Timing..

[Capinoy123]

Yup. Still on the 3065. I just wanna get my car tuned to the T! In dsm link as my car builds boost timing is falling and continues to fall through out the entire pull.... Not sure why?

[niterydr]

Originally Posted by Capinoy123

Yup. Still on the 3065. I just wanna get my car tuned to the T! In dsm link as my car builds boost timing is falling and continues to fall through out the entire pull.... Not sure why?

As engine load increases generally timing values will decrease until MBT is hit, then steadily increase as RPM increase, assuming load holds constant.

[turbotalon1g]

Originally Posted by niterydr

As engine load increases generally timing values will decrease until MBT is hit, then steadily increase as RPM increase, assuming load holds constant.

I thought you don't want to increase over MBT no matter what?

From what I understand you want to try and increase timing with RPM until you hit that MBT point.

[Capinoy123]

I know that timing retards as boost increases, but when I hit max boost 30 psi yhe timing is still falling. I guess im not understanding your question? What map am I using? Do you mean maf? If so im using a 3 1/2" gm maf. As for the load holding constant. Im 80% sure that it is. Checked for boost leaks 2 years ago, none. I know the weather can effect vaccum hoses over time so ill double check those, and do another boost leak test over the weekend. Checked compression, 180 across the board. What am I missing?!!

[niterydr]

Originally Posted by turbotalon1g

I thought you don't want to increase over MBT no matter what?

From what I understand you want to try and increase timing with RPM until you hit that MBT point.

MBT is dependent upon certain load and rpm combinations, it isn't a set timing value for all rpm point.

For example, let us say a car makes peak power with 10 degrees of ignition timing at 5000rpm and you rev to 7000rpm.
6000rpm, you may want 11 degrees of timing (to get to MBT again for that RPM/Load), and 7000rpm you may want 12 degrees of timing (to get to MBT again for that RPM/Load).

[turbotalon1g]

Originally Posted by niterydr

MBT is dependent upon certain load and rpm combinations, it isn't a set timing value for all rpm point.

For example, let us say a car makes peak power with 10 degrees of ignition timing at 5000rpm and you rev to 7000rpm.
6000rpm, you may want 11 degrees of timing (to get to MBT again for that RPM/Load), and 7000rpm you may want 12 degrees of timing (to get to MBT again for that RPM/Load).

Yeah I get that, but I thought overall though you still want timing to climb with RPMs, as too much retard can be bad.

Capinoy, i meant your base timing map is it for a 1g or 2g. Assuming you are on corn run the 1g map and work off of that.

[niterydr]

Originally Posted by turbotalon1g

Yeah I get that, but I thought overall though you still want timing to climb with RPMs, as too much retard can be bad.

Capinoy, i meant your base timing map is it for a 1g or 2g. Assuming you are on corn run the 1g map and work off of that.

Aaron that is what I am saying. AS RPM goes up, timing goes up.

As load increases, timing value decreases

You end up with a timing map like this:
(load)
1 million boost 1 1 2 3 5
.5 million boost 2 3 4 6 10
no boost 7 10 15 20 25
all vacuum 15 20 25 30 35
idle 4000 6000 vtec 15000 (rpm)

[Capinoy123]

Oh ok. I will have to drive the car tomorrow and check. I am on E85 by the way running 1650 bluemaxx injectors with a bosch 044 fuel pump in the tank. About to put another 044 in line. Injectors are at 98% last time I checked...