Originally posted by andrew.brandon:
and back in the day HP was not measured the same way as today. engines were tested with as little powertrain loss as possible for marketing ploys. not quite sure how to put it but its like manfacturs saying the 3.8L has 200hp when only maybe 160hp reaches the ground. I am sure someone else can explain it better than I can though
and back in the day HP was not measured the same way as today. engines were tested with as little powertrain loss as possible for marketing ploys. not quite sure how to put it but its like manfacturs saying the 3.8L has 200hp when only maybe 160hp reaches the ground. I am sure someone else can explain it better than I can though
Back before the early 70's, cars were measured in gross HP. The engines were hooked up to dynos with no accessories, a completely open intake, and a completely open exhaust. Then they were dynoed to get a hp rating. In the early 70's, they switched over to net HP which consisted of testing the engines with all accessories hooked up to them and the stock intake/exhaust on them (more realistic of how the car sits). Both ratings were at the flywheel, however, net shows how the engine sits in the car while gross shows bare engine specs. While I've never seen concrete numbers, it's suspected that the gross HP are HIGHLY inflated over net HP (some have said as much as almost 100hp depending on the engine). Add into that poorer gripping/thinner tires and less gearbox gears and you can see why the quarter miles don't match up to the power ratings.
Of course when they switched from gross to net and the emmissions equipment started getting added and compression ratio's dropped (all about the same time), the numbers shot way down.
Chris
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