No Device: General question about Spark tables
#1
General question about Spark tables
How about a nice simple question about Spark Tables??
Most anything I've read on automotive tuning and the couple of spark table calculators I've found seem to suggest a Spark timing table should look something like...
Most advance bottom left, least advanced top right.
Indeed an awful lot of the Harley maps I look at are the same generic shape. So here's the question...
Why do older Dyna/Softail 358 map spark timing tables look like this...
Looking at the current Harley maps for 358 configuration files, they have both types, even at stage 3 or 4. The current Dyna/Softail have switched to 617 maps with the top "more typical" (if that is the right way to look at it) strategy.
So, Pro tuners, do you have your own spark tables or which is the right? best? whatever? style to use and why?
Now I know the trick about making flames come out of the exhaust that the ricers/showmen use, but from a tuning perspective, what do you think Harley is doing here? Is one strategy better than the other?
cheers
Most anything I've read on automotive tuning and the couple of spark table calculators I've found seem to suggest a Spark timing table should look something like...
Most advance bottom left, least advanced top right.
Indeed an awful lot of the Harley maps I look at are the same generic shape. So here's the question...
Why do older Dyna/Softail 358 map spark timing tables look like this...
Looking at the current Harley maps for 358 configuration files, they have both types, even at stage 3 or 4. The current Dyna/Softail have switched to 617 maps with the top "more typical" (if that is the right way to look at it) strategy.
So, Pro tuners, do you have your own spark tables or which is the right? best? whatever? style to use and why?
Now I know the trick about making flames come out of the exhaust that the ricers/showmen use, but from a tuning perspective, what do you think Harley is doing here? Is one strategy better than the other?
cheers
#2
My guess would be that the spark tables that is calculated is based on trapped air/fuel and compression ratio. The actual maps is based on empirical measurements for performance with one slight twist. Once the useable part of the timing table was mapped the guy tuning stopped. The High RPM/Low MAP pressure section is not really seen that much. It's typically on deceleration. it possible that some other function shuts off fuel during this time so the spark advance is not needed.
Bet Cole knows..
Bet Cole knows..
#3
No fuel, who cares when the spark happens ...that makes sense
I've also heard about changing the amount of engine braking effect, and if you look at F1 (maybe not quite as popular over there, sorry) they keep putting fuel in and use part throttle during deceleration so as not to hammer the crank ...or something like that anyway ...although Harley EFI was maybe not designed with quite that level of techie input?
I've also heard about changing the amount of engine braking effect, and if you look at F1 (maybe not quite as popular over there, sorry) they keep putting fuel in and use part throttle during deceleration so as not to hammer the crank ...or something like that anyway ...although Harley EFI was maybe not designed with quite that level of techie input?
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