Wednesday, January 21, 2009

Car Specs

I'm sure no one cares about these specifications, but a recent discovery inspired me to collect the following specifications about the vehicles I've owned. Keep in mind that these numbers are quoted by the factory, so they may not be entirely accurate at the time of manufacture, and they probably were less accurate during my ownership of the car. (All power and torque values are measured at the crankshaft, not the wheels.)

Specifications of the Automobiles I've Owned
Year, Make, and ModelCurb Weight* (lb)Power (BHP)Torque (ft-lbs)Power-Weight Ratio (BHP/ton)Torque-Weight Ratio (ft-lb/ton)
1977 Datsun 280Z2875149163104113
1980 Honda Prelude202072947193
1991 Honda CRX210392898785
2004 Mazda Mazdaspeed MX-5 Miata2530178166141131


I should point out that the Miata is now about 40 pounds heavier (when wearing the stock wheels), because I added a 50-ish-pound rollbar and removed about 10 pounds of material from the car. Additionally the Miata probably puts out something like** 182 horsepower and 170 ft-lb now, since I'm getting about half a PSI more boost due to the larger intercooler.

Anyway, the discovery that prompted this post was the true weight of my old Z. I think, when I went looking for it before, I read the value for the 240Z: 2355 lb. (The 280 is 500 pounds heavier because of the larger engine, beefier bumpers, stronger structure to support the bumpers, thicker carpet, a heavier dashboard, and other, more minor changes.) This means that Mia is not the heaviest car I've ever had, as I previously claimed. That makes me feel better. However, I'll miss the looks people give me when I tell them my Miata is the largest car I've owned.

* Curb weight includes all necessary consumables, such as lubricant, coolant, and fuel.

** To make this calculation, I assumed power to be proportional to oxygen consumed, which should be proportional to intake-air pressure. The total pressure is the boost (about 8 PSI, stock) plus atmospheric pressure (about 14.7 PSI). That's all very rough, as is my assumption of a 0.5-PSI increase in boost.

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