General Base timing and timing table

[gutoblauth]

Hey, I'm a bit confused about base timing and timing table.

When setting the base timing to 5* BTDC, are we just setting a starting/base reference to the ECU, right? Also, BTDC means advanced timing? (5* advanced)
So when the timing table below says 5*, is it actually at 10* then? 5* + 5* = 10* BTDC

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For some reason my brain it's tricking me to think 5* BTDC means -5*, and the table saying 5* will result in 0*

 

[1990TSIAWDTALON]

It is always Before Top Dead Center otherwise you will be starting the combustion process as it is exiting the exhaust valve (which can spool a turbo but not your normal timing).
You are correct that when we set Base Timing, we are giving the ECU a starting point to work from.

 

[gutoblauth]

It is always Before Top Dead Center otherwise you will be starting the combustion process as it is exiting the exhaust valve (which can spool a turbo but not your normal timing).
You are correct that when we set Base Timing, we are giving the ECU a starting point to work from.

Thanks for the answer.
About the table question and my 5* exemple, the idle timing is 10* then? (5* base + 5* table)
When the table says 12*, it's actually 5* base + 12* table = 17*? It's that it?

 

[1990TSIAWDTALON]

The timing table is the exact timing you are asking the ECU to give the engine.
The 5* Base is just for the ECU to use as its reference. In your table, if it says 10*, then 10* is what you are asking the ECU to provide to the motor. When I look at a log of mine and compare the timing from my table to what the engine is getting, it is what I am asking or moving in that direction. It isn't adding them together.

 

[Mello]

Everything is based off of degree rotation of the crankshaft. BTDC is counter clockwise from TDC (0°), ATDC is clockwise on our 4G63's.

Base timing is set to 5° BTDC. Ignition events occur BTDC & the timing table values are how much before the timing event needs to occur. Remember TDC is 0° crank rotation.

 

[steve]

If it isn't already clear, setting the base timing is just synchronizing the mechanical with the electrical. They could have chose 13 degrees if it would have made it easier.

Once the two are in agreement, the ECU knows where TDC is and all it's tables are relative to that. (and it's correct in it's knowledge, rather than hopelessly confused)

 

[Tyeler18]

Setting base timing means adjusting the cam sensor so that when the ecu commands 5* BTDC the cam sensor is adjusted so that it fires 5*BTDC. If you set it at 6* you're entire table would be off by 1* since the computer now thinks 6* actual is 5* commanded. Base timing just locks the ecu command to 5*.

 

[Mello]

Setting base timing is a 1G thing because they don't have a specific crank angle sensor. Mitsubishi separated the cam sensor from the crank sensor on 2G's and from the factory 2G's base timing can not be adjusted. The 2G ECU determines base timing from the angular difference the ECU sees from these 2 separate sensors. A 2G cam sensor can not be rotated like the 1G cam sensor (which is actually a bundled cam & crank sensor).

 

[jed344]

As some have said already the 5 deg at idle is what ecu is targeting. But it is also assuming you already have the base timing at 5 deg. So if you have it at say 0 but the ecu thinks you are at 5 deg you can see how this is a issue. Every value in your timing map in reality is 5 deg less then target.

 

[gutoblauth]

Glad for all answers, now I got it.

I'm making the timing table for the aftermarket ECU I have installed in my 2G and I wasn't sure if by copying the same table from DSMlink/ECUFlash was going to ruin my engine.
Basically my mind was tricking me because the aftermarket ECU syncros to the engine different from the 5* BTDC, and that was making me think that maybe the values on the timing table should be different.
The ECU I'm using is a Fueltech.

Now the only thing I need to know is the proper way to convert from Load% into Boost, since the ECU uses Speed Density.
Comparing a post from Ceddy and one articule I found when googling the stock 2G table, they are one column/line off in the boost axis.
Ceddy's - https://www.dsmtuners.com/threads/lets-see-your-tuned-timing-maps.362539/

Spoiler: Ceddy's

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JeffGST's - http://www.jeffgst.com/id20.html

Spoiler: JeffGST's

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In Ceddy's post, boost starts (Zero PSI) at 100% Load, but in JeffGST's article the Zero PSI line is the same as the 90% Load in Ceddy's post.
My belief is that any load beyond 100% means boost, am I right? If so, Ceddy is the one to go.