PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

how do I optomize spark advance???

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Old 04-27-2005 | 07:58 PM
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Default how do I optomize spark advance???

what is the best method for doing my timing??

do a drive...log it all....
take table and paste special subtract???
then add 1 everywhere and go driving again....?? till I get 1*-2* knock everywhere and then back off 2???
and -4 for the low octane??

or am I thinking about this the wrong way.....???

I am ready to do my timing tables...just dont want to screw anything up...

Last edited by soundengineer; 04-27-2005 at 08:07 PM.
Old 04-28-2005 | 01:05 AM
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Yeah. Slowly add timing till you get kr and then back it off. I did the -4 for my low octane too.
Old 04-28-2005 | 01:36 AM
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I matched low and high octane for now. Once my new engine is in, will back it off the norm -4.
Old 04-28-2005 | 01:36 AM
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Jimmy Blue had some good posts regarding knock decay rate.
Old 04-28-2005 | 07:55 AM
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I read quite an interesting post about spark advance, but now I can't remember where I saw it. I want to say it was in the HPTuners Getting Started forum. Anyways, it was saying how advancing spark until you see knock isn't the way to do this. You really need a dyno (preferably a mustang dyno that will put a load on the motor) to dial in your spark advance. It is possible to advance too far and make less power with no knock. The post went into the science of it all and I'm not about to try and explain it. What I would suggest until you can measure your rwhp on a dyno is stick with the 27-28* standard. If you see knock with that, back it off some. But, don't go adding 29*, 30*, and 31* of spark advance just because you don't see knock retard. Just my $.02 .
Old 04-28-2005 | 09:53 AM
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what #'s am I looking at for that 27-28 degrees....
timing changes with load....and there is quite a large table...
can I just add 1 degree at a time for the entire table?? or do I need to onlyadd it in a certain spot??

or am I looking in thwe wrong area all together??
Old 04-28-2005 | 10:06 AM
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Scott, do a log with Histogram and drive a lil bit with varying loads, and then do a few WOT blasts, letting go through the entire RPM range for the first few gears. Play it back and you will see exactly where the WOT timing is needed or not needed. Simply cut and paste into the editor and your good to go for the WOT timing. Good luck,.
Old 04-28-2005 | 10:12 AM
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Originally Posted by CAT3
Scott, do a log with Histogram and drive a lil bit with varying loads, and then do a few WOT blasts, letting go through the entire RPM range for the first few gears. Play it back and you will see exactly where the WOT timing is needed or not needed. Simply cut and paste into the editor and your good to go for the WOT timing. Good luck,.

so I only want to add for the WOT Spark..not for any part throttle?
Is that what you are telling me??
Old 04-28-2005 | 10:22 AM
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These cars can stand quite a bit more timing in the part throttle area. I have added four degrees in some spots. Adding some timing at part throttle seemed to make the car a little more responsive.




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