Problem that i've had is there is a lot of range the fuel content can be. For example it can be as pure as 50/50 mix and up to 90% ethanol.
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Originally Posted by triple88a
(Post 937914)
Problem that i've had is there is a lot of range the fuel content can be. For example it can be as pure as 50/50 mix and up to 90% ethanol.
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I've had my afr lean out by nearly a full point after filling up and then richen up by a full point after the next fill up and 13 in boost is bad. 11 in boost is also bad (e85 values)
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11 afr on the gauge?
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Originally Posted by dvcn
(Post 845192)
The Baby Bottle Method For methods to measure E content without getting your hands dirty. I've seen two methods that OEM's have used to measure E content for flex fuel cars. 1 is obviously the flex fuel sensor. They work great, but they're expensive and the ones I've seen go inline in the fuel return line and can only flow a limited amount of fuel. So if your fuel pump flows too well you will have idle issues. 2nd method is a lot more sneaky. They let the car run in closed loop till the long term fuel trim evens out after filling up and then you know how much fuel you needed to add or subtract and you know the stoich of the fuel previously in the tank, so you can determine the stoich of the fuel in the tank. OEM's actually have a look up table for it in the ecu. And with either option in a flex fuel car it will interpolate between the e values (could tune to either e85 or e98) and the gasoline values for commanded lambda, timing, etc. Of course for the straight gas to e85 switch you'll need fuel trims with sufficient range. And if you're using this method manually, dear god stay out of boost until you compensate it. |
Originally Posted by 18psi
(Post 937947)
11 afr on the gauge?
Problem with E85 is sub 11 you might start see pre ignition. |
absolutely not true. at least not with the stuff we use here. I tune for mid 11's no matter what
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Originally Posted by 18psi
(Post 937987)
absolutely not true. at least not with the stuff we use here. I tune for mid 11's no matter what
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Originally Posted by Savington
(Post 938138)
You're just wasting fuel. I was tuning to ~12.2:1 on E85. Actual AFRs are somewhere in the 8-9:1 range, but my head works in gasoline AFRs so I don't bother switching the wideband translation.
Just a guess... |
Originally Posted by Savington
(Post 938138)
You're just wasting fuel. I was tuning to ~12.2:1 on E85. Actual AFRs are somewhere in the 8-9:1 range, but my head works in gasoline AFRs so I don't bother switching the wideband translation.
And you're right, I'm probably being too conservative staying in the 11's but better safe than sorry. (esp if there is a swing/variation in batches of e85) (and yes most my tuning is on Scoobs) |
Originally Posted by 18psi
(Post 938322)
I'm not sure how much fuel is wasted between 11.6-11.8 and 12.2 but I'd guess not that much.
And you're right, I'm probably being too conservative staying in the 11's but better safe than sorry. (esp if there is a swing/variation in batches of e85) (and yes most my tuning is on Scoobs) |
So you tune for 12.2 and I tune for 11.8 (just check my fxt maps) and you're saying that .4 afr is the difference between dumping buckets of fuel and a non-sloppy tune? LOL ok.
I'm not arguing with you, its just you're bashing my targets when the difference isn't even significant....And on cars that love to run richer. Thanks for the input. I actually do plan to experiment with much leaner mixtures on my current miata. |
11.8 doesn't sound like mid 11s to me. Sounds closer to just under 12.
As far as cars that love to run richer... its not about the car.. its that the fuel igniting while being compressed because its so rich. |
Not sure if trolling or really that stupid. In any case, I'm not going to waste any more time on this argument. Carry on.
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Hi
I have no experience tuning E85 on Subaru motors. But clearly, you are doing it wrong. I don't care how many reliable, 350+awhp Subarus you have tuned, you obviously have no idea what you are doing and you are a sloppy tuner at best. Eff you |
In his defense. Tuning subies rich is common practice. You'll see tunes that people pay good money for commanding as rich as 10.5:1 on 93 octane tunes. I think they're being silly and its way to rich. BUT the fuel mixture thats going to make the most power depends on a metric shit load of factors like combo chamber geometry for example. People think you've built a grenade if you've tuned leaner than 11.
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Originally Posted by Leafy
(Post 938595)
In his defense. Tuning subies rich is common practice. You'll see tunes that people pay good money for commanding as rich as 10.5:1 on 93 octane tunes. I think they're being silly and its way to rich. BUT the fuel mixture thats going to make the most power depends on a metric shit load of factors like combo chamber geometry for example. People think you've built a grenade if you've tuned leaner than 11.
dumbass Even with miatas there's a whole bunch of peopele on here who pulled out pistons scorched and melted around the ringlands/tops from lean mixture. |
2 Attachment(s)
I apologize for jacking this thread. My posts must seem non sequitur. I know, I should start my own thread that has useful E85 information, mea culpa.
Here is a baby bottle that requires no math: Echecker - E85 Fuel Test Tube https://www.miataturbo.net/attachmen...ine=1350064237 |
:laugh:
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Neat widget!
Ok, so how are you bastards even finding E85? Is there some magical website that I'm unaware of that will direct me to this nectar of the gods? |
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