Make a spreadsheet (and graph) of drive wheel thrust available, for each gear in turn. This will give you a set of overlapping curves, one for each gear ratio. As you go up through the gears, you will notice that there is less thrust is available, the reason for the top out limit of a vehicle. Selecting effective shift points is very obvious with this type of graph.
When rear wheel thrust available = total drag power required, you are done accelerating. A diff/trans/overdrive ratio change MAY change your top speed, slightly, but without more bhp, you are done.
Most vehicles accelerate best using the GREATEST AREA UNDER THE POWER CURVE. This may or may not include peak torque. It is going to depend on the shape of your power curve. Ie, wide and relatively flat Vs. narrow and peaky. You want to make an informed choice here.
The formula required is available in several places, I think Sumner has it somewhere on his pages, it is in several vehicle dynamics text books and in Carroll Smith's tome as well. You might be rewarded by a Google search.
This is a pointless exercise without an ACCURATE dyno sheet with torque and bhp curves. Your current engine's bhp, tq & gearing tells you where you are. Some sort of plan for future changes is an excellent idea.
To quote one of my mentors:
"Information based decision making is ALWAYS better than Voodoo and killing chickens at midnight." It has always worked well for me, thank you HB2!
My advice is: Start keeping a notebook, get a laptop and some racing specific software, or freeware. MOST of the time, you get what you pay for. You can keep good records in a notebook by hand, for next to nothing. Well, except for the discipline to actually do it. BTW, if you are computer savvy, you can do a lot of analysis with Excel, especially if you can write your own formulas.
Fordboy
P.S. I know at least one guy on this board who got pretty good results with the information based approach. He posted just prior to me.
