Timing Question??????

Bill and Jim have got the answer. Actually high gear the engine see's the most load, most leverage on the engine. And it's not able to be in an accelerating state like early in the run. Being in high gear is like being on the dyno against the water brake....it really don't like it.

If you really want to see which gear places the most load (detonation) on an engine, try running a blown gas engine.

Blessings............Ron.

 

An engine builds peak power with the peak cylinder pressure occuring so many degrees after top dead center, to reach peak cylinder pressure at the said number of degrees after top dead cylinder requires that the plug be fired a certain number of degrees before top dead center a lot of things affect the amount of advance ( bore stroke fuel type etc ) that is required to achieve peak pressure at the correct point, the reason for this is they all change the amount of time it take to burn the fuel in the chamber.

The things that change this as you go down the track are the load you place on the motor in high gear as mentioned, the reason for this is that the load generates more heat....now we are on to something... as the heat builds in the motor in high gear the fuel needs less and less time to burn to reach peak pressure I think this the main reason for pulling more in high gear and the reason that has been overlooked.

Richard Gavle

 

I dont think this is entirely accurate. Most blown door cars now are running two speeds and most only take timing out to get off the line with alot of clutch and then put the timing back in it. By doing this we are seeing cars run .30 to .40 faster than ever before and with alot more mph. We actually gained 3 mph by adding 1 degree of timing. How do we fit into this equation?

 

Blwnaway, have you ever tried adding a little more timing than you now run mid track and then pulling it back at something like 1000'? Could be it would like a degree or two as engine is accelerating through the gear and then pull it back out as it settles into high gear. Just a thought..

Pulling it out at the launch has more to do with power management of the starting line with shorter wheel base cars.

Blessings...........Ron.

 

Bottle Fed, Thanks for taking the time to say what I wanted to!

 

This info has been really helpfull. thanks for all the input. I'm building my timing curve now with MSD's GraphView and i'm going to set it for best power on the dyno for high gear and click it up a few ticks for some of low and all of second.

 

Just a heads up, typically the engine likes a little less timing and a little more fuel from the dyno to the track. So you might want to pull it back a little when you first put it on the track to be safe.

Have fun.............Blessings............Ron.