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Off idle surges

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Old May 4, 2004 | 02:01 PM
  #1  
3.8TransAM's Avatar
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From: Schererville , IN
Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
Off idle surges

This is just something that I have learned after burning many many chips :-) (and still no where near perfect)

Hope it helps some of u out.

Even though your cars configuration idles at 60kpa at say 737rpm, remember that when u go to accelerate from a stop(lite throttle conditions) u actually end up using the 40 and 50 kpa regions if u are accelerating lighltl like in traffice or subdivisions..


U idle at 60kpa at 738 rpm and accelerate backwards diagonally across your MSA table...

This (I've remem and forgotten *** knows how many times) has resulted in by far the smoothes leave from a stop under normal driving conditions that i have managed thus far.

Seems if your car idles at 40-45kpa or less this is nowhere near as noticeable, its the diagonal backtracking that seems to cause unwanted flutters or surges due to a severe timing jump that u may miss because of what is actually happening as your car accelerates

later
Jeremy
PS may be a ramble but i hope it helps someone else out
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Old May 5, 2004 | 07:09 AM
  #2  
Grumpy's Avatar
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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: Off idle surges

Originally posted by 3.8TransAM

U idle at 60kpa at 738 rpm and accelerate backwards diagonally across your MSA table...

This (I've remem and forgotten *** knows how many times) has resulted in by far the smoothes leave from a stop under normal driving conditions that i have managed thus far.

Seems if your car idles at 40-45kpa or less this is nowhere near as noticeable, its the diagonal backtracking that seems to cause unwanted flutters or surges due to a severe timing jump that u may miss because of what is actually happening as your car accelerates
The worst part is that with the 160 baud ALDLs you can miss that whole event. And even with the faster ALDLs miss how far the spike actually goes.
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Old May 5, 2004 | 11:54 AM
  #3  
3.8TransAM's Avatar
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Joined: Feb 2000
Posts: 7,015
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From: Schererville , IN
Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
lol

Ive had people tell me it doesnt happen like that and rbob has experienced the same ... Log it enuff and u can watch it happen and playing with the timing there is really beneficial to leaving the line clean, at least form my experience
later
Jeremy
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