Variocam Surge?

Trying to self-diagnose very short, random surge in my �04 996 Cab. It occurs at between 2-3K RPM usually second or third gear with steady throttle. It feels like a surge but could also be the rebound of a hesitation- hard to tell. I started searching the forum and �variocam� came up in a couple older posts related to power surge and hesitation. Asking the knowledge base if this is a reasonable direction to follow and your experience with variocam failure modes. /X3

I have a 03 C4S and it "surges" at 3k rpm as well. If I'm driving normally it hits harder than if I'm hitting it hard. I had the ECU flashed with an update that Porsche put out to smooth out the transition of the variocam, and it helped a little, but it's still noticeable. I don't know if it's a sign of something going wrong or just the way it works, but mine has always done it. The only bad thing is that 3k is right where the car is when I'm on the highway driving to work (approx 70mph), so it can be annoying. If you find out more on this, please post the info.

Not much experience with the VarioCamPlus system in your 04 but I do have some After Sales training manual that describe in detail how the system works. If you PM me your email I can send you a dropBox link with this info. Also, if you don't have the Service manual I have them too. Good luck

Variocam should be at higher rpm. Are you sure it's not a sticky throttle pedal? Have you scanner the car with Porsche-specific scanners?

Its around the changeover point, just consider it a little turbo like kick.

3120rpm is the point where the intake resonance flap shifts and splits the intake chambers, it shifts again at 5120rpm to improve VE in the upper RPM's. The flaps are either On or OFF and are never in-between (partially open).

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Thank you for this post! I recalibrated my sense of the power surge and concur it�s closer to the 3120 rpm rather than 2-3K as originally reported. Not driving steady throttle at 5120 rpm to feel a change in power around that range. /X3

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You�re right, the surge is closer to 3k rpm rather then 2-3k as originally reported. /X3

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It is at higher rpm, 3120 to be exact, according to previous posts. /X3

I discovered the same behavior soon after purchasing my c4s and read every thing I could find. Several other owners reported the same behavior and were told by dealers and indies it was �normal.� Porschetech�s explanation is what I found online as well but was never able to determine if it was indicative of a sticky Variocam actuator or just the way the system works. Easy to prevent when driving aggressively but not so much when cruising on the interstate. I�ve just come to live with it.

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Cool info. I've never heard that before. I wonder why this isn't more widely known? I took my C4S to a well respected Porsche shop and they didn't suggest to me that the surge could be from this. I wonder if it's because they mostly work on air cooled models??? Thanks

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I have stacks/tons of Porsche training/repair/TSB literature on watercooled 996 up models. The intake design and resonance flaps are referenced in several places, but the details of the specs are only listed in one place, (The Porsche Way?)....The abundance of the technical literature with the sparsity/scatter of the detailed specs is a challenge that Porsche Technicians face ,welcome to my world !! Edit :FWIW sometimes I wonder if Porsche thinks us Techs are not smart enough to make good use of the detailed specs, or they just want to leave them out, encase they change their mind !!!

Amazing that we all (996 drivers) must feel these surges at 3.2k and 5.2k rpm and yet no info on this from Porsche, no tech guidance, and few forum posts. /X3

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That is strange. Maybe they want to hide these kinds of things since they are an annoyance, and there's probably no way to fix it, at least not inexpensively.