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Max power air-fuel ratio for e10 fuel? #1405326 03/20/13 01:05 PM 03/20/13 01:05 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	I know that straight gas is generally expected to produce peak power with an air-fuel ratio in the range of 12.8 - 13.2. What about the typical 10% ethanol blend that everything local to me sells year around now? With the addition of a wideband O2 setup once The MoPig is back on the street, I'd like to have a general idea of what's "normal" for e10 pump gas. Thanks!

Re: Max power air-fuel ratio for e10 fuel? [Re: BradH] #1405327 03/20/13 02:24 PM 03/20/13 02:24 PM
Joined: Jan 2003 Posts: 5,443 Indiana Y YO7_A66 master
YO7_A66 master Y Joined: Jan 2003 Posts: 5,443 Indiana	Brad, I have been running the O2 sensors for the last two years and I have been reading everything that I can to try and determine what the best A/F might be for my steup on E10. From what I have gathered, there might be a "range" to shoot for and then tweak from there. Since there are so many variables (outside temperature, octane, compression, timing, altitude, vehicle combo, etc.), I have been testing with 12.5-13.0 WOT A/F's for my WOT range. I do think that the "seat of the pants" shows that 12.8-13.0 feels quicker for my street car. You will find that there are some people who will aim for 12.0 and some that will aim for 13.4. I was finding so many different opinions on what number to aim for, so I started testing different A/F numbers and found what my car seemed to like. Two years ago I aimed for 12.8-13.2. Last year I aimed for 12.4-12.8. This year I will aim for somewhere in the middle around the 12.8-13.0 range. 1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)

Re: Max power air-fuel ratio for e10 fuel? [Re: BradH] #1405328 03/20/13 02:54 PM 03/20/13 02:54 PM
Joined: Mar 2007 Posts: 3,300 Northern Indiana Dunnuck Racing master
Dunnuck Racing master Joined: Mar 2007 Posts: 3,300 Northern Indiana	Stoich X 90 percent is a good general guideline . So approximately12.6 to 1 for E10. If you get a chance ,read my A/F article in the May Mopar Muscle. I gave some of the information there,on the track and dyno. Keith www.dunnuckracing.com

Re: Max power air-fuel ratio for e10 fuel? [Re: Dunnuck Racing] #1405329 03/20/13 03:04 PM 03/20/13 03:04 PM
Joined: Jul 2004 Posts: 19,317 State of confusion T Thumperdart I Live Here
Thumperdart I Live Here T Joined: Jul 2004 Posts: 19,317 State of confusion	Quote: Stoich X 90 percent is a good general guideline . So approximately12.6 to 1 for E10. If you get a chance ,read my A/F article in the May Mopar Muscle. I gave some of the information there,on the track and dyno. Keith Got a link I`d b interested also.......... 72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....

Re: Max power air-fuel ratio for e10 fuel? [Re: Thumperdart] #1405330 03/20/13 03:19 PM 03/20/13 03:19 PM
Joined: Mar 2007 Posts: 3,300 Northern Indiana Dunnuck Racing master
Dunnuck Racing master Joined: Mar 2007 Posts: 3,300 Northern Indiana	I just checked and its not on their website yet. It should be pretty soon,they usually post tech articles about a month after the print issue. Basically,I showed the effects of varying A/F ratios against power on the dyno with race fuel and then tested E10 on a street/strip car at the track. Keith www.dunnuckracing.com

Re: Max power air-fuel ratio for e10 fuel? [Re: Dunnuck Racing] #1405331 03/20/13 03:21 PM 03/20/13 03:21 PM
Joined: Jul 2004 Posts: 19,317 State of confusion T Thumperdart I Live Here
Thumperdart I Live Here T Joined: Jul 2004 Posts: 19,317 State of confusion	Cool, maybe post it when it`s ready. 72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....

Re: Max power air-fuel ratio for e10 fuel? [Re: Dunnuck Racing] #1405332 03/20/13 03:57 PM 03/20/13 03:57 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	Quote: Stoich X 90 percent is a good general guideline . So approximately12.6 to 1 for E10. If you get a chance ,read my A/F article in the May Mopar Muscle. I gave some of the information there,on the track and dyno. Keith I did pick up that issue (specifically because of your articles in it), but will go back and re-read the article. I didn't remember you really finding a "sweet spot" during the e10 tests and the combination you ran seemed to want closer to 12.0 a-f IIRC.

Re: Max power air-fuel ratio for e10 fuel? [Re: BradH] #1405333 03/20/13 04:15 PM 03/20/13 04:15 PM
Joined: Mar 2007 Posts: 3,300 Northern Indiana Dunnuck Racing master
Dunnuck Racing master Joined: Mar 2007 Posts: 3,300 Northern Indiana	Brad, I will look at the article and my original draft and notes. Some things get editing for space and may have had something like that happen. Usually the the 90% of stoich is a good starting point for max power. But how good the base fuel is that the ethanol went into and gown efficiently the engine can use the fuel matters too. The track testing was done on a low compression stock bottom end 440 with aluminum heads and a custom solid lifter cam. Certainly not the best quench I have ever seen to help with efficiency. Keith www.dunnuckracing.com

Re: Max power air-fuel ratio for e10 fuel? [Re: Dunnuck Racing] #1405334 03/20/13 04:49 PM 03/20/13 04:49 PM
Joined: Mar 2007 Posts: 3,300 Northern Indiana Dunnuck Racing master
Dunnuck Racing master Joined: Mar 2007 Posts: 3,300 Northern Indiana	Something else to keep in mind with E10, just like E85, is that it doesn't necessarily contain10% exactly. By law if it states 10 % ethanol on the pump,it must contain a minimum of 6% and out of 10 stations I tested fuel from,only one was above6% I have been testing a few different carburetors and doing some emulsion circuit tuning lately with pump gas and there is a lot of power to be found getting the mixture where the engine likes it everywhere. Keith www.dunnuckracing.com

Re: Max power air-fuel ratio for e10 fuel? [Re: YO7_A66] #1405335 03/20/13 04:50 PM 03/20/13 04:50 PM
Joined: Jan 2003 Posts: 16,925 NC 440Jim I Live Here
440Jim I Live Here Joined: Jan 2003 Posts: 16,925 NC	Quote: From what I have gathered, there might be a "range" to shoot for and then tweak from there. 12.5-13.0 WOT A/F's This is my opinion as well. Different combo's will use the fuel more efficiently, which allows a lean mixture for maximum power. Others don't atomize as well, scavenge/fill the cylinder, etc. I think it is interesting to see tests, but I don't believe it will be the same answer for each application. 1993 Daytona, 5.50 at 130mph (1/8) 1.19 sixty ft (PG). Link to 572 B1 - Part 1

Re: Max power air-fuel ratio for e10 fuel? [Re: 440Jim] #1405336 03/20/13 05:10 PM 03/20/13 05:10 PM
Joined: Mar 2007 Posts: 3,300 Northern Indiana Dunnuck Racing master
Dunnuck Racing master Joined: Mar 2007 Posts: 3,300 Northern Indiana	Quote: Quote: From what I have gathered, there might be a "range" to shoot for and then tweak from there. 12.5-13.0 WOT A/F's This is my opinion as well. Different combo's will use the fuel more efficiently, which allows a lean mixture for maximum power. Others don't atomize as well, scavenge/fill the cylinder, etc. I think it is interesting to see tests, but I don't believe it will be the same answer for each application. That was the main point of the article. Too many guys are buying A/F meters then asking for a magic number to shoot for without realizing that their combination and even their fuel may make a difference Keith That was exactly the point of my article . Too many guys look for a magic number to try and tune to with all the A/F meters out there now. But they have no idea how their combination or even their fuel compares to the guy they are asking. Keith www.dunnuckracing.com

Re: Max power air-fuel ratio for e10 fuel? [Re: Dunnuck Racing] #1405337 03/20/13 05:22 PM 03/20/13 05:22 PM
Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually B BradH OP Taking time off to work on my car
BradH OP Taking time off to work on my car B Joined: Jan 2003 Posts: 15,439 Val-haul-ass... eventually	I'm 100% with you on there not being a "magic number" for everyone. I was looking for a general range that e10 seems to perform best at. Your comments on how much ethanol the pumps labeled as 10% really contain reminded me that I was looking for some type of ethanol tester to check the local stations. I know Quick Fuel markets one targeted towards the e85 crowd, but I'd like to be able to run spot checks on the e10 stuff to see what it really shows and how consistent it is from fill-up to fill-up...

Re: Max power air-fuel ratio for e10 fuel? [Re: BradH] #1405338 03/22/13 11:38 AM 03/22/13 11:38 AM
Joined: Jan 2003 Posts: 16,925 NC 440Jim I Live Here
440Jim I Live Here Joined: Jan 2003 Posts: 16,925 NC	Brad, One other thing to remember... The wide band oxygen sensor actually measures Lambda, the ratio of actual mixture to stoichiometric mixture and it doesn't care what fuel you are running (100% gas, 95% gas, 90% gas, E85, alcohol, etc. i.e. it already accounts for the percent alcohol. The display device can be programed to show Lambda, or A/F based on the stoichiometric ratio you input. I still like to talk in A/F ratio. So I convert Lambda to A/F based on 100% gasoline stoichiometric ratio of 14.7, this is called using the gasoline scale. Gas: Lambda 0.85 x 14.7 = 12.5 A/F E85: Lambda 0.85 x 9.76 = 8.3 A/F Alky: Lambda .85 x 6.40 = 5.4 A/F And E10 might have a stoichiometric ratio around 14.3, FWIW. From running all those fuels, the "best" Lambda is not significantly different for any of those fuels. So leave your display in gasoline scale and shoot for 12.5-13.0

Re: Max power air-fuel ratio for e10 fuel? [Re: 440Jim] #1405339 03/22/13 12:09 PM 03/22/13 12:09 PM
Joined: Mar 2007 Posts: 3,300 Northern Indiana Dunnuck Racing master
Dunnuck Racing master Joined: Mar 2007 Posts: 3,300 Northern Indiana	Stoich for E10 is closer to 14.1 The 360 mule I am testing with right now ,makes its best power and torque at 12.1-12.2 with 5 different carburetors I have been testing with. This is another non efficient combination though,8.8 to 1 compression aluminum heads,Comp Thumper cam. How well the mixture is prepared can make a big difference. Part throttle tuning with different carburetors has been pretty revealing as far as rich/ lean conditions vs torque Keith www.dunnuckracing.com

Re: Max power air-fuel ratio for e10 fuel? [Re: Dunnuck Racing] #1405340 03/22/13 12:25 PM 03/22/13 12:25 PM
Joined: May 2004 Posts: 12,387 Taxes & Virus's R-US, NY Dragula I Live Here
Dragula I Live Here Joined: May 2004 Posts: 12,387 Taxes & Virus's R-US, NY	On my pump gas rides I am running between 12.2-12.6...No leaner at WOT. I used to use 12.7-12.9, but with E10 that is too lean. '70 Cuda,...605 EFI Hemi Street Car (6.20 best pass, 1.33 60ft) https://www.youtube.com/watch?v=WYw6RA-k5Bk (6.25 at 108.75mph from inside car) https://www.youtube.com/watch?v=3zQEb9uxFng (6.25 at 108mph from outside car) https://www.youtube.com/watch?v=JCvfzsC4NgM (9.9) '66 Barracuda AWB Stretched nose Blown 440 Car in build stage '71 Duster Drag Car 400 Low Deck 512 best 6.002 at 115.44mph https://www.youtube.com/watch?v=Znuo3jMUXTk

Re: Max power air-fuel ratio for e10 fuel? [Re: Dunnuck Racing] #1405341 03/22/13 12:27 PM 03/22/13 12:27 PM
Joined: Jul 2004 Posts: 19,317 State of confusion T Thumperdart I Live Here
Thumperdart I Live Here T Joined: Jul 2004 Posts: 19,317 State of confusion	Quote: Stoich for E10 is closer to 14.1 The 360 mule I am testing with right now ,makes its best power and torque at 12.1-12.2 with 5 different carburetors I have been testing with. This is another non efficient combination though,8.8 to 1 compression aluminum heads,Comp Thumper cam. How well the mixture is prepared can make a big difference. Part throttle tuning with different carburetors has been pretty revealing as far as rich/ lean conditions vs torque Keith When I chassis dynoed my heap a few years ago max power was bet. 12.2-12.4 and that was w/Trick 110 leaded. I now run VP-100 unleaded and it`s at 12.8 and feels ok but I`m going to get it a bit fatter then check the plugs since I live/drive bet. 2500-4000 ft. depending on conditions and race way lower. This fuel in also apparently 10% so hopeing for a bit more power.......... 72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....

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