What happens when you reduce horsepower in a car and increase torque? 2009 Acura TSX vs. 2010 Diesel Acura TSX?
The current 2009 TSX has 201hp and 174 lb/ft torque and it’ll run 0-60 in mid 6 sec. Rumor has it that Acura will be bringing over the diesel powered Euro-Accord in 2010, which will be an option for a new TSX. The specs on that car is 148hp and 255 lb/ft torque. With so much extra torque, does it mean it’ll hit 0-60 faster and have less of a top speed? Rumor also says that combined city/hwy epa will be 50+mpg. How accurate is that?
There is a direct connection between torque and horsepower. Horsepower = Torque x Engine Speed (RPM) / 5252. As a result, the gasoline TSX makes its 201 horsepower at approximately 6000 RPM. Diesels have much lower redlines than conventional gasoline motors, so they do not benefit from having a horsepower peak occurring at a higher engine speed than 5252 RPM. Most of the time, diesels make peak power at their redline (around 3500-4500 RPM). Assuming that the same transmission is used, 0-60 should take about the same time, but perhaps a little slower. The added torque of the diesel is offset by the necessity for more shifts. Again, assuming that the same transmission is used in both cars, the diesel will have a lower top speed. However, the extra torque of a diesel means that a higher gear ratio can be used. 50+mpg sounds a little optimistic to me, but I believe it will be over 40+mpg. Of course, both of these figures refer to highway mileage. Volkswagen used a similarly powered diesel and achieved over 40mpg highway. However, it is Honda (which makes Acuras), so you never know what technology they have to exceed 50mpg highway.
Wild Acura: 2010 Acura ZDX @ 2009 New York Auto Show
