Timing Advance Curve
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Timing Advance Curve

  1. #1
    21 Daytona Outlaw's Avatar
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    Default Timing Advance Curve

    I need to build a timing curve for my EFI setup, it comes from the factory with
    15 degrees advance from 0 to 10,000 RPM.

    I was thinking of using the MSD factory timing curve as a guideline.

    how do I want the timing to advance on my setup

    502 with a Procharger, pulleys are setup for 8 psi boost, pump gas EFI
    IMCO powerflow exhaust.

    going to start off with 29 degrees of total advance, at what RPM should the total
    be in at?

    oh yeah in a jet boat
    Last edited by Outlaw; 08-30-2010 at 12:46 PM.
    #55

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  3. #2
    I'm famous ! Lucky's Avatar
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    Would the cam not dictate that ? Where is your curve at ?


    Quote Originally Posted by Outlaw View Post
    I need to build a timing curve for my EFI setup, it comes from the factory with
    15 degrees advance from 0 to 10,000 RPM.

    I was thinking of using the MSD factory timing curve as a guideline.

    how do I want the timing to advance on my setup

    502 with a Procharger, pulleys are setup for 8 psi boost, pump gas EFI
    IMCO powerflow exhaust.

    going to start off with 29 degrees of total advance, at what RPM should the total
    be in at?

    oh yeah in a jet boat
    " my carbon footprint is gonna kick your green ass"


    Quote Originally Posted by 396_Ways_To_Spit View Post
    WOWO!!!!! THat has to be the most beautiful crank that Ive ever seen!!!!!!!!!!!!!!!!


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    He has been allowing me to park my equipment in his backyard for a few years now...
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    Senior Member ap67et10's Avatar
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    Default

    Quote Originally Posted by Outlaw View Post
    I need to build a timing curve for my EFI setup, it comes from the factory with
    15 degrees advance from 0 to 10,000 RPM.

    I was thinking of using the MSD factory timing curve as a guideline.

    how do I want the timing to advance on my setup

    502 with a Procharger, pulleys are setup for 8 psi boost, pump gas EFI
    IMCO powerflow exhaust.

    going to start off with 29 degrees of total advance, at what RPM should the total
    be in at?

    oh yeah in a jet boat

    you want it all in before 3k. probably somewhere around 2500 actually. another thing (which is a benefit) is that you might want to play with pulling out some timing at or around max rpm and load. play with it....if for no other reason....cause you can! haha

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    Highaboosta Unchained's Avatar
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    You will want to base the timing on the load more than the rpm.

    At a cruising speed of 3000 - 3500 rpm and if you're still pulling vaccuum then the motor can use a lot more timing, like 40 degrees +.
    As the load increases and you pass the 0 vaccuum point then the timing needs to decrease to around 34 degrees. As the boost comes on then the timing needs to decrease to the 29 degrees you want at max boost.

    Starting and idling, around 20 degrees will work good.

    With EFI you have a whole lot of flexibility on fine tuning the timing table.

    Twin Turbo 1800 HP V-Drive lake boat

    http://s621.photobucket.com/albums/t...t=MAH05771.mp4

    Quote Originally Posted by Trigger View Post
    No one cares about your buddies old antiquated garden hose technology.
    Quote Originally Posted by MAXIMUS View Post
    I think I could run more boost but it's a real hand full right now

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    Senior Member ap67et10's Avatar
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    Quote Originally Posted by Unchained View Post
    You will want to base the timing on the load more than the rpm.

    At a cruising speed of 3000 - 3500 rpm and if you're still pulling vaccuum then the motor can use a lot more timing, like 40 degrees +.
    As the load increases and you pass the 0 vaccuum point then the timing needs to decrease to around 34 degrees. As the boost comes on then the timing needs to decrease to the 29 degrees you want at max boost.

    Starting and idling, around 20 degrees will work good.

    With EFI you have a whole lot of flexibility on fine tuning the timing table.

    i wasn't going to go there, but glad you mentioned it Mark! You just went right out past the linear timing curve that a distributor is limited to jumped right into a graph with infinite adjust-ability....up and down and any load or rpm.

    Paul you will definitely benefit from going above 29*, it just needs to be put in at the right places, most people here, only know total advance. that mentality can be tossed in the trash!

    AP

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    21 Daytona Outlaw's Avatar
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    Quote Originally Posted by ap67et10 View Post
    i wasn't going to go there, but glad you mentioned it Mark! You just went right out past the linear timing curve that a distributor is limited to jumped right into a graph with infinite adjust-ability....up and down and any load or rpm.

    Paul you will definitely benefit from going above 29*, it just needs to be put in at the right places, most people here, only know total advance. that mentality can be tossed in the trash!

    AP
    I'm trying to get away from that mentality, but I'll start off just like I have weights in my dist then ween myself off.

    thanks for the responses,


    Mark I would love to see one of your old Haltech maps, have any left?

    Looks like I have a map for starting then another based on engine load
    with corrections on intake air temps and coolant temps
    #55

  9. #7
    Highaboosta Unchained's Avatar
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    The program I had to run the Haltech on went out with the last laptop meltdown. I'm not sure if I could run a DOS program on Windows 7.

    Send me a link to your program and I'll see what I can do.
    [email protected]

    After you get it running you need to monitor your manifold vaccuum and that will determine what timing it will like the best.

    Old school methods just lock it in and leave it but with EFI we can optimise.
    Fuel burns slower under vaccuum and can use more timing.

    Here's my FAST E85 ignition table.
    http://i621.photobucket.com/albums/t...0/DSC07382.jpg

    Left to right is rpm from 800 to 8000.
    Bottom to top is manifold absolute pressure in kpa. (load)
    The 100 kpa point is 0 vaccuum.
    I have a 3 bar MAP sensor so it goes to 314 kpa which is 29# boost .

    Twin Turbo 1800 HP V-Drive lake boat

    http://s621.photobucket.com/albums/t...t=MAH05771.mp4

    Quote Originally Posted by Trigger View Post
    No one cares about your buddies old antiquated garden hose technology.
    Quote Originally Posted by MAXIMUS View Post
    I think I could run more boost but it's a real hand full right now

  10. #8
    gn7
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    Unchained is right. With a blower and a efi cpu on board, you really should map the advanbe based on load. And with a blower, even more so. But its relatively easy. You just decide your base, like 36* at zero boost, and pull out 1* or 1.5*, degress for every PSI of boost. But with a centrif, you'll be much happier with the most advance you can handle in a unboosted condition.



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  11. #9
    21 Daytona Outlaw's Avatar
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    you guys are correct, with the centrifugal I'll need more timing
    at lower RPM's until the boost starts building.
    #55

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