Merc 4.5L 250HP

[ITD]

Originally Posted by 8gv

I think the car/boat comparison gets off track due to the use of multi speed transmissions in cars.

Yes today's cars get great performance with less displacement. Much of that comes from improved valve train and injection technology. The delivery of that performance requires gearing. Does anyone recall cars with a two or three speed automatic? Now it's 6, 7, 8 or a CVT.

I'd like to see some torque curves on the engines in question.

The transmissions allow the engines to remain in their optimum power band, maximizing efficiency increasing gas mileage. In the case of the Chrysler ZF transmission, it actually shifts so fast that in the Hellcat Challenger that the 0 -60 and 1/4 mile times are fast for the auto than the manual. These auto transmissions are huge technological breakthroughs and they keep squeezing more and more ratios into those transmissions. I think one company is up to 10 or 11 for an automobile.

Transmissions do not increase engine horsepower, they actually decrease it due to mechanical and system losses.

[8gv]

I concur.

My Subaru with its CVT is no race car but it does ok when called on to do so. A rolling start helps get the CVT to perform without wasting high revs.