Nissan truck engines vs. car engines

All--

Curious as to why the truck engines (2005,6, Frontier, Xterra, pathfinder) are about the same hp as the Maxima (265), but are such gas guzzlers--about

1/2 the mpgs.

I have a 2004 Frontier, 3.3 L V6, 180 hp, also lousy mileage, middling power. I thought the newer engines would have better efficiency along w/ better power, like the Maxima.

Some may reply that the truck engines have more torque. First, do they? Second, why would that affect mpg's so much? Third, couldn't an auto transmission w/ more gears make up for a non-torquey but efficient engine?

Thanks.

-- Johnny

Reply to
Jennifer Duquesne
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Can't tell you about those engines in particular. As a general rule trucks are geared to pull loads and as a consequence the engine will be turning over more. Additionally trucks are not as efficient as sedans when it comes to wind resistance.

Reply to
John S.

guzzlers--about

It is not so much the engine as it is the vehicle the engine is in. My 2006 Frontier weighs 4400 lb, has the drag coefficient of a brick (0.35 or worse), and 35 sq. ft of frontal area. A 2006 Maxima weighs 3500 lb, has a

0.3 drag coefficient, and only 29 sq. ft. of frontal area. An extra 900 lbs and at least 40% more air resistance are going to dramatically affect fuel economy. The weight will have the biggest affect on the around town numbers (.EPA City - Frontier 17, Maxima 20) and the air resistance is going to have a really big affect on high speed driving (EPA Highway - Frontier 21, Maxima 28).

Moral - if you want the best fuel economy, get a car.

Ed

Reply to
C. E. White

You're missing the forest for the trees. The difference in mileage has NOTHING to do with the engines, and EVERYTHING to do with the fact that the Frontier, Xterrible, and Pathfogger are big, square, and heavy like all trucks. The amount of fuel consumed is directly proportional to how hard it is to move a vehicle through the air, away from stoplights, and up hills.

No. Torque is important *at the engine level* in any heavy vehicle. If it weren't, 18-wheelers wouldn't have engines that redline at 2500 RPM and produce over 1000 ft-lb of torque, they'd have high-revving high-horsepower engines like a sports car does. In theory a CVT could let the engine whing along at high speed all the time, but in practice it works better all-around to make the engine as efficient as possible with as broad a torque curve as practical in a heavy vehicle.

Reply to
Steve

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