School me please.

[SNK-BITE]

After reading the thread yesterday on "why advance spark" I figured I would do some logs today. My question is on the differences between "Max allowed spark" and
"actual spark". I am seeing 23-24 degrees @ wot with 11.3a/f and 100-115 iat2, but at the same points in the logs the max allowed spark is only 21.75-22.00 degrees. So how is the car running on more timing than is allowed according to the "max allowed spark"?

Mods:2.76 upper, jlt cai, mafia, lt's, or-x, magnaflow cat back, bf idlers, 93 octane.

 

[cobracide]

At WOT?

 

[SNK-BITE]

After reading the thread yesterday on "why advance spark" I figured I would do some logs today. My question is on the differences between "Max allowed spark" and
"actual spark". I am seeing 23-24 degrees @ wot with 11.3a/f and 100-115 iat2, but at the same points in the logs the max allowed spark is only 21.75-22.00 degrees. So how is the car running on more timing than is allowed according to the "max allowed spark"?

Mods:2.76 upper, jlt cai, mafia, lt's, or-x, magnaflow cat back, bf idlers, 93 octane.

At WOT?

Correct

 

[cobracide]

Something has be pulling timing from your tune. How were your temps? IAT2s.

 

[SNK-BITE]

Something has be pulling timing from your tune. How were your temps? IAT2s.

Log is posted in first post iat2's are in the 112 range. So which is the actual spark; Max allowed spark, or spark?

 

[cobracide]

Actual spark is actual, so key off that.

 

[SNK-BITE]

There is not a PID that says actual spark.

 

[DSG2003Mach1]

can you link the thread you were referencing (why advance spark?), a search didnt bring it up for me

 

[SNK-BITE]

can you link the thread you were referencing (why advance spark?), a search didnt bring it up for me

Mis-quote...sorry:bash:

http://www.svtperformance.com/forums/engine-tuning-214/960905-why-advance-timing.html

 

[DSG2003Mach1]

Mis-quote...sorry:bash:

http://www.svtperformance.com/forums/engine-tuning-214/960905-why-advance-timing.html

thanks!

 

[SNK-BITE]

I guess maybe I asked the question wrong. According to my log above my WOT "spark" @ 6300rpm is 24 degrees. According to the "max allowed spark" It should be at 22 degrees @ 6300rmp. So how or why am I exceeding my max allowed spark limit of 22 degrees?:shrug:

 

[racecougar]

I guess maybe I asked the question wrong. According to my log above my WOT "spark" @ 6300rpm is 24 degrees. According to the "max allowed spark" It should be at 22 degrees @ 6300rmp. So how or why am I exceeding my max allowed spark limit of 22 degrees?:shrug:

Likely due to the ECT and IAT spark modifiers in the tune.

 

[SNK-BITE]

Likely due to the ECT and IAT spark modifiers in the tune.

Thanks. I got to looking and when my iat2 reach 115 timing goes to 23 and when they hit 130 it drops to 22.5 degrees.

 

[03Steve]

Could be a few things...

Global Spark Adder of +2 is one guess.

The calculation for spark is pretty lengthy, but that adder is at the very end. Want to see for yourself? Change the Global Spark Multiplier from "1" to "0" and set the Global Spark Adder to "X". Your timing will remain at "X" no matter what.

 

[03Steve]

Another thing to note...

2002+ PCMs use MBT Spark (Maximum Brake Torque) in place of Maximum Allowed Spark in the calculation. The Maximum Allowed Spark may be present within the PCM, but it may not be used in the calculation.

In addition to Maximum Allowed Spark, log MBT Spark, Borderline Spark, and Spark Source. The last item will tell you where the spark is coming from.

Good luck.

 

[SNK-BITE]

Could be a few things...

Global Spark Adder of +2 is one guess.

The calculation for spark is pretty lengthy, but that adder is at the very end. Want to see for yourself? Change the Global Spark Multiplier from "1" to "0" and set the Global Spark Adder to "X". Your timing will remain at "X" no matter what.

Another thing to note...

2002+ PCMs use MBT Spark (Maximum Brake Torque) in place of Maximum Allowed Spark in the calculation. The Maximum Allowed Spark may be present within the PCM, but it may not be used in the calculation.

In addition to Maximum Allowed Spark, log MBT Spark, Borderline Spark, and Spark Source. The last item will tell you where the spark is coming from.

Good luck.

Well you definitely make me feel uneducated:bowdown: I appreciate the input. Do you feel 24 degrees is safe on 93 pump gas with iat2's below 115?

 

[03cobra#694]

A lot of us running 23* on 93 including myself (Eaton cars), and 03Steve will make you feel like a dummy.

 

[03Steve]

<--- 12* of timing, 4" upper, 2.3L Whipple, 7psi, 93 octane

I've heard of others running mid 20s on the stock motor pullied Eaton combos. I'm always leaving power on the table when pump gas is in the tank for safeties sake. Just my preference.

 

[leegro1015]

Low ignition timing has its down falls... increased exhaust temp's can burn up cats. And rob power.