E85 diary
 

I normally don't post anything that is in progress but I thought I'd try something different.

It took a long time to find any real info. This is what I found to be the most helpful:
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http://forums.evolutionm.net/alterna...notes-afr.html
http://forums.evolutionm.net/alterna...ing-notes.html

E85 has a stoichiometric fuel mixture of roughly 9.78-9.8:1 in E85's purest form (Class 1 85% Ethanol summer blend). As the fuel's Ethanol content goes up the stoich range goes down. For instance, 100% Ethanol's stoich is about 9.0:1.

E85 will maintain max brake torque much richer than stoich than gasoline will. But, because of it's excellent detonation threshold(due to lower combustion temps, lower peak cylinder pressures..etc), it can be run much closer to stoich than gasoline safer. E85 reaches max thermal efficiency at about 13% richer than stoich, whereas gasoline is about 16% richer than stoich(with pump gas being even richer). But again, E85 can maintain Max Brake Torque well into the 30% richer than stoich range, unlike gasoline which is limited to about 18% rich of stoich. DISCLAIMER: Just because E85 itself will still make power at super rich AFRs, doesn't mean it's a good idea or even recommened. A whole host of issues come with running super rich AFRs, that you need to be aware of, but i will cover later.

Therefore Max Rich Torque of E85 is 7.1:1- 8.5:1

With that being said, here is what i would consider a very safe and conservative fuel tune on E85. *AFR's listed in bold are for widebands o2s that are calibrated for gasoline, AFR's in ( ) are actual E85 AFR:
http://forums.evolutionm.net/alterna...notes-afr.html

Part Throttle lean (max eco) AFR of 16.5:1(11.0:1) 12.4% leaner than STOICH
Part Throttle rich AFR of 14.7:1(9.8:1)
Spool up... AFR of 13.5:1(9.00:1)
WOT... AFR of 12.1:1(8.06:1) 17.7% richer than STOICH


*If you're using a wideband that is calibrated for gasoline(14.7:1) and cannot change the calibration of the wideband, take your gasoline AFR and divide it by 1.5 to get actual e85 AFR or use the wideband in lambda mode. 1 lambda is 9.8:1

Here are some common AFR conversions(Gas AFR on left, e85 on right):

18.0:1=12.000
17.5:1=11.666
17.0:1=11.333
16.5:1=11.000
16.0:1=10.666
15.5:1=10.333
15.0:1=10.000
14.5:1=9.666
14.0:1=9.333
13.5:1=9.000
13.0:1=8.666
12.5:1=8.333
12.0:1=8.000
11.5:1=7.666
11.0:1=7.333

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All afr numbers that I give are in gasoline numbers and not E85. My brain is too old to translate. This is my summary of the info:

-You can run very lean at cruise, possibly reducing the huge hit on mpg. 16-17:1

-Heavy timing will also help mpg and it is better to err on advancing past the ideal timing than being under.

-E85 won't knock as easily as gas when you pass MBT. Tuning can't be done by ear or det can. It has to be done on a dyno or with an accelerometer.

-Running too rich is bad as you may run into preignition(not knock)

-12.0:1 seems to be the sweet spot for power.

-It will make more power just tuning the fuel but there is massive power in the timing.

-EGT's are reported at 200°C lower.


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A few days ago I swapped out the RX-7 550's for FIC1100's from ZX-Tex. For me, the 550's at 50psi base fuel pressure were hitting 90% duty cycle. I'm not speculating at what boost/whp.

I spent 20 minutes retuning on 93. The next day I drained the tank and filled up with E85. I added 30% fuel and 3° timing across the board. The fuel was close enough to run. I think I had to add a little more fuel but it was in the ballpark. The timing increase is super conservative and I will end up spending a lot of time tuning it.

I need to upgrade my stock 91 coils to the GM LS2 D585's. They've been sitting on the shelf for over a year and I think the E85 is harder to light off.

Had an autox yesterday. At the same boost level as I was running with 93, the car definitely had more power. The other benefit is that the coolant temps barely rose 2°C during the run. I didn't check the actual numbers with the IR but the underhood temps are considerably lower.

After tuning, I'm considering running the engine hotter than the current 84°C. I suspect that if the IAT's and/or coolant temps are too cold then things might go downhill. During tuning I didn't shoot water but I did during the autox. Have to figure that out too.

It will be interesting to see what others have to add to this thread, I'll be getting my 1200cc injectors any day now and will be switching over some time next month after the miata challenge.

Good info.
I still run afr close to gasoline just to be safe (I know I know) on mine. 14.7-15.5 in cruise, 13.5 low boost, 11.5-8 full boost.

Guess I'll up everything half a point or so when I get some time to fiddle with the tune again.

Forgot to mention that I was rough tuning the cruise today. I am shooting for 17.0. It might have been bucking in the high 17's but definitely in the 18-19 range. Even at 18 it wasn't as violent as 16 on gas.

I'm not even on my first half tank. It has tuning and an autox on it so this should be as bad as it gets. Maybe I'll fill up tomorrow to check it.

That is right where my tune sits as well.

"Where is max power on E85" is on my to-do list when our dyno finally shows up.

You guys are getting a dyno!!?

That's awesome! Which Dyno setup are you getting ?

- Jason

Interesting reading on the sensitivity to temp variations.

Good post. I can help you work on your car this weekend if you want.

Tuning by ULP afr's...
yeah cant go much past 17.5 without it missing. good power in the high 12's for me, that 10.5:1 NA atm.

Up to 48 degrees of timing on my map (NA!!) no audible ping, id like to see whats up on the dyno with it.

Still cant get great economy, about the same miles per dollar ad pulp though

Dann

Thank you for posting your numbers.

This is the best info I've found on timing vs mpg for E85:
http://e85vehicles.com/e85/index.php...5952c#msg10885

The first 75miles on E85 had one autox, hard tuning and generally very rich cruise afrs gave ~16.5mpg.

The next 70 miles were low speed cruise(40-60mph) with afr's between 15-17 and timing around 40° yielded ~25.5mpg. My average 93 gas mileage is 27-28mpg. I really need to spend time tuning the ignition. I'm going to try 37° and 43° on the next couple tanks.

Yesterday it was a steady (for me) idle at 16. When cruising it would definitely buck at 19. It was sometimes ok at 18. I'm still going to shoot for 17 for now.

Local E85 is $2.80/gal and 93 is $3.34. As long as I get over 22.5mpg then E85 is cheaper to run and that doesn't even take into account the other benefits! Too lazy to do 3rd grade math so: http://e85prices.com/milesperdollar.htm

Ill post a fuel and timing map, along with a log in a few days time when i can. Ill have to provide a link to the software to view the log as I use a kiwi computer.

Dann

PS keep em coming.

22.5mpg mixed driving - same style would have yielded 26.5-27mpg on 93.

E85 - $2.89
Crap 93 - $3.48
Good 93 (Chevron) - $3.59

$/mileage, E85 is slightly cheaper to run. I'm happy so far. Still haven't tuned the WOT timing. Cruise afr's are rough, still going into the bucking zone of >18. It's averaging 17:1.

On a closely related note I drove a different (not DVCN's) E85 turbo Miata over the weekend and it absolutely ripped. The maps have not even been optimized yet. I was impressed. Built motor, GT2871.

Excellent information about being able to get $/mileage so low with lean cruise. I soooo want to convert a non-Miata vehicle of mine.

Haven't done any tuning, too lazy.

Filled up at $3.26/gal the other day but was annoyed since it was $3.09 a week ago. After seeing 93 for $3.95 I didn't feel quite as bad.

At 24.7mpg on E85 it is definitely cheaper to run than 93 and actually equal to 87 right now.

After the last fillup the afr's are .3-.4 leaner. E85 can be anywhere between 70%-85% so it's possible that the current mix has a bit more ethanol in it.

What did you change when you went to E85? Did you mess with the fuel pump or fuel lines at all?

What did you end up adjusting on the timing? Just add 3` across the range?

At last i'm confused by the chart you show. Let say i'm using my regular fuel LC1 Wideband. For gasoline i am looking for 14.7 on the gauge and 12 in low boost. What would the same gauge show when running E85?

I tuned timing properly as if I had no map, just went to base and did it all over, No change to fuel lines or pump, on an LC1 set to Gasoline, your looking at 14.7 for stoich, 17:1 for cruise and 12:1 for full power.

Dann

I may have to give this a try, in a month I could buy a spare BP with the savings :o

Basically the same. The gauge just takes the lambda measurement and converts it to gasoline AFR. The stoich ratio changes, but the lambda measurement doesn't, so the AFRs you see will essentially remain the same between the two fuels. You can run E85 a little "leaner" than gas - exactly how much leaner is on my list of things to play with on the dyno.

All I did was swap in big injectors and drained the gas. There are long term Evo's and Honda's with no problems - as far as my searches went. I don't think I've found any Miata people with E85 problems.

Yes, I am at +3° which is extremely conservative, considering my gas tune was conservative. I have a feeling I'll be able to go a lot further but just haven't put in the time to tune.

The chart converts from E85 readings to gasoline readings so you don't have to recalibrate your mind. If the wideband display read between 8 and 12 my head would hurt.

Many people tune for 14.7 cruise which is just fine. I am at 17 or leaner, this definitely made a difference to my mileage.

I shoot for 12.0 under boost. I don't really care if it drifts up or down with the differences in ethanol content. Running too rich, closer to 11.0-11.2?, increases the chance of pre-ignition. I think the Evo guys have info on this effect.

So we're filling up with E85 and not changing lines? That's pretty cool. Will 550cc injectors pump enough fuel for 250whp on a Walbro 255 with a stock regulator?

If I have any (corrosion) issues I will immediately report them.

I don't think the 550's will cut it unless you run ultra high pressure, which I'm not a fan of. The pressure vs volume specs are ugly.

What are your duty cycles now? Base pressure? Somewhere around 45psi base I was hitting almost 90% at around 250whp.

71% at 240whp/12psi on gasoline, I don't know the base pressure. I'd need about a 35% increase in flow so I'll need larger injectors, which I'm not buying.

71% multiplied by 1.3 = 92%, youll be sweet with a few more psi (maybe 10)

Dann

This looks pretty good read.
http://www.ls1.com/forums/showthread.php?t=33448

I've yet to find/see pictures of E85 carnage to the fuel system.

Honestly i think some of the shiny coating the fuel filler has on it is corroding off mine. Its the only shiny plated part of the system though.

Dann

anybody try the oxytane shit thats out? its supposed be like the lead substitute of ethanol of our time....lol... but ive read of people using it and getting a bit better milage from it........ link----> http://www.oxytane.com/

has or does anyone use any of the ethanol treatments? i got a bottle of the lucas stuff, you add like an oz of fluid per 5 gallons, the bottle should last a few fills atleast... i just figured id ask here while you guys are talking about corroding the lines and other crap....

E85 Carnage due to running lean.

http://www.jeepstrokers.com/forum/vi...&t=453&start=0

heres some other carnage from a different forum, this is more what i see people complaining about more than anything.... which is why after running e85 more than a month and about 1500 miles i thaught it might be a good idea to start using the treatment to keep shit clean inside.......lol.....see if it works i guess...lol....

http://www.turbobuick.com/forums/e85...ctor-gunk.html

You do know that E85 is a cleaner, not a gunk builder like gasoline right? The only carnage logically possible would be if something melted away (other than the obvious wrong combustion carnage).

My guess on what that crap is, E85 attracts moisture. The incoming air can only be cleaned by the air filter so much therefore attracting the "mud" to the tips of the injectors. Reading some more on those forums, people are reporting fuel lines and fuel rail to be spotless and clean.

ya i get that, i seen how clean my few year old plugs looked after running it 2 weeks..lol.... im just talking about all the shit people are throwing around the net about stuff breaking down and plugging stuff. but it wasnt much , and i just figured id try it, and throw it in every other few tanks.... id rather get the oxytane shit, but i cant get ahold of the place local i found who carries it...

I'd rather switch my tunning every other month for a week and run 93 than to bother with ordering snake oils online.

oxytane one caught my interest on a volvo forum cause they where going from a high 20 low 30mpg car to high 30s low 40s. if it works id be totally down to buy a case, its like 100 for a case and you only use a little bit of a bottle per tank. its supposed to help the ethanol burn , add power and some milage.... kinda like the one chemical people found and started putting in gas... i dont wanna go to far OT but i was just curious of others opinions on the crap...lol...

You see my line calling it snake oil? Yup, thats my opinion on it.

i also said others opinions too... lol...

Great information in this thread, I have been tempted to change to E85 when I pick up an ECU. San Diego has so few E85 stations which poses a problem. What kind of MPG have you seen on E85?

I'm planning on switching to 75% O93-25%E85 mix and see how it goes then adjust the afr, then go to 50-50, adjust then on to full e85, any one see a problem with that?

Just a lot more work than a straight swap, and you cnt go to a servo and buy 50-50, can you. I can see you could buy 50-50 but that would be a pain when you can just add 30% across your whole map, or with injector scaling and just tune it...why NOT do that?

Dann

I find it safer to tune and add 10% extra fuel to a map thats 1 point lean vs a tune thats 3-4 points lean.

So today i filled 7.5 gals of 93 and 2.8 of E85. Added 10% across the entire map. I'm running half a point rich in vac and about a full point in boost...down to 11afr. So i'd assume 5% should be good for a 75-25 mix. It seems to be running smoother and with less hickups.

Alrighty just an update, today was my 2nd partial fill up with more E85.

So my 1st tank i started with 5%, ended up adding it to 7% and it ran good. Today almost at empty i filled it with 2 gals 93 and 3 gals E85. I added 7% across the entire map ran rich so i removed 7% to get it to stock then added 5% and its good now.

Keep in mind 7% and then 5% is not just 13% as you'd expect.
1ms x 1.07 = 1.07ms
1.07 x 1.05 = 1.1235 not 1.13 as you'd get by just adding the total from above.

I've had to change boost also as it was running in the 13s so in boost its more like a 15% while in vac its only 12 so its not flat % across the entire map in other words you'll need to rework your map.

Now how the hell are u guys tunning the spark with that juice?

Personally i feel like its running smoother and quieter.

I wish Canada would get with the times and bring E85 in.

On a side note, our gas is now E10. If I get it tuned on 91 oct E10, and then run a track day in states with 92 Oct (no E) is it safe to assume I'll be just fine?

Gas in the states all has 10% Ethanol content.

Oh does it now? I guess they pumps I use in Blaine don't feel like posting a sticker.


Follow up question.. if tuned on 91 E10, running 94 pure should be fine, yes? 94 up here does not have E in it YET.

Yeah i was looking at that today, the octane pump does not say 10% ethanol on it however the ethanol pump does say minimum 70% alcohol in it so i dont know.

Yeah here in Canada it says on a sticker on the 87, 89 and 91 pumps "May Contain Up to %10 Ethanol". No sticker on the 94Oct.

It isnt that simple. Remember that although the timing may be ok (your argueing octane rating vs detonation right?), the stoichiometric ratio is different.

So although you may not detonate due to too much timing for the octane rating, the car will run uber rich on the gas compared to the ethanol blend.

Dann

Yeah I geuss that. So if I tune on 91 to keep it close to the US 92, then up here don't even bother with the 94..

uber rich? Actually .2 points that the stock ecu compensates for.. thats nothing.

Tuning on 100% E85 and then running octane.. that will be uber rich.

Not talking stock ECU's though. Don't know a stock Miata ECU that you can tune...

I found out today that Shell stations up here don't have any ethanol in their 91 yet. So if given the option for what gas to tune on (and run both once it's tuned) would you choose E10 gas or gas with no E? I'm thinking tune with 91 E10, and it should be fine to run 91 with no E?

0.2 points? Its 30%. I ran mine dry a few weeks ago driving laps around a block a sevo was on, just to see what it did with just gasoline and a spanner to drop 15 odd degrees of timing out of it. It was uber rich.

Dann

I could be wrong but i'm pretty sure hes talking about tuning O94 vs 91 with 10% blend.

Cheers

Alrighty today was the day i went full E85. I added 5% across the map but i decided to scrap it as its clearly lean as rpm/pressure increases. In other words a flat % increase wont do it, cells in boost have to be increased more.

Got some more tunning done. I have not done anything with the timing yet still working on the fuel. My car no longer dies when the fans turn on and its the smoothest it has ever ran.... I'll update my standalone over the weekend to V9 and hope for some luck.

Still haven't properly tuned for power.

I am very interested in power vs mixture temp. E85 doesn't light off as easily if things are too cold. I think that temp is <50°-55°F. I'm wondering if water injection is detrimental to performance at a certain point. If/when I tune I'm planning on testing with and without WI.

I have to admit that I started to add MMO a few tanks ago. Might not be necessary but it probably doesn't hurt anything. Just hedging my bets. Any good two stroke oil is probably better but I use MMO because it's dirt cheap.

Gas mileage is around 22.5-23 mpg with a/c usage.

WI is absolutely unnecessary with E85. If I can find MBT at 17psi and 350whp through the torque peak on E85, water injection is doing absolutely nothing for you.

E85 is magical shit.

Yeah I was wondering if you really needed the WI as well.

I want to convert my supercharged E36 M3 to E85 sooooooo bad.

So you guys ever figure out a way to tune the timing?