Silly question

[Six_Shooter]

If you have a smart phone, search and download unit converter lite. I have it on my phone and it has conversions for about anything and everything you and think of! One of the best apps I have. It even has a spot where you can save your favorite conversions for quick access. I know its on android phones, but not 100% if its on iphone (since I dont have one)

iPhone has several unit conversion apps. I have a couple on my phone, for different reasons, some just straight common conversions such as temp to temp or pressure to pressure, and some that are a little nerdy, like hex to binary to decimal, though I can basically do those conversions now without using an app. lol

[brian617]

Now on to "spark bias". If the bias is set to 9.89* in the .bin does that mean the actual timing the engine sees is 9.89* higher or 9.89* lower that what is in the spark table?

[Six_Shooter]

It means that base timing should be 10* BTDC.

[Fast355]

Now on to "spark bias". If the bias is set to 9.89* in the .bin does that mean the actual timing the engine sees is 9.89* higher or 9.89* lower that what is in the spark table?

There is Initial and Bias values in the .bin parameters. The Initial should match the distributor but the bias is factored into the spark table.

[EagleMark]

Not in $0D, Base timing is called "Initial Spark Advance" and this is what distributor base timing should be set at.

"Main Spark Bias" is the bias for the Main Spark tables! But it is automatically removed from the Spark Advanced tables in $0D. SO what you see is actual.

[Six_Shooter]

Oops, missed the ambiguity of the question.

Which bias setting?

[brian617]

Not in $0D, Base timing is called "Initial Spark Advance" and this is what distributor base timing should be set at.

These I have set to match.

"Main Spark Bias" is the bias for the Main Spark tables! But it is automatically removed from the Spark Advanced tables in $0D. So what you see is actual.

It was my understanding the Main Spark Bias was used to permit negative advance figures. However I noticed in $0D the table had negative figures in it already. So what is the purpose of the bias if the table reflects actual numbers?

[EagleMark]

It was my understanding the Main Spark Bias was used to permit negative advance figures. However I noticed in $0D the table had negative figures in it already. So what is the purpose of the bias if the table reflects actual numbers?

You could not have negative numbers in the spark advance table without the Bias.

[brian617]

Ok now I'm confused

So what happens to the spark map when I zero out the bias other than the negative figures?

[EagleMark]

Ok now I'm confused

So what happens to the spark map when I zero out the bias other than the negative figures?

First dont'! Just leave "Main Spark Bias" alone. It works fine and in your $0D when you look at either Idle or Off Idle spark advance tables they are actual, meaning if you checked with a timing light it would be the same.

Some masks, like the old $42, or even first edition $0D, did not have the bias automatically linked/removed so the spark advance table was not actual! It was all, say 9.84 degrees higher on SB but actual on BB because the Bias on BB was 0*!

If you remove "Main Spark Bias" and then re-open your Idle or Off Idle Spark Advance table it will be 9.84 or whatever you removed higher and not actual. The issues that arise from this can be very confusing when your trying to figure out what Actual Spark Advance is when adding for say PE, DFCO, Decel, Cold start etc... and how it effects everything else.

So your not confused. Just curious! Now if you want to be confused then change the Main Spark Bias and try and figure out what your actual timing is?

As far as changing "Initial Spark Advance" is if you have changed your distributor base setting. And there's no reason to do that unless you have a very large cam. Why? Because if you advance your distributor to say 10*, then set your "Initial Spark Advance" to 10* the timing is still the same! "Initial Spark Advance" is subtracted from the spark advance. But you have advanced injector firing by 10*.

[brian617]

OK thanks for the explaination! I think I got it.

[brian617]

Adjusted my first VE table and had some cells with VE over 100 using the spreadsheet. After some manual smoothing and TP smoothing they went away.

Is VE over 100 good or bad?

[brian617]

Here are couple screen shots to look at for some advice.