Heading Legend
	Car - Line is for the OEM tire size & axle ratio.
	Axle - OEM axle ratio for the M/T equipped car listed.
	Trans Ratio - Third gear ratio in OEM transmission.
	Tire Size - Section Width (mm) - Aspect Ratio (%) - Rim Diameter (in)
	TRPM - Tire revolutions per mile
	Engine RPM @ 40 MPH
	Engine RPM @ 70 MPH
	MPH @ 4000 RPM
	MPH @ 4500 RPM
	MPH @ 7000 RPM
	MPH @ 7500 RPM
	MPH @ 8000 RPM

Note 1 - If you are using non-standard tires, just divide your TRPM by that in the chart and multiply that result by the table entry to get your speed or RPM.

Note 2 - If you are using non-standard axle, just divide your ratio by that in the chart and multiply that result by the table entry to get your speed or RPM.

However, for comparing the results of modifications designed to increase power, assuming you don't have a real dyno or a G-Tech, the test should be run through the heart of the power band. If you examine the chart above, you will see that for nearly every car listed, 40 MPH is below the engine's torque peak, and 70 MPH is below the engine's power peak and redline, usually way below. With the Miata, T2, FD & unmodified NA rotaries, a much better test is one run from 4000 RPM to 7000 RPM. Porting and headers move the NA rotary's power band up, so a test from 4000 or 4500 to 7500 or 8000 does a better job of centering on the power band, giving a much better indication of the results of any changes made.

Why third gear? First of all, the test must be run in a single gear to prevent shifting variations from producing an uncontrolled variable. Second gear may be OK for cars with low power to weight ratios, such as totally stock 12A first gens, but for the rest, particularly those using shorter rear gears, the timing interval in second is so short that statistical variation becomes a misleadingly large percentage of the indicated measurement. Using fourth gear instead requires a much larger testing area, which is without question unacceptably dangerous using the space available to most of us.

First, the test should be run someplace where the test speeds are safe and lawful.

The location should be level, or as close to level as possible. To account for any grade and less than perfect stopwatch or other skills, several runs should be made in each direction and the results averaged. Mash the pedal to the floor several hundred RPM or MPH before the start speed or RPM and hit the stopwatch button as the needle crosses the starting point, and again when it reaches the end point, then reducing your speed for your analysis or next run. Hitting the pedal early allows all systems to stabilize before measurement begins, reducing variables to the minimum, such as the effects of boost lag or accelerator pump shot. Also, you aren't trying to coordinate your button finger with your right foot while driving.

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