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E10 AFR different?

Old 12-17-2010, 12:45 PM
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Default E10 AFR different?

I remember that around 12.3 afr was optimal for WOT and 14.7 is stoich, but with the gas now adays being E10 is there a different a/f ratio I should shoot for? Thanks.
Old 12-17-2010, 01:02 PM
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i dont know alot about this but i came across a post the other day and i believe if 14.7 is stoich, then with e10 the a/f will read more like 15.2. it will show lean by about half a point but is actually on the money. like i said not an expert. there was a post a few days ago on it. " still running lean at idle even in closed loop" was the name of it. check it out
Old 12-17-2010, 02:27 PM
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Stoich is 14.1 for E10% instead of 14.7
If you have E10 on a 14.7 tune the AFR can show over 15.2 when in open loop.

A Wide-Band is not an AFR gauge. It is a Lambda gauge.

E10 Stoich is 14.1 -- Lambda for E10 = 1.0
E0 Stoich is 14.7 -- Lambda for E0 = 1.0

I typical Wide-Band Gauge is programmed to display 14.7 at 1.0 Lambda. See the issue.

OK so lets look at an E85 tune. It runs a Narrow-Band O2 sensor, but it can accurately read AFR's from say 9 to 1 all the way to 16 to 1. Hmmmmmm. A Narrow-Band just means it has a narrow window when operating at a given AFR.

Now WOT tuning.
It is just like E0 tuning. You have to find the Sweet Spot.
You will need to add timing to the E10 tune
Old 12-17-2010, 08:29 PM
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Maybe i'm just not thinking about the math right but if the sensors read lambda then even though the optimal AFR for E10 is 14.1 it will still read as though it's 14.7. Is there any way to correct for this to eliminate confusion? so it will actually read 14.1 if I have a stoich E10 mixture.
Old 12-17-2010, 08:51 PM
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Originally Posted by Pavetim
Maybe i'm just not thinking about the math right but if the sensors read lambda then even though the optimal AFR for E10 is 14.1 it will still read as though it's 14.7. Is there any way to correct for this to eliminate confusion? so it will actually read 14.1 if I have a stoich E10 mixture.
yes. use units of lambda.
Old 12-17-2010, 09:23 PM
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Originally Posted by Pavetim
Maybe i'm just not thinking about the math right but if the sensors read lambda then even though the optimal AFR for E10 is 14.1 it will still read as though it's 14.7. Is there any way to correct for this to eliminate confusion? so it will actually read 14.1 if I have a stoich E10 mixture.
what year is the tune?
Old 12-17-2010, 09:25 PM
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I'ts a 2001 S10 with the 4.3L
Old 12-17-2010, 10:12 PM
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Tim,

With EFILive FlashScan V2 reading your LC-1 via the serial cable (see other thread), you can display lambda.

You multiply lambda by the stoich AFR to obtain the actual AFR... your LC-1 does this for you;

you can program the stoich AFR into your LC-1 using Innovates LM programmer software.

[ for any fuel, the stoich mixture will always be lambda = 1.00 ]
Old 12-17-2010, 10:17 PM
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regardless of fuel just dial your narrow bands in to around +/- 4% which will be stoich regardless of fuel and then in your PE table had your desired WOT enrichment, i would say start at setting your PE @ 1.2 and go from there
Old 12-17-2010, 10:19 PM
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Originally Posted by Pavetim
Maybe i'm just not thinking about the math right but if the sensors read lambda then even though the optimal AFR for E10 is 14.1 it will still read as though it's 14.7. Is there any way to correct for this to eliminate confusion? so it will actually read 14.1 if I have a stoich E10 mixture.
correct if the AFR controller setup for Gas it will read stoich at 14.7 even though its really 14.1


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