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Old 07-18-2018, 03:09 AM   #1
PDXREALTOR
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Default Last timing column in primary ignition table

I have the last two timing columns in my table at 3.72 and 4.00. In winter with cold Temps I would hit 4.00 to 4.5 loads never dropping below 4.00. When WOT.

When the warmer air came, I found myself bouncing around between the 3.72 and 4.00 load columns and, also got more knock.

Whats the proper way, or a couple different ways, to deal with this situation of hitting two load cells on Wot runs or driving?

I was thinking of pushing the last table out to 3.70, and rescaling from 1.60 to 3.75 (or similar) then, I would remove any added timing in the IAT timing compensation table. I'm thinking this would offset the higher load.

I'm just not confident if this is a good or proper approach and need some opinions....
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Old 07-18-2018, 10:42 AM   #2
86Dreams
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wait, why are you rescaling the table to 3.7 when youre hitting 4.5 load? do you mean rescale to 4.7?
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Old 07-18-2018, 12:37 PM   #3
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I'm only hitting the higher loads in winter. In summer I stay in the lower loads and waffle between two load columns. This cause knock as one load column has more timing than the other

My car is happy with timing values in the last load column when WOT, it's not happy when it bounces to the second to the last load column and the higher timing values.
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Old 07-18-2018, 01:59 PM   #4
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I see so you want to rescale the table to 3.7 except for the last load column. And in the last load column breakpoint you will set to 3.75 and fill its cells with the 4.5g/rev timing values.
that could work as long as youre not worried about the effects of losing a few degrees around 4.1g/r

My strategy is I set the end of my table up with these break points: 2.9 3.1 3.9. and trust the ecu to interpolate between the last two cells. Take an educated guess at what timing should be for 4.7 g/s(in your case) then put those values into the last load column, then rescale either all of the columns before that or just the one immediately before.
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Old 07-18-2018, 02:13 PM   #5
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No, I was going to move the second to the last column, 3.72, to the last column, change to an even 3.70, and then interpolate the load cells from 1.60 -3.70.

I would keep the 4.00 load cell values in the last column (now 3.70) since I know the car runs knock free at higher loads in the colder weather with those timing values.

In your example, I may as well leave my table at the way it is, but, as I said in the warmer air the car doesn't like hopping over to the higher timing values in the 3.72 column.

**EDITED TO ADD** I see what you mean with your strategy. You have a large load spread and hand over the control to the ECU and interpolation. Hmmmm..... interesting.

Here's my table -

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Old 07-18-2018, 02:14 PM   #6
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Old 07-18-2018, 02:44 PM   #7
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so youre leaving the timing values as is and just changing the break points? Yeah I guess that works, its quick and dirty. Are you only getting this knock at wot?
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Old 07-18-2018, 03:14 PM   #8
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Quote:
Originally Posted by 86Dreams View Post
so youre leaving the timing values as is and just changing the break points? Yeah I guess that works, its quick and dirty. Are you only getting this knock at wot?
I can take any approach, that's why I am here. I wanted to explore the options.

I know that from 4.00 and up to 4.70 loads my car does not knock with the values in the 4.00 load column. Once I bounce over to the 3.72 load column the timing is too high and I start to get knock.

Yes - this is only WOT.

I was thinking of changing the last column to 3.70, and the interpolating both load and timing values from 1.60 - 3.70.

I'm not sure how I would use your strategy (I like the idea) without adding a lower timing value than what is currently in my 4.00 load column.

If I enter 4.75 in the last column, then interpolate the last two columns I end up with higher numbers in the 3.70 (2nd to the last) column and that would only make my problem worse.

I'm hitting 4.30 at PT , but about 5600 rpms I'm back in the 3.72 column. Only in the warmer air. Say, 75 ambient and above.
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Old 07-18-2018, 03:57 PM   #9
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Use Airboys Spreadsheet to rescale it?
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Old 07-18-2018, 04:12 PM   #10
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Use Airboys Spreadsheet to rescale it?
How would that help vs. using the tools in ATR IE interpolation? Serious question, as I'm not familiar with the spreadsheet you speak of.
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Old 07-18-2018, 04:47 PM   #11
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Originally Posted by PDXREALTOR View Post
I can take any approach, that's why I am here. I wanted to explore the options.

I know that from 4.00 and up to 4.70 loads my car does not knock with the values in the 4.00 load column. Once I bounce over to the 3.72 load column the timing is too high and I start to get knock.

Yes - this is only WOT.

I was thinking of changing the last column to 3.70, and the interpolating both load and timing values from 1.60 - 3.70.

I'm not sure how I would use your strategy (I like the idea) without adding a lower timing value than what is currently in my 4.00 load column.

If I enter 4.75 in the last column, then interpolate the last two columns I end up with higher numbers in the 3.70 (2nd to the last) column and that would only make my problem worse.

I'm hitting 4.30 at PT , but about 5600 rpms I'm back in the 3.72 column. Only in the warmer air. Say, 75 ambient and above.
You could combine the two strategies. Instead of rescaling all of your break points all the way back to 1.6 you could do what you were planning and just interpolate the breakpoints back to 3.18 or 3.44 even. That way you wouldnt be removing timing from cells that are not affected.

or even more simply just take timing out of that 3.72 column.
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Old 07-27-2018, 12:41 AM   #12
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I think I'm going to go out to 4.5 (I'm now seeing 4.75 loads on my new turbo).

I like what you suggest, 86 dreams, of letting the ecu do some interpolation work.

So, I will keep the second to the last load column at 3.70 and the last column at 4.5, set my values accordingly based on the data I have now. Ie, I will lower the values a bit in the 3.70 load column and put what I know is working in the 4.5 column. Good?

Is this a good strategy to use in the polf table?

Example, put a 11.1 commanded fuel value in the last column of 4.5 load, and 11.5 in the 3.70 colum then, as you're doing with timing, let the ecu adjust accordingly.
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Old 07-27-2018, 11:09 AM   #13
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I do use this for both ignition and fueling tables and dont have any problems (albeit I only see about 3.25 max load at low rpm). My rational was that I know Im only going into that I dont spend a lot of time in that load range so why was a lot of overal map space on it. If I spent a lot of time there I might just rescale the whole table.

If you do this just look at the graph and make sure it 'looks right'.
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Old 07-27-2018, 11:34 AM   #14
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Cool thanks. Ya.... Your rational is rational lol. Seriously though..... It makes such perfect sense I couldn't quit thinking about it and how to implement it.

I already have my fuel table scaled to be ~11.5 in the last load column but with recent heat and higher boost, and some dyno time, I found I did best running fwot /max loads with 11.1 fuel, even running 100 octane. So, simply changing my last polf column from 4 to 4.5 will set me up for a nice spread. It will look like this - - 11.5 /3.70 load column - 11.1/4.5 load column

How much timing spread do you have between your last two columns?

Do you know the smallest amount of timing the ecu will adjust based on load location between the last two cells? Is it . 35,. 70 or?
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Old 07-27-2018, 01:14 PM   #15
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Quote:
Originally Posted by PDXREALTOR View Post
Cool thanks. Ya.... Your rational is rational lol. Seriously though..... It makes such perfect sense I couldn't quit thinking about it and how to implement it.

I already have my fuel table scaled to be ~11.5 in the last load column but with recent heat and higher boost, and some dyno time, I found I did best running fwot /max loads with 11.1 fuel, even running 100 octane. So, simply changing my last polf column from 4 to 4.5 will set me up for a nice spread. It will look like this - - 11.5 /3.70 load column - 11.1/4.5 load column

How much timing spread do you have between your last two columns?

Do you know the smallest amount of timing the ecu will adjust based on load location between the last two cells? Is it . 35,. 70 or?
I drop ~10* from 3.1 to 3.9 in ignition. I actually no longer do it for fuel so anything over the final load column just runs that value.

Interpolation appears to be in .5* steps but ive got a 16bit ecu, im not sure if that makes a difference. Just watch your ignition timing while you drive and it should be obvious.
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Old 07-27-2018, 03:27 PM   #16
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Damn... 10* is a huge spread. How is it that you need 10* less timing between less than 1 full g/r?

I was thinking 3* total.....
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Old 07-28-2018, 06:53 PM   #17
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Quote:
Originally Posted by PDXREALTOR View Post
Damn... 10* is a huge spread. How is it that you need 10* less timing between less than 1 full g/r?

I was thinking 3* total.....
I have a v9 ej207 so its a little different. Im not that familiar with the ej25's timing. I stepped 10* by following the trend of the map and then taking a little extra.
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