Walking around our G35 Sport after Wednesday's antics in the wet I noticed something strange through the wheelwell opening.
Closer inspection proved this something was visible from both sides (first image is the right side, this is the left side). In this detail shot you can see exactly what I'm talking about: dead weight -- about 1.4 pounds (22.16 ounces) of it per side. Bolted to both of the G35's mufflers is the below weight:
This weight is a physical manifestation of the efforts manufacturers go to to make modern cars smooth and quiet. Look under almost any modern car and you'll find similar weights hanging there on the differential, the transmission or, in this case, the exhaust. They exist to damp rogue resonances and vibrations produced by the powertrain.
I know why they're there, but as an enthusiast I can't help but hate the idea that most cars are packing around this extra ground-hugging mass for the sake of civility. And here it's painfully visible from above. But hey, I guess there's an additional benefit: Reducing dangerous horsepower.
Josh Jacquot, Senior road test editor @ 18,479 miles
mrryte says:
07:19 AM, 02/22/08
If this dead weight WASN'T there, people would be complaining nonstop about the very same vibrations that this piece is dampening....
It may not look pretty; but hey it works and most people won't even notice it.
jdub53084 says:
07:59 AM, 02/22/08
mrryte is right, those weights, also known as "boom" weights are very important to damping the NVH oddities that can come from a car. Yes, they are ugly though...
ahightower says:
08:01 AM, 02/22/08
The Geo Metro my wife had back in high school could have used a few more of those...
firstwagon says:
08:28 AM, 02/22/08
Just curious, if you take them all off, do you know any difference in NVH?
mrnoodley says:
09:16 AM, 02/22/08
How exactly does an extra 3lbs attached to the exhaust "reduce horsepower"?
Sure, it minutely affects your power/weight ratio, but reduce horsepower? I think not.
bgw says:
09:18 AM, 02/22/08
Hold on there - these weights do NOT reduce horsepower, dangerous or elsewise. They serve to reduce NVH and as an aside they increase mass. But they do not in any way, shape or form reduce horsepower.
They do, however, reduce the hp/kg ratio, making the car perform less than a car with a higher hp/kg ratio. But any change these little weights will have, will be very slight, not noticeable to the driver.
Reduce horsepower. Ha, that's a good one!
jriz says:
09:39 AM, 02/22/08
"The Geo Metro my wife had back in high school could have used a few more of those... "
A Geo Metro could basically be used as one of those weights.
And from one Canadian to another, a big welcome to our new friend from the Rock.
siblur says:
10:05 AM, 02/22/08
When I first saw the photos, I thought they were safety devices. I remember seeing something very similar on a Saturn SL2 (at least I'm pretty sure that's what it was). The salesperson told me the car had wedges that were designed to slam into, and stop, the tires in the event of a collision. I assume this was to minimize how far the car slid after being hit, or to keep the car from being pushed into oncoming traffic. Coulda sworn that's what I was looking at on the Infiniti. Sounds a little dumb, I know...now I know something new!
banhugh says:
03:13 PM, 02/22/08
if there is some relative motion of the attached mass to its the mounting base, then it's a tuned mass damper.
ittazvic says:
01:24 PM, 02/25/08
I wonder how much gas is used each day accelerating these weights on all the cars produced each year.
jederino says:
06:06 PM, 03/ 6/08
To be fair, autocompanies should be required to disclose the total mass of the NVH weights included on their cars, so that driving enthusiasts will have an incentive to drop the identical weight from their bellies. This simple procedure would also lower the center of gravity. On the other hand, it could lead to longer life of enthusiast drivers and thereby contribute to overall global warming...