Stock Spark table q's

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Oct 29, 2003 | 08:26 PM

lykan

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Stock Spark table q's

Ok, from what I gather from reading (I may be way off) When you nail the throttle to the floor, your timing should advance.. I was looking at my stock spark table. I noticed the higher the MAP value (more throttle?) at low RPMS, the less timing the table allows.

for example at 100 kpa, and 400 rpm. its actualy taking out .7 degrees of timing.. why is this? Im feeling kind uneducated here., i had assumed when you put the pedal to the floor, the timing would advance to allow for more power on accel...maybe its for fuel economy and longevity of the motor?

I know im probably asking for along complicated answer.. but if your willing to type it up, I am willing to read..if you have anything to add to help my understanding of map vs timing I would sure appreciate it.

Just for giggles here's my table (bone stock 350 with tbi mods)

Code:

  RPM                                                MAP (Kpa)
         20    25    30    35    40    45    50    55    60    65    70    75    80    85    90    95    100 
   400  20.0  20.0  20.0  20.0  20.0  18.3  17.2  12.3  11.3   9.1   6.3   4.2   3.2   2.1   1.1   0.0  -0.7 
   600  20.0  20.0  20.0  20.0  20.0  18.3  17.2  12.3  11.3   9.1   6.3   4.2   3.2   2.1   1.1   0.0   0.0 
   800  20.0  20.0  20.0  20.0  20.0  20.0  20.0  16.2  14.1  10.2   9.1   5.3   4.2   2.1   1.1   0.0   0.0 
  1000  20.0  20.0  20.0  20.0  20.0  20.0  20.0  18.3  15.1  13.0  10.2   7.0   5.3   3.2   1.1   0.0   0.0 
  1200  20.0  20.0  20.0  20.0  20.0  20.0  20.0  18.3  16.2  14.1  11.3   9.1   7.0   5.3   3.2   2.1   1.1 
  1600  21.1  21.1  21.1  21.1  21.1  21.1  21.1  19.0  18.3  15.1  13.0  11.3   9.1   7.0   5.3   4.2   4.2 
  2000  22.1  22.1  22.1  22.1  22.1  22.1  22.1  20.0  19.0  16.2  14.1  12.3  10.2   9.1   7.0   6.3   6.3 
  2400  23.2  23.2  23.2  23.2  23.2  23.2  23.2  22.1  21.1  18.3  16.2  14.1  12.3  11.3   9.1   9.1   8.1 
  2800  25.3  25.3  25.3  25.3  25.3  25.3  25.3  23.2  22.1  19.0  17.2  15.1  13.0  12.3  11.3  10.2   9.1 
  3200  26.0  26.0  26.0  26.0  26.0  26.0  26.0  24.3  23.2  22.1  18.3  17.2  16.2  14.1  13.0  12.3  11.3 
  3600  27.1  27.1  27.1  27.1  27.1  27.1  27.1  26.0  24.3  22.1  20.0  18.3  17.2  15.1  14.1  13.0  12.3 
  4000  30.2  30.2  30.2  30.2  30.2  30.2  30.2  30.2  25.3  23.2  21.1  20.0  19.0  17.2  17.2  16.2  15.1 
  4400  30.2  30.2  30.2  30.2  30.2  30.2  30.2  30.2  26.0  24.3  22.1  21.1  20.0  18.3  18.3  18.3  17.2 
  4800  30.2  30.2  30.2  30.2  30.2  30.2  30.2  30.2  26.0  24.3  22.1  21.1  20.0  18.3  17.2  16.2  15.1 
  5200  30.2  30.2  30.2  30.2  30.2  30.2  30.2  30.2  26.0  24.3  23.2  22.1  21.1  19.0  18.3  17.2  16.2 
  5600  30.2  30.2  30.2  30.2  30.2  30.2  30.2  30.2  26.0  24.3  23.2  22.1  21.1  19.0  18.3  17.2  16.2 
  6000  30.2  30.2  30.2  30.2  30.2  30.2  30.2  30.2  26.0  24.3  23.2  22.1  21.1  19.0  18.3  17.2  16.2

Oct 29, 2003 | 08:46 PM

Grumpy

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Joined: Jun 2000

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From: In reality

Car: An Ol Buick

Engine: Vsick

Transmission: Janis Tranny Yank Converter

Re: Stock Spark table q's

Quote:

Originally posted by lykan
Ok, from what I gather from reading (I may be way off) When you nail the throttle to the floor, your timing should advance.. I was looking at my stock spark table. I noticed the higher the MAP value (more throttle?) at low RPMS, the less timing the table allows.

for example at 100 kpa, and 400 rpm. its actualy taking out .7 degrees of timing.. why is this? Im feeling kind uneducated here., i had assumed when you put the pedal to the floor, the timing would advance to allow for more power on accel...maybe its for fuel economy and longevity of the motor?

I know im probably asking for along complicated answer.. but if your willing to type it up, I am willing to read..if you have anything to add to help my understanding of map vs timing I would sure appreciate it.

Just for giggles here's my table (bone stock 350 with tbi mods)

[/code]

Lean mixtures are slow to burn so you need more time, ie advance for them to burn so in cruise mode when the engine is running lean you need alot of advance.

WOT developes alot of heat, and the mixture lights easy, so not as much timing is needed.

The only time the engine sees the 100 K/Pa 400 entre is went the engine first starts as is gaining speed from the starter spinning the engine to actual idle RPM

Long explainations made short.
HTH