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    1 out of 1 members liked this post. Yes Reputation No

    What could be causing my timing drops if it's not octane?

    I'm still seeing pretty severe drops when running a high E85 mixture. I'm probably at over 70% currently. I'm running JB4 with MHD E85 BEF. FBO car. It happens in Map 5 with conservative boost targets under 16psi and Map 7 is worse.

    After reading more and more about this, it seems pretty bad (even though the car feels fine) and I'm not trying to grenade my engine. Can someone please take a look at these logs made with the high e85 mix? Certainly this is some sort of hardware issue if it's not octane? What needs to be checked? Car generates no codes. Spark plugs are pretty much brand new and are the NGK one step colder plugs, gapped to .022
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    One more map 7 log attached
    Attached Files Attached Files

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    You're hardly running any boost. Probably way too much ethanol for what you are running.
    You're probably better on like E20.
    At E70 you might well need the upgraded coils. BL or PR.
    Best:11.79@119mph on stock turbos.
    11.74@129 on GCs.
    FBO+Meth Port injection, GC Turbos, custom bucketless stage2, JB4, Trebila flash.

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    Click here to enlarge Originally Posted by AWSAWS Click here to enlarge
    You're hardly running any boost. Probably way too much ethanol for what you are running.
    You're probably better on like E20.
    At E70 you might well need the upgraded coils. BL or PR.
    I dumped a lot of ethanol in to try to resolve these timing issues, as I kept thinking it was octane. Does over 70% really require upgraded coils? I thought there were people out there running 100% e85 with only the stage 2 fuel pump.

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    As I understand it, ethanol does not combust as easily as gas, hence the normal cold-start issues. A stronger spark helps this.

    Neil

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    Just close your plug gap a bit. You'll be fine.

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    I run full e85 with stock coils no problem. 1 step colder plugs gapped appropriately. You don't need upgraded coils.

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    Click here to enlarge Originally Posted by romnation Click here to enlarge
    I dumped a lot of ethanol in to try to resolve these timing issues, as I kept thinking it was octane. Does over 70% really require upgraded coils? I thought there were people out there running 100% e85 with only the stage 2 fuel pump.
    You've got way more ethanol than you need. If you reduce the ethanol then you wont need as powerful a spark to ignite it. By running 70% ethanol the car is probably pumping 33% more fuel than straight gas, depending on AFR targets. Every molecule of ethanol has a higher activation energy than gasoline so it could explain your troubles. Especially if you have older weaker coil packs.
    Personally I'd go to 16 psi on pump gas. Any higher and I'd start adding ethanol. But if you do run pump gas try a pump flash so you target the right AFRs and fuel trims etc.
    Best:11.79@119mph on stock turbos.
    11.74@129 on GCs.
    FBO+Meth Port injection, GC Turbos, custom bucketless stage2, JB4, Trebila flash.

  9. #9
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    As others have said thought. I've run 0.5 mm and 0.45mm gaps in the past when trying to improve timing on high ethanol blends.
    Best:11.79@119mph on stock turbos.
    11.74@129 on GCs.
    FBO+Meth Port injection, GC Turbos, custom bucketless stage2, JB4, Trebila flash.

  10. #10
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    also if you have not changed your coils in the last 40k they probably need changed (may or may not be a causative factor). The multispark has a tendency to wear them out.

    Some very experienced people here i'm sure they are correct about the fuel as well

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    .
    2009 535i Sport
    Software: JB4 G5 | MHD | Trebila Tune | XHP Stage 3
    Hardware: GC Lites | Inlets | Outlet | 3" D-P's | 7" FMIC | S2 LPFP | TBI | DCI | ER CP | Forge DV's | 3.5 TMAP | RB PCV | Koni FSD

  12. #12
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    I'd reduce ethanol mix to 40%.

    do you have an upgraded LPFP?

    Click here to enlarge Originally Posted by romnation Click here to enlarge
    Spark plugs are pretty much brand new and are the NGK one step colder plugs, gapped to .022
    Click here to enlarge Originally Posted by dyezak Click here to enlarge
    Just close your plug gap a bit. You'll be fine.
    Could try tighter at existing ethanol content, but he's already at 0.022 so pretty tight already.

    Click here to enlarge Originally Posted by DisCiteFullRetard Click here to enlarge
    You don't need upgraded coils.
    +1
    2009 535i Sport
    Software: JB4 G5 | MHD | Trebila Tune | XHP Stage 3
    Hardware: GC Lites | Inlets | Outlet | 3" D-P's | 7" FMIC | S2 LPFP | TBI | DCI | ER CP | Forge DV's | 3.5 TMAP | RB PCV | Koni FSD

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