AFR What you should know.... LONG - Page 2

fishin-nole · 02-11-2009, 06:34 AM

I'm glad I don't have to deal with the e85 yet. We still have real gas here. The station owner put signs on the pumps stating it was ethanol free gas.

Z7What · 02-11-2009, 04:48 PM

Edited the post to name author!

Wayne

'02 H-D #677 · 02-11-2009, 05:37 PM

Wideband sensors and an Interceptor for monitoring will eliminate concern for the everyday "Joe" that might be on the "edge".

rtkjadams · 02-11-2009, 07:50 PM

Quote:

Originally Posted by Z7What

Here are a few common fuel types and their approximate stoich value. Each of these stoich values are also represented as a lambda of 1.00:

* Unleaded 93 octane: 14.64
* E5 93 octane: 14.35
* E10 93 octane: 14.08
* E15 93 octane: 13.79
* VP C16: 14.77
* e85: 9.76
* e100: 9.00

Now say you want a richer mixture for a supercharged car under boost – typically I will command about 0.80 lambda. To get this into an air to fuel ratio you will take the stoichimetric value of your fuel (14.64 in this example) and multiply it by the lambda – 0.80 * 14.64 = 11.712:1. In order to use your O2 sensor and meter you must know the stoich point (14.64 used in the previous equation) if converting the O2 output to A/F and one can only use a wideband sensor for output not a narrow band sensor.

Wayne

I think I understand alittle.... Using the info from above, if I'm running 93 my A/F will be 11.712:1, but if filled up with E10 then I need to tune to get my A/F to show 11.264:1 (14.08 * .80) to be safe?????

Ray

Z7What · 02-11-2009, 08:01 PM

Quote:

Originally Posted by rtkjadams

I think I understand alittle.... Using the info from above, if I'm running 93 my A/F will be 11.712:1, but if filled up with E10 then I need to tune to get my A/F to show 11.264:1 (14.08 * .80) to be safe?????

Ray

Thats the way i understand it.

Wayne

lightning25 · 02-11-2009, 08:25 PM

wayne, thanks for posting the write ups, i will be reading as more come!

i have a question. where i live they say the gas contains up to 10% ethanol. so does that mean my gas has E10 in it??

i found this on the sunoco web site:

"In compliance with federal law and as stipulated by most automobile manufacturers, Sunoco gasolines contain no more than 10% ethanol."

i have never used race fuel or any higher ethanol fuel, but it appears i should be aware if i do.
how can we measure for this and change our readings so we are reading the correct and "true" A/F??

Sean

Z7What · 02-11-2009, 09:51 PM

Quote:

Originally Posted by lightning25

wayne, thanks for posting the write ups, i will be reading as more come!

i have a question. where i live they say the gas contains up to 10% ethanol. so does that mean my gas has E10 in it??

i found this on the sunoco web site:

"In compliance with federal law and as stipulated by most automobile manufacturers, Sunoco gasolines contain no more than 10% ethanol."

i have never used race fuel or any higher ethanol fuel, but it appears i should be aware if i do.
how can we measure for this and change our readings so we are reading the correct and "true" A/F??

Sean

Sean, i am not expert nor did i write this but have been studying and speaking with the person that did write it. When you see contains no more than 10% ethanol on the pumps that IS E10 fuel!

The way i see it is that if you are tuned for lets say a 11.6 A/F @ WOT on straight gas and then run E10 you want to be tuned for an 11.04 A/F @ WOT to make up for the difference in stoich.

Wayne

rtkjadams · 02-12-2009, 07:47 PM

Does the WB show leaner if you switch to E10? Or does it show the same A/F reading but the truck is actually running leaner????

Thanks,

Ray

Z7What · 02-13-2009, 04:53 AM

The way I under stand it is that it will show the same but it will be lean.

autenb · 02-13-2009, 06:20 AM

Humm... 11.264 is safe for E10 (AKA 93+10% Ethanol)
Well I asked JDM yesterday if they took into account for E10 in their tunes and they said that yes... they did. I'm currently on my break-in tune and haven't gotten into the boost at all yet, but when I get onto the throttle a bit on the HW to pass, I'll let my boost go all the way to 0 and my AEM Wideband will read as low as 10.8 right before it shifts. So that would be a tidge lean... correct? So I think it would be safe to say that if/when I get into the boost that it will be really lean. I'm just guessing here, because I haven't done it yet. But the truck idles @ around 15-16... which is really rich.

SAL · 02-13-2009, 01:02 PM

Quote:

Originally Posted by autenb

Humm... 11.264 is safe for E10 (AKA 93+10% Ethanol)
Well I asked JDM yesterday if they took into account for E10 in their tunes and they said that yes... they did. I'm currently on my break-in tune and haven't gotten into the boost at all yet, but when I get onto the throttle a bit on the HW to pass, I'll let my boost go all the way to 0 and my AEM Wideband will read as low as 10.8 right before it shifts. So that would be a tidge lean... correct? So I think it would be safe to say that if/when I get into the boost that it will be really lean. I'm just guessing here, because I haven't done it yet. But the truck idles @ around 15-16... which is really rich.

Your assumptions are backwards...

Z7What · 02-13-2009, 04:45 PM

Sal is correct the high number lean, lower number rich. Meaning a 10.80 is richer than a 14.4

And it sounds like you have a nice safe tune! With those A/F numbers.

Wayne

autenb · 02-13-2009, 08:00 PM

So... since it's 15.5 while cruising... and as high as 16 and my meter even reads -- when i'm @ idle sometimes... That's lean, but it's ok, since there's no load on it?
But... 10 and 11 is GOOD when i'm giving it throttle... but 13 or 14 while i'm giving it throttle is NOT good? (sorry... i'm trying to grasp a concept here.)

Z7What · 02-13-2009, 08:01 PM

Quote:

Originally Posted by autenb

So... since it's 15.5 while cruising... and as high as 16 and my meter even reads -- when i'm @ idle sometimes... That's lean, but it's ok, since there's no load on it?
But... 10 and 11 is GOOD when i'm giving it throttle... but 13 or 14 while i'm giving it throttle is NOT good? (sorry... i'm trying to grasp a concept here.)

Correct!

Wayne

autenb · 02-13-2009, 08:27 PM

so here's the back breaker... how lean does it have to be before it causes detonation? I mean... since it runs @ 14.7-15.5 while @ 2Krmp @ 65mph... does that mean that it is very likely detonating?

02-11-2009, 04:48 PM	#17 (permalink)
Z7What Powered By Eaton! Join Date: Apr 2007 Location: New Orleans, LA Posts: 927 View this user's gallery iTrader: 1 / 100%	Edited the post to name author! Wayne __________________ 2003 F-150 FX4 Powered by 2003 Lightning Engine #2005 AFCO H/E With Fans, Killer Chiller, Ported Throttle Body, Ported Plenum, Ported C&L Elbow, Metco Idlers, 4# Lower Pulley, Bosch 255LPH Fuel Pump, 90MM MAF, NGK TR6, FTVB K&N Filter, EGR Delete, Flex-A-Lite EFans, 170* T-Stat, JLP Street Reseroir Tuned By Wes @ Total Performance Solutions 331RWHP/411RWTQ On 38's Best 1/4 14.569@ 90.84MPH Best 60' 2.08

02-13-2009, 06:20 AM	#25 (permalink)
autenb Registered User Join Date: Apr 2008 Location: Chesapeake, VA Posts: 1,436 View this user's gallery iTrader: 0 / 0%	Humm... 11.264 is safe for E10 (AKA 93+10% Ethanol) Well I asked JDM yesterday if they took into account for E10 in their tunes and they said that yes... they did. I'm currently on my break-in tune and haven't gotten into the boost at all yet, but when I get onto the throttle a bit on the HW to pass, I'll let my boost go all the way to 0 and my AEM Wideband will read as low as 10.8 right before it shifts. So that would be a tidge lean... correct? So I think it would be safe to say that if/when I get into the boost that it will be really lean. I'm just guessing here, because I haven't done it yet. But the truck idles @ around 15-16... which is really rich. __________________ 2003 DSG Lightning Build #1409 Performance: Staley Racing Longblock, Steigmeier Stg V Port, Ported C&L Truflow Plenum, LFP SBTB, C&L TruFlow Elbow, SCT BA2400 MAF, Siemsens 60# Injectors, JLP CAI, 2C FTVB, 6# (9") Lower, Optima Red Top, NGK TR6's gapped @ .033, Precision Fabrication Intercooler Reservoir, Triple-Pass Fluidyne H/E, Kooks LT's, JDM Mids, Hi-Flo Cats, Borla Catback, EGR Delete, 4X4 Trans Pan, 555's up front, NT05's out back. HP:509.7@4577 TQ: 569.5@4316

02-13-2009, 04:45 PM	#27 (permalink)
Z7What Powered By Eaton! Join Date: Apr 2007 Location: New Orleans, LA Posts: 927 View this user's gallery iTrader: 1 / 100%	Sal is correct the high number lean, lower number rich. Meaning a 10.80 is richer than a 14.4 And it sounds like you have a nice safe tune! With those A/F numbers. Wayne __________________ 2003 F-150 FX4 Powered by 2003 Lightning Engine #2005 AFCO H/E With Fans, Killer Chiller, Ported Throttle Body, Ported Plenum, Ported C&L Elbow, Metco Idlers, 4# Lower Pulley, Bosch 255LPH Fuel Pump, 90MM MAF, NGK TR6, FTVB K&N Filter, EGR Delete, Flex-A-Lite EFans, 170* T-Stat, JLP Street Reseroir Tuned By Wes @ Total Performance Solutions 331RWHP/411RWTQ On 38's Best 1/4 14.569@ 90.84MPH Best 60' 2.08

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02-11-2009, 06:34 AM	#16 (permalink)
fishin-nole Bone idle and work shy! Join Date: Oct 2004 Location: Where the crazy folks stay!!! Posts: 697 View this user's gallery iTrader: 8 / 100%	I'm glad I don't have to deal with the e85 yet. We still have real gas here. The station owner put signs on the pumps stating it was ethanol free gas.

02-11-2009, 05:37 PM	#18 (permalink)
'02 H-D #677 Registered User Join Date: Nov 2004 Location: Seattle Posts: 267 View this user's gallery iTrader: 0 / 0%	Wideband sensors and an Interceptor for monitoring will eliminate concern for the everyday "Joe" that might be on the "edge".

02-11-2009, 08:25 PM	#21 (permalink)
lightning25 Registered User Join Date: Aug 2007 Posts: 170 View this user's gallery iTrader: 0 / 0%	wayne, thanks for posting the write ups, i will be reading as more come! i have a question. where i live they say the gas contains up to 10% ethanol. so does that mean my gas has E10 in it?? i found this on the sunoco web site: "In compliance with federal law and as stipulated by most automobile manufacturers, Sunoco gasolines contain no more than 10% ethanol." i have never used race fuel or any higher ethanol fuel, but it appears i should be aware if i do. how can we measure for this and change our readings so we are reading the correct and "true" A/F?? Sean

02-12-2009, 07:47 PM	#23 (permalink)
rtkjadams Registered User Join Date: Nov 2002 Posts: 148 View this user's gallery iTrader: 0 / 0%	Does the WB show leaner if you switch to E10? Or does it show the same A/F reading but the truck is actually running leaner???? Thanks, Ray

02-13-2009, 04:53 AM	#24 (permalink)
Z7What Powered By Eaton! Join Date: Apr 2007 Location: New Orleans, LA Posts: 927 View this user's gallery iTrader: 1 / 100%	The way I under stand it is that it will show the same but it will be lean.

02-13-2009, 08:00 PM	#28 (permalink)
autenb Registered User Join Date: Apr 2008 Location: Chesapeake, VA Posts: 1,436 View this user's gallery iTrader: 0 / 0%	So... since it's 15.5 while cruising... and as high as 16 and my meter even reads -- when i'm @ idle sometimes... That's lean, but it's ok, since there's no load on it? But... 10 and 11 is GOOD when i'm giving it throttle... but 13 or 14 while i'm giving it throttle is NOT good? (sorry... i'm trying to grasp a concept here.)

02-13-2009, 08:27 PM	#30 (permalink)
autenb Registered User Join Date: Apr 2008 Location: Chesapeake, VA Posts: 1,436 View this user's gallery iTrader: 0 / 0%	so here's the back breaker... how lean does it have to be before it causes detonation? I mean... since it runs @ 14.7-15.5 while @ 2Krmp @ 65mph... does that mean that it is very likely detonating?