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Thread: E85 Stoich numbers make tooo rich

  1. #1
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    E85 Stoich numbers make tooo rich

    After a couple years playing around i finally decided to try e85 without adding more pump.
    As my gas tune i'm in the 50-60% IDC at wot. (850/750-14lbs)

    When I changed the stoich too read 14.7 down to 8.9, it runs super rich. Also rpm's go up and down bad.
    I swapped over to lambda and it reads .60-.80 at idle.

    Now, here is the question as I see plenty of posts on this. Something about doubling the Stoich number if injectors are larger on e38 cars??
    But my numbers don't seem to be double. I'm running 127lb injectors.
    Here is my current gas tune stoich numbers and the car runs "ok" normal driving if i leave the stoich e85 tune with this.
    current stoich.JPG

    Thanks in advance

  2. #2
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    e85 stoich is 9.765 find a flex tune and use its stoich table then do the double stoich halve ifr half ivt terms, if the inj data is right it will work fine

  3. #3
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    Thanks, gonna try that now

  4. #4
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    Something like this? Also, my IVT AFR2 is zero'd out ? Otherwise I doubled the Stoich and halved the IFR and IVT. Thanks Again

    Dbl Stoich.JPGhalf IFR.JPGHalf IVT AFR term.JPGIVT AFR2.JPG
    Last edited by fleebag; 1 Week Ago at 09:58 AM.

  5. #5
    Tuning Addict 5FDP's Avatar
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    Don't worry about the AFR2 table.

    The rest look ok but just make sure you have the flow rate correct. If the injectors you have are 127lb/hr at 58psi your 408kpa cell would read 63.5lb/hr. Are they flowed at 3 bar or 4 bar pressure?
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

  6. #6
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    Quote Originally Posted by 5FDP View Post
    Don't worry about the AFR2 table.

    The rest look ok but just make sure you have the flow rate correct. If the injectors you have are 127lb/hr at 58psi your 408kpa cell would read 63.5lb/hr. Are they flowed at 3 bar or 4 bar pressure?
    The injectors are FIC(connection) Bosche 127's and data shows @4bar.

    However, after looking over the injector data(instructions) you are right it shows 127@400. But my good gas tune shows below before I cut in half.
    Now, on the last page of the data sheet it talks about scaling etc due to the 1.36g limit since mine is older 2010 e38. Would this be why my original tuner put these stoich numbers and IFR#'s as shown above starting with 18. and ending with 11.xx?

    If so, would I leave the IFR alone as is and cut in half like I did? The concern is my current tune as is works and works great for gas. So I don't want to mess that up. lol
    Thanks again
    Gas IFR good tune.JPG

  7. #7
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    if u are 2010 your spark airmass should be adjustable row axis so u can make it higher if u need to, also with the 127lb IFR i may get away without scaling but if not then just make stoich values correct and then do the double stoich deal so then its correct, not sure why any of that would be changed it just dosnt need to be as it throws any of this stuff u want to do off so if its done right first time it all just works from then on

  8. #8
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    Thanks for the help, it runs ok cruising and think it actually runs cooler? Attached is just a cruise log and at the end I went for a wot run but detector started going off.
    Felt a little sluggish but certain there is plenty left to tune.
    Lambda showed around 70-80 when I got on it for a second. Shouldn't that be 1.0 ish? I am just starting the Lambda as i've always done afr.
    Now once I do make a good wot run, I add timing and +\- fuel in the PE uppers until 1.0ish Lmda and no KR and IDC <95ish ? Like normal .
    on Gas, I was 14-15lbs boost at 50-55 IDC, about 17* timing wot.
    Thanks againe crz 1.hpl
    Last edited by fleebag; 1 Week Ago at 01:22 PM. Reason: Adding

  9. #9
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    lambda 1.0 is stoich for any given fuel type, when ur in PE it should be lower like lambda 0.83 (richer) boost and lambda 1.0 = bye bye engine, also i wouldnt just add timing without being on a dyno so u can see any gains

  10. #10
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    Quote Originally Posted by 07GTS View Post
    lambda 1.0 is stoich for any given fuel type, when ur in PE it should be lower like lambda 0.83 (richer) boost and lambda 1.0 = bye bye engine, also i wouldnt just add timing without being on a dyno so u can see any gains
    Thanks again

  11. #11
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    Pretty good run at the end. I think I may add the dsx extra pump now as duty cycle is in the 90's with 70% e.
    Not too bad with a Adm twin setup. All I did was swap the umps out for DW300's. But still think I need more pump for safety??
    Thanks again for the advice!
    gggg.hpl

  12. #12
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    looks good u could command a little less like 0.8 will give u some head room as u lean out to that up top anyway but yea id be adding some pump to it or injectors, what injectors u using ? or if u can raise the fuel pressure and still support the flow that will get u back in the 80-90% range if u can see 58psi are u boost referenced regulator ?