Removing Counter weight
03-09-2015, 02:52 PM
#21
Simplewon, when you drive the tires are constantly picking up energy as they roll over the graininess of the pavement surface. The back wheels will transmit vibration forward and the front wheels will send vibration rearward. So, looking at the vibration from the rear wheels it will take two paths as it travels forward, one through the frame and floor pan and a second path up and over the roof. The frequency of these vibrations is the same, but the longer path over the roof and down the windshield and A pillars will cause the vibration to arrive slightly later. As these two impulses collide they will effectively cancel each other out.
Roadsters and convertibles tend to only send the road vibrations along one path. At certain speeds the combined vibrations from the front and rear will form a harmonic wave that will be felt inside the car. The weights you see are suspended in a flexible medium. Any vibrations in the vicinity also set the weight to vibrating, however the isolation of the weight means that it vibrates slightly out of sync and will also cancel out any harmonics that are building up.
I’ve been reading this forum for over 10 years and I’m continually amazed that people call the smaller similar device inside the coupe’s hatch a “counter weight”. This is not its purpose; it is also a vibration damper to take care of vibrations that build in the hatch.
Roadsters and convertibles tend to only send the road vibrations along one path. At certain speeds the combined vibrations from the front and rear will form a harmonic wave that will be felt inside the car. The weights you see are suspended in a flexible medium. Any vibrations in the vicinity also set the weight to vibrating, however the isolation of the weight means that it vibrates slightly out of sync and will also cancel out any harmonics that are building up.
I’ve been reading this forum for over 10 years and I’m continually amazed that people call the smaller similar device inside the coupe’s hatch a “counter weight”. This is not its purpose; it is also a vibration damper to take care of vibrations that build in the hatch.
03-09-2015, 03:19 PM
#23
Registered User
DeusExmaxima, the weights referenced in this thread are exclusive to the Roadster.
Yes Bmccann, products like Dynamat do add an engineered mass capable of absorbing vibrations etc. and I don’t mean to dismiss all the inherent science, but it isn’t meant for the same the same problem.
My dad had no formal engineering education, in fact he didn’t even finish high school. However he had an inherent ability to problem solve. Most of his work entailed fabricating and machining components for some of the most demanding antique car restorers. The odd time he would machine up an engine part or whatnot for someone restoring a rare old Brough Superior, Harley or Indian to be a driver. These things would buzz and vibrate the handlebars like mad. Owners who didn’t want to change any original parts would come to my dad for a solution. He would fill the last ten inches or so of the handlebars with liquid rubber and suspend heavy fishing weights in the rubber as it cured to a solid. The bars would vibrate, which would set the weights vibrating. The slight time delay of the vibrations passing through the rubber meant that weights (having the same frequency but having a small time delay) could perfectly cancel the vibrations in the handlebars.
Yes Bmccann, products like Dynamat do add an engineered mass capable of absorbing vibrations etc. and I don’t mean to dismiss all the inherent science, but it isn’t meant for the same the same problem.
My dad had no formal engineering education, in fact he didn’t even finish high school. However he had an inherent ability to problem solve. Most of his work entailed fabricating and machining components for some of the most demanding antique car restorers. The odd time he would machine up an engine part or whatnot for someone restoring a rare old Brough Superior, Harley or Indian to be a driver. These things would buzz and vibrate the handlebars like mad. Owners who didn’t want to change any original parts would come to my dad for a solution. He would fill the last ten inches or so of the handlebars with liquid rubber and suspend heavy fishing weights in the rubber as it cured to a solid. The bars would vibrate, which would set the weights vibrating. The slight time delay of the vibrations passing through the rubber meant that weights (having the same frequency but having a small time delay) could perfectly cancel the vibrations in the handlebars.
03-10-2015, 09:17 AM
#27
350Z/370Z Tech Moderator
MY350Z.COM
MY350Z.COM
DeusExmaxima, the weights referenced in this thread are exclusive to the Roadster.
Yes Bmccann, products like Dynamat do add an engineered mass capable of absorbing vibrations etc. and I don’t mean to dismiss all the inherent science, but it isn’t meant for the same the same problem.
My dad had no formal engineering education, in fact he didn’t even finish high school. However he had an inherent ability to problem solve. Most of his work entailed fabricating and machining components for some of the most demanding antique car restorers. The odd time he would machine up an engine part or whatnot for someone restoring a rare old Brough Superior, Harley or Indian to be a driver. These things would buzz and vibrate the handlebars like mad. Owners who didn’t want to change any original parts would come to my dad for a solution. He would fill the last ten inches or so of the handlebars with liquid rubber and suspend heavy fishing weights in the rubber as it cured to a solid. The bars would vibrate, which would set the weights vibrating. The slight time delay of the vibrations passing through the rubber meant that weights (having the same frequency but having a small time delay) could perfectly cancel the vibrations in the handlebars.
Yes Bmccann, products like Dynamat do add an engineered mass capable of absorbing vibrations etc. and I don’t mean to dismiss all the inherent science, but it isn’t meant for the same the same problem.
My dad had no formal engineering education, in fact he didn’t even finish high school. However he had an inherent ability to problem solve. Most of his work entailed fabricating and machining components for some of the most demanding antique car restorers. The odd time he would machine up an engine part or whatnot for someone restoring a rare old Brough Superior, Harley or Indian to be a driver. These things would buzz and vibrate the handlebars like mad. Owners who didn’t want to change any original parts would come to my dad for a solution. He would fill the last ten inches or so of the handlebars with liquid rubber and suspend heavy fishing weights in the rubber as it cured to a solid. The bars would vibrate, which would set the weights vibrating. The slight time delay of the vibrations passing through the rubber meant that weights (having the same frequency but having a small time delay) could perfectly cancel the vibrations in the handlebars.
The weight/mass of the dampener is designed to counter the inherent chassis' harmonic vibration and is an integral part of the Nissan design.
There are actually three weights on the Z serving the same purpose (at least there are on the Z34R, believe it is carried over from Z33) - one front on the structural support, one rear in the trunk, and one on the transmission x-member (I believe... It's mid-ship somewhere.)
While it isn't a structural component per se, removal of same *MIGHT* lead to additional NVH (noise, vibration, harshness) - something a factory suspended, street driven Z doesn't need.
My take, trust Nissan engineering. Is the weight savings of removing it worth the possible downside of incurring discomfort while driving on the street? Only you can prevent forest....er, I mean, only you can make that judgement.
FWIW, the weight you take out is negligible unless you are completely stripping and gutting for track use. If it's a track car, sure, throw it out but be careful that scrutineers at the next regional you run don't foul you out for illegal weight removal for your class. Scales at impound do not lie.
Edit: Dayam, just noticed the origin date of this thread...... hahahahahaha. Oh well, add it to the Roadster FAQ!
Last edited by MicVelo; 03-10-2015 at 09:20 AM.
03-10-2015, 10:33 AM
#28
New Member
03-10-2015, 10:48 AM
#30
New Member
03-10-2015, 01:00 PM
#31
350Z/370Z Tech Moderator
MY350Z.COM
MY350Z.COM
As tempted as I am to chime in on this one, I'm going to TRY to be a gentleman.
But I like your style, Syner!
To stay on topic, I think Nissan sub-contracted with Hitachi on stuff for the Z.
And with that, this thread PROBABLY SHOULD DIE as I don't see it going much lower than the gutter it's in.
But I like your style, Syner!
To stay on topic, I think Nissan sub-contracted with Hitachi on stuff for the Z.
And with that, this thread PROBABLY SHOULD DIE as I don't see it going much lower than the gutter it's in.
03-10-2015, 02:11 PM
#34
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C'mon guys back on track here. Iv been away for a year or so and came back for a bit of nostalgia .
I have roadster and while installing a HKS S/C i had to remove said swinging thing to enable the fitting of the intercooler ducting. It was pretty bloody heavy as i recall . Was driving home one night and at about 130 kph the front wanted to lift. It was dark and there were lots of strange lights in the sky.
But since installation the car drives fine, no vibes at all. I even tracked it a few times at Eastern Creek. Sweet.
remember to floss!!!!
I have roadster and while installing a HKS S/C i had to remove said swinging thing to enable the fitting of the intercooler ducting. It was pretty bloody heavy as i recall . Was driving home one night and at about 130 kph the front wanted to lift. It was dark and there were lots of strange lights in the sky.
But since installation the car drives fine, no vibes at all. I even tracked it a few times at Eastern Creek. Sweet.
remember to floss!!!!
Last edited by pez1111; 03-10-2015 at 02:12 PM.
03-11-2015, 05:59 AM
#35
New Member
04-28-2021, 11:58 PM
#37
New Member
C'mon guys back on track here. Iv been away for a year or so and came back for a bit of nostalgia .
I have roadster and while installing a HKS S/C i had to remove said swinging thing to enable the fitting of the intercooler ducting. It was pretty bloody heavy as i recall . Was driving home one night and at about 130 kph the front wanted to lift. It was dark and there were lots of strange lights in the sky.
But since installation the car drives fine, no vibes at all. I even tracked it a few times at Eastern Creek. Sweet.
remember to floss!!!!
I have roadster and while installing a HKS S/C i had to remove said swinging thing to enable the fitting of the intercooler ducting. It was pretty bloody heavy as i recall . Was driving home one night and at about 130 kph the front wanted to lift. It was dark and there were lots of strange lights in the sky.
But since installation the car drives fine, no vibes at all. I even tracked it a few times at Eastern Creek. Sweet.
remember to floss!!!!
Yeah, that rotating weight put a hole in bottom of a 2row aluminum radiator. Had to take it out for the new one.
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