Best timing tuning method hptuners
The biggest problem I see usually is someone is tuning on an inertia dyno and tuning off of peak numbers only. Inertia only isnt going to give you enough load to give you good enough data to get the tune dialed in accurately especially on a higher hp car.
The type of dyno makes a huge difference. I went from an inertia only to a dyno with a huge eddy brake and its a world of difference. You can actually tune high hp cars and get useable data while on the data. I also like to tune off average hp vs peak which i think helps alot also. Not every dyno will give a breakdown of average hp. We have taken numerous high hp car straight from the dyno and ran them at the track and the tune was spot on.
Something else I've considered doing... after it was tuned on a dyno, using elapsed time to determine which AFR gives the shortest elapsed times between RPM ranges, and picking the least timing which generates the lowest ET's per RPM range. Then repeat for timing advance. Of course, there's more variables on the street so maybe all I'd be doing is wasting gas money?
Airflow or airmass readings will change with ignition timing.
The better the bang, the better the next air charge is pulled in. Now... getting the best bang is a bit more complicated.
http://www.hindawi.com/journals/jc/2011/678719/
" It is expected that power should increase with spark advance to a point and then drop off. Best performance will be achieved when the greatest portion of the combustion takes place near top dead center. If the spark is not advanced enough, the piston will already be moving down when much of the combustion takes place. In this case, we lose the ability to expand this portion of the gas through the full range, decreasing performance. If ignition is too advanced, too much of the gas will burn while the piston is still rising. As a result, the work that must be done to compress this gas will decrease the net work produced. These competing effects cause a maximum in the power as a function of spark advance.
As is evident in Figure 4, the torque increases with increasing ignition advance. This is due to increasing pressure in the compression stroke, and consequently more net work is produced. It is necessary to mention that by further increase in spark advance, torque will not rise largely due to in-cylinder peak pressure during compression period and a decrease of pressure in expansion stroke. For this reason, determining the optimum ignition timing is one of the most important characteristics for an SI engine. "
The better the bang, the better the next air charge is pulled in. Now... getting the best bang is a bit more complicated.
http://www.hindawi.com/journals/jc/2011/678719/
" It is expected that power should increase with spark advance to a point and then drop off. Best performance will be achieved when the greatest portion of the combustion takes place near top dead center. If the spark is not advanced enough, the piston will already be moving down when much of the combustion takes place. In this case, we lose the ability to expand this portion of the gas through the full range, decreasing performance. If ignition is too advanced, too much of the gas will burn while the piston is still rising. As a result, the work that must be done to compress this gas will decrease the net work produced. These competing effects cause a maximum in the power as a function of spark advance.
As is evident in Figure 4, the torque increases with increasing ignition advance. This is due to increasing pressure in the compression stroke, and consequently more net work is produced. It is necessary to mention that by further increase in spark advance, torque will not rise largely due to in-cylinder peak pressure during compression period and a decrease of pressure in expansion stroke. For this reason, determining the optimum ignition timing is one of the most important characteristics for an SI engine. "
