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Chevrolet Malibu

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What is this discussion about? Chevrolet Malibu, Sedan

Messages Page 464 of 498

#4623 of 4972 by ronbo10

Oct 13, 2005 (6:40 am)

Replying to: scott1256 (Oct 12, 2005 3:09 pm)
Been a while since I've posted...busy with allot of stuff, including a newborn (it's been 4 months and I've still got 5 cigars in my mouth!). I've been wondering the same thing. The EPA has just put out their new 2006 Fuel Economy Guide (found at www.fueleconomy.gov), and here's how I understand the EPA process works: The manufacturer submits their estimates of what the EPA will find were the EPA to verify using their own tests. Reading the EPA's FAQ's, it turns out that the EPA verifies the manufacturers' submitted numbers (e.g.24/32) in only 10% of the cases, i.e. they test only 10% of all cars for which they publish results. I didn't know that. So with that in mind, I would suggest that GM has decided to take the hit marketing-wise by estimating the Malibu 4 cylinder down to 24/32 from the prior year's higher number. Perhaps GM doesn't want the Malibu 4 Cylinder to outperform the smaller Cobalt, which has the same power train (LS/LT models, anyway). I recall when the Cobalt was introduced that GM made a decision to accept lower mileage on the Cobalt due to the higher performance but "dragier" tires they fitted to the car. I doubt that the tires account for a 2 mpg difference, and I think a lot of folks were surprised that the Cobalt didn't do better with its EPA mileage rating. I'd venture to say that the 05 Malibu 4 Cylinder EPA numbers were valid, and one could expect similar results with the '06. Real world I've seen a few owners report close to 40 mpg highway with their 4 cylinder Malibu’s.
 
Of note, found in the description of testing in the 2006 Fuel Economy Guide, is that the EPA takes their lab results (they apparently use dynamometers vice actual road tests) and then apply a 15% reduction factor "to better reflect real world driving conditions for the average motorist" (their words). I don't know if this was the case with their 2005 Fuel Economy Guide, but I do recall last year the complaints from drivers claiming that the EPA published numbers were overly optimistic.
 
On the other hand, I would hazard a guess that the numbers that manufacturers submit might themselves be slightly conservative- the PR nightmare of manufacturers' submitted numbers not being repeatable in EPA tests is probably not something they wish to have to contemplate. For example, the Chevrolet Impala 3.9 is rated at 19/27, though I've already seen one owner write he's gotten 27.6 with a mix of 25/75 city/highway, this on a motor that's still being broken in. Hardly a scientific survey, I know. Still, I'll bet the real world numbers of the Impala 3.9 might turn out to be a bit better than the 19/27 published number would suggest.
 
Finally, I see some revisions in the other direction for '06. For example, Buick's Lacrosse (3800) had an EPA rating of 20/29 for 2005, but for 2006 they show 20/30. Has the car changed year over year? Probably not. But 30 mpg is a psychologically important number that is nice to be able to show on the window sticker. Perhaps there is a certain amount of politicking that goes on between manufacturer and the EPA, though they'd both probably bristle at the suggestion.
 
Sorry for the long post!

#4624 of 4972 Thanks for all the info. [ronbo10] by scott1256

Oct 13, 2005 (8:01 am)

Replying to: ronbo10 (Oct 13, 2005 6:40 am)
You explained the EPA testing and manufacturer fuel economy estimates quite clearly. A lot of these details I never heard before.
 
I looked closely at the specs of the 2006 and 2005 Malibus and could find no changes. It makes sense Chev would not want the Malibu to be more economical than the Cobalt.
 
The EPA estimates for hybrid vehicles have been shown by CU to be completely invalid - as much as 40% too high.

#4625 of 4972 Re: EPA mileage rating [scott1256] by micweb

Oct 13, 2005 (10:21 am)

Replying to: scott1256 (Oct 12, 2005 3:09 pm)
You said:
 
on the 2006 Malibu w/4 cylinder has changed from 2005.
  
2005 was 24/35
2006 now 24/32
  
Is there a new final drive ratio, transmission change or engine modification?
  
Or did EPA change their test?
 
Chevy cleaned up the appalling emissions on the '05 Malibu and the "highway" mileage took a slight hit as a result. I have long been considering a Malibu 4-banger but did not like the "minimum legal standard" emissions on the engine in that car - it got a "3" out of 10 rating on the EPA pollution score. The version of this year is up to a "6" so it is much cleaner, and matches the pollution from the Cobalt and Pontiac G6 versions of this engine.
 
BTW, the Pontiac G6 gets the 2.4 version, which loses 1 mpg on the city rating but picks up 2 mpg on the highway end of things - despite being bigger. I supect they use a lower final overall gear ratio to drop the rpm a bit, the 2.4 has more torque. Although I would prefer a Chevy, I will look at the Pontiac to see what it's like - it's a bargain at $18k, and may - may - have sportier handling since it is from the Pontiac line.
 
Overall mileage on the 4 banger still beats the base 6 cylinder, and handling should still be better - Consumer Reports liked the handling on the 4 cylinder version slightly better than on the 6 cylinder version. In the near future GM will probably phase in the variable valve timing version of the 6, which might further narrow the mileage gap.
 
BTW, I find Consumer Reports a better guide to actual mileage. Since their driving is heavily biased towards city cycles, it is overall much lower than the EPA scores, but their 150 mile trip and pure highway cycle readings are more in line with what I see on my freeway commute.
 
Finally, the 2.4 used in the Pontiac G6 runs on regular, vs. the premium recommended for this version of the engine in the HHR and Cobalt SS (non-supercharged edition). It would be interesting if the HP and torque figures given for the G6 version are based on using regular, the HHR based on using premium, and otherwise there are no differences - in otherwords, change your gas and you'll change your performance.

#4626 of 4972 Re: EPA mileage rating [micweb] by ronbo10

Oct 13, 2005 (2:21 pm)

Replying to: micweb (Oct 13, 2005 10:21 am)
Very interesting- I hadn't even considered that the state of tune of the 2005 Malibu was significantly dirtier than the 2006. It's unfortunate that cleaner exhaust can be less efficient- sort of contrary to intuition: You might think that cleaner exhaust would mean that more energy is being generated by the combustion, with fewer pollutants as a result. Wishful thinking, I guess.
 
With respect to the 2.4 liter's better mileage, I wonder if the the variable nature of it's cam timing allows it to run more efficiently at cruise (and for that matter, is the cam phasing sophisticated enough that it takes into account more variables than simply RPM- e.g. it's ideal phasing at cruise, 2500 rpm might be different than 2500 rpm under acceleration).
 
I hope you're right about the Malibu getting the V6 with VVT in the near future. It sounds like a superior engine, good as the current Malibu's V6 is. Interestingly, the Malibu's V6 has almost nothing in common with the new generation VVT V-6's (think I read it shared only valve guides!).
 
I wonder if much advantage is gained (with respect to variable valve timing design) with having separate camshafts for intake and exhaust, as is the case with DOHC engines. With OHV engines having a common camshaft for both intake and exhaust, by design they must vary together rather than independently. I've seen several journalists describe the VVT system in the new generation GM OHV V-6's as "rudimentary". Not sure why they should describe it in these terms. Also of note is that Ford's Duratec 2.3 liter 4 cylinder, as well as their Duratec 3.0 V-6 have only variable intake valve timing. Perhaps little is to be gained by varying the exhaust valve timing. Or perhaps it is only a question of cost, and/or cost/benefit ratio.

#4627 of 4972 Re: EPA mileage rating [ronbo10] by micweb

Oct 13, 2005 (4:17 pm)

Replying to: ronbo10 (Oct 13, 2005 2:21 pm)
Whether to vary intake only, or both intake and exhaust valves is a topic I don't know a lot about...but I have heard that most of the benefit of variable valve timing is being able to vary the intake valves, and the next major benefit is being able to vary the shift continuously instead of in "bumps" as in the original Honda system. Finally there is the issue of varying valve overlap, which you wouldn't get with a system that shifts intake and exhaust valves at the same time by the same amount.
 
I think you have to look at the results. The 2.4 with vvt on the HHR is rated at the same mpg as the 2.2 on the HHR without vvt; the 2.4 on the G6 vs the 2.2 on the 'bu; the extras horsepower with similar mileage on the Mazda3's vs. the Focus. This stuff seems to work, if you can get past the extra cost of the engine design (which is why the Focus, an "ordinary" economy car, doesn't get it, but the "premium" Mazda3 does).

#4628 of 4972 EPA mileage rating: micweb and ronbo10 by scott1256

Oct 14, 2005 (7:11 am)

Replying to: micweb (Oct 13, 2005 10:21 am)
Thanks to you both for your research.
 
Maybe the hiway mileage change is a combination of these two factors. Chevy engineers might think "Hey, if we lose 1 mpg on the Malibu hiway rating due to emissions changes let's take 2 more off so the hiway mpg is below the Cobalt."

#4629 of 4972 Rear drum removal by kduong

Oct 14, 2005 (9:15 am)

Hi, can anyone please tell me how to remove the rear drum on my 98 Malibu 2.4L?
Thanks in advance.

#4630 of 4972 2005 Malibu LS brakes by dwstechie

Oct 14, 2005 (1:45 pm)

My new Malibu ran fine for the first 1672 miles until yesterday. After driving about 40 miles from home to my daughter's house and parking for about 20 minutes, I restarted the car, drove a block to the first stop sign, and felt my brake pedal slowly go all the way to the floor as I (fortunately) managed to stop. I drove my son-in-law about a mile to his work, and decided to park the car after the brakes got more mushy. There were no error lights of any kind on the dash. I called Chevy Roadside Assistance, and got the car towed to the nearest Chevy dealer a couple of miles away (not the dealer where I bought the car), then caught a ride to work on the local dealer shuttle. Much to my surprise, they found nothing wrong with car! After a road test and check for computer error codes, they could not reproduce the problem. I told them I would not drive the car until they found the cause of the soft brake pedal, and my wife drove over to give me a ride home.
 
This morning I drove to work in my trusty Silverado, and decided to call AAA to tow the car from the local (huge) dealer to the (very small, owner knows me by my first name) dealer where I bought the car. I retrieved my keys from the local dealer service advisor, and while I was calling AAA, started up the car, and slowly pressed the brake pedal all the way to the floor! While I was waiting for the tow truck, the service manager came by and told me that he had driven the car yesterday for 2 miles and had not noticed any brake problems. When I told him that I had just felt the brake pedal go down to the floorboard, he told me that if you press the brake pedal hard enough, it will always do that!
Since I had already determined that I was NEVER getting any vehicle more advanced that a skateboard serviced by this dealer, I decided to just walk away before I broke something.
 
Anyway, my Malibu has been towed to the original dealer, and since I'll be in Las Vegas for a conference all next week, they'll have plenty of time to fix it.
 
BTW, I haven't even made the first payment yet, and I really love this car!.
 
Oh well, down, and to go....
 
Thank you, I feel better know.

#4631 of 4972 Re: 2005 Malibu LS brakes [dwstechie] by micweb

Oct 14, 2005 (2:29 pm)

Replying to: dwstechie (Oct 14, 2005 1:45 pm)
I had a similar problem with a Honda CR-V; it occured at about 3 mph when I mashed the brake pedal to stop for a pedestrian who suddenly entered the crosswalk. The pedal just went to the floor, while the car barely stopped.
 
The dealer hasn't been able to replicate the problem, and it hasn't recurred, but a friend told me that the ABS systems can cause brakes to act in unexpected ways, particularly at lower speeds. Anyway, I doubt it means the car is a lemon, but keep pressing until you get a proper explanation. The Honda dealer told me the same thing, that the pedal is supposed to go to the floor if you keep pushing it, but it only happened that one time and hasn't happened to me on other ABS equipped cars. I don't think the service techs have gotten a hand on this little problem, which is apparently not unique to Chevy.

#4632 of 4972 2006 Malibu 2.2 liter test mpg by ronbo10

Oct 24, 2005 (11:40 am)

I read today a reviewer's road test of an '06 Malibu with the ecotec (epinions- not technically a forum), and the reviewer gave it lots of kudos. In spite of the EPA mileage rating of 24/32, he stated that he was getting between 36 to 41 on the highway (probably according to the Driver Information Center, though reviewer didn't specify), and 31 to 32.5 on twisty roads. Overall he was very impressed, with the only real criticism being with the stock Bridgestone tires.
 
BTW, I noticed that the Ecotec Malibu comes stock with disc/drums front/rear, but ordering it with ABS gives it 4 wheel disc brakes, which is a $440 option, if I recall.

Messages Page 464 of 498

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