why do nissans have poor gas mileage?

[urameatball]

their 350z gets about the same mileage as a 5.7L corvette C5.
I heard the xterra is absolutely horrible in gas.

and generally, the cars in their line-up are generally not very fuel efficient, especially when compared to other japanese car makers (well, I guess the sentra is pretty decent, but nowhere near the efficiency of a toyota/honda of the same class)

[Rocky03]

I thought the Altima 4cyl was the best gas milage in it's class beating the Camry & Accord.


EDIT: (looks like the Honda is the worse)

new EPA:
4 cylinder Altima: 26mpg
4 cylinder Camry: 25mpg
4 cylinder Accord: 24mpg

6 cylinder Altima: 22mpg
6 cylinder Accord: 21mpg
6 cylinder Camry: 23mpg

[XxXSnake23XxX]

I thought the Altima 4cyl was the best gas milage in it's class beating the Camry & Accord.

i can vouch for that one
have a I4 altima amazing gas!

[urameatball]

cool, my bad :P
guess they're not all that bad :P

[KorruptioN]

You say it like all Nissans are terrible at efficiency.

Comparing the Nissan VQ35DE to the Chevy LSx is beyond apples and oranges. They do different things, they're designed differently, and even in terms of performance, they do not compare.

[urameatball]

You say it like all Nissans are terrible at efficiency.

Comparing the Nissan VQ35DE to the Chevy LSx is beyond apples and oranges. They do different things, they're designed differently, and even in terms of performance, they do not compare.
but isn't it a little strange that a higher powered 5.7L is getting the same mileage as a 3.5L? I find it strange.... strange indeed.

[ShadowVlican]

older subaru n/a engines get the same gas mileage as current turbo models.... go figure :(

[ES_Revenge]

but isn't it a little strange that a higher powered 5.7L is getting the same mileage as a 3.5L? I find it strange.... strange indeed.
You're comparing a pushrod motor to an overhead cam motor. It's not a good idea to do this just looking at displacement, however it's all too common that people do this.

The Corvette's LSx engine has 16 valves for example, the VQ35xx has 24 valves.

VQ35 has to rev to make it's power, whereas the large-displacement Vette engine has lots of low end. In regular driving people are perhaps more likely to rev the Nissan higher between shifts which could net lower fuel economy. Tap the throttle in the Vette and it goes, the 350Z needs a little bit more enthusiasm ;)

There's many other factors which can affect fuel economy. For example axle, final drive, gear ratios all affect overall fuel economy. It's certainly not as simple as saying "hey this engine is x litres and this one is y litres" and then automatically assuming that whichever is the lower of x or y should have better fuel economy. It simply doesn't work like that.

Plus as someone else said, not all Nissans can have poor economy can they? I mean I'm sure the Versa and the Sentra are fine in their class right?

[camber]

but isn't it a little strange that a higher powered 5.7L is getting the same mileage as a 3.5L? I find it strange.... strange indeed.

Not really...

The 360HP 6.0L LS2 found in the Pontiac G8 gets way worst mileage then the 3.5L engine in the Infiniti(Nissan) M35. Both cars are similar weight and size...

That's more of an apples to apples comparison.

Corvette and 350Z is an apples to orange comparison. One is a cheap and mass produced sport car based off a widely used platform and the other is a from the ground up made only to be a sports car.

Outside of the Corvette, the LSX series engines returns rather average fuel economy for that particular application and segment.

[malecoke]

actually my x-trail is on par with the 2008 CR-V, accroding to the recent test by canadian driver.
Doing around 12.5L/100km with full city driving in such horrible weather conditions.

[mr_raider]

their 350z gets about the same mileage as a 5.7L corvette C5.
I heard the xterra is absolutely horrible in gas.

and generally, the cars in their line-up are generally not very fuel efficient, especially when compared to other japanese car makers (well, I guess the sentra is pretty decent, but nowhere near the efficiency of a toyota/honda of the same class)

Because they make more powerful cars in equivalent segments to Honda and Toyota, i.e. G35 vs. is250, sentra vs. civic. Power eats gas. Two cars with similar power and torque curves will have similar gas consumption, regardless of engine displacement.

[Engi-Nir]

Not really...

The 360HP 6.0L LS2 found in the Pontiac G8 gets way worst mileage then the 3.5L engine in the Infiniti(Nissan) M35. Both cars are similar weight and size...

That's more of an apples to apples comparison.

Corvette and 350Z is an apples to orange comparison. One is a cheap and mass produced sport car based off a widely used platform and the other is a from the ground up made only to be a sports car.

Outside of the Corvette, the LSX series engines returns rather average fuel economy for that particular application and segment.

not really, one is 18 mpg (G8 6L ) vs M35 3.5L 19mpg

[KawaiiTentacleBeast]

The 360HP 6.0L LS2 found in the Pontiac G8 gets way worst mileage then the 3.5L engine in the Infiniti(Nissan) M35. Both cars are similar weight and size...

The G8 GT does not use the LS2, it uses the L76/Gen IV Vortec 6000, same or similar to the Suburban/Yukon.

Also according to fueleconomy.gov,
Car city/highway/combined

G8 V6: 15/25/20
G8 V8: 15/24/18
M35: 16/23/19

Engine displacement really has very little to do directly with fuel economy, I don't see why anyone would come to such a conclusion.

[Tomy]

my 2000 altima gets good mileage when i had it..

i forgot the numbers.. but i remember gas mileage was one and horsepower was one of the positives of this car =)

[Asad_A203]

their 350z gets about the same mileage as a 5.7L corvette C5.
I heard the xterra is absolutely horrible in gas.

and generally, the cars in their line-up are generally not very fuel efficient, especially when compared to other japanese car makers (well, I guess the sentra is pretty decent, but nowhere near the efficiency of a toyota/honda of the same class)

Really hard to say; i get poor gas mileage; worse than if owned a F350/Corvette. I think it really comes down to the Corvette engine being alot more simplier; the VQ is mass produced and is definately not as simple as a pushrod. Probably didn't fit well with the vehicle; and lets not forget the 350Z/G35 are heavy vehicles too.

For the 350Z lacking torque; it doesn't really; I get around mostly under 2000 RPM. Anything above 2XXX; I am going to fast for general traffic. The 350Z/G35 put out 90% torque (243 lb/tq) from 2000 RPM to 7000 RPM; Corvette Z06 puts out fricken 400 lb/tq from 2400 to 6600 RPM. Difference between Corvette and G35 is well the torque output of 2-3 Honda Civics there :cheesygri. That being said; the 350Z puts out more torque at 2000 RPM than most vehicles on the road; so the 350Z having to rev higher is probably not the reason.

To be honest I have no idea why a Corvette would be more fuel efficent than my vehicle. Sure it sucks; but I think the car has alot of other qualities that make it worth it. Nissan has put newer engines in the G which has increased fuel economy; the HR (high rev) is now both in the G35 Sedan and the 350Z. The G37 3.7L has that BMW M3/M5 feature thing (can't remember off top of my head); but apparently it has better fuel economy than the prior G35C while producing 60 more RWHP.

[hoob]

i can vouch for that one
have a I4 altima amazing gas!


The 07 Altima 3.5 V6 is great on gas as well... I've hit 7.1 for highway driving, 6.8 for rural driving (80kph), even better than rated.

[KawaiiTentacleBeast]

To be honest I have no idea why a Corvette would be more fuel efficent than my vehicle.

It's not difficult at all. The Corvette isn't a really heavy car, and it's very aerodynamic. Other than that, GM is cheating with CAGS (Computer Aided Gear Selection) - based on throttle position, 2nd and 3rd gear are disabled. So during the test the car is essentially going from 1st to 4th all the time. Gearing does the rest. A Corvette has enough torque to make it work, a Civic doesn't.

Bottom line is that if you are drive slow, you save gas, no matter what kind of engine you have. Only with a bigger engine, you have the option of going fast too.

[Asad_A203]

It's not difficult at all. The Corvette isn't a really heavy car, and it's very aerodynamic. Other than that, GM is cheating with CAGS (Computer Aided Gear Selection) - based on throttle position, 2nd and 3rd gear are disabled. So during the test the car is essentially going from 1st to 4th all the time. Gearing does the rest. A Corvette has enough torque to make it work, a Civic doesn't.

Bottom line is that if you are drive slow, you save gas, no matter what kind of engine you have. Only with a bigger engine, you have the option of going fast too.

G35 is very aerodynamic as well; coefficient of drag is 0.27; The Corvette coeffecient of drag is 0.28...

G35 weights 3400 lb; Corvette curb weight is 3130lb. Kinda what happens when you need to sacrifice performance for all the things in the G you don't get with a Corvette. Corvette is a dedicated sports car. G35 is supose be a sports coupe while still being a luxury coupe; doesn't work too well; haha. So it is probably what you are mentioning about CAGS and the extra weight that make the Corvette get that MPG.

I guess it really isnt about the G35/350Z getting poor fuel economy; it is about a Corvette getting THAT kinda fuel economy :twisted:.

[KawaiiTentacleBeast]

Heavier cars usually do as well as lighter cars on highway fuel economy, because once you reach cruising speed, weight is less of an issue than aerodynamics. Heavier cars do need more energy to get moving, for city driving.

[VivienM]

It's not difficult at all. The Corvette isn't a really heavy car, and it's very aerodynamic. Other than that, GM is cheating with CAGS (Computer Aided Gear Selection) - based on throttle position, 2nd and 3rd gear are disabled. So during the test the car is essentially going from 1st to 4th all the time. Gearing does the rest. A Corvette has enough torque to make it work, a Civic doesn't.

They can only do THAT with the manual transmission...

But yes, big pushrod engine + very conservative gearing = good balance of performance and fuel economy. Now if all you Honda fans would realize that... ;)

[aquariaguy]

their 350z gets about the same mileage as a 5.7L corvette C5.
I heard the xterra is absolutely horrible in gas.

and generally, the cars in their line-up are generally not very fuel efficient, especially when compared to other japanese car makers (well, I guess the sentra is pretty decent, but nowhere near the efficiency of a toyota/honda of the same class)

I drive from Philly to Toronto 2 times with my friend who has a 98 Camaro V8, and I have my 02 Accord V6. Fill up gas before we leave, and fill up again halfway, he gets similar if not better mileage. I pay maybe 50 cents more. IT's sad :( Apparently because when we're cruising at high speeds, his engine is doing less work? I guess so, since I my whole car screams when I accelerate, and his is so easy to take off.. Sucks for me!!

[camber]

Engine displacement really has very little to do directly with fuel economy, I don't see why anyone would come to such a conclusion.

The displacement thing is not my point... It's the original poster's point...

[KawaiiTentacleBeast]

No, your point was that the G8 used the LS2 and got much worse fuel economy than the M35, and you are wrong in both respects.

[urameatball]

so big honking V8's aren't gas guzzlers?
nor are little japanese motors fuel efficient?

my world has turned upside down :(

[movieman]

VQ35 has to rev to make it's power, whereas the large-displacement Vette engine has lots of low end. In regular driving people are perhaps more likely to rev the Nissan higher between shifts which could net lower fuel economy. Tap the throttle in the Vette and it goes, the 350Z needs a little bit more enthusiasm ;)

Yeah. I had two Lancia stationwagons in the 90s; one was a 1.6 liter, the other a supercharged 2.0 liter with about 30% more power and 50% more torque, otherwise the cars were basically identical. The supercharged car was much less efficient in town, but typically used 15-20% less gas than the 1.6 on long highway journeys... probably because the 1.6 was gutless below 3000 rpm and the gearing was significantly lower so it ran at higher rpms in 5th.

So there's a lot more to fuel efficiency than just engine size.

[camber]

No, your point was that the G8 used the LS2 and got much worse fuel economy than the M35, and you are wrong in both respects.

Oh... I'm sorry for confusing the million different names for variants of gen 4 small block. L76 is basically a slightly altered LS2 that can run 87 octane. :rolleyes:

My overall point was to compare more similar cars together. I'm sorry if I didn't choose an ideal comparison. Although, you can quite easily see that the disparity isn't as large as the Corvette versus 350Z.

Crap, even the M35 versus G8 isn't a totally apples to apples to comparison. The G8 uses a 6AT versus the M35's 5AT and M35 has way more power robbing luxury features. Also, the L76 is much newer evoultion of an the engine found in M35(VQ35DE). It probably would be better to compare the Cadillac STS versus the M35/45.

Right now... No foreign make has a cheap DOHC V6 or V8 RWD sedan. I guess the closest thing would be the upcoming Hyundai Genesis.

[camber]

so big honking V8's aren't gas guzzlers?
nor are little japanese motors fuel efficient?

my world has turned upside down :(


It just depends on the application. "little japanese motors" are quite fuel efficient in small cars. Push Rod V8s are deliver respectable fuel mileage if there in a 3000lb sports car, tiny frontal area, low cd and good gearing..

The Hemi powered STR8 Jeep Cherokee is the single cause low world fuel supplies:lol:

[KawaiiTentacleBeast]

It probably would be better to compare the Cadillac STS versus the M35/45.


http://img338.imageshack.us/img338/5112/compks5.th.jpg (http://img338.imageshack.us/my.php?image=compks5.jpg)

Hmm. Strange how the EPA has the STS and the Prius in the "Midsize "Category, but the M35 and the Accord in the "large car" category.

[mr_raider]

so big honking V8's aren't gas guzzlers?
nor are little japanese motors fuel efficient?

my world has turned upside down :(

Of course not. Fuel consumption is tied directly to energy required to move the car. That means how heavy the car is and how fast you are accelerating. Whether you generate the energy by spinning a 1L twin turbocharged engine at 10000rpm or a 10L pushrod v8 at 500rpm is irrelevant. To produce power you need to break carbon bonds in gas, period.

If two cars weigh the same and have the same 0-60mph acceleration time, you can bet they have the same fuel consumption, regardless of engine size.

[skidz88]

Nissans don't have terrible gas milage. Ok, so my Nissan does worse than a Camry but for what it is, it doesn't do that badly at all and I'd stomp a Camry any day.

[ES_Revenge]

They can only do THAT with the manual transmission...

Well they can do it with the auto too, just with programming. It's well possible the auto is programmed to operate similarly and skip gears. A normal auto is not constrained to sequential gear operation so it's certainly possible.

I was gonna mention CAGS/skip shift but I wanted to keep it more simple. I didn't think it really made a huge difference either because even very small increases in economy make a huge difference for the manufacturer who pays fines based on the number of vehicles produced, not just individual economy numbers. Some cars have this removed/elminated, stock though, no? I always thought the Z06 did not have this, for example, due to it's max. performace nature. But then I'm not sure.

[ShadowVlican]

Of course not. Fuel consumption is tied directly to energy required to move the car. That means how heavy the car is and how fast you are accelerating. Whether you generate the energy by spinning a 1L twin turbocharged engine at 10000rpm or a 10L pushrod v8 at 500rpm is irrelevant. To produce power you need to break carbon bonds in gas, period.

If two cars weigh the same and have the same 0-60mph acceleration time, you can bet they have the same fuel consumption, regardless of engine size.
some engines are more efficient at making power than others

a simple graph charting fuel economy vs power output will show you that

[movieman]

If two cars weigh the same and have the same 0-60mph acceleration time, you can bet they have the same fuel consumption, regardless of engine size.

To a first approximation. But there are many variables in engine efficiency, drivetrain efficiency, air resistance, etc.

For cars of a similar era there probably won't be more than a 20-30% difference, but the difference will still be there.

[ES_Revenge]

some engines are more efficient at making power than others
Yep, and advancements are being made all the time. Even small changes in ignition and fuel delivery methods can create a few MPG here and there over the years.

In general, older cars, even ones made 5-10 years ago are less efficent even with very similar engines, gearing, weight etc. Even comparing the numbers when those cars were new, fuel economy has slowly risen and so has power output over the years.

Even on the EnerGuide site, I believe it recommends you buy a newer rather than older car to enjoy better fuel economy. ;)

I'm not saying older cars can't be fuel efficient but you could probably find that today's 120hp or whatever Civic, is just as efficient as yesterday's 70hp Civic or at least a lot closer than some people might expect.

Forced induction (which increases an engines volumetric efficiency beyond 100%) and direct injection are pretty much surefire ways to increase engine efficiency in terms of power derived from the fuel burned. Whether or not cars with these features are actually more fuel efficient mileage-wise compared to their non-equipped competitors is again a whole other story. There's still a lot of variables in the mix. This is really a large reason for fuel economy ratings. You can't just guess at the numbers give an few things you know about the car, it's better to go with the ratings. Of course the ratings have their own flaws, but I'm not going to get into that. If you at least have a standardised system to go by, it's better than just guess work.

[BartBandy]

actually my x-trail is on par with the 2008 CR-V, accroding to the recent test by canadian driver.
Doing around 12.5L/100km with full city driving in such horrible weather conditions.

Our X-Trail sees mostly highway. We get between 9 and 10L/100km. Pretty damn good for the size and class of vehicle.

I count Nissan among the better engine manufacturers. Their designs have won many engine awards. That said, not all their engine applications lend themselves to good fuel economy.

[VivienM]

Well they can do it with the auto too, just with programming. It's well possible the auto is programmed to operate similarly and skip gears. A normal auto is not constrained to sequential gear operation so it's certainly possible.

I was gonna mention CAGS/skip shift but I wanted to keep it more simple. I didn't think it really made a huge difference either because even very small increases in economy make a huge difference for the manufacturer who pays fines based on the number of vehicles produced, not just individual economy numbers. Some cars have this removed/elminated, stock though, no? I always thought the Z06 did not have this, for example, due to it's max. performace nature. But then I'm not sure.

No, the Z06 has CAGS, too. In fact, AFAIK, every pushrod/6MT GM car does: CTS-V, F body, GTO, etc.

CAGS is about avoiding the "gas guzzler" label (which means an additional tax that the buyer must pay). It was GM policy for about 10-15 years that they would not produce anything that got a gas guzzler label from the US government.

Then they introduced the AWD STS. :) Then the CTS-V, GTO (originally designed for Australia, so with less fuel economy tricks), came along. And that was the end of GM not making gas guzzlers...

[KawaiiTentacleBeast]

I always thought the Z06 did not have this, for example, due to it's max. performace nature. But then I'm not sure.

It does, but really it's just GM gaming the system by shipping cars with it and artificially forcing down the fuel consumption. There's nothing stopping you from skipping gears regardless of whether you have CAGS or not. If you really wanted to stretch out the fuel economy you would do that, but who the hell would do that on a Corvette anyway?

SAAB, before GM destroyed..I mean, bought them, use to tout some of their turbo engines as having better fuel economy than their NA engines, because they would use taller gearing to take advantage of the increased torque.

SAAB use to sell cars that came with water/methanol injection from the factory too. We never have nice things anymore. :(

[mr_raider]

To a first approximation. But there are many variables in engine efficiency, drivetrain efficiency, air resistance, etc.

For cars of a similar era there probably won't be more than a 20-30% difference, but the difference will still be there.

Of course. But the general principle holds, torque curves determine fuel consumption much more than engine displacement, assuming similar generation engines.

[Asad_A203]

It does, but really it's just GM gaming the system by shipping cars with it and artificially forcing down the fuel consumption. There's nothing stopping you from skipping gears regardless of whether you have CAGS or not. If you really wanted to stretch out the fuel economy you would do that, but who the hell would do that on a Corvette anyway?

SAAB, before GM destroyed..I mean, bought them, use to tout some of their turbo engines as having better fuel economy than their NA engines, because they would use taller gearing to take advantage of the increased torque.

SAAB use to sell cars that came with water/methanol injection from the factory too. We never have nice things anymore. :(

Well I understand how a Corvette; with its lighter weight and gear ratio; but how does that explain SUVs getting better fuel economy than the G35C? Most of these SUVs don't even have as much torque as the G35C and definately weigh alot more than it. Just a bit wierd too me.

[Asad_A203]

http://img338.imageshack.us/img338/5112/compks5.th.jpg (http://img338.imageshack.us/my.php?image=compks5.jpg)

Hmm. Strange how the EPA has the STS and the Prius in the "Midsize "Category, but the M35 and the Accord in the "large car" category.

Yeah; Accord is smaller than the M35/STS. STS is also longer than the M35 too. I love the M45:

http://z.about.com/d/philadelphia/1/0/-/p/4/2007_auto_show_038.jpg

19s look like 15s on it :cheesygri. 22s FTW!

[KawaiiTentacleBeast]

Looking on fueleconomy.gov, All the SUVs that get better fuel economy than the G35 are some combination of tiny, 4-cylinder, or hybrid. The only one that seems to stick out is the V6 RAV4, but even then it's only marginally better. Maybe since the RAV4 is like their top selling model other than the Camry, they really pull all the tricks to get the best fuel economy ratings? Whats the gearing like? I think B000rt drives a V6 RAV4?

[VivienM]

Well I understand how a Corvette; with its lighter weight and gear ratio; but how does that explain SUVs getting better fuel economy than the G35C? Most of these SUVs don't even have as much torque as the G35C and definately weigh alot more than it. Just a bit wierd too me.

Are you comparing the same years? The 2008 US numbers are using a different test procedure than the pre-2008s...