. Public has a clue as to what will run the vehicle - or what octane ratings are - for that matter. Nothing but snake oil salesmanship in my opinion.

Short and sweet - this E30, etc. conversion would likely take an afternoon at most fuel stations, and would make the greatest difference (for the time being, and based on what we know) to our air and our foreign relations.

I am all for it myself because I know it would actually make a difference to our air and our planet - and I don't really care what the stuff costs. Unlike special vehicles and replacing everything we have that rolls, ethanol enhanced fuels would apply to a hybrid, a moped, or the latest SUV Tank minus a turret.

Incidentally, has anyone out there run across testing or the possible effects of an ethanol mix for premium fuel replacement? This would be the only thing standing in the way of a wide rollout of ethanol blends for your local fuel station (other than supply/ demand issues of course). Not to mention the benefits (and potential savings) of simplifying the refinement of oil-based fuels into one quality level.

Re: How to Blend Your Own Fuel, and Why You Should
 

What am I missing here?

I thought rust, rubber and plastic deterioration in the fuel linings and systems were significant enough issues with ethanol that many manufacturers PROHIBIT using more than a 10-15% ethanol mix. And they will VOID coverage on warranty issues if excessive ethanol-use was considered the cause.
SOME newer cars (flex-fuel and others) allow any % of ethanol. But many new cars (and almost all older cars) still specifically mention avoiding a high percentage of ethanol.

Re: How to Blend Your Own Fuel, and Why You Should
 

I know that is a common belief. I'm not sure why.

I've never seen ( or heard ) of a vehicle's warranty being voided from ethanol. I talked to Ford higher-ups more than a year ago about putting all the way up to E85 into a FEH. Above about 50% ethanol it will trip fault codes, as the data from the O2 sensors may go out of range. Also, above about 50% the fuel injectors may reach maximum duty cycles, and trip fault codes, give check engine lights, and may, ask you to "stop safely now" on the message center. In the rarest of cases, it ( the software ) may shut the car down.

Ford will not pay for re-setting the fault codes, and/or draining the E85 out of your tank if you accidently put it in. So you may have to foot the bills for the cost to "reset" your car back to normal. No warranty was voided in any of the ( two ) cases I heard of when E85 was put into a Ford Escape Hybrid.

The claims about rust & corroision are unwarranted.
A small amount of corrosion inhibitor is added to the ethanol when it is still 100% or 200 proof. The allowable combined acid content is limited to 0.007% and that is for all acids combined, mostly acetic acid, which is the same as vinegar, and comes from trivial amounts of bacteria that live in the corn before the alcohol is distilled. Trace amounts of sulfuric acid may be present, but in parts per million. The pH of ethanol is very close to 7.0. The governmental mandate is ethanol can never contain more than 1.2% water at the pump in the U.S. I think the limit is less in Canada, 0.8%, but I'm not positive, other than Canada accepts less. Ethanol distilleries always keep the water to below 0.75% so there's a little room to pick up water along the distribution process. Ask any good mechanic what 1% water will do to your car. He'll probably say "nothing" or point out there's probably more than that in your gas tank now. Ethanol has been used for over 100 years to remove water from gas tanks, without the need to drain them. Ethanol dissolves the water, and passes it harmlessly through your engine and out the tailpipe.

Very high concentrations of ethanol ( like E85 ) may dry out rubber and some plastics. Gasoline is a thin oil, and a lubricant, where ethanol is not.
But having a 50/50 mix or less keeps the "oily" properties, and will not readily dry out rubber and plastics. The rubber and plastics that are not compatible with high amounts of ethanol were phased out in the early 80's, and some states have been using ethanol at the pump for more than 25 years already. How many engine complaints from ethanol have you heard about over the past 25 years?

Ethanol will lower MPG, but not so dramatically as once thought.
I have measured no loss in horsepower, or performance, or response from the engine with 30% ethanol in my FEH. MPG is lower, but about the same as 10% ethanol.

I bought E30 for $2.54 last week, and lost about 12-15% MPG tops.

-John

Re: How to Blend Your Own Fuel, and Why You Should
 

Taken from "Over the River and Through the Woods" thread in FEH section:
On blends with ethanol, it should be 10% in Iowa unless marked otherwise.
Gasoline in Colorado also has 10% ethanol, incidently. Since 10% has become the "norm" in more than half of the U.S., it no longer is marked at all in many locations. This makes things difficult for those of us in forums like this to keep good records on how our car's MPG is really doing. :(
EPA is just now allowing blends of 20% and 30% but those are only at a very few locations ( fewer than a dozen nation-wide ) and must be clearly marked. -John

Re: Ethanol blender pumps at every gas station
 

That "only" part includes a whole range of cars. Civic Si, Other sports compacts, luxury cars, etc...

When performance is part of the selling point I think quite a few owners and enthusiasts would be offended by the suggestion their fuel is to be phased into a less capable and greener mix. People who buy V8 powered Corvettes are not normally thinking about greener driving habits.

Re: How to Blend Your Own Fuel, and Why You Should
 

gpsman1,

I well know about E10 being available in many states (and for years now). Ethanol issues should be very minimal over the past 20+ years, now that some of the plastics and rubber have been upgraded to withstand E10. That's not the issue here, for me. The issue is in recommending greater than E10. This is not even close to widely available at the pump (unless you use E85 - not a good idea). So asking about "how many engine complaints from ethanol" is talking apples and oranges, as you're not talking about the widely available E10.

And while all that you say may be true, it does not matter to me until manufacturers (& dealers too) agree with you, and stop putting this verbiage in the owner's manual:

"Some gasoline today is blended with oxygenates such as ethanol or MTBE. Your vehicle is designed to operate on oxygenated gasoline containing up to 10% ethanol by volume and up to 15% MTBE by volume. Do not use gasoline containing methanol."
(quoted from p.150 of my 2006 Honda Civic Hybrid owner's manual)

The 10% ethanol message is likely due to the use of a 10% ethanol mix, especially in the winter months. It does NOT indicate to me, that the engine, valves, fuel pumps, fuel injectors, O2 (and other) sensors, CATs, exhausts, fuel linings, rubber and plastic parts have all been significantly upgraded to handle ANY amount of ethanol (or even 50%). If they have been, it's a small step to make the vehicles truly "Flex-Fuel".

I, for one, will take heed this cautionary message in my HCH2.

Re: Ethanol blender pumps at every gas station
 

Shame on them.
They cannot use the full power potential legally on city streets anyhow.
Only on a closed circuit, race track, maybe.
Ethanol use will be transparent for almost all owners in the performance category. The only visible manifistation is lower MPG. A good trade off for better air if you ask me.

Re: How to Blend Your Own Fuel, and Why You Should
 

My comments in RED.

Cheers,
-John

Re: How to Blend Your Own Fuel, and Why You Should
 

The previous posters' message about V8 powered Corvette owners not caring about the air we all breathe, etc is highly accurate in what I have seen myself. But then I've always felt that many consumers in this category are lacking a little more than just horsepower.... if some might get my meaning.... :P

The dealers have always (and I mean always) been a poor source of information on absolutely anything regarding their vehicles - other than what they can "put you in today". I've dropped some notes about this in past postings, as their best sales tactics are usually the main concern and focus of any brand dealer.

The message regarding the statements located in an operators manual are interesting to me, as if I followed every indication in an operators manual - I would have run into much trouble in a variety of vehicles that I've owned. I read these as "suggestions" and take them with a grain of salt, as these are written by the folks that would love you to purchase a new car from them as often as possible until the end of time.

Examples:

The service reminders in a brand new 99 Buick Regal GS supercharged (29mpg hwy loaded to capacity and 240HP) recommended a 5,000 mile interval for every oil change (normal non-synthetic oil) and was further programmed into the "adaptive" service minder function of the dash display. Yet on a road trip across the US, I checked the oil at 3,900 miles while filling the tank and noticed I was 2 quarts below full on flat ground and the oil was dark. The dash told me I had 2,200 miles to go to the next adjusted oil change.
I promptly drove it to the nearest Buick dealership, had the oil changed and had the engine checked for signs of leakage - there were none. In the words of the service manager, it was "perfectly normal" for an engine to consume oil without leaking it (Hack!). Incidentally this car never made it to the second oil change with us - I traded it in on an import after we returned home. Waiting until 5,000 miles would most likely have caused the new engine to seize or damage itself, and there was no indicator light that told it was low on oil either (3 of the 5 US quarts left). Imagine if I waited until the fancy pants dash display indicated I should change it @ 6,100 miles as Buick recommended.

A further example would be trying to find the service interval for flushing power steering and brake fluids on almost any vehicle (other than high-end imports). This interval is absent from almost every operators manual (and repair manual) ever written, and yet is highly important to the safe operation of these systems. Change these fluids every 3 years/ 30,000 miles and you will most likely never have serious problems related to brake leaks, pump and rack failures, etc unless they were faulty or cheaply equipped. I offer up my 1995 Dodge Neon Highline I recently sold to a friend with 110,000 miles and the original power steering, ABS master cylinder, calipers, lines, etc. Water intrusion in these systems is normal, and not mentioned or discussed by the manufacturer until they can sell you something.

And lastly, please do not listen to the manufacturers regarding tire pressures - this is optimized to a nice soft, comfy ride out of the compromise (cheap as possible) tires and components they equipped your car with. My 2005 Scion would like me to run my 205/45R17 stock tires at 29psi as specified on the doorframe sticker. When was the last time anyone got optimum mpg or performance at 29psi - it can't happen. I have them at 32 psi for traction in the winter, and will increase that to about 34-36 psi once summer hits again.

Thanks again for everyone's input - and please remember not to believe everything you read in the manual. This is like asking a bartender how many drinks you should have ;)

Re: How to Blend Your Own Fuel, and Why You Should
 

There is a popular myth that higher octane in fuel gives you additional power - it does not. Premium gasoline has the exact same energy content as regular (about 111,400 BTU's per gallon).

The ONLY thing the higher octane is needed for is engine knock. High-performance engines are more sensitive to the octane level because they have higher compression ratios, so they tend to knock on lower octanes.

Plus, the computers in today's engines also detect knocking and will adjust the spark timing and other settings to control it.

There is also a claim by some people that they put premium in once in a while to "clean out the system". Most of the time, the detergents suppliers put into their fuels are the same in all grades.

So in reality, most cars on the road today need nothing more than the regular old 87 octane fuel.

Re: How to Blend Your Own Fuel, and Why You Should
 

Sometimes it doesn't. My testing in Huntsville indicates three brands, Shell, Exxon, and Chevron, appear to have about 11% more energy in their 87 octane gas than the other brands, Conoco, BP, Texaco, and Citgo. The lower energy brands have the same energy content as the better brand, 93 octane, Shell and Texaco.

I was able to see this in my gasoline testing at the higher power levels.

Bob Wilson

Re: How to Blend Your Own Fuel, and Why You Should
 

Higher octane fuel allows for higher compression engines. Higher compression engines are capable of getting more energy out of gasoline than are lower compression engines. At least at their thermodynamic limits. This is the ONLY reason that diesels get better mileage than gas cars.

So while there might not be any more energy in the fuel, you can access more of it.

Also, low octane fuel in a high compression engine can self ignite due to the compression. This is the cause of engine knocking. Adjusting the spark timing won't do jack for it. But, fuel mixtures can be adjusted to prevent it.

You can not get the full engine power off of low octane fuel.

In my experience premium fuel has more detergents than regular. Now, does it matter? I don't know. I'm betting not, but still I think it's important to be accurate.

BTW, I'm looking forward to the results of the E30 testing. I had read the articles mentioning it as the sweet spot, and have been really curious about the results.

Re: How to Blend Your Own Fuel, and Why You Should
 

Maybe I should have stated my sources - the American Petroleum Institute themselves. Here are direct quotes from their website:

http://www.api.org/aboutoilgas/gasol...ine-octane.cfm

"Octane number is a measurement of fuel’s resistance to engine knock. Engine knock is an abnormal combustion associated with using gasoline with too low of an octane number. Ordinarily, your vehicle will not benefit from using a higher octane than is recommended in the owner’s manual."

"Knock Sensors
Many modern vehicles are equipped with an electronic device that detects and eliminates light knocking before you can hear it. The devices suppress knock by retarding the spark."

"Gasoline with a higher heating value (energy content) provides better fuel economy. Traditionally, premium gasoline has had a slightly higher heating value than regular, and, thus, provides slightly better fuel economy, but it is difficult to detect in normal driving. There can be even larger differences in heating value between batches of gasoline from the same refinery, between summer and winter volatility classes, or between brands of gasoline from different refineries because of compositional differences. The differences are small and there is no practical way for the consumer to identify gasoline with a higher-than-average heating value."

But this is from the API, so they do have to claim that there is some value in that premium gasoline you are buying. They do represent the petroleum industry, you know.

And higher compression engines don't actually gain any power using higher octane gasoline, they just don't lose that portion of power that sometimes happens during acceleration from pre-ignition (knocking) that they would with lower octane. The power in the gasoline is the same, it's just the point in the compression cycle when the ignition happens that determines how much power the engine gets out of the gasoline. Knocking happens when the fuel starts to ignite before the piston reaches the top of its stroke. If that happens you lose horsepower because then some of the energy from fuel combustion is working against the power stroke of the engine. That's being a bit simplistic because the ignition phase of the stroke actually does start just before the absolute top of the stroke (Top Dead Center), usually about 10-25 degrees before TDC, but the maximum power of the combustion cycle doesn't happen until just after TDC. Knocking happens when the fuel burns too fast and the maximum power of the combustion happens before TDC instead of after. Modern engines will detect that this is happening and retard the spark so that maximum power happens after TDC.

Re: How to Blend Your Own Fuel, and Why You Should
 

i use 110 octane in my track car... then again it is 10.2:1 compression, 12psi and turns at 8000rpm :shade:

Re: How to Blend Your Own Fuel, and Why You Should
 

I was just reading up some more on E85. I don't think I saw it mentioned here, but they have a winter/summer mix of E85 too! in the winter E85 is really E70. can someone else please confirm this as it would put our table all off.

Also, even in the summer E85 is the rating of the gas before it's denatured. So it's really about E81 given the standard 4% denatured rate of normal. Flex fuel vehicles don't have a problem with the variation in percentages since they have a fuel sensor. but since we're trying to work off of a fixed value we need the proper values to start with.

Re: How to Blend Your Own Fuel, and Why You Should
 

Ethanol is manufactured as 200 proof, or E100 at the distillery.

This is, for all practical purposes, whisky, and could be digested by humans.

In order to comply with ATF rules, the pure "whisky" must be poisioned, or "denatured" on the premises... no 100% ethanol is allowed to leave the property, or else it would be taxed as a beverage, and cost the same as liquer. ( What does Vodka cost per gallon anyways? $40 a gallon? More? )

So to comply with ATF rules, all ethanol leaves the plant with 2.5% to 5% gasoline in it from the get go. All rail tankers, and all truck tankers are denatured with on average, 4% gasoline.

The gas station then adds 10% of whatever gasoline they have on hand ( probably in most cases the lower Octane ).

The E85 pumps in Minnesota say "contains at least 85% ethanol".

If the ethanol they got this week had 4% denaturant, they would be selling E86 this week. Next week they could get ethanol with the minimum amount of denaturant ( as gas prices rise, this is more likely ) and they could be selling E87.5

I have never ever heard of "winter E70".

-John

P.S. Cars would run fine in warm weather on pure alcohol. Indy cars run on E98, only because they too must have denaturant to comply with ATF. The 15% gasoline is added, mostly, to make it burn easier in cold weather.

Re: How to Blend Your Own Fuel, and Why You Should
 

http://genomicsgtl.energy.gov/biofue...ortation.shtml

Re: How to Blend Your Own Fuel, and Why You Should
 

Fadi, thanks for the insight into this matter.
I did additional research and here is what I found.

The American Society for Testing and Materials (ASTM) and the Alliance of Automobile Manufacturers have

Re: How to Blend Your Own Fuel, and Why You Should
 

sure, and thanks for your additional legwork.

I actually came about that info as I was researching what it would take to convert my track car to run on E85.

Re: How to Blend Your Own Fuel, and Why You Should
 

This morning I was getting irritated getting 'only' 32 MPG.

It was 15'F outside, but I did use the block heater this A.M.
What gives?! I was thinking to myself.

Oh ya.... I forgot I was using ( appox. ) 35% ethanol this week.
Until I get my graduated cylinders and pipets, I can't be sure on the %.

I did notice on "Long term fuel trim" with a ScanGauge, I was running with fuel trim at +8.5. Normally with plain gas, this number hovers about zero.

I'm not sure if that number really equals 8.5% more fuel, or if it is just some number. Ideas?

With gas, the number will be negative a few (%?) when coasting, and positive a few (%?) when accelerating, with the median about zero. With 30% ethanol and greater, this number hovers about 8.5, and goes to 12.x when accelerating, and down to 3.x when coasting.

-John

P.S. The mechanics handbook says -20 to +20 are normal values with regular gas. I wonder if that is some limit, or if +25 is possible?
The lowest I've ever noticed was -10 and greatest was +15.