info on E 85 tune

[soutthpaw]

I was not trying to compare E85 to regular gasoline...What I was getting at was that you could have a more advanced timing and probably a longer injector "on" time to dump more fuel in the engine due to the Air/Fuel ration that E85 can burn at thus giving more power than running E85 on the factory stock settings. (this would probably negate any $$ savings compared to gasoline as it would use more e85 than the stock tune) As far as i am aware the engine cannot tell the pecentage of E85 vs gasoline in the fuel tank to make changes.. thus it would need to be done manually.. So from that perspective an E85 tune would be a great idea. Also, unless you run it exclusively or drain your fuel tank before filling you probably are running a mixture more like E50 or E60 for example.
I was not trying to compare E85 to regular gasoline... as I mentioned before I am aware of and pointed out that Octane only inhibits combustion.

[Jackpine]

Exactly correct southpaw! I knew you understood octane, but I've found there are a lot of people who really don't. And, I agree with you. It DOES seem you would have to "tune" for E85 to get any benefit from it, doesn't it?

- Jack

[Sburn]

Originally Posted by soutthpaw

...probably a longer injector "on" time to dump more fuel in the engine ....

That's how Brazil implemented wide scale ethanol use in cars originally designed for gasoline. It's a wiring harness that goes between the fuel injectors and the (gasoline) PCM that just keep the injectors on for 20% longer.

...As far as i am aware the engine cannot tell the pecentage of E85 vs gasoline in the fuel tank to make changes...

FFV Taurus use a sensor in the fuel line that measures the optical property difference between gasoline and ethanol and is able to tell the PCM about that percentage. PCM can then manage fuel and timing for any mix between 100% gaoline and 100% E85. I'd assume that FFV F150s likely use the same scheme, but I have no first hand experience.

[shaody]

I have a gryphon custom tuned with 87, 91 & E85 performance tunes. I have run them all at one time or another and was pleased with the performance of each. My uncalibrated butt dyno places them in this order 91 best, E85 next and 87 heading up the rear. I did see a reduction in MPG with the E-85 of about 10-15% depending on the driving habits. MPG was about the same with the two regular gas tunes, some people see an increase useing the higher octane tunes but I didn't, sure is fun to drive though!

Jeff

[Jackpine]

Originally Posted by Sburn

FFV Taurus use a sensor in the fuel line that measures the optical property difference between gasoline and ethanol and is able to tell the PCM about that percentage. PCM can then manage fuel and timing for any mix between 100% gaoline and 100% E85. I'd assume that FFV F150s likely use the same scheme, but I have no first hand experience.

Nice point, Sburn! I vaguely remember someone posting that there WAS a sensor somewhere, but I don't think I ever saw anything more about it (so it got filed in secondary memory).

It really makes sense doesn't it, that if one of their vehicles has the sensor, all flexfuel ones would have it? I guess Bill would know for sure, or, perhaps one of the techs on the forum?

- Jack

[Sburn]

Originally Posted by JackandJanet

Nice point, Sburn! I vaguely remember someone posting that there WAS a sensor somewhere, but I don't think I ever saw anything more about it (so it got filed in secondary memory).

It really makes sense doesn't it, that if one of their vehicles has the sensor, all flexfuel ones would have it? I guess Bill would know for sure, or, perhaps one of the techs on the forum?

- Jack

OK, so I did a little digging on this starting with my 2007 Ford F150 Wiring Manual and the Powertrain/Emissions Manual. No mention of a separate FFV sensor in either. Only slightly different wires for fuel pump and fuel gauge with FFV options are shown. NO PCM inputs for a FFV sensor.

So more digging on Google seems to suggest that Ford went away from the fuel line-style FFV sensor sometime around 2000.

Looks like Ford now does the calculations all in software with the only hardware change being a wideband oxygen sensor in place of a narrow band oxygen sensor in front of the catalytic converter(s).

Best as I can wrap my noggin around it at this late hour is that the PCM, via the wide band O2 sensor, always tunes air/fuel ratio for a lambda of 1.0 A lambda of 1.0 indicates complete burn, irrespective of the fuel used. So with the PCM software always tuning the AFR for a 1.0 lambda for whatever gas/E85 mix is being burned, you get a Flex Fuel Vehicle pretty much via software.

[Jackpine]

Excellent post, Sburn. Of course the closed loop lambda of 1.0 takes care of everything! I hate it when the "obvious" is right there in front or me and I don't see it! My stupidity really amazes me sometimes. :o

And, in case anyone missed it, Sburn just explained that there is no specific tuning needed for changing from "real" gas to the E85 "fake" stuff.

However, Bill can certainly modify the way fuel is delivered to provide even more performance gains over "stock" with this stuff, just as he does with real gas.

- Jack

[Sburn]

Originally Posted by JackandJanet

Excellent post, Sburn. Of course the closed loop lambda of 1.0 takes care of everything! I hate it when the "obvious" is right there in front or me and I don't see it! My stupidity really amazes me sometimes. :o

- Jack

Yeah, took a while for it to "click" with me, too. I'm still unclear how open-loop (cold start & WOT) mixtures get handled. I assume PCM uses a static map for that is rich for E85 and really rich for gasoline under the assumption that the open-loop operation won't be happening for long. But that' s just my guess.


I think in an earlier E85 post, I stated that the Feds mandated E85 to the auto makers. I believe that happened, but it sounds like Detroit didn't shed too many tears about it. From a 2006 "Car and Driver" article"

"With fewer than 600 stations selling E85 fuel in 37 states, why have GM, Ford, and DaimlerChrysler been cranking out these flex-fuel vehicles by the millions?

The answer is the mandatory Corporate Average Fuel Economy (CAFE) standards. Federal law requires that the cars an automaker offers for sale average 27.5 mpg; light trucks must achieve 22.2 mpg. Failure to do so can result in substantial fines. However, relief is available to manufacturers that build E85 vehicles to encourage their production.

The irony here is that although E85 in fact gets poorer fuel economy than gasoline, for CAFE purposes, the government counts only the 15-percent gasoline content of E85. Not counting the ethanol, which is the other 85 percent, produces a seven-fold increase in E85 mpg. The official CAFE number for an E85 vehicle results from averaging the gas and the inflated E85 fuel-economy stats.

Calculating backward from our test Tahoe's window-sticker figures (which are lower than but derived from the unpublished CAFE numbers), we figure the E85 Tahoe's CAFE rating jumped from 20.1 mpg to 33.3 mpg, blowing through the 22.2-mpg mandate and raising GM's average. What's that worth? Well, spread over the roughly 4.5-million vehicles GM sold in 2005, the maximum 0.9-mpg benefit allowed by the E85 loophole could have saved GM more than $200 million in fines. That's not chump change, even for the auto giant"
From:

http://www.caranddriver.com/reviews/...stuff/(page)/1

[Jackpine]

That Car and Driver article is really an "eye opener" isn't it?

I keep hoping, now that we have someone who is scientifically trained in the Dept of Energy, (at least I think we do?) we might just finally move forward in this process of converting sources of energy into useful results. I think the Engineering Community is up to the task, if they can just get a little incentive and the resources to forge ahead.

And, I believe you are correct regarding open loop - the fueling is taken off a map that probably tries to be the best of "both" worlds. Since E85 has a much richer ideal A/F ratio, (and it's possibly less prone to ignite?), I think you're dead on too about the mixture being VERY rich for a flex fuel vehicle running real gas at start. Personally, though, I'm quite surprised at how long it takes my truck to come out of open loop after start (I can tell it has because the torque converter will suddenly lock up).

I imagine this could be an area where Bill's custom tunes would really stand out. Since WOT is also open loop, he could tweak the fueling to be appropriate for the particular fuel used - rather than tuning a compromise.