lightweight flywheel

[karlooz]

just got it installed (thx akkurat) and the the ol' 996 feels really zippy. i think it'll get even better after the computer relearns my driving habits :D

like everyone else says there are NO drivablility issues. i also got an uprated clutch and still drives like stock. pedal action is actually lighter now, my old clutch was at the rivets :eek:

like everone says there's a rattle at idle with the clutch is disengaged BUT no one ever mentioned the much increased gear noise while driving hard. when accelerating, there is gear noise, not too bad, but the first time heel/toeing into a corner and with heavy compression/engine breaking the gear noise scared the bejezzuz out of me! the vibrations/noise is transmitted up throught the transmission tunnel, through the shifters cable all the way up to the shift knob.

so right now, i am not sure if it is a worth while upgrade in performance, downgrade in comfort. i will be getting some dynamat and applying it to the underside of the center console. if this appears to have any effect then i'll apply more under the carpet.

interesting thing, when the car is cold there is no gear noise but once the car warms up to operating temps the noises come back. can i run a heavier weight transmission oil to counteract the noise?

does anyone have any tricks to lessen the noise?

[Tool Pants]

The transmission gear noise heard by the driver is one of the reasons Porsche uses the dual-mess flywheel. I was told it is because the way the gears are cut.

At the Santa Cruz tech session the Monster Boxster had a lightweight flywheel and the owner did not complain about the noise. So cut your roof off and reverse the powertrain unit.

[karlooz]

The transmission gear noise heard by the driver is one of the reasons Porsche uses the dual-mess flywheel.  I was told it is because the way the gears are cut.

At the Santa Cruz tech session the Monster Boxster had a lightweight flywheel and the owner did not complain about the noise.  So cut your roof off and reverse the powertrain unit.

<{POST_SNAPBACK}>

that's a performance mod right? :P :D

[ben, lj]

just got it installed (thx akkurat) and the the ol' 996 feels really zippy.  i think it'll get even better after the computer relearns my driving habits :D 

like everyone else says there are NO drivablility issues.  i also got an uprated clutch and still drives like stock.  pedal action is actually lighter now, my old clutch was at the rivets :eek:

like everone says there's a rattle at idle with the clutch is disengaged BUT no one ever mentioned the much increased gear noise while driving hard.  when accelerating, there is gear noise, not too bad, but the first time heel/toeing into a corner and with heavy compression/engine breaking the gear noise scared the bejezzuz out of me!  the vibrations/noise is transmitted up throught the transmission tunnel, through the shifters cable all the way up to the shift knob.

so right now,  i am not sure if it is a worth while upgrade in performance, downgrade in comfort.  i will be getting some dynamat and applying it to the underside of the center console.  if this appears to have any effect then i'll apply more under the carpet.

interesting thing,  when the car is cold there is no gear noise but once the car warms up to operating temps the noises come back.  can i run a heavier weight transmission oil to counteract the noise?

does anyone have any tricks to lessen the noise?

<{POST_SNAPBACK}>

when i had the lightweight flywheel (and stronger clutch) in my 996, the chatter was pretty much only at idle and only with the clutch out. my cgt makes the same chatter from idle to appx 2k. once you get used to it, it's no big deal. but, i'm very surprised your 996 is making the chatter off idle.

[DeAd-EyE]

do you have to get the ECU tuned for the lighter flywheel?

i read a lot of threads over @ rennlist and it seems that the GT3 owners who go from the stock to the single mass unit recommend a computer tune in order to get full benifit.

[Chads996]

I had a LTW fly on my last car. Loved it!

A rattle is a normal thing. However...it is well worth the throttle response. I noticed a slight (butt-dyno) gain. Please note the word - slight!! This is usually due to the transfer of the reduced rotational mass to the wheels. It was very slight, but there seemed to be a little more oomph. Besides...the rev-matching was SOOOO much easier. If you have the $$, I recommend it. Eventually...I plan to do the same.

Chad

[Steve L.]

Can anyone tell me just how load the rattle is? I am considering adding this with a supercharger install. How about the duration of the rattle? Is it usually for a half of second or so? I would like to add this based on feedback from some of the people who have it but I want to make sure that it is work the extra $$$. Any driving impressions would be extremely helpful.

Thanks,

-Steve

[Chads996]

I would say a medium - "ticka, ticka, ticka" as the clutch is let out and the car is resting at idle.

[karlooz]

do you have to get the ECU tuned for the lighter flywheel?

i read a lot of threads over @ rennlist and it seems that the GT3 owners who go from the stock to the single mass unit recommend a computer tune in order to get full benifit.

<{POST_SNAPBACK}>

no ecu tune was recommended for the 996 but i will check it out. thx

[karlooz]

I had a LTW fly on my last car.  Loved it!

A rattle is a normal thing.  However...it is well worth the throttle response.  I noticed a slight (butt-dyno) gain.  Please note the word - slight!! This is usually due to the transfer of the reduced rotational mass to the wheels.  It was very slight, but there seemed to be a little more oomph.  Besides...the rev-matching was SOOOO much easier.  If you have the $$, I recommend it.  Eventually...I plan to do the same.

Chad

<{POST_SNAPBACK}>

i was in need of a new clutch so i took the plunge and got an up-rated clutch with the LWF. ya, at first i thought the noise was annoying but as it breaks in it seems to have quieted down... really. maybe i am just getting used to it but i am LOVING the throttle response and acceleration from the lightened flywheel and find the noise is a small price to pay.

[karlooz]

Can anyone tell me just how load the rattle is?  I am considering adding this with a supercharger install.  How about the duration of the rattle?  Is it usually for a half of second or so?  I would like to add this based on feedback from some of the people who have it but I want to make sure that it is work the extra $$$.  Any driving impressions would be extremely helpful.

Thanks,

-Steve

<{POST_SNAPBACK}>

exactly what ben,lj said. rattle at idle and added gear noise up to 2K~3K rpms. i find that when i am lugging the car (driving around at low rpms while putting a load on the engine) there is added gear noise (shouldn't be driving this way anyway ;) )

i would say if you need a new clutch then think of doing it. since you are getting the SC then just enjoy it. i find i like to do mods in steps to see if i can feel the difference.

[ntrylvl]

Karlooz,

Did you ever try the Dynamat to mitigate some of the increased chatter?

I have a 2002 C2 with lightweight flywheel, and the chatter is quite obvious. I second the observations that: 1) there is a constant chatter with the car at idle and the clutch disengaged, 2) the chatter only becomes obvious when the car is at operating temperature, and 3) gear noise is also noticeable when driving, particularly at lower RPM's.

Like everyone else who owns these cars, I am a perfectionist and cannot stand the smallest rattle or chatter. However, I do appreciate the feel of the lighter flywheel. Is it enough of a (perceived?) performance improvement to justify the extra noise? Maybe. But I'd be an easier sell if I could make the idle chatter quieter.

On a funny note, I bought this car only 1+ months ago, upgrading from my 2001 986S. When I test drove the car, the extra flywheel chatter wasn't present. It was only when I drove it home that I noticed the sound, and--not knowing what it was--it scared the **** out of me! So I took the car back to the dealer, who--of course--didn't know about the lightweight flywheel and agreed there might be a problem. Turns out they pulled everything apart and found the single mass flywheel, which apparently was/is brand new.

Not only did I discover something new about my car, but I also got a new RMS out of the deal, all at no charge.

I don't know if there is a moral to this story, but I have owned several Porsches, including a '72 914 (still have it), '89 944S2, '99 Boxster 2.5, '01 Boxster S, and now the 996, and what I've realized is that knowing the ins and outs of your car is invaluable, not only for self-diagnosis/saving cash, but also being able to sleep at night!

Sorry for the dissertation...figured someone would enjoy my story.