Jump to content

Server Lease Renewal/Software Licenses

Our yearly server lease, software licenses, as well as hardware operating costs, ARE due Dec 4th, 2022. Our current donations have fallen far short of the funds we need to renew. Please remember the RennTech.org community is Member supported so please consider a donation to help...  THANK YOU!

Welcome to RennTech.org Community, Guest

There are many great features available to you once you register at RennTech.org
You are free to view posts here, but you must log in to reply to existing posts, or to start your own new topic. Like most online communities, there are costs involved to maintain a site like this - so we encourage our members to donate. All donations go to the costs operating and maintaining this site. We prefer that guests take part in our community and we offer a lot in return to those willing to join our corner of the Porsche world. This site is 99 percent member supported (less than 1 percent comes from advertising) - so please consider an annual donation to keep this site running.

Here are some of the features available - once you register at RennTech.org

  • View Classified Ads
  • DIY Tutorials
  • Porsche TSB Listings (limited)
  • VIN Decoder
  • Special Offers
  • OBD II P-Codes
  • Paint Codes
  • Registry
  • Videos System
  • View Reviews
  • and get rid of this welcome message

It takes just a few minutes to register, and it's FREE

Contributing Members also get these additional benefits:
(you become a Contributing Member by donating money to the operation of this site)

  • No ads - advertisements are removed
  • Access the Contributors Only Forum
  • Contributing Members Only Downloads
  • Send attachments with PMs
  • All image/file storage limits are substantially increased for all Contributing Members
  • Option Codes Lookup
  • VIN Option Lookups (limited)

VarioCam vs VarioCamPlus - A Primer

Recommended Posts

Thought some of you might be interested in this write-up I found on Engine Management Systems, specifically the Cam Timing Control. It is a pretty thorough explanation of how the two systems, VarioCam and VarioCamPlus work. I also shows why upgrading from a 3.4/VarioCam engine to a 3.6/VarioCamPlus engine is not as simple as some might think.

The VarioCam system is a pretty simple on/off setup. The exhaust cam position is fixed relative to the crank, and the intake cam position moves a fixed 24 degrees relative to the exhaust cam. Note that the diagram shown is for the 1-3 head. The movement of the tensioner is reversed for the 4-6 head. At approx 1,500 rpm the cam solenoid/tensioner moves to advance the intake cam, and at 5,500 rpm it returns to the original position. I assume that the advance also takes place as rpm's fall. So the VarioCam systems is relatively simple.

With the VarioCamPlus system the amount of the movement of the intake cam relative to the exhaust cam is variable based on engine load, etc. And the exhaust tappets also adjust hydraulically to vary the valve lift from 3mm to 10mm. This is a much more sophisticated system.

What this shows is that the 7.2 DME that is used with a 3.4 engine has a simple on/off function for the VarioCam function. The 7.8 DME has a much more complicated function to adjust both the variable intake cam position and the exhaust valve lift. So there really is no way for the 7.2 DME to properly control the VarioCamPlus system. When I was researching the upgrade from 3.4 to 3.6 some sources said that they added a rpm based switch to the 7.1 DME to control the VarioCamPlus, but you can see that this really won't do the job properly. You would need to put a 7.8 DME in the car to get it to work.

Just some interesting info for those of use getting more involved with the complexities of our engines. Let me know what you think.





Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.