Spark for H/C cars
#1
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Spark for H/C cars
Hey guys (and gals). I have my fueling pretty much dialed in but I was wondering, what do you guys do about your spark tables? I mean, is there any rule of thumb or a spread sheet that can help me figure out how to optimize the spark table for my car.
I have the spark set-up on mine so that at WOT I'm at 28* which I believe is where my engine made the most HP on the dyno. But I'm wanting to optimize the other areas such as cruise, part throttle, etc. I've added 3* to all other areas on the spark map and I'm not getting any KR but I'm not so sure that is a wise thing to do.
How does GM do it when plotting a spark map for a particular cam? I'm sure there is a lot of math involved and if I have to go that route it's fine by me.
Any and all help much appreciated.
I have the spark set-up on mine so that at WOT I'm at 28* which I believe is where my engine made the most HP on the dyno. But I'm wanting to optimize the other areas such as cruise, part throttle, etc. I've added 3* to all other areas on the spark map and I'm not getting any KR but I'm not so sure that is a wise thing to do.
How does GM do it when plotting a spark map for a particular cam? I'm sure there is a lot of math involved and if I have to go that route it's fine by me.
Any and all help much appreciated.
#5
Kleeborp the Moderator™
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Originally Posted by jub jub
Thanks GuitsBoy. This must still be a grey area or it's been beat to death.
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I'm using the old rule of thumb "Advance it until it knocks and then back off a few degrees". I'm not real comfortable with this but it's all I can do without spending all day on a dyno.
I just thought I could use a spread sheet or something to help calculate proper spark at various loads and RPMs.
I just thought I could use a spread sheet or something to help calculate proper spark at various loads and RPMs.
#7
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Originally Posted by jub jub
I'm using the old rule of thumb "Advance it until it knocks and then back off a few degrees". I'm not real comfortable with this but it's all I can do without spending all day on a dyno.
I just thought I could use a spread sheet or something to help calculate proper spark at various loads and RPMs.
I just thought I could use a spread sheet or something to help calculate proper spark at various loads and RPMs.
Don't put too much stock in that. An engine only needs so much advance to achive MBT, you could advance it more without incurring trace knock but make absolutley nothing in terms of power, infact all you'll serve to do is increase the effective compression and heat in the chamber with nothing to show for it.
FWIW, my T/A made it's peak power at 24* @ WOT on a dyno, stock timing is 28*.
Food for thought.