Nissan tweeks car to improve MPG

[Q45tech]

"Nissan has reportedly sent its engineers back to the lab in order to pinch every last mile out of each gallon of fuel. As it is written, the program offers a sweeter incentive when consumers purchase vehicles with greater efficiency (based on the difference in fuel economy between the purchased vehicle and the trade-in).

Putting the squeeze on the Sentra's four-cylinder powerplant yielded a 1 mpg improvement – not bad for some minor drivetrain tuning. If the EPA reviews and confirms the bump, the small gain may create the necessary 10-mpg difference Nissan's customers need for the top $4,500 credit.

The program is set to expire this November. That isn't enough time for Nissan, or any automaker for that matter, to make drastic changes. However, engineers are able to focus on quicker fixes such as using lightweight wheels, subtle engine tuning, and changing option packages to reduce weight. According to Nissan, the lure of trade-in bonuses to attract new customers has promoted the automaker to divert much of its engineering to the cause. "

[Q451990]

Nothing like playing to tax laws instead of productivity to kill a business model...

Heath

[Skibane]

"Buy any Nissan between now and November, and get an optional back seat and spare tire for absolutely free!*"

(*Customer must install options after taking delivery of vehicle.)

[Q45tech]

Have you ever wondered why Japanese use 130 pound test drivers. It isn't are fault Americans weigh so much. Obviously the city [acceleration] will be worse than specified with our typical drivers.

[MinisterofDOOM]

"Buy any Nissan between now and November, and get an optional back seat and spare tire for absolutely free!*"

I'm pretty sure there are already economy versions of some cars with supertall final drive ratios and deleted spare tires for weight savings, actually.

[Denver90Q]

What is wrong with diesels (or natural gas)? I believe they make up most of the new car sales in europe and japan and the turbo diesels perform as well as gasoline engines now. Also they last longer and need less maintenance. Maybe I just answered my own question

I have yet to see a diesel hybrid for sale which is what I had hoped to have in my next new car. Hopefully in a good sized stationwagon or sport SUV version.

[MinisterofDOOM]

There are actually (unfortunately) a lot of things "wrong" with diesels in the US.

First, there are tremendously strict emissions controls on them. This makes them expensive to make and buy and can make them expensive and complicated to own and maintain. Fuel also has strict regulations, which raises costs there. I'm not sure about on the east half of the continent, but here in the west diesel is still at least 10 cents more than premium, which tends to negate (or outweigh) any fuel economy benefits.

Also, most US buyers have negative misconceptions about diesels being noisy and smelly. Part of this is the fault of crappy diesels in the past. But it would take a lot to dispel those misconceptions and in the meantime they would hurt sales.

There are a handful of manufacturers who were talking big about plans to move forward with diesel models in the US who have since withdrawn such plans stating that sales aren't looking like they'd match targets and that it's just not feasible to introduce those models to our market on a profitable basis.

Another problem, though much easier to overcome, is the issue of diesel models in the US historically costing significantly more than gasoline counterparts. If a diesel version is going to cost you $5k more up front (which is the difference between the base model and TDI Jettas right now), who is going to buy the diesel? $5k is a lot of gas, yet another strike against diesels' fuel economy strength.

Your diesel hybrid comment is something I agree with, though. I've stated my reasons for thinking mainstream hybrids like the prius a joke. A diesel powerplant could shift them into being genuinely effective. Except we need a true diesel-electric hybrid car; one that operates like a diesel-electric locomotive. Have a diesel powerplant designed to produce a lot of torque at very low (under 2000) rpm and never rev past that point. Have it powering an electric motor and charging batteries. When you're dealing with engines designed to operate super-efficiently at a specific RPM which don't need to rev high efficiently or really operate outside that RPM range at all, you can extract a lot more fuel economy for power being produced, which means you can get a more efficient means of power storage for electric motors.

[greg_atlanta]

I've always wondered if an economy mode for the transmission could be incorporated in the 07+ G35. The LCD display is standard without the NAV package so an on/off toggle could be operated via the LCD screens' menu. The transmission tends to downshift a little too soon as you decelerate and will downshift on its own around corners based on steering input and G-force sensor. It's all fun.... but I feel like the car eats 10% more gas than it really needs.

[Q45tech]

What GM use too do to make a decent police carhttp://www.zianet.com/kc5kto/9c1/9c1.htmlBefore MPG mattered much

[maxnix]

Quote »The LT1 itself is a marvel of engineering. GM realized that compression could be raised without detonation/knock problems if the cool water from the radiator was first routed to the heads instead of to the cylinder water jacket.[/quote]Wow, just like a VH45DE! Of course instead of 260 HP out of 350 ci, the VH was more like 300 HP out of 274 ci. Top speed on the G50 would leave the Caprice gasping in its wake.

[MinisterofDOOM]

I'm frankly surprised it took GM (or any automaker) so long to figure out the benefits of reverse coolant flow. You'd think it would have taken off in the mid-late 60s when compression ratios in performance V8s were hitting 13:1 and higher.

[Q45tech]

Remember the differences in wedge vs 4V heads............the time for flame front to travel to the circumference [bore].

There is an ideal displacement per cylinder for high rpm efficiency 500>550cc or 4.0 to 4.4 liters for a V8 wereas GM used 712.5cc and Q cheated a little with 561cc.

See what happen when they tried to keep the same displacement and build a Q45 type engine:http://www.zr1netregistry.com/lotusengine.htm"a 1992 ZR-1 that it was the least expensive, most civilized and reliable exotic car, despite its humble Chevrolet insignia. The special V-8 whisked the car to 60 mph from a standing start in 4.3 seconds and to 100 mph in 11.5 seconds. It allowed an unmodified Corvette ZR-1 to average 173.8 mph for 5,000 miles in 1990 on a Texas track during a sanctioned run. .

Almost sounds like a Q45 reliability except for higher speed 155-160 vs 174.

Just proves that the average uneducated owner can destroy anythinghttp://www.zr1netregistry.com/...m#OilAmazing how the GM maint sounds so familiar change oil every 3,000 miles.

"the radiator is highly susceptible to restrictions and blockage. This is the main cause of any rise in operating temperatures and should be addressed first. This airflow restriction occurs when particles are collected in the small space between the AC condenser and the radiator and is not visible until the top radiator shroud is removed and the radiator fully viewed from the top"

Shocks"This gradual oil loss will not affect the performance of the shock except after a long service life (50,000-75,000 miles) depending on driving conditions"