MarcusP Posted April 27, 2022 Report Share Posted April 27, 2022 Is it normal that the e85 map actually has less VE than the 91 map? Seems backwards to me, but we keep pulling fuel and the e85 map is still rich. Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 27, 2022 Report Share Posted April 27, 2022 If injector data is correct they should end up pretty similar. VE is effectively air flow - air flow shouldnt change much when you only change the fuel. Quote Link to comment Share on other sites More sharing options...
MarcusP Posted April 27, 2022 Author Report Share Posted April 27, 2022 So the fuel charging coefficient for 91 octane which is e10 here is set to 10. On the flex side we are at e80 and the fcc is set to 30. the 91 tune is petty set, should I change the fcc for flex to 10 to get the numbers to line up? Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 27, 2022 Report Share Posted April 27, 2022 It is most likely the injector flow rate setting that is incorrect. Was the injector flowrate tested with both fuels or do you have the same flowrate entered for both fuels? If flowrate is unknown I normally set fuel table 2 to the same numbers as table 1 (or leave it turned off) and then adjust the flowrate up or down until the fuel mixture is in the ballpark at medium RPM/load. Then in some cases you may need to make some small tweaks in the 2nd table to get mixture to track well over all condition. Quote Link to comment Share on other sites More sharing options...
MarcusP Posted April 27, 2022 Author Report Share Posted April 27, 2022 Just now, Adamw said: It is most likely the injector flow rate setting that is incorrect. Was the injector flowrate tested with both fuels or do you have the same flowrate entered for both fuels? If flowrate is unknown I normally set fuel table 2 to the same numbers as table 1 (or leave it turned off) and then adjust the flowrate up or down until the fuel mixture is in the ballpark at medium RPM/load. Then in some cases you may need to make some small tweaks in the 2nd table to get mixture to track well over all condition. I’m running the older ID 1700x injectors. I only find one flow number on their site and it’s not fuel specific that I can tell. I have both fuels set to the same number Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 28, 2022 Report Share Posted April 28, 2022 Yeah, ID only test with a fluid that is something close to gasoline in terms of physical properties. Do you have smaller VE numbers all over table 2 or have you only tuned around idle area so far? Quote Link to comment Share on other sites More sharing options...
MarcusP Posted April 28, 2022 Author Report Share Posted April 28, 2022 19 hours ago, Adamw said: Yeah, ID only test with a fluid that is something close to gasoline in terms of physical properties. Do you have smaller VE numbers all over table 2 or have you only tuned around idle area so far? This is still very rough on the e80 side but you will get an idea. Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 28, 2022 Report Share Posted April 28, 2022 Ok, I potentially see some of the problem. You have all the multifuel properties (density, stoich ratio etc) set up for pure ethanol, but your multifuel blend ratio table is set up to use 100% of the pure ethanol properties for anything over 80% Eth. If you want to tune the 2nd VE table using E85 rather than pure ethanol, then it would be best to change those multifuel properties to represent E80 or E85 instead of E100. You could then leave the blend ratio table as is. Suggest values about 0.7824 for density, 0.001069 for density temp coef, 9.8 for stoich ratio. Quote Link to comment Share on other sites More sharing options...
MarcusP Posted April 28, 2022 Author Report Share Posted April 28, 2022 22 minutes ago, Adamw said: Ok, I potentially see some of the problem. You have all the multifuel properties (density, stoich ratio etc) set up for pure ethanol, but your multifuel blend ratio table is set up to use 100% of the pure ethanol properties for anything over 80% Eth. If you want to tune the 2nd VE table using E85 rather than pure ethanol, then it would be best to change those multifuel properties to represent E80 or E85 instead of E100. You could then leave the blend ratio table as is. Suggest values about 0.7824 for density, 0.001069 for density temp coef, 9.8 for stoich ratio. I’ll try that in the morning. Thank you! Quote Link to comment Share on other sites More sharing options...
koracing Posted April 28, 2022 Report Share Posted April 28, 2022 Is it not advisable to simply change the blend ratio tables to only use 100% of table 2 when Ethanol % is 100% interpolating the values from zero to 100 and leave the rest alone? Quote Link to comment Share on other sites More sharing options...
MarcusP Posted April 28, 2022 Author Report Share Posted April 28, 2022 5 minutes ago, koracing said: Is it not advisable to simply change the blend ratio tables to only use 100% of table 2 when Ethanol % is 100% interpolating the values from zero to 100 and leave the rest alone? I figured you should set table 1 at the lowest E and table 2 at the highest E you plan to run and let it blend between them. I’m never going to run e100 Quote Link to comment Share on other sites More sharing options...
koracing Posted April 28, 2022 Report Share Posted April 28, 2022 That's fine and while you are tuning I agree that is the simplest way to set it up. I know the customer may in the future desire to buy E0 or E90 or something after I'm done with the car and so in principle I like to know the ecu could handle any mixture above or below the original tune points when the tune is finalized. Quote Link to comment Share on other sites More sharing options...
MarcusP Posted April 28, 2022 Author Report Share Posted April 28, 2022 1 minute ago, koracing said: That's fine and while you are tuning I agree that is the simplest way to set it up. I know the customer may in the future desire to buy E0 or E90 or something after I'm done with the car and so in principle I like to know the ecu could handle any mixture above or below the original tune points when the tune is finalized. Makes sense. E0 isn’t available here and e85+ can only be bought as race fuel. Neven e85 from the pump is hard to find. I would think that if your e10-e85 tune was on point the ecu can handle corrections for e0 and e90 without a hiccup. Quote Link to comment Share on other sites More sharing options...
koracing Posted April 28, 2022 Report Share Posted April 28, 2022 Not perfectly if you set the tune up the way you are saying. It doesn't automatically extrapolate beyond your settings. Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 28, 2022 Report Share Posted April 28, 2022 6 hours ago, koracing said: Is it not advisable to simply change the blend ratio tables to only use 100% of table 2 when Ethanol % is 100% interpolating the values from zero to 100 and leave the rest alone? Not If you are only running E85 when tuning table 2. You really want to isolate any error due to blending from the primary fuel properties and table. If you want to be able to blend all the way to E100 then you should really tune on E100. TTP 1 Quote Link to comment Share on other sites More sharing options...
koracing Posted May 5, 2022 Report Share Posted May 5, 2022 I still don't know why you guys don't make the tables extrapolate beyond the tuned tables if so desired. Quote Link to comment Share on other sites More sharing options...
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