Got mine running at 11.7 clean all through the RPMs but I've heard it should be in the low 11s.
Fuel AFRst FARst Equivalence Ratio Lambda
Gasoline stoichiometric 14.7 0.068 1 1
Gasoline max power rich 12.5 0.08 1.176 0.8503
Gasoline max power lean 13.23 0.0755 1.111 0.900
E10 stoichiometric 14.0 - 14.1 ? ?
E85 stoichiometric 9.765 0.10235 1 1
E85 max power rich 6.975 0.1434 1.40 0.7143
E85 max power lean 8.4687 0.118 1.153 0.8673
E100 stoichiometric 9.0078 0.111 1 1
E100 max power rich 6.429 0.155 1.4 0.714
E100 max power lean 7.8 0.128 1.15 0.870
that means you should IDLE and regular driving should be around 9.8 (idle could go much lower like 13's) and WOT should be in the high 6's and any boost should be in the 8.5 range
E-85 pulls more heat than gas and will run leaner (in lambada standards) but you are far short of maximizing your set up
When you say 11.7 are you referring to a wideband scale meant to be used for gasoline ? Have you set your wideband to display an AFR scale for a ethanol based fuel , or is it the same scale you use for gasoline .
If its a gasoline scale , then I would say 11.7 at wot is fine . To tell you the truth , I have commanded the ECU to run a Lambda AFR of 8.1 (12.0 in the gasoline scale) at wot on the street with no problems , It depends on how much "margin of error" your setup needs . Im on total ECU control (no boost controller , no crazy WGA preload , no piggy-backs , Stock static fuel setup) & it stays pretty tight on the WOT power enrichment target , so I dont mind it being a little close to the high side of whats considered safe . If I was running more than 20 psi , I might back off that a little , but for now , I feel safe where its at . sure , my EGTs might be a little higher than Mopar would like , I might be a little rough on my manifold , but what gonna happen ? Will I hasten the development of the hairline crack next to the WGA flapper ? maybe , but im not worried about it .
E85 rox ive had my A/F's really high in the 14-15's and the exhaust temps still stay low and Ive never seen any knock no matter what the circumstances are. oh BTW im useing a UEGO to look at A/F's as im sure most people are
see my air/fuel has been acting up for some time. now it can be just the E85. the cars mix is usually 70/30 E85/pump for the cold start ups. some times i run 100% E85. now i have a good idle air fuel ratio 14.7-15.3 and driving in normal conditions under light load (cruising between 25mph-and40mph). the weird thing is the car will show a air fuel ratio of 13.7-14.3 when ever im driving between 50-75 MPH. about 2,200-3,000 rpm's.
here is another kicker. i had mopar stage 2's and recently changed them for Deatsch werks 750's. i re set the pcm and re downloaded my modified stock tune. The car was running fine in those upper rpm ranges for like two days, then the car pulled a engine code. system too lean Bank 1 sensor 1. i replaced that sensor not even 2,000 miles ago. the car again was driving 13.8-14.3.
now im on stock pcm and running with out a rescale at this moment (money issues) could a rescale fix the air fuel ratio in that range? it just sees weird to me.
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Last edited by GreaseMonkey69 : 11-09-2009 at 05:37 PM.
see my air/fuel has been acting up for some time. now it can be just the E85. the cars mix is usually 70/30 E85/pump for the cold start ups. some times i run 100% E85. now i have a good idle air fuel ratio 14.7-15.3 and driving in normal conditions under light load (cruising between 25mph-and40mph). the weird thing is the car will show a air fuel ratio of 13.7-14.3 when ever im driving between 50-75 MPH. about 2,200-3,000 rpm's.
here is another kicker. i had mopar stage 2's and recently changed them for Deatsch werks 750's. i re set the pcm and re downloaded my modified stock tune. The car was running fine in those upper rpm ranges for like two days, then the car pulled a engine code. system too lean Bank 1 sensor 1. i replaced that sensor not even 2,000 miles ago. the car again was driving 13.8-14.3.
now im on stock pcm and running with out a rescale at this moment (money issues) could a rescale fix the air fuel ratio in that range? it just sees weird to me.
yup simular issue here.. from 2-2.5k afr is 14.0-14.3.... but once over 2.5k 14.5afr like it should be... weird...
other than that car runs good. been runnin 80% e85 and 20%91oct.. i finally put 100% e85 and all is good.. im out of fuel on my 650s w/RTL.. afrs 11.5 accross rpmz..
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yea my WOT is 11.2 right now with the warm weather. i need to tune it a bit more, but it is weird that the AFR's would be just that much off. it was normal until the car pulled a lean condition then it started showing the weird AFR's after the engine code appeared.
E85 rox ive had my A/F's really high in the 14-15's and the exhaust temps still stay low and Ive never seen any knock no matter what the circumstances are. oh BTW im useing a UEGO to look at A/F's as im sure most people are
Are you referring to your AFRs at part throttle ? I wouldnt reccomend that at WOT to anybody reading this . Being a little leaner than stoichiometric is ok at cruise & idle , but at wot I would reccomend a AFR no leaner than 13.0 or so (for street use).
Now that we have thrown a bunch of ratios around in this thread , I would like to reiterate that there are different ways to express the AFRs we are talking about . Nutz's post above shows that at a stochiometric ratio , more ethanol is required than gasoline . So if you are using a wideband to make sure you are not running lean , then using the gasoline scale on your wideband is fine .
Just know that when dealing with an ethanol mixture , that scale is incorrect . if you try to make calculations for fuel programming , or your next mixture , it will lead you astray .
If , like me , all this crap starts to make your head hurt , set your wideband to display Lambda . It does away with the ratio differences in these fuels . Lambda works by using stociometric as a reference point , That "perfect" mixture is expressed as 1.0 lambda , for ALL fuels . The richer you go , the lambda value will go lower . Check out the Lambda value column in nutz's post shows that dispite the large differences in fuel volumes required to reach stociometric , the Lambda values for rich power & lean power are very similar between fuels . When you get into ethanol mixtures , you will also begin to understand that the exact ethanol content in a fuel will fluctuate quite a bit between vendors , or between seasonal blends .
Sometimes you may need to make calculations that require knowing the true AFR value , but when conceptualizing this crap in my head , I find Lambda much more friendly than all these different ratios .
Many of you already know this , Im just putting it out there .
Last edited by apexcrazy : 11-09-2009 at 06:42 PM.
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Perfect Air/Fuel for E85
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New turbo setup and transmission setup
Linear Mode
