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Thread: Running E85

  1. #1
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    Default Running E85

    I am in the process of installing a used LQ4 with 799 heads and compression will be nearly a percentage point higher than the old LQ4 at 10.4:1. I am going to run the same pulley, so I am thinking boost will still be at around 8#. My plan is to get the motor in, reduce timing in the low and high octane tables by 3 degrees and ensure the VE and boost VE tables are still accurate on 91. Once the airflow is right, I wanted to begin working on an E85 tune. I have been running an open loop speed density tune for the last 2 years with success, so I wanted to keep the tune this way. Also, I am running a COS5 OS 02 Operating System. I assume that if airflow has been correctly modeled in the VE tables, I will only need to change the commanded fueling in the various tables??

    From what I have read, I need to convert my log and tuning files to display air/fuel in EQ Ratio as opposed to AFR. I can reprogram my lc-1 to do the same.

    In the tune, what do I need to change? I know I have to change the stoich ratio table, but the lower limit appears to be 10, and the stoich ratio of E85 is 9.7.

    Once I have the fueling figured out, I would start to work on the spark tables. As far as the fuel system, I have 72# injectors, a 255 in tank walbro feeding an inline 044, through a return style fuel system. I think that will be enough based on the calculators I have used.

    Any help would be greatly appreciated!!
    00 Silverado Z71, LQ9 w/ LS3 heads, BTR cam, Whipple 2.9@8#, 4l80E

  2. #2
    Joe (Moderator) joecar's Avatar
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    Yes, correct, VE/MAF model air and are not effected by change of stoich AFR.

    Yes, use EQR units in scantool/tunetool; you can use Lambda for wideband; BEN is commanded EQR * wideband Lambda (see the Calc.VET tutorial for a calc_pids.txt file).

    Do you have FlashScan V1 or V2...?

    Avoid using AFR units unless the scantool/tunetool and wideband base their AFR on the stoich AFR for E85; BUT it is much easier/better to work in EQR.


    Change B3601 to the stoich AFR of E85.

    With the larger injectors remember to adjust edit IFR B4001 to match (and edit the other injector tables that you have new injector data for).

    If your PE B3618 table is sufficiently rich you should be ok.

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    Quote Originally Posted by joecar View Post
    Yes, correct, VE/MAF model air and are not effected by change of stoich AFR.

    Yes, use EQR units in scantool/tunetool; you can use Lambda for wideband; BEN is commanded EQR * wideband Lambda (see the Calc.VET tutorial for a calc_pids.txt file).

    Do you have FlashScan V1 or V2...?

    Avoid using AFR units unless the scantool/tunetool and wideband base their AFR on the stoich AFR for E85; BUT it is much easier/better to work in EQR.


    Change B3601 to the stoich AFR of E85.

    With the larger injectors remember to adjust edit IFR B4001 to match (and edit the other injector tables that you have new injector data for).

    If your PE B3618 table is sufficiently rich you should be ok.
    Joecar - you still out there??

    Reviving this from the dead! I converted everything to EQR, well I think! I am getting ready to change the stoich value and see how it does. Also going to paste in low octane and high octane tables and use the boost timing table to reduce timing while in boost. The IFR should be accurate, I been running the injectors for several years without any issues.

    I plan to shoot for .75 EQ ratio while in boost with E85.

    Anything else I need to know??
    00 Silverado Z71, LQ9 w/ LS3 heads, BTR cam, Whipple 2.9@8#, 4l80E

  4. #4
    Joe (Moderator) joecar's Avatar
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    What are your injectors rated to flow...?

    What is your measured rail pressure...?

    Post you tune file.

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    They were rated to flow 625cc at 3 bar, so at 4 bar (58 psi), I have them at 69.45 lb/hour. I have a return fuel system, so the base pressure should be 58 plus 8 psi (66 total) when is boost.

    I haven't put a gauge on it for a long time, but I am assuming 58, or close to it.

    I have attached my tune file. I set the ratio to 10 (lowest value in EFI Live), but I may need to raise it a bit since I will have some gas in the tank.

    Can you also look at my low/high octane timing tables to see where I should begin with timing? The LQ9 with 799 heads did not like an timing, so that is the reason for the low timing.
    Attached Files Attached Files
    00 Silverado Z71, LQ9 w/ LS3 heads, BTR cam, Whipple 2.9@8#, 4l80E

  6. #6
    Joe (Moderator) joecar's Avatar
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    Rail pressure 58+/-8 psi is not correct...

    Measure rail pressure with FPR reference hose removed (i.e. so FPR sees baro) with engine running.

    I'll look at your file later today (I've been swamped).
    Last edited by joecar; October 26th, 2013 at 06:59 AM.

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    Quote Originally Posted by joecar View Post
    Rail pressure 58+/-8 psi is not correct...

    Measure rail pressure with FPR reference hose removed (i.e. so FPR sees baro) with engine running.

    I'll look at you file later today (I've been swamped).
    I'll try to get a gauge on it this weekend.

    I changed the stoich value to 10.4 and it seemed to be within a few percent of where it was on gas.

    I went from 13.5 degrees at WOT to 18 with no KR. A/F was around .75 the whole run. I am going to try and get it on a dyno to see where it stops making power. With my LQ4, I ran up to 24 degrees of timing and each degree was worth almost 1/2 mph.
    00 Silverado Z71, LQ9 w/ LS3 heads, BTR cam, Whipple 2.9@8#, 4l80E

  8. #8
    Joe (Moderator) joecar's Avatar
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    I forgot that B3601 on that OS has a minimum value of 10.00... that's no good.

  9. #9
    Joe (Moderator) joecar's Avatar
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    Why do you want to run E85...?


    It will be easier to run E85 on another OS that allows B3601 to go below 10.00.

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    Quote Originally Posted by joecar View Post
    I forgot that B3601 on that OS has a minimum value of 10.00... that's no good.
    I want to run E85 because I don't want to pull the heads and put the 317's back on so I can run 17-18 degrees of timing with pump gas like I did on my LQ4. The 11:1 compression ratio does not allow for too much timing on pump gas, 13.5 at WOT was the max before I got KR.

    I don't want to go the methanol injection route either. I had an Alky Control kit, and I went through 2 pumps over the course of a few years. Also at low rpm, 7-8 psi, it flooded the motor with meth. I tried adjusting ramp rates and gain, and it got better, but still sucked. I had a huge hole in my VE table to try to compensate.

    The E85 I am getting does not appear to be 85% ethanol, I think it is more like E70. I filled up on an empty tank, loaded 10 as the stoich ratio and it was super rich. Idling in the .70-.75 range. I just got back from doing a few runs, and I added another and at 19 degrees at WOT, there is no KR.

    I think I need to rent some time on a dyno to see where timing either stops making power or I get knock. I don't know if I am on the edge or room to still add timing. I can tell you going from 13.5 to 19 feels a ton better.
    00 Silverado Z71, LQ9 w/ LS3 heads, BTR cam, Whipple 2.9@8#, 4l80E

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