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Old 07-24-2010, 12:00 AM   #21 (permalink)
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240Z - '73 Datsun 240Z 240Z
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Im running an e6x haltech, not the best but work with what you got, next chance i get I can post a full table. The cars been gradually worked up tot he paint its at now where i feel confident to take it out of my general area and on trips. its got about 900 kms on it, lot of test and tune and its all boiled down to where it is now. fingers crossed for tomorrow

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Old 07-24-2010, 10:16 PM   #22 (permalink)
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240Z - '73 Datsun 240Z 240Z
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Currently at my friends place with the datsun, made it the 100km trip down so thats good right? Didnt guzzle an insain amount of fuel, not sure how much but I think im on the right track. I think I need to work on my 2000 and 2500 timing maps next. I played with them a bit on the drive down but not for long as i was driving. If at 1500 my crusing rpm is 34 deg and light accell or incline is 28, what about 2k and 2.5k? I know theres a substantial jump when u start to rev up a bit, would 39 deg at cruse and 32 light accell/incline @2k be too far foward?

the timing sugested on page one, 34 deg and 28 degrees works nicely, based on that what would you think 2 and 2.5k should be based around?


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Old 08-01-2010, 12:12 PM   #23 (permalink)
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This post IRT the picture of your spark table:

I almost always make the columns the same between 0 RPM and 1000 RPM (your first three sections) to cover the idle - usually reduces fluctuations, corrections, and smooths the idle.

If your X axis is actually in inches of HG, then
cranking will start out at Zero vacuum and "pump down" (towards the left of your table) from there to about 12-ish. So if you can imagine the load cell moving from the zero-RPM row and zero-vacuum column down to the 500-RPM row and to the left, jumping in steps of vacuum as the manifold pressure goes through it's pump-down while cranking.

Your first two rows (0-RPM and 500-RPM) should indicate your desired cranking spark from the 13.5"-vacuum column and to the right. That is unless your ECM uses a separate table for just cranking spark, and/or another cranking spark modifier constant or table. There is usually at least a crank modifier table based on coolant temp, so that must be taken into consideration when determining your cranking spark values on your main spark table. A good warm cranking spark value is usually between 6* and 10*.

The 0-RPM through 1000-RPM rows, from 13.5"-vacuum and to the left should represent your desired idle spark. I usually start out by making all of those cells 20* and start from there - experimenting to see what the engine likes best.

The lower left quadrant of your table looks fine. That's all heavy DECEL and/or DFCO area.

Your load cells in the range between 17.44"-vacuum, 7.6"-vacuum, AND 1000-RPM, 2500-RPM (inclusive) is where the meat of your driving will be and will require the most work to get right.

Generally speaking, it looks to me that this area does not drop off quick enough as you move to heavier load cells (towards the right) starting from about the 13.5"-vacuum column. As I said in another post, there should be a fairly steep slope somewhere in there as the load increases from light-cruise, to light-ACCEL, to heavier-ACCEL during most of your normal driving. The lower the RPM, the more sensitive to loading the engine is, and the steeper the slope between one load cell and the next load cell beside it (left-to-right).

Your SA values are only changing one or two degrees as you move left-to-right across load changes in this area of normal driving. That's the biggest problem I see. Without driving your car and watching test equipment I can't tell you for sure where the big changes need to start, but:
If your steady light-cruise is around 13.5"-vacuum, then you will need to reduce your SA numbers in larger steps in the columns to the right of 13.5".
I can imagine a progression from your 30* SA at 13.5"-vacuum down to 18* or 20* by 7.6"-vacuum.
That's my best remote guess to give you an idea the basic shape to shoot for.

A knock sensor will be helpful, but you can do it by ear if you're careful. If you find that your ACCEL isn't causing knock even though your SA values are high, then suspect you have an AFR that's too rich.
The richer the AFR, the less sensitive it is to spark advance changes. I'm guessing that any loads higher than 7.6"-vacuum will be covered by your Power-Enrichment (PE mode). Generally an AFR between 12.2:1 and 12.8:1 will cover PE up to around the zero vacuum point.

The rest of the table should be fine, assuming your PE mode covers 3000-RPM and up.

Best I can do from a distance.
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Old 08-01-2010, 12:47 PM   #24 (permalink)
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What does SA mean ?
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Old 08-01-2010, 07:47 PM   #25 (permalink)
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Spark Advance

Call me crazy, but I actually try for mpg with this Jeep:

Typical driving: Back in Rochester for school, driving is 60 - 70% city
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