9 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHHow VarioCam and VarioCamPlus works - A Primer
Leading reported evidence
Use with a 3.4 engine has a simple
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
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.
Leading evidence: 'Use with a 3.4 engine has a simple' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, The most frequently discussed action is 'Adjust hydraulically' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
And the exhaust tappets also adjust hydraulically to vary the valve lift from 3mm to 10mm.
Adjust variable intake cam position and the exhaust valve lift
Suggestion or failed attempt
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that contain suggestions
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suggestion · Original poster
The 7.8 DME has a much more complicated function to adjust both the variable intake cam position and the exhaust valve lift.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
9 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T181445Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
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.
Mark is correct, the exhaust cam timing and lift are fixed on all Porsche engines from m96/7 and back, the first Variocam was the 968 engine in 1991...
This is a source reference. Confirm exact model applicability in the original material.
