3 ms·

> more fuel efficient engine is more powerful for the same displacement than one that isn't Not necessarily true, but for kinda stupid reasons. Carburetors oft

by fhood 7y ago

> more fuel efficient engine is more powerful for the same displacement than one that isn't Not necessarily true, but for kinda stupid reasons. Carburetors often run cooler at the intake than fuel injection, resulting in more peak power despite worse economy. I am aware that this is not actually relevant here, I just think it's interesting. My main point is that in that in the early 70s Chevy's small blocks could make damn near 400 horsepower. Fast forwards and it isn't until that late 80s that you see a consumer car with north of 250 (grand national), and that was a pretty extreme outlier. Move to the early 2000s and we finally get modern Chevy LS motors which are once again making north of 400hp from the factory. These are still single cam, 2 valve per cylinder V8s though. WTF actually happened?

perl4ever 7y ago
Measurement of power changed, I think. In 1971, Car & Driver claims a Corvette with 425 hp did 0-60 in 5.3 seconds[1]. 1/4 mile was maybe 13.8 s. A 2008 Corvette with supposedly similar power did 0-60 in 4.1 seconds and 1/4 mile in 12.5.[2] Yeah, there's some difference in weight, and modern transmissions, tires, and suspension are better and so on, but there is usually such a big difference that I think most of it is that horses used to be smaller. [1]https://www.caranddriver.com/features/g15379023/the-chevrolet-corvette-a-history-in-zero-to-60-times/?slide=14 https://www.caranddriver.com/features/g15379023/the-chevrole... [2]https://www.motortrend.com/cars/chevrolet/corvette/2008/2008-chevrolet-corvette/ https://www.motortrend.com/cars/chevrolet/corvette/2008/2008...
- sliken 7y ago
  I've seen several cases where a famous old sports car, likely running at 75% of the power when new, manages to beat the 0-60, 1/4 mile, and lap times of old. Just because tire technology has come that far in the last several decades. But also keep in mind that significant engineering has gone into the best engines of today to broaden the torque and HP curves. It's not unusual to have 90+% of torque from 1800 rpm to 6500 rpm. That alone could significantly help performance numbers. After all it's the area under the torque/hp curve that matters, not the peak. Imagine judging a runner by their peak speed, instead of the time to get across the finish line.
  - perl4ever 7y ago
    "the mammoth 500 cu. in. (8,194 cc) engine in the Cadillac Eldorado fell from 400 gross horsepower (298 kW) in 1970 to only 235 net horsepower (175 kW) for 1971. The real decline wasn’t quite as steep as it looked; the 1971 engine did have a lower compression ratio to prepare for the adoption of unleaded gasoline, but the 1971 gross rating was still 365 hp (272 kW), so the actual loss was about 10%, not more than 40%" https://ateupwithmotor.com/terms-technology-definitions/gross-versus-net-horsepower/ https://ateupwithmotor.com/terms-technology-definitions/gros...

by fhood 7y ago

perl4ever 7y ago

Measurement of power changed, I think. In 1971, Car & Driver claims a Corvette with 425 hp did 0-60 in 5.3 seconds[1]. 1/4 mile was maybe 13.8 s. A 2008 Corvette with supposedly similar power did 0-60 in 4.1 seconds and 1/4 mile in 12.5.[2] Yeah, there's some difference in weight, and modern transmissions, tires, and suspension are better and so on, but there is usually such a big difference that I think most of it is that horses used to be smaller. [1]https://www.caranddriver.com/features/g15379023/the-chevrolet-corvette-a-history-in-zero-to-60-times/?slide=14 https://www.caranddriver.com/features/g15379023/the-chevrole... [2]https://www.motortrend.com/cars/chevrolet/corvette/2008/2008-chevrolet-corvette/ https://www.motortrend.com/cars/chevrolet/corvette/2008/2008...

sliken 7y ago
I've seen several cases where a famous old sports car, likely running at 75% of the power when new, manages to beat the 0-60, 1/4 mile, and lap times of old. Just because tire technology has come that far in the last several decades. But also keep in mind that significant engineering has gone into the best engines of today to broaden the torque and HP curves. It's not unusual to have 90+% of torque from 1800 rpm to 6500 rpm. That alone could significantly help performance numbers. After all it's the area under the torque/hp curve that matters, not the peak. Imagine judging a runner by their peak speed, instead of the time to get across the finish line.
- perl4ever 7y ago
  "the mammoth 500 cu. in. (8,194 cc) engine in the Cadillac Eldorado fell from 400 gross horsepower (298 kW) in 1970 to only 235 net horsepower (175 kW) for 1971. The real decline wasn’t quite as steep as it looked; the 1971 engine did have a lower compression ratio to prepare for the adoption of unleaded gasoline, but the 1971 gross rating was still 365 hp (272 kW), so the actual loss was about 10%, not more than 40%" https://ateupwithmotor.com/terms-technology-definitions/gross-versus-net-horsepower/ https://ateupwithmotor.com/terms-technology-definitions/gros...