Why do fuel efficeny ratings seem to be

[Newbiewar]

Okay, I just glanced at the Solstice review in the pontiac section and it said fuel ecconomy of 20-28 20 on the street and 28 on the highway... where as the miata is 24-28 24 on the street and 28 on the highway... for most of GM models it seems their city mileage is below everyone elses where as the highway mileage is competative... Why is there such a big gap on GM vehicles?

[Hudson]

Okay, I just glanced at the Solstice review in the pontiac section and it said fuel ecconomy of 20-28 20 on the street and 28 on the highway...

where as the miata is 24-28 24 on the street and 28 on the highway...

for most of GM models it seems their city mileage is below everyone elses where as the highway mileage is competative...

Why is there such a big gap on GM vehicles?

In this case, Mazda has a smaller engine.

[haypops]

Doesn't the miata weigh hundreds of pounds less?

[Northstar]

Yeah, the Miata is both lighter and has a smaller enine (and is also less powerful). Lots of GM cars suffer vs. the competition in terms of fuel economy because of the old 4-speed automatics.

[Teh Ricer Civic!]

why? because they actually produce power in the low end. thats why an RSX can be powerful AND get good mileage cause its a very small engine and doesnt use much gas at slower engine speeds, but if you want power its still there in the higher end. whereas GM gives power all across the board and hence worse gas mileage.

[regfootball]

the solstice got better mileage in the real test in car and driver's recent comparo.

[prototype66]

transmissions and gear ratios imo

[ToniCipriani]

It seems that GM tends to be more conservative about ratings. A lot of stated ratings are lower than real world.

[Teh Ricer Civic!]

It seems that GM tends to be more conservative about ratings. A lot of stated ratings are lower than real world.

[post="51899"]<{POST_SNAPBACK}>[/post]

EPA issues fuel economy ratings

[capriceman]

Yeah, the Miata is both lighter and has a smaller enine (and is also less powerful).

Lots of GM cars suffer vs. the competition in terms of fuel economy because of the old 4-speed automatics.

[post="51367"]<{POST_SNAPBACK}>[/post]

Don't Bash 4 speed trans as being the problem. Tecnically its a 8 speed if you count overdrives.

[Newbiewar]

EPA issues fuel economy ratings

[post="51920"]<{POST_SNAPBACK}>[/post]

The ratings are presented from the automakers...

[Teh Ricer Civic!]

Why does the EPA go through the whole process of determining fuel estimates for cars if the automakers present the numbers? the automaker has their own numbers before the EPA rates it and then the automaker has to put down the numbers that the EPA rated it at.

[Newbiewar]

Why does the EPA go through the whole process of determining fuel estimates for cars if the automakers present the numbers? the automaker has their own numbers before the EPA rates it and then the automaker has to put down the numbers that the EPA rated it at.

[post="52096"]<{POST_SNAPBACK}>[/post]

no the company will run the tests do all the work for the EPA... they present the vehicle with its results and the EPA will aprove of it... the EPA also tells consumers to not expect the results posted... as they gennerally dont take into account the average drivers habbits

[haypops]

... as they gennerally dont take into account the average drivers habbits

[post="52112"]<{POST_SNAPBACK}>[/post]

Hell they don't even take into account wind resistance. The test are performed on a dynometer utilizing a very specific standard drive cylce including idle time, stops, rate of acceleration, etc.

[Newbiewar]

Hell they don't even take into account wind resistance.  The test are performed on a dynometer utilizing a very specific standard drive cylce including idle time, stops, rate of acceleration, etc.

[post="52113"]<{POST_SNAPBACK}>[/post]

but they do generally take a 10-15% decrease from the results... so some error is accounted for..

[Drew Dowdell]

Don't Bash 4 speed trans as being the problem. Tecnically its a 8 speed if you count overdrives.

[post="51982"]<{POST_SNAPBACK}>[/post]

...uh.... :blink:

[Newbiewar]

Don't Bash 4 speed trans as being the problem. Tecnically its a 8 speed if you count overdrives.

[post="51982"]<{POST_SNAPBACK}>[/post]

I'm gonna pull a flag on that... :bs:

the definition of an overdrive is one where the driveshaft spins faster then the rpm of the motor...

on both of my f-bodys the gears are...

1rs...3.059
2nd..1.625
3rd...1.000
4th(overdrive)0.696

Reverse...2.294

that makes mine 4 different gears and reverse...

Trucks have overdrives... not cars...

[Teh Ricer Civic!]

my car says 4spd w/overdrive... so your telling me my car doesnt have overdrive? :P

[Drew Dowdell]

my car says 4spd w/overdrive...

so your telling me my car doesnt have overdrive?  :P

[post="52217"]<{POST_SNAPBACK}>[/post]

overdrive.... not overdrives

[Newbiewar]

my car says 4spd w/overdrive...

so your telling me my car doesnt have overdrive?  :P

[post="52217"]<{POST_SNAPBACK}>[/post]

big rigs have one overdrive per gear, generally...


most 6speeds have 2 overdrives...

[pow]

What's overdrive anyway? I don't think I've ever driven a car with one.

[capriceman]

What's overdrive anyway? I don't think I've ever driven a car with one.

[post="52260"]<{POST_SNAPBACK}>[/post]

Say if you wanted to pass some one and your in your 4th gear, you step on the gas, to get more power the car downshifts in to 3rd or uses a overdrive whcich is installed either inside or out side of the transmission so the power band is in the higher rpms to give you more power and acceleration to get around the idoit in front of you. does that make sense.

Yeah i was talking about a truck and I understand the bashing but the 4 speed is not a bad trans. Road and track said something like "put the Ferrari 612 in auto and you might be wishing to have a GM Hydramatic 4 speed"

I driven that 500 ford with the 6 speed and F**kin hated it!!!!!! It kept switching gears and was not smooth, When they improve it maybe ill change my mind, But stick shift is always my first option :) .

Also the GTO with the 4 speed is Faster then the smae version with a stick. But the trans needs torque thats another reason GM cars take more gas. they produce more low end torque which burns gas, making people think its the trans.

But thats my opinion based on fact!

[razoredge]

caprice - your understanding of OD is all messed up. Overdrive in common automatics and standard trannys is simply a higher gear in the transmissions that reduces engine RPM's and it has absolutely no power what so ever. The output shaft of the tranny actually turns faster than the crankshaft, OD is for reduced RPMs at highway speed only. Not all heavy trucks have three ranges, the third would be your overdrives. The 13 speed, 15 speed and 18 speed have the OD range. THe 8,9,10 speeds have a low range and the normal range in which your highest gear is direct drive, that 1:1 crankshaft : output shaft. Then many of the trucks that are used for construction and go "off pavement" also have a deep reduction for even slower ruff terrain travel. The exact opposite of overdrive.

[Drew Dowdell]

Say if you wanted to pass some one and your in your 4th gear, you step on the gas, to get more power the car downshifts in to 3rd or uses a overdrive whcich is installed either inside or out side of the transmission so the power band is in the higher rpms to give you more power and acceleration to get around the idoit in front of you.  does that make sense.

Yeah i was talking about a truck and I understand the bashing but the 4 speed is not a bad trans. Road and track said something like "put the Ferrari 612 in auto and you might be wishing to have a GM Hydramatic 4 speed"

I driven that 500 ford with the 6 speed and F**kin hated it!!!!!! It kept switching gears and was not smooth, When they improve it maybe ill change my mind, But stick shift is always my first option :) .

Also the GTO with the 4 speed is Faster then the smae version with a stick. But the trans needs torque thats another reason GM cars take more gas. they produce more low end torque which burns gas, making people think its the trans.

But thats my opinion based on fact!

[post="52273"]<{POST_SNAPBACK}>[/post]

Complete wrong.
Overdrive means that in the top gear <top two for 6-speeds>, the engine is turning at a slower RPM then the drive shaft. For example, for every .90 turns of the crankshaft the driveshaft makes one full turn. Generally, this is for cruising and the engine is near the lowest point on it's powerband. This is how the Corvette acheives 28mpg at 60 because it loafs along at 1700rpm in 6th.

To pass a person, the transmission or driver must shift out of overdrive to bring the engine back into the heart of it's powerband. This is where you get your acceleration.

That the Ford 500 hunts for gears is troublesome to me. Is this the same 6-speed GM intends to use? I know GM and Ford were supposed to have a partnership on a 6-speed. I always hated how the Sable would hunt for gears when I would borrow my ex-BF's mother's car.

[haypops]

I think that we are confusing several possibilities. When trying to pass a transmission shifts out of overdrive if it has an overdrive. In the 50' and 60's there was a vacume opearted separate gear ratio that changed the final drive ratio and was refered to as an overdrive. Todays automatic transmissions generally have a top ratio of less than 1.0 and are also refered to as an overdrive ratio, but is not a separate available ratio or speed to be added to the 4 listed for a typical GM automatic transmission. What the typical automatic does have nowadays is a locking and unlicking tougue converter. This usually operates on the top two gears and does indeed change the rpm observable on the tachometer. In at least one case that I can think of (ford powered gas motor homes) the operator can manualyu unlock the torque converter for higher revs but poorer fuel milage.

[razoredge]

The reason GM's are slightly lower in fuel economy is they are slightly behind in developement. That and most likely the Japs are lying, they always come up a little short. :P

[razoredge]

I know those 6 speeds are going to stink around here, the 4 sppeds do, I use D or 3rd to avoid all the upshifting downshifting all the time with the hills. That and the fact that if you in OD you going down the hills at 70 unless your one of those hot brake riders. The six speed may have a few limited uses out in the pararies but for the most part I believe they are "gotta have" mental masterbation. You know like the guitar amp that goes to 11 on the dial so that way you have 1 more. I drove my buddys C5 and never even made it to 6th, not that we were cruising. Edited December 3, 2005 by razoredge

[Guest carpetbagger]

I drove my buddys C5 and never even made it to 6th, not that we were cruising.

[post="52288"]<{POST_SNAPBACK}>[/post]

your just a penis envy little pansy who cant drive

[capriceman]

Well thats why I try to stay away from transmissions. I'll do minor work but nopt tear into one. Thanks I have a better idea of how it works. I always got the impression that it downshifts to get the high rpm Power band.

[Drew Dowdell]

Well thats why I try to stay away from transmissions. I'll do minor work but nopt tear into one.

Thanks I have a better idea of how it works. I always got the impression that it downshifts to get the high rpm Power band.

[post="52321"]<{POST_SNAPBACK}>[/post]

It does downshift.... it downshifts out of not in to overdrive.

[razoredge]

your just a penis envy little pansy who cant drive

[post="52298"]<{POST_SNAPBACK}>[/post]

What the fudge is this crap moderators ?

That is not my spelling moderators ! Edited December 4, 2005 by razoredge

[NeonLX]

Ya know, I've been looking at it from another angle--GM's fuel economy ratings seem to be higher than I'd expect, at least for the vehicles I'm interested in. Big cars like the LeSabre and Bonneville with the torquey 3800 V6 are achieving ratings not too far off from smaller, lighter 4-cyl. cars. And the Malibu V6 is simply astounding IMHO--23/32 MPG for a mid-sized car with a large displacement V6 is quite an accomplishment. And of course there are the high-powered Cadillacs and Corvettes w/ rip-snorting V8s pulling 25 to 28 MPG on the highway--that amazes me too. Back when I drove my gargantuan '72 Olds 98, I'd stop and throw a big celebration whenever I saw the high side of 10 MPG... :blink: Drew

[Hudson]

Don't Bash 4 speed trans as being the problem. Tecnically its a 8 speed if you count overdrives.

This one I do not understand at all. I'm glad you're not working on my cars.

Simply put, overdrive is a gear with a ratio numerically less than 1:1. Most 4-speed automatics have ONE overdrive gear.

[Flybrian]

This one I do not understand at all. I'm glad you're not working on my cars.

[post="53074"]<{POST_SNAPBACK}>[/post]

I'm sorry, but this made me actually LOL.

[Newbiewar]

here we go...

http://autos.msn.com/advice/article.aspx?c...8&src=LP%20utes

Chances are you're watching the needle in the fuel gauge of your car a little more closely these days. And you're frustrated at the fuel economy you're seeing.
Join the club.

The fuel economy estimates for new cars, provided in large black type on window stickers, can overstate fuel mileage by as much as 34 percent, according to the Bluewater Network. The network is a California-based environmental group that petitioned the U.S. government more than two years ago to change the way fuel mileage is calculated.

These estimates, mandated by the federal government starting in the 1970s, were never based on real-world driving. Instead, they're derived, sort of backhandedly, from emissions test procedures.

And the process of developing the estimates has been updated only once, in 1985.

Why the Focus Now?
While some people considered gasoline to be affordable, many American drivers didn't notice—or care to make a fuss about—the inaccuracy of the fuel economy numbers.

But after several years of gasoline and diesel price jolts, as well as an increasing awareness of the costs involved in getting oil from the Middle East, Americans are more interested than ever in the fuel economy they're getting. Or, as the case may be, the fuel economy that their vehicles are not getting.

It's also easier today for a consumer to check a vehicle's fuel economy because many vehicles have electronics that automatically calculate fuel economy as they drive.

This is especially true for gasoline-electric hybrid vehicles, where real-world fuel economy results are computed and prominently displayed on an ongoing basis.

It has become such an issue, in fact, that some frustrated hybrid owners who aren't getting the fuel economy numbers posted on their window stickers have asked dealerships to "fix" their vehicles. They've also complained to automakers.

Following Government Requirements
Automakers may not be the ones to blame.

The federal government decided not to overburden carmakers with multiple, costly tests from the start.

In the 1970s, the government already required emissions testing by automakers for each new model. So measurements for fuel economy were piggybacked on the emissions testing, where companies could utilize the same test equipment.

Current Testing Details
The emissions testing is based on a driving regimen conducted in labs. Because vehicles are stationary while being tested, they don't suffer any fuel-sapping aerodynamic drag, as they do on regular roads. During testing, the vehicles are on a dynamometer, where tires spin on rollers as a driver accelerates. It's sort of an automotive treadmill.

In testing, only one person—the driver—is inside the vehicle. There's no extra weight as there is when the car, minivan or SUV is carrying more people or cargo.

The test driver must accelerate, brake and idle the car according to a prescribed routine where the average city speed is about 20 miles an hour. Indeed, the city driving test cycle simulates an 11-mile, stop-and-go trip that takes 31 minutes and has 23 stops, the EPA says. About 18 percent of the time is spent idling, as if the car is at stoplights and in rush-hour traffic.

The testing is conducted in controlled conditions, with ambient temperature between 68 degrees Fahrenheit and 86 degrees Fahrenheit. There's no simulation of wintry weather or hot desert climes.

The highway portion—which the EPA also calls "non-city" because it incorporates travel on rural roads—is a 10-mile trip that averages 48 mph and has no stops, according to the EPA. The maximum speed is 60 mph, far below the 70- to 80-mph speed limits that drivers today encounter on interstates.

The impacts of fuel-using accessories such as air conditioning and heating are not measured, because this equipment is not turned on during the test. Even daytime running lights, which have been estimated to use up to a tenth of gallon of fuel, aren't considered.

The depletion of fuel isn't measured directly in this testing, either, and test vehicles don't use gasoline.

They operate on a special laboratory fuel called indolene clear. It's a test fuel that's free of the variability in quality that can be found in gasoline, and it has just eight carbon atoms.

As the vehicles run, emissions are collected from the tailpipes. Because the carbon content of the fuel is known, technicians calculate fuel economy by measuring the carbon compounds expelled in the exhaust.

Automakers conduct the tests, using pre-production prototypes of their upcoming new vehicles, the EPA said. You can bet they make sure that anything that would lessen fuel economy—such as underinflated tires, misaligned wheels and poorly tuned engine—are fixed before the test.

The EPA, which announces the top vehicle in fuel economy for each new model year, does its own testing in its own lab—to confirm the numbers from the automakers—on only 10 percent to 15 percent of new models.

Lab vs. Real World
Acknowledging that lab conditions don't reflect what drivers encounter in the real world, the EPA does allow the lab figures to be adjusted.

The laboratory city value is multiplied by 0.90 and the highway value is multiplied by 0.78 after an agency study several years ago reported drivers on the roads get 90 percent of the EPA's city figure and 78 percent of the highway figure.

But there are still plenty of drivers who complain they don't get anywhere near the official figures. This fact and the Bluewater Network petition have forced the EPA to look at updating these figures.

The EPA isn't going to change the underlying emission test procedure. But it is considering more aggressive adjustment figures for city and highway mileage in the hopes of putting out more realistic fuel economy numbers by the 2008 model year.

"The bottom line is in the real world, [fuel economy] is variable," said one official at General Motors Corp. "In general, all the different things that can affect fuel economy tend to make those numbers lower [than the EPA's]."

What Affects Fuel Economy?
Weather conditions, aerodynamic drag as a vehicle moves through the air, use of accessories, tire inflation and wheel alignment, the tuning of the engine, how much weight a vehicle is carrying, its speed and a driver's habits all play a role.

For instance, driving up a mountain road with a 7 percent grade can cut fuel economy by as much as 25 percent.

If tires aren't properly inflated, fuel economy can be cut by up to 6 percent, and misaligned wheels also decrease fuel economy, said one Ford engineer.

And drivers who manage their driving habits—accelerating gradually, driving smoothly and with care—can boost fuel economy as much as 20 percent compared to a more aggressive driving style, the EPA says.

Using the Rating
Is there any reason to look at the fuel economy numbers on the window sticker?

Yes. They can be a decent "relative measurement" for vehicle comparisons.

Since all automakers use the same procedure, the numbers can be compared from one kind of vehicle to another to help shoppers get a relative sense of which vehicles are more fuel-efficient.

But remember, there's no guarantee that a driver will reach an exact fuel economy number.

And don't forget the fine print. Every window sticker also states the range of fuel economy that's expected in a certain vehicle segment.

It's in smaller print on the label. On a 2006 Ford Explorer 4X4 with V8, for instance, the label states that the city driving range could be as low as 11 mpg and as high as 17 mpg. Meantime, the big, black number on the sticker that catches a shopper's eye says city mpg is 14.

The posted highway mileage for the same Explorer is 20 mpg. But the range, in the small print, says it could be as low as 17 mpg or as high as 23 mpg.

And to be fair, even the biggest fuel economy numbers come with a caveat printed right by them: "Actual mileage may vary with options, driving conditions, driving habits and vehicle's condition."

How to Get This Info
Readers can find official fuel mileage numbers at the government's Web site at www.fueleconomy.gov.

It's easy to compare vehicles. Once you're on the Web site, click "Find and Compare Cars." There, at the left, you will be able to select a list of vehicles by their market class, which is basically the broad sales categories they fit into, or their official EPA size class.

So, if you're shopping for an SUV, you can get a list of market SUVs that shows the highest-to-lowest fuel economy numbers, by model.

The EPA's fuel economy Web site also maintains mileage numbers for vehicles going back to the 1985 model year. So, it can be something of a reference for people buying used cars, except consumers need to remember that the archival fuel economy figures were derived from the vehicles when they were brand new.

An older vehicle's current condition and maintenance over the years has a lot to do with the kind of fuel mileage it gets today. In other words, don't expect that bargain-priced 1987 Cadillac Allante that's on the used-car lot to get the 16/24 mpg that it was rated at when it was a new car.

Consumer Reports' Figures
There is another good source of mpg information: It's the well-known Consumer Reports magazine.

Officials at CR provide their own combined city and highway fuel economy rating for each vehicle they've tested recently.

Unlike the government ratings, CR's figures are based on real-world experience.

The downside: CR doesn't have mpg figures for all models, the way the EPA does, and CR only provides a combined figure, not a breakdown of city and highway ratings.

See Consumer Reports' study on cars with the best and worst in overall economy.

Improving Performance of Your Car
Remember, you don't have to be a frustrated bystander as the needle dips to "empty." Even an older car can get better mileage with some help.

First, make sure your vehicle is in tip-top form, because a poorly tuned car can use more fuel than a vehicle that has been properly maintained.

How much more? According to AutoZone, an auto parts store, a new oxygen sensor alone can improve fuel economy by up to 15 percent.

As mentioned, tires need to be checked often for proper inflation, especially in areas where punishing blows from potholes can adversely affect tire pressure.

The nasty potholes can cause wheels to get out of alignment, too, which can reduce fuel economy by up to 10 percent.

Clean out your car and get rid of extra, unnecessary weight, such as sports equipment or heavy tools that you may not need to carry around with you. AutoZone estimated that an extra 200 pounds of weight can reduce a vehicle's fuel economy by 1 mile per gallon.

Drive more smoothly, avoiding jackrabbit starts that can waste fuel.

Look down the road as you drive, safely modulating your car's speed so you flow with traffic and don't have to stop, then accelerate, repeatedly. Aggressive driving is estimated to reduce fuel economy by up to 20 percent.

When you can, plan your travel to take advantage of times when roads are least congested. This will lessen your drive time.

If you're going to someplace new, get directions ahead of time so you don't waste time—and fuel—driving around trying to find your destination.

Ann Job is a freelance auto writer. [/quote]

• Quote

[Polish_Kris]

Don't Bash 4 speed trans as being the problem. Tecnically its a 8 speed if you count overdrives.

[post="51982"]<{POST_SNAPBACK}>[/post]

Ummm... Yeah...... And my 5 speed manual is actually a 10 speed....

[Newbiewar]

Ummm... Yeah...... And my 5 speed manual is actually a 10 speed....

[post="53098"]<{POST_SNAPBACK}>[/post]

:withstupid: maybe if you had a 4x4 with a low :P

[Teh Ricer Civic!]

i get EPA estimates with my car. :)

[Hudson]

i get EPA estimates with my car.  :)

I get BETTER THAN EPA estimates with my car.

[regfootball]

rear your new car and driver. the car out of all the cars that they tested in 2005 the one that got the best mpg on their testing was a CHEVY COBALT 27mpg. a) that only confirms what i suspected, which is that the ecotec coblt gets damn good real user mpg B) and, if 27mpg is the best they can get, they must drive their cars HARD. Edited December 6, 2005 by regfootball

[regfootball]

Complete wrong.
Overdrive means that in the top gear <top two for 6-speeds>, the engine is turning at a slower RPM then the drive shaft.  For example, for every .90 turns of the crankshaft the driveshaft makes one full turn. Generally, this is for cruising and the engine is near the lowest point on it's powerband.  This is how the Corvette acheives 28mpg at 60 because it loafs along at 1700rpm in 6th.

To pass a person, the transmission or driver must shift out of overdrive to bring the engine back into the heart of it's powerband. This is where you get your acceleration.

That the Ford 500 hunts for gears is troublesome to me. Is this the same 6-speed GM intends to use? I know GM and Ford were supposed to have a partnership on a 6-speed. I always hated how the Sable would hunt for gears when I would borrow my ex-BF's mother's car.

[post="52281"]<{POST_SNAPBACK}>[/post]

since i own a 500 i can chime in here. the 500's tranny does soemties seem to shift a bit much, but its been way overrated in road tests. the time that it hunts the most is in town at mid range speeds when you are on and off the gas a lot. on steeper hills it shifts a lot too, until you keep your gas steady and it finds the right gear then it holds like a bulldog. the tranny actually holds and keeps gears better than my old 99 SHO, however. my SHO used to short shift a lot. the 500 does stay pretty decisive about what gear its in as long you are not fking with the gas pedal. if you punch the pedal hard, it picks a gear and sticks with it and doesn't shift that much once at cruising speed. on the interstate at high speeds, it stays firmly planted in 6th or whatever and loafs along merrily at 1700-2200 rpm, depending on how fast you are going. 78 mph is like 2200 rpm i think, and it will accelerate easily up from that or kick down quite fast and find a great passing gear with some good snap. the first trip i took with the car over t'giving my last leg i got 26 mpg and that was with plenty of stopped in the ice storm interstate traffic. once it breaks in, i should see close to 30 on a good trip.

Sometimes I wish it would shift quicker, but I am made aware that there is a TSB out now on getting a tranny flash to improve the shifting...i might get that done. Shifts themselves are not 100% smooth, but still way better than almost any older Ford and not jerky or anything like that.

The big culprit is the lack of low end torque and power in the engine, and the powertrain buzziness at low speeds and taking off from a start. If the engine had more gusto, then no one would need to make any comments about the tranny. The tranny is simply doing its job with an underspecced engine. Its almost never that it picks a wrong gear, actually and it must be adaptive because since about 1500 miles, its been holding gears longer, too.

And even though it feels slow off the line, overall the car feels quick. above 30 mph the wholecar comes alive and has good kick down and that's when having the 6 speed really makes it shine. Any car that cracks 8 seconds is doing good. the thing revs great and never feels winded like the 3400 in my aztek does. i mean, there's NO comparison. the 3400 is more sedate in town and feels better from a stop but is quite breathless and busy on the highway in upper speeds.

The Duratec 35 or Yamaha v8 will solve those issues when they and the new 6 speed hit market in 12 to 18 months. the 3.0 duratec will be fine as a base model engine.

bottom line, the 6 speed is very useful, enhances the function of the car, and the overdrive gears help it get great mpg. Anything beyond 6 speeds wuld be useless IMHO, but Ford and GM will benefit greatly from their jointly developed 6 speed.

i bet the 6 speed teamed with the 3.6vvt will be a great combo in the Aura and other GM cars if the tight ass beanounters let them put it in. The Impala SS alone would benefit tremendously. i didn't much care for the 4 speed in the SS when i drove it. the 6 speed teamed to that small block or even the north star will be a great combo. Edited December 6, 2005 by regfootball

[Newbiewar]

Okay, I just glanced at the Solstice review in the pontiac section and it said fuel ecconomy of 20-28 20 on the street and 28 on the highway...

where as the miata is 24-28 24 on the street and 28 on the highway...

for most of GM models it seems their city mileage is below everyone elses where as the highway mileage is competative...

Why is there such a big gap on GM vehicles?

[post="51288"]<{POST_SNAPBACK}>[/post]

to add to this... Motor trend said after an 800 mile trip... the Miata averaged 21, and the Solstice averaged 23... so why do the epa reflect a good average on the pontiac(GM vehicle) but on other vehicles why arent the EPA records correct?

[haypops]

At saturnfans.com many owners seem to report poor gas milage to begin with followed by considerable improvements as the engine is broken in. The same posters report not observing such an increase in other cars they have owned.