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Obormot

timing advance for E85 and ethanol

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Welcome to the forum!  The search button is your friend.  In short, some say more advance, some say less, some say about the same.

 

My personal opinion is if your engine is operating under optimal parameters on gasoline, then based on the flame speed of ethanol and the testing I've personally done, the engine should develop max efficiency on E85 with slightly LESS advanced timing.

 

http://e85vehicles.com/e85/index.php/topic,1893.0.html

 

If your engine has the timing purposely retarded to eliminate detonation from gasoline, then it may appear to like MORE advanced timing on E85.   But in reality, 105 octane E85 has just removed the timing limitation to the engine and allowed it to operate at the optimal setting.

 

There are many anecdotal stories of engines liking more advance on E85 - even when physics (flame speed) seems to suggest it would like a little less advance.  Of course we have quite a few anecdotal stories floating around...some more outrageous than others...so it's really best to experiment with your own set-up and see what works best.

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I tend to run advanced timing due to the increase of antiknock indexing of E85. If I was to run less timing, I could run the lowest of octane gasoline without knock. Since I dont have to worry, I would put a car on a dyno, and raise it until you achieve your highest gains.

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Most of FFV electronic kit manufacturers say that timing adjustment is not necessary. I have found this claim B.S. When I drive my Peugeot 406 (2,0l, 16 valve, 99/100 kw) on E85 at very high rpm (engine max is 7000 and red zone starts from 6000) then sometimes "Check Engine" light appears. The fault code is P0300 - Random/Multiple Cylinder Misfire Detected. I have got the same fault code with different FFV kits. My car has brand new NGK Iridium spark plugs and ignition coil pack and it does not happening when driving on pure gasoline or 70% gasoline/30% ethanol mix.

As much as I have understood at low rpm the timing for gasoline and ethanol is nearly the same but at high rpm ethanol should be more advanced. I have been talking to Brazilian FFV kit manufacturer and they recommend timing advance module with adjustment 6...12 degrees more advanced. It should improve fuel economy and car overall performance (torque, power). My next setup will include timing advance processor as well.       

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I am wondering if you are just a tad lean at those high RPMs. This would slow the burn rate a bit. Guys running carbs do tend to advance 2-4 degrees more on E85 than on gas but they are often checking for enleanment with a LM1. At slightly rich of stoich the burn rate is reportly faster than gas but it slows as one goes lean- at least that is what I see reported.

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Welcome to the forum!  The search button is your friend.  In short, some say more advance, some say less, some say about the same.

 

My personal opinion is if your engine is operating under optimal parameters on gasoline, then based on the flame speed of ethanol and the testing I've personally done, the engine should develop max efficiency on E85 with slightly LESS advanced timing.

 

http://e85vehicles.com/e85/index.php/topic,1893.0.html

 

If your engine has the timing purposely retarded to eliminate detonation from gasoline, then it may appear to like MORE advanced timing on E85.   But in reality, 105 octane E85 has just removed the timing limitation to the engine and allowed it to operate at the optimal setting.

 

There are many anecdotal stories of engines liking more advance on E85 - even when physics (flame speed) seems to suggest it would like a little less advance.  Of course we have quite a few anecdotal stories floating around...some more outrageous than others...so it's really best to experiment with your own set-up and see what works best.

What you have to consider, is the fact that some engines are "mapped" to be able to run on lower grade fuels.

 

Those engines are sometimes "pulled" on the ignition, so they can be run on the lower grade fuels. I know this is true for most older volvos..

 

Example of E85 conversion on a LH2.4 volvo:

turbo injectors + resistors

 

That's it! You dont have do do anything more..

But, it's not like E85 alone will give you more power, but on the ignition control unit, you can control ignition -6 | -3 | 0 | +3.

 

So, connecting pin 18 + pin 19 + pin 20, you get +3.

pin 18 + pin 20 = -3

pin 19 + pin 20 = -6

nothing, or 18+19 = 0.

 

I know this is mumbojumbo, but the +3 works even on premium unleaded and it does indeed give more power. On E85 it works too!

I must say that the engine also makes a more powerfull sound (maybe because e85 also gives a bit more exhaust?).

 

Havent dynoed it, but my guess is about 5% increase in power..

Ps the engine has fairly high CR.. 9.5:1.. Will fit a very tight squish headgasket and turbocharge it, for more power. ~~200hp vs stock 116hp, with used parts from turbo volvos :-)

 

oh btw.. advancing the ignition gives more exhaust emissions.. retarding gives hotter exhaust which helps burn gasses. So, remember to not over advance before emissions test :-)

 

I'll go for colder plugs when the turbo comes on.. bkr7es or bkr8es instead of bcpr6es.

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Welcome to the forum olavxxx.  The points you bring up are mainly what I was referring to (or at least trying to) in stating the case of timing being purposely retarded due to octane (or lack there of) in the engine fuel.

 

Good to know the info on the Volvo's.  I didn't know there were vehicles on the road today which could have the base timing altered by pin settings.

 

Though I would be careful about making blanket statements such as 'advancing the ignition gives more exhaust emissions'.  In general, most emission monitoring programs look at the full spectrum of emissions...unburned hydrocarbons (HCs), oxides of nitrogen (NOx), oxides of sulfur (SOx) and carbon monoxide (CO).  Since the HCs represent unburned fuel and NOx, SOx and CO represent burned fuel, any adjustment usually results in one dropping while the other rises.  ie retarding timing usually results in cooler combustion and an increase in HCs but a decrease in the products of combustion - especially NOx.  Conversely, increasing timing results in hotter combustion, more NOx, but less HCs.

 

Either way, the dyno should have the ultimate say as far as timing.  There is an optimal setting for a given engine/fuel combination.  Setting timing either higher or lower will reduce power/efficiency.

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I didn't know there were vehicles on the road today which could have the base timing altered by pin settings.

 

Though I would be careful about making blanket statements such as 'advancing the ignition gives more exhaust emissions'.  In general, most emission monitoring programs look at the full spectrum of emissions...unburned hydrocarbons (HCs), oxides of nitrogen (NOx), oxides of sulfur (SOx) and carbon monoxide (CO).  Since the HCs represent unburned fuel and NOx, SOx and CO represent burned fuel, any adjustment usually results in one dropping while the other rises.  ie retarding timing usually results in cooler combustion and an increase in HCs but a decrease in the products of combustion - especially NOx.  Conversely, increasing timing results in hotter combustion, more NOx, but less HCs.

 

Either way, the dyno should have the ultimate say as far as timing.  There is an optimal setting for a given engine/fuel combination.  Setting timing either higher or lower will reduce power/efficiency.

 

Many FI Ford's have had an Octane adjust function since the late 80's/early 90's, done 2 different ways. #1  there is a jumper that can be removed (and used to activate the fuel pump prime) which will retard the timing 3 degrees it is usually located near the fuel pump prime connector or the EDIS module. Some TFI engines use an Octane Rod in the dist which come in a couple of versions one with 0 change which would have been installed from the factory and +3, -3, and -6. Here is a pic of the jumper, or shorting bar in Ford speak, style.

 

attachment.php?attachmentid=623&stc=1&d=1066681709

 

Over advanced timing can cause an increase in some emissions, primarily NOx, that is why many engines today can make more power, and MPG, through the use of a "chip" or power programmer device, but exhaust emissions suffer.

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Please look at this table, regarding retardation/advance of ignition:

http://www.msextra.com/ms2extra/MS2-Extra_Tuning_Manual.html#emissions

 

I know E85 is not regular gasoline and that most emissions are lower on E85.

Though, this is not true for 100% of the emissions, also the same physics would apply to E85 as the regular fuel, when retarding or advancing emissions.

 

I know that url is for megasquirt too and that it's an unknown engine, engine-x.

You can see that retarding the timing and leaning the mixture slightly gives the best possible compromise, increasing only the NOx slightly among the regulated emissions. (The above was without a catalytic converter. With a converter, emissions would have been best at stoichiometric mixtures and the timing retarded somewhat.)

 

Also, remember:

Retard your ignition timing by ~5° to 10° (this creates a hotter exhaust that prolongs the burn and also helps the catalytic converters to operate at peak efficiency),

 

Retarding creates a hotter exhaust, not a colder one!

Selecting the right spark plugs could also be a challenge, maybe one range colder.. eg. if you had bkr6es, go to bkr7es. If turbo, maybe bkr8es..

 

Howver, this is emissions, not peak power.. but it's some basic info that holds true for most of us.

On my gf's car, we ran the e85 + 3 deg. advanced and it runs very well.

 

I use two rocker switches to choose -3|0|+3, but it's always used in the +3 position :-) I can feel it's much stronger at part throttle.

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I wonder if there's too much concentration on "parts per million" and not the total amounts exiting the exhaust pipe.  Retarding timing that much will definately affect mileage, causing a greater amount of fuel and air to be burned for the same amount of work.  I think this could potentially cause more of the emissions they are trying to prevent, even though the concentrations would be lower.

 

Example:

My dad had a 2000 Silverado pickup.  When new, it got 20-23mpg, with it's 4.8L V8.  We got an "emissions recall."  So we took it in, like good responsible owners.  After that, it got 14-15mpg, no matter where you went, how you drove or what.  That's all it ever got.  We took it back to have 'em undo it; to get the mileage back up... no record of that recall even existed in their computer system!  And then people wonder why GM is failing.

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