Optimal A/F ratio for NA
07-08-2014, 01:39 PM
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Optimal A/F ratio for NA
What is the best desired air/fuel ratio for a naturally aspirated LT-1 with long tube headers? what would O2 volts be at that ratio?
07-08-2014, 02:08 PM
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stock narrowband O2 volts are 450 mv at stoich and in closed loop you don't need to worry about it as long as your fuel trims are around -3% (pulling fuel).
If you want to measure your AF ratio in open loop (wide open throttle) then you need a wideband and you need to measure lambda, not AF ratio.
If you want to measure your AF ratio in open loop (wide open throttle) then you need a wideband and you need to measure lambda, not AF ratio.
07-09-2014, 11:21 AM
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using 02s for wide open isn't the best thing to do as there not very accurate.
890-910MV used to be the rule of thumb but that's not a exact and could honestly be anything, LOL , thats why you always use a wideband for WOT runs. and as long as your fuel trims are Like Higgs said your AFR in cruise is ok
890-910MV used to be the rule of thumb but that's not a exact and could honestly be anything, LOL , thats why you always use a wideband for WOT runs. and as long as your fuel trims are Like Higgs said your AFR in cruise is ok
07-11-2014, 03:54 PM
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using 02s for wide open isn't the best thing to do as there not very accurate.
890-910MV used to be the rule of thumb but that's not a exact and could honestly be anything, LOL , thats why you always use a wideband for WOT runs. and as long as your fuel trims are Like Higgs said your AFR in cruise is ok
890-910MV used to be the rule of thumb but that's not a exact and could honestly be anything, LOL , thats why you always use a wideband for WOT runs. and as long as your fuel trims are Like Higgs said your AFR in cruise is ok
If that's a good method, would I need to back and check the 1st bank after adjusting the 2nd bank? And which side is bank 1 and which is bank 2?
shoot for 12.9 - 13.1 at that sensor location?
07-11-2014, 04:04 PM
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St. Jude Donor '14-'15
12.9-13.1 is a good AFR to shoot for N/A (or really even FI in general). Thumbs up for Innovate WBs, as well - dead-on accurate.
07-11-2014, 04:28 PM
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Nothing wrong with that at all - the rears are just dummies now. If you want to switch side to side, you can, but it's a little bit of overkill.
12.9-13.1 is a good AFR to shoot for N/A (or really even FI in general). Thumbs up for Innovate WBs, as well - dead-on accurate.
12.9-13.1 is a good AFR to shoot for N/A (or really even FI in general). Thumbs up for Innovate WBs, as well - dead-on accurate.
07-11-2014, 05:02 PM
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if you are catless you can run the WB in the rear O2 bung. If you have cats then I would weld in a new bung in front of them. i would also recommend using the driver side.
07-11-2014, 07:13 PM
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07-11-2014, 07:16 PM
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American Racing Headers. I'll double check but don't recall seeing an extra bung. Nope. I'll get one installed tomorrow morning and start tuning. Thanks for the help.
Last edited by typhoon186; 07-11-2014 at 07:38 PM.
07-22-2014, 04:14 AM
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St. Jude Donor '13-'14-'15
The AFR on the C7 is now set at 14.11 rather than all previous cars that had the AFR at stoich. of 14.68--They said they did this because of the ethanol content used today and also for cheap Calif 91oct premium
So in part throttle the correct AFR should be 14.11. So far there are NO tables available to change 02 switching point to compensate for LT headers--
The stock fueling tables for PE are all over the map from 12.10 to 11.63- The leaner AFR's reflect less timing and the richer more timing--
You have to remember that the E92 ECM is tuned like no other before--All you really need to do is "ask for " more TQ in the TQ response table and the ECM will try to make it with both fuel and timing--- No more tweaking of AFR's in PE or timing adjustments in the hi Oct table---
In EFILIVE they have now added a new table called "maximum brake TQ timing" this table sets the max limits the ECM can use to try and achieve the requested power from the TQ response tables--In some instances it can ask for 30* of timing and will subsequently richen up the fuel----This E92 computer does all the work for you !! If you ask for more TQ than the stock tunes produces the ECM will try to get that #within the bounds of the Max Brake TQ timing table and the PE fuel table
As far as your installation of LT headers so far there us no table that can change the switching points---( usually the correction in the past") The only way to see what the PT AFR is is with a wideband When you know what the average is--then you can look for a fix---EFILIVE is coming up with new tables all the time as they crack the GM software
Latest update was July 12th--where they added about 7 tables--
I would be more concerned about the WOT AFR right now over the PT---See what the wideband says or if you are trying to use the stock narrowbands you would still want them around .900 millivolts-- (approx. 12.6 AFR) Higher is richer Always error n the side of rich
On my 2014 car with nothing but a catback and a tune my car showed a 30 RWHP gain--Tune was worh about 20 25 RWHP AND I did not alter any of the timimg tables or any of the PE AFR's !!!! all stock !!!! Confirms my position that the E92 makes all the changes in timing and fuel for you in concert with the TQ Response tables
So in part throttle the correct AFR should be 14.11. So far there are NO tables available to change 02 switching point to compensate for LT headers--
The stock fueling tables for PE are all over the map from 12.10 to 11.63- The leaner AFR's reflect less timing and the richer more timing--
You have to remember that the E92 ECM is tuned like no other before--All you really need to do is "ask for " more TQ in the TQ response table and the ECM will try to make it with both fuel and timing--- No more tweaking of AFR's in PE or timing adjustments in the hi Oct table---
In EFILIVE they have now added a new table called "maximum brake TQ timing" this table sets the max limits the ECM can use to try and achieve the requested power from the TQ response tables--In some instances it can ask for 30* of timing and will subsequently richen up the fuel----This E92 computer does all the work for you !! If you ask for more TQ than the stock tunes produces the ECM will try to get that #within the bounds of the Max Brake TQ timing table and the PE fuel table
As far as your installation of LT headers so far there us no table that can change the switching points---( usually the correction in the past") The only way to see what the PT AFR is is with a wideband When you know what the average is--then you can look for a fix---EFILIVE is coming up with new tables all the time as they crack the GM software
Latest update was July 12th--where they added about 7 tables--
I would be more concerned about the WOT AFR right now over the PT---See what the wideband says or if you are trying to use the stock narrowbands you would still want them around .900 millivolts-- (approx. 12.6 AFR) Higher is richer Always error n the side of rich
On my 2014 car with nothing but a catback and a tune my car showed a 30 RWHP gain--Tune was worh about 20 25 RWHP AND I did not alter any of the timimg tables or any of the PE AFR's !!!! all stock !!!! Confirms my position that the E92 makes all the changes in timing and fuel for you in concert with the TQ Response tables
07-22-2014, 07:29 AM
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The AFR on the C7 is now set at 14.11 rather than all previous cars that had the AFR at stoich. of 14.68--They said they did this because of the ethanol content used today and also for cheap Calif 91oct premium
So in part throttle the correct AFR should be 14.11. So far there are NO tables available to change 02 switching point to compensate for LT headers--
The stock fueling tables for PE are all over the map from 12.10 to 11.63- The leaner AFR's reflect less timing and the richer more timing--
You have to remember that the E92 ECM is tuned like no other before--All you really need to do is "ask for " more TQ in the TQ response table and the ECM will try to make it with both fuel and timing--- No more tweaking of AFR's in PE or timing adjustments in the hi Oct table---
In EFILIVE they have now added a new table called "maximum brake TQ timing" this table sets the max limits the ECM can use to try and achieve the requested power from the TQ response tables--In some instances it can ask for 30* of timing and will subsequently richen up the fuel----This E92 computer does all the work for you !! If you ask for more TQ than the stock tunes produces the ECM will try to get that #within the bounds of the Max Brake TQ timing table and the PE fuel table
As far as your installation of LT headers so far there us no table that can change the switching points---( usually the correction in the past") The only way to see what the PT AFR is is with a wideband When you know what the average is--then you can look for a fix---EFILIVE is coming up with new tables all the time as they crack the GM software
Latest update was July 12th--where they added about 7 tables--
I would be more concerned about the WOT AFR right now over the PT---See what the wideband says or if you are trying to use the stock narrowbands you would still want them around .900 millivolts-- (approx. 12.6 AFR) Higher is richer Always error n the side of rich
On my 2014 car with nothing but a catback and a tune my car showed a 30 RWHP gain--Tune was worh about 20 25 RWHP AND I did not alter any of the timimg tables or any of the PE AFR's !!!! all stock !!!! Confirms my position that the E92 makes all the changes in timing and fuel for you in concert with the TQ Response tables
So in part throttle the correct AFR should be 14.11. So far there are NO tables available to change 02 switching point to compensate for LT headers--
The stock fueling tables for PE are all over the map from 12.10 to 11.63- The leaner AFR's reflect less timing and the richer more timing--
You have to remember that the E92 ECM is tuned like no other before--All you really need to do is "ask for " more TQ in the TQ response table and the ECM will try to make it with both fuel and timing--- No more tweaking of AFR's in PE or timing adjustments in the hi Oct table---
In EFILIVE they have now added a new table called "maximum brake TQ timing" this table sets the max limits the ECM can use to try and achieve the requested power from the TQ response tables--In some instances it can ask for 30* of timing and will subsequently richen up the fuel----This E92 computer does all the work for you !! If you ask for more TQ than the stock tunes produces the ECM will try to get that #within the bounds of the Max Brake TQ timing table and the PE fuel table
As far as your installation of LT headers so far there us no table that can change the switching points---( usually the correction in the past") The only way to see what the PT AFR is is with a wideband When you know what the average is--then you can look for a fix---EFILIVE is coming up with new tables all the time as they crack the GM software
Latest update was July 12th--where they added about 7 tables--
I would be more concerned about the WOT AFR right now over the PT---See what the wideband says or if you are trying to use the stock narrowbands you would still want them around .900 millivolts-- (approx. 12.6 AFR) Higher is richer Always error n the side of rich
On my 2014 car with nothing but a catback and a tune my car showed a 30 RWHP gain--Tune was worh about 20 25 RWHP AND I did not alter any of the timimg tables or any of the PE AFR's !!!! all stock !!!! Confirms my position that the E92 makes all the changes in timing and fuel for you in concert with the TQ Response tables
Almost all incorrect and it sounds like EFILive is still missing tables. This guy's posts should be disregarded.