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Old 12-14-2011, 12:19 AM   #10 (permalink)
California98Civic
Cyborg ECU
 
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Join Date: Mar 2011
Location: Coastal Southern California
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Black and Green - '98 Honda Civic DX Coupe
Team Honda
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Quote:
Originally Posted by mwebb View Post
if the system does not have a knock sensor
switch it back to the recommended
Base Ignition timing value or you will find degraded performance increased emissions and
engine damage

peak combustion pressure must happen right about 14 degrees after
TDC at all loads and engine speeds except
DFCO and idle

you just changed your peak combustion pressure timing by the amount you changed your base ignition timing by
bad idea , there is no benefit for doing this .

and for the others
who are considering setting their base ignition timing properly
understand that
the system will not go to base timing if
the closed throttle switch is not closed

so if there is a TPS problem in your system
do not adjust your base ignition timing
Thanks for the caution. I appreciate it. It's important that people think carefully about whether they do anything to their ignition timing. But I'm not sure the situation is quite as simple as you are representing. I talked about this with guys who were experienced in it, and I read about it. I saw no reason to believe that two degrees is an automatic engine damaging move. But I have seen plausible discussions too that advancing timing will affect the torque curve by bringing it very modestly down the RPM scale. Even modestly more low-end torque is good for the P&G hypermiling technique in which I accelerate between 1700-2200 RPMs. It is one of a group of small things I do to produce the results I have. My DX does not have a knock sensor. But I have driven it for ten years, and I know thoroughly the sound and conditions under which it has occurred. I almost never hear it, and my 2* timing advance changed nothing about the ping/knock events (or lack of 'em).

Here's an interesting link for anyone wanting more detail about advancing the timing and torque and other issues: What Happens When the Timing Is Advanced

Regards,
james
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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.


Last edited by California98Civic; 12-14-2011 at 12:35 AM..
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