NVH Chief Concern For GM Engineers On ’08 Chevrolet Malibu

[Perian]

Link: http://wardsauto.com/ar/nvh_chief_concern/

By James M. Amend - WardsAuto

MILFORD, MI – Ask a General Motors Corp. engineer which aspect of the redesigned ’08 Chevrolet Malibu sedan really gets his blood pumping and odds are he’ll say it’s the lack of noise, vibration and harshness.

Sexier attributes can be found on the new model, such as a lively 252-hp 3.6L DOHC V-6 with variable valve timing mated to a fuel-efficient, 6-speed automatic transmission – a combination GM first used on the award-winning ’07 Saturn Aura.

But GM clearly has given extra attention to making the ’08 Malibu’s cabin quieter and its ride more refined, which portends a pleasant surprise to consumers cross-shopping the Toyota Camry and Honda Accord, says Mike Meloeny, chief engineer for GM midsize vehicles.

“We’re real proud of what we accomplished with NVH because it so important to the segment, and it is such an extremely and brutally competitive segment,” Meloeny says during a recent media backgrounder here for the ’08 Malibu.

“People in the midsize segment want an upscale-feeling car, but they don’t want to pay for it,” he adds.

To meet this challenge, the decision was made to dampen the Malibu’s mechanics and provide the sort of atmosphere car buyers expect in a larger, more-expensive vehicle.

Engineers started with the chassis, strengthening and lengthening the same Epsilon-based global midsize vehicle architecture that underpins the Aura and Pontiac G6.

Exterior design forgoes generic styling that typifies midsize segment.
“We got the engine out in front, instead of in your lap, but we also stiffened the engine cradle so it wouldn’t twist or resonate with the exhaust,” Meloeny says.

The auto maker used liquid spray-on sound deadener, laminated steel and composite wheel liners to further deaden noise from the chassis.

Engineers also concentrated on dampening noise from the Malibu’s 4-cyl. engine, a 2.4L DOHC setup that delivers 169 hp and is a lock to be the car’s most popular mill. Because GM’s 4-bangers are not known for their pleasant acoustics, engineers added nine tuners and resonators.

“They’re all geared to knock out the nodals in the induction system,” Meloeny says.

GM mates the 4-cyl. to a familiar 4-speed transmission, for now. But in a segment-first, the auto maker will provide a 6-speed gearbox to the engine by the end of first-quarter 2008.

Other noise-reduction targets included the vehicle pillars, where GM added extra baffles, and also the rocker panels, which received baffles as well as a sound-dampening coating. Engineers even borrowed the laminated “quiet glass” found on the Aura.

GM’s efforts to make the new Chevy Malibu seem more expensive – the highest-trim-level LTZ version will start in the upper-$20,000, GM product chief Bob Lutz says unofficially – didn’t end with NVH.

Article continues at link.

[VCDJ]

I just wish that gm made that v-6, like in a new accord where it can work or 3,4 or 6 cylinders. If gm put standard 6-speed on this car it would be very good. Imagine what reporters would say. 6-speed is standard on every malibu that would be great news. I bealive gm would be able to sell more malibu then. It is good that gm is making their cars quieter. Most people think if car is noise, that it is poor quality.

[69Firebird400]

Sounds like they did their homework. Will these improvements make their way to the Aura as well, since it's ostensibly higher on the food chain?

On a side note, I can't imagine having to look at that orange and black interior every day for five years. I don't like the similar scheme in the 4LT Corvettes and I don't like it here.

[1487]

the Malibu could probably be within 1mpg of the Accord's mileage if they used the electronic steering but as we all know that system has come under lots of criticism.

The 6 speed is great news, but most people dont care. I mean the Accord and Camry only have one more gear iin their four cylinder cars and most people only know their car has an "auto" and could care less about how many gears the car has. Interestingly enough the Malibu matches the mileage of Accord and Camry 4s in spite of having more weight and less gears. The 6 speed should be enough to make the Malibu as fast as the Accord and slightly more efficient than Camry.

[CamaroCrazy]

Originally Posted by VCDJ

If gm put standard 6-speed on this car it would be very good. Imagine what reporters would say. 6-speed is standard on every malibu that would be great news. I bealive gm would be able to sell more malibu then.

I *hope* this is just a matter of ramping up 6 speed production, achieving economies of scale, and getting the quality bugs out. Really, how much more money can a 6 speed auto cost versus a 4 speed auto? The 4 speed has paid for itself 10 times over, let's see some investment and move on. But yes, a standard 6 speed in the Malibu regardless of engine choice would be a great selling point.

[JBsZ06]

that new Malibu V6 is a very nice vehicle.

Glad to hear the NVH has been a top priority.

I recently drove an altima sedan and was surprised at the amount of road noise coming through the chassis. I would guess it was tire roar but kept thinking for the few dollars more it would have been smart money spent..

I could never own a sports sedan that was that noisy. I was more than disappointed.

[windvale]

Interesting - hopefully not tell-tale - approach to reducing NVH. Instead of actually eliminating the source of the NVH (which Toyota concentrated on with the initial Lexus), GM is allowing the NVH to be produced...but is concentrating on concealing it with sound-deadening materials. It's sort of like not going on a diet and losing weight, but rather just developing new clothes that hide your fat...

[VCDJ]

Originally Posted by CamaroCrazy

I *hope* this is just a matter of ramping up 6 speed production, achieving economies of scale, and getting the quality bugs out. Really, how much more money can a 6 speed auto cost versus a 4 speed auto? The 4 speed has paid for itself 10 times over, let's see some investment and move on. But yes, a standard 6 speed in the Malibu regardless of engine choice would be a great selling point.

I agree with you

[camaro_freak]

Originally Posted by windvale

Interesting - hopefully not tell-tale - approach to reducing NVH. Instead of actually eliminating the source of the NVH (which Toyota concentrated on with the initial Lexus), GM is allowing the NVH to be produced...but is concentrating on concealing it with sound-deadening materials. It's sort of like not going on a diet and losing weight, but rather just developing new clothes that hide your fat...

good points

all that noise reduction stuff adds weight... weight that the car doesn't need that could be improving fuel economy

[jkennedy293]

Originally Posted by CamaroCrazy

I *hope* this is just a matter of ramping up 6 speed production, achieving economies of scale, and getting the quality bugs out. Really, how much more money can a 6 speed auto cost versus a 4 speed auto? The 4 speed has paid for itself 10 times over, let's see some investment and move on. But yes, a standard 6 speed in the Malibu regardless of engine choice would be a great selling point.

It may be a matter of getting that particular drivetrain certified. I don't believe GM has any other vehicles with a 2.4 and 6-speed auto meshed together. I would rather they take the extra time and make sure its right, than to just throw it in the car and hope for the best.

[BigThreeForever]

For me, personally, NVH is an absolutely crucial aspect of vehicle performance. It makes a world of difference to travel in a hushed environment, free of buzzes, rattles and vibration. Excellent NVH control adds the equivalent of thousands of dollars in value when it comes to how buyers perceive a product.

Back in the glorious heyday of the American body-on-frame full-size automobile, ride quality and NVH were paramount considerations. Isolation was the prime goal, a goal that eventually became deeply unfashionable when the media somehow managed to convince the public that every car needed to handle and respond in the manner of a BMW.


It was not just old-school cars, either. When GM shifted its C-bodies to a front-drive, unit-body platform for the 1985 model year, it did a truly commendable job in making the downsized '85 luxury cars quiet and free from NVH isues. It was a real advantage American cars had over their competition at that time.

Yet, since then, I feel that NVH has been put on the back burner - and perhaps especially guilty are Chrysler and Ford (the Panthers being honorable exceptions).

It is heartening, then, that GM has once again grasped the relevance of smoothness and quiet, and especially so in a high-volume moderately-priced sedan. I look forward to sampling the fruits of the engineers' labors.

[K-1]

Originally Posted by windvale

Interesting - hopefully not tell-tale - approach to reducing NVH. Instead of actually eliminating the source of the NVH (which Toyota concentrated on with the initial Lexus), GM is allowing the NVH to be produced...but is concentrating on concealing it with sound-deadening materials. It's sort of like not going on a diet and losing weight, but rather just developing new clothes that hide your fat...

So, if I open the hood of a Camry while it's running, it'll be as quiet as in the cabin? Keep dreaming. Toyota piles on the sound deadening material too. The only way to eliminate the source of NVH is to eliminate the engine. Last I checked, Toyota still uses engines.

[drew770]

Originally Posted by windvale

Interesting - hopefully not tell-tale - approach to reducing NVH. Instead of actually eliminating the source of the NVH (which Toyota concentrated on with the initial Lexus), GM is allowing the NVH to be produced...but is concentrating on concealing it with sound-deadening materials. It's sort of like not going on a diet and losing weight, but rather just developing new clothes that hide your fat...

I agree with you but unlike Toyota during the Lexus development, GM didn't have the money nor the time to re-engineer the Malibu EPI platform to that extent.
Granted an automaker shouldn't make excuses but it was just reality at the time.
Now, since weight and NVH are issues on EPI then GM should make sure they take care of those issues before the EPII debuts.

[fastball]

Originally Posted by windvale

Interesting - hopefully not tell-tale - approach to reducing NVH. Instead of actually eliminating the source of the NVH (which Toyota concentrated on with the initial Lexus), GM is allowing the NVH to be produced...but is concentrating on concealing it with sound-deadening materials. It's sort of like not going on a diet and losing weight, but rather just developing new clothes that hide your fat...

I agree. The source of the noise needs to be engineered out, and that's where engineers make their money. Not by spraying on insta-foam insulation.

The note about the 4 cylinder really irks me. GM admits the engine is noisy, so they came up with what is essentially nothing more than a band aid for a bullet wound.

Listen to the engines in any Honda or Toyota. With the hood open. Put your ear right on the valve cover. The engine itself is smooth and yes, like a sewing machine. You will see hardly any vibration.

Do the same with any GM motor. Granted, it's not like a '72 Impala with a 350 rumbling about, but it's still not close to the near silent operation of Honda and Toyota engines.

[espo19047]

Originally Posted by windvale

Interesting - hopefully not tell-tale - approach to reducing NVH. Instead of actually eliminating the source of the NVH (which Toyota concentrated on with the initial Lexus), GM is allowing the NVH to be produced...but is concentrating on concealing it with sound-deadening materials. It's sort of like not going on a diet and losing weight, but rather just developing new clothes that hide your fat...

It is already a plus that you have to compare the much more expensive Lexus to make your point. Who cares how as long as it is quiet and feels and rides like a car that cost 10k more.