Notices
996 Forum 1999-2005
Sponsored by:

Variocam engagement abrupt

Thread Tools
 
Search this Thread
 
Old 10-31-2006, 03:57 PM
  #16  
LVDell
Nordschleife Master
 
LVDell's Avatar
 
Join Date: Oct 2003
Location: Tobacco Road, NC
Posts: 5,225
Likes: 0
Received 28 Likes on 23 Posts
Default

No problem. Let me know if you change your mind.

Cheers,
Old 05-22-2007, 01:37 PM
  #17  
Benjamin Choi
Banned
 
Benjamin Choi's Avatar
 
Join Date: Jan 2004
Location: Pacific Northwest
Posts: 3,473
Likes: 0
Received 2 Likes on 2 Posts
Default

Happens to mine as well - interesting stuff. VTEC baby!
Old 05-23-2007, 12:29 AM
  #18  
Dave S
Rennlist Member
 
Dave S's Avatar
 
Join Date: Jun 2001
Location: New York, USA
Posts: 257
Likes: 0
Received 0 Likes on 0 Posts
Default

My 02 does it too but I feel it most in 5th or 6th on light acceleration. It is just noticeable if you look for it, I think it's normal and just something to get used to.
Old 05-23-2007, 09:37 AM
  #19  
rcg412
Rennlist Member
 
rcg412's Avatar
 
Join Date: Sep 2005
Location: Back-Country Greenwich, CT
Posts: 1,815
Received 122 Likes on 81 Posts
Default

Same in my 03
Old 05-23-2007, 10:01 AM
  #20  
wdonovan
Instructor
 
wdonovan's Avatar
 
Join Date: Apr 2007
Location: Bayville, NJ
Posts: 155
Likes: 0
Received 0 Likes on 0 Posts
Default

If the car had 700HP it would be an issue. But at 320, it doesn't make it hard to drive. It's just the power that you've been waiting for.
Old 05-23-2007, 03:37 PM
  #21  
UCrazyKid
Pro
 
UCrazyKid's Avatar
 
Join Date: Nov 2006
Location: SF Bay Area
Posts: 698
Likes: 0
Received 0 Likes on 0 Posts
Default

normal for me too in an '02. became smoother when i switched to 5W-40 oil.
Old 05-23-2007, 05:52 PM
  #22  
Greg D.
Addict
Rennlist Member

 
Greg D.'s Avatar
 
Join Date: May 2002
Location: North bay area
Posts: 1,753
Received 279 Likes on 139 Posts
Default

That drove me nuts for a while (03)... It still bugs me because I'm often cruising at 3200 or thereabouts in 6th on the freeway, so I can feel it all the time. I wish I could "move" the activation point 300 RPM north !!! I'd probably never feel it then.... It's always when crusing at light throttle that it's noticeable...
Old 05-24-2007, 12:20 AM
  #23  
jasper
Three Wheelin'
 
jasper's Avatar
 
Join Date: Nov 2002
Location: north vancouver
Posts: 1,413
Received 17 Likes on 13 Posts
Default

Ah - so that's what I'm feeling. New owner here and sometimes, only somtimes I get a little on-off feel. I hadn't really noted what revs I was at - I'll feel that out soon. Wasn't bothering me too much, but since a buddy of mine just had a catastrophic IMS failure in his 2003, I am hyper sensitive to every little thing!

Originally Posted by UCrazyKid
normal for me too in an '02. became smoother when i switched to 5W-40 oil.
What oil did you switch from? Or is this just a ploy to get 1999Porsche911's goat? FWIW - I'm going with 5W50 Mobil1 when I do my first oil change...soon.
Old 05-24-2007, 01:48 AM
  #24  
Benjamin Choi
Banned
 
Benjamin Choi's Avatar
 
Join Date: Jan 2004
Location: Pacific Northwest
Posts: 3,473
Likes: 0
Received 2 Likes on 2 Posts
Default

some of you guys are assuming that the smoother feel means better - it may, it may not, no one really knows for sure
Old 05-24-2007, 08:36 AM
  #25  
Greg D.
Addict
Rennlist Member

 
Greg D.'s Avatar
 
Join Date: May 2002
Location: North bay area
Posts: 1,753
Received 279 Likes on 139 Posts
Default

Yeah, that is why I just laid down $3400 smackaroos for a 4 years, 100K miles, 0 deductible, dealer sponsored extended warranty when mine expired last month ! Not cheap, but cheaper than a new motor someday and peace of mind until I can afford a used 997 with GT3 aerokit ;-)

I read somewhere that since variocam + uses engine oil for actuation, thicker oil like 15-50 or 20-50 was not recommended by the factory. I think 10-40 mobil one is IT... so it makes sense that 5W-40 would make it even smoother... It's an odd thing though, my previous 987 also has variocam I think and I could not feel this... I wonder if the 997 does it too !!

Another glitch of the 996 to my eyes, is the sometimes abrupt clutch operation (pressing or releasing). It's not me, I've driven nothing but clutch smoothly all my life, but now and then it feels like I am shocking the drivetrain on the 996 when I press or release the clutch pedal, a little "doink", I think it is related to the above, it might be when I release the clutch and the RPMs land on the variocam activation "rpm range". Just a guess... The car checked out everytime I mentioned this to a dealer or mechanic !
Old 05-24-2007, 11:01 AM
  #26  
JBRipps
Three Wheelin'
 
JBRipps's Avatar
 
Join Date: Jun 2003
Location: New City, New York
Posts: 1,676
Received 4 Likes on 2 Posts
Default

Hi,

Is this something you can feel thru all 6 gears? Or in a tip? Elaborate please.....thanks.
Old 05-24-2007, 11:36 AM
  #27  
1999Porsche911
Race Car
 
1999Porsche911's Avatar
 
Join Date: Apr 2004
Location: Chicagoland
Posts: 4,159
Likes: 0
Received 7 Likes on 5 Posts
Default

Originally Posted by jasper
Ah - so that's what I'm feeling. New owner here and sometimes, only somtimes I get a little on-off feel. I hadn't really noted what revs I was at - I'll feel that out soon. Wasn't bothering me too much, but since a buddy of mine just had a catastrophic IMS failure in his 2003, I am hyper sensitive to every little thing!



What oil did you switch from? Or is this just a ploy to get 1999Porsche911's goat? FWIW - I'm going with 5W50 Mobil1 when I do my first oil change...soon.

I believe he ment he switched from 0W40 to a higher viscosity. In most cases (all that I have seen) the timing change is much smoother going with a higher viscosity oil. Smoother as measured by feel and Porsche Tester by Porsche Technician plotting timing changes. I run 15W50 and cannot feel the changover and can cruise at the changover speed all day, nice and smoothly.
Old 05-24-2007, 11:48 AM
  #28  
Benjamin Choi
Banned
 
Benjamin Choi's Avatar
 
Join Date: Jan 2004
Location: Pacific Northwest
Posts: 3,473
Likes: 0
Received 2 Likes on 2 Posts
Default

now is the heavier oil making things better cuz it supposedly smooths it out or is the "abruptness" , which it really is not abrupt, the natural function/design result of porsche engineering?

not sure why people are insinuating that smoother is better inthis case
Old 05-24-2007, 12:17 PM
  #29  
JimB
Addict
Rennlist Member

 
JimB's Avatar
 
Join Date: May 2001
Location: MN
Posts: 2,569
Likes: 0
Received 3 Likes on 3 Posts
Default

I'm not sure how thicker oil will smooth out the cam shift (good or bad Ben). There really isn't any magic going on. There is an on/off (not variable) switch that changes which cam lobes are used. You have two sets of lobes, a taller center as I recall with a shorter lobe on each side. You might be able to zoom in on the picture in the X51 thread and see them. I think the valves have to be being lifted by one or the other. I don't think there is an in-between.

When we put the 3.6L in my 1999 race car the computer didn't have the ability to shift the cams so we just put a switch on the dash and did it manually. Later I added an RPM switch it do it. We shifted them at 2500 which worked fine. The car runs great on the high rpm lobes except at idle.

Not sure why I wrote this. Just trivia I guess.
Jim
Old 05-24-2007, 12:25 PM
  #30  
Benjamin Choi
Banned
 
Benjamin Choi's Avatar
 
Join Date: Jan 2004
Location: Pacific Northwest
Posts: 3,473
Likes: 0
Received 2 Likes on 2 Posts
Default

The thing is, it's funny how there are similarities between VTEC and variocam (essentially same tech, no?)

except the VTEC doesn't have this "Abruptness" so it must be better - how about them apples rennlist?


Quick Reply: Variocam engagement abrupt



All times are GMT -3. The time now is 12:26 AM.