Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical chat

Reply
 
LinkBack Thread Tools Display Modes
Old 11-13-2005, 03:16 PM   #1
Registered User
 
Join Date: Jul 2005
Location: boulder, co
Posts: 1
mount vibration?

i've been round and round on the forums reading about boxster vibrations such as the dual-mass flywheel vibration at 3000 rpm and the ďoil valve" at 2000. diagnosing sounds on the internet is a ridiculous game i admit; however i'm hoping i can pick up a couple parts and do this fix myself.

whatís inside the dual mass flywheel or is it two separate metal places separated by a rubber adapter? what, per se, makes the flywheel on the 986 a dual-mass type?

it seems curious that i havenít heard anyone say they eliminated the 3000 rpm vibration by exchanging in an aftermarket light flywheel. it seems such an approach would work as itís a simpler part; but, i suppose it stands to reason that a new dual mass flywheel would actually have less vibration than a non dual mass aftermarket flywheel.

initially my vibrations seemed related to rpm only - a resonance at 2000 and 3000 rpm. particularly when the engine was cold. but then i discovered that by veering left i could intensify it, and by veering right eliminate it almost entirely. maybe it's one of the side engine mounts? how do i inspect the side mounts? must they be removed for inspection?

thanks!

farmboy is offline   Reply With Quote
Old 11-13-2005, 03:39 PM   #2
Registered User
 
Join Date: Jul 2005
Location: Austin, TX
Posts: 22
Sounds like your engine or exhaust system is barely hitting something......

Quote:
Originally Posted by farmboy
but then i discovered that by veering left i could intensify it, and by veering right eliminate it almost entirely.
Due to the difference in sound when you veer.
__________________
Best regards,
Gordie

'04 Boxster S 550 SE
grease is offline   Reply With Quote
Old 11-13-2005, 03:52 PM   #3
Registered User
 
deliriousga's Avatar
 
Join Date: Jun 2005
Location: USA!!
Posts: 1,159
Quote:
Originally Posted by farmboy
whatís inside the dual mass flywheel or is it two separate metal places separated by a rubber adapter? what, per se, makes the flywheel on the 986 a dual-mass type?

it seems curious that i havenít heard anyone say they eliminated the 3000 rpm vibration by exchanging in an aftermarket light flywheel. it seems such an approach would work as itís a simpler part; but, i suppose it stands to reason that a new dual mass flywheel would actually have less vibration than a non dual mass aftermarket flywheel.
The dual mass flywheel is just a heavier weight than a single mass. I'm not sure if there is a different composition inside. It is supposed to make the clutch engage a little slower so the car does not jerk as much and also lowers gearbox noise.

A new dual mass flywheel should have less vibration and noise than a lightweight one while the lightweight flywheel allows the engine to spin the gears more easily for quicker starts, but does not actually "add" power (hp) to the car. The lightweight flywheel is more fun to drive with until you hit traffic, then you get more jumpy starts when your foot starts to get tired and your clutching gets sloppy.

One of these days when it's time to replace the clutch I'm going to put in the lightweight flywheel and I'll report back what happens.

Quote:
Originally Posted by farmboy
initially my vibrations seemed related to rpm only - a resonance at 2000 and 3000 rpm. particularly when the engine was cold. but then i discovered that by veering left i could intensify it, and by veering right eliminate it almost entirely. maybe it's one of the side engine mounts? how do i inspect the side mounts? must they be removed for inspection?
That sounds to me like one of the right wheel bearings or control arm bushings is wearing out. I don't believe a bad engine mount vibration should not be affected by turns. It would change with rpms, the faster the more vibration.

One thing I would like to know is if you put in a lightweight flywheel will your gas mileage increase since the engine does not have to work as hard to get the gears going?
__________________
1987 928S4 Silver Metallic (980)/Navy (TP) 5-Speed
2000 Boxster Speed Yellow/Black 5-Speed
1966 Wife White/Brown Top
1986 Daughter White/Brown Top (Sold!)
1992 Daughter White/Blonde Top
deliriousga is offline   Reply With Quote
Old 11-13-2005, 03:54 PM   #4
Registered User
 
Join Date: Jun 2005
Location: Fort Worth, Tx
Posts: 55
I agree with grease.
As for a dual mass flywheel, I don't know what that is. Can anyone tell me?

Richard

my89_928gt is offline   Reply With Quote
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 01:53 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page