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Old 11-07-2013, 03:59 AM   #1
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Vario-Cam???

Most people are aware that it is best to keep these cars at high RPMs (after warm up). My questions to the hive is this.......

At what RPM (DANGER ZONE!!!) does the vario-cam transition?

I can't seem to get a definitive answer as to what RPM range to stay away from. I LOVE to drive my Box hard but when I'm just crusing around town I'm usually in the 2000-3000 RPM range.

At what point do you feel safe to rev the car past 3000 RPMs (after warm up)?

I always give my Box a few minutes at start up to get the fluids moving. I'm just wondering at what point does everyone feel the car is adequately warm enough to take it over 3000 RPMs.



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Old 11-07-2013, 05:19 AM   #2
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I have read in a thread recently that the oil takes longer to warm up even when the water temp is in the middle of the guage - in my case 80C(which I believe is 180F).
I try to keep the revs above 3000 rpm but when I am in the city which is most of the time the speed limit is 60 kph or about 40 mph so I am juggling between 2nd and 3rd gear. Oh yes I have a base Box 2.7 so I would think that the S would be like keeping a racehorse reined in!.
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Old 11-07-2013, 01:23 PM   #3
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I am sceptical about this vario-cam transition thing being the problem some say.

The vast, vast, vast majority of these cars have been bought and run by non enthusiasts who just wanted a fancy looking car with a Porsche badge and a roof that dropped. I would bet most of them drive around nearly all the time in exactly the rev range that is meant to be problematical.

If it really caused problems, they'd be utterly rife. But they're not. So I surmise it's not something to worry about.
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Old 11-07-2013, 01:56 PM   #4
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This is the first I've heard of problems related to variocam. Can you provide a link to more details on this?
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Old 11-07-2013, 02:18 PM   #5
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+1 with pothole. Think about all the tips. In auto mode you're in that range all the time. No big deal IMHO.
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Old 11-07-2013, 02:50 PM   #6
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Quote:
Originally Posted by pothole View Post
I am sceptical about this vario-cam transition thing being the problem some say.

The vast, vast, vast majority of these cars have been bought and run by non enthusiasts who just wanted a fancy looking car with a Porsche badge and a roof that dropped. I would bet most of them drive around nearly all the time in exactly the rev range that is meant to be problematical.

If it really caused problems, they'd be utterly rife. But they're not. So I surmise it's not something to worry about.
Seeing is believing, the wear below on the VarioCam chain pads is what puts the hard plastic like pieces into the oil system. Depending on how much you drive in the 2200-2600rpm range, the pads should be changed to the updated material pads between 50,K-60,Kmiles.

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Last edited by BYprodriver; 11-07-2013 at 02:51 PM. Reason: sp
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Old 11-07-2013, 03:00 PM   #7
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Seeing is believing, the wear below on the VarioCam chain pads is what puts the hard plastic like pieces into the oil system. Depending on how much you drive in the 2200-2600rpm range, the pads should be changed to the updated material pads between 50,K-60,Kmiles.

Sorry, but that does not prove that frequent transitions are a problem that requires action.

Moreover, while we do see engine failures on the forum, vanishingly few, I would argue, relate to this.

There are a bazillion things I would prioritise over this.
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Old 11-07-2013, 06:04 PM   #8
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It would seem that these bits of bakelite will wear no matter whether you drive like grampa or whether you flail the bejesus out of them. Your tires wear out faster and they're not $17 a pair!
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Old 11-07-2013, 08:36 PM   #9
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Quote:
Originally Posted by Meat Head View Post
My questions to the hive is this.......

At what RPM (DANGER ZONE!!!) does the vario-cam transition?
There is no fixed or set point for the Variocam transition. IIRC the Variocam logic is based on rpm, throttle position, and oil temperature. It is primarily used in the mid-rpm range to boost torque (~1,500 to 5,000rpm) when the throttle is opened, so its operation is more of a function of how often you step on the throttle than simply what rpm you happen to be cruising around at.
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Last edited by thstone; 11-07-2013 at 08:48 PM.
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Old 11-07-2013, 08:39 PM   #10
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Aha! I found the exact conditions:

When the ignition is switched on, the electromagnetic valves of the camshaft adjusters are supplied with positive potential. If the engine is started, the control unit applies ground to terminal 25 (camshaft adjuster for cylinder line 4 - 6) and to terminal 52 (camshaft adjuster for cylinder line 1 - 3) if the following conditions are fulfilled (VarioCam activated);
1 - Engine oil temperature between -3C and 133C
2 - Engine speed > 1,300 rpm
3 - Throttle opening > 5%
or
1 - Engine oil temperature > 133C
2 - Engine speed > 1,480 rpm
3 - Throttle opening > 3.9%

Variocam is deactivated by the DME control unit if: engine speed > 5,120 rpm"
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Old 11-08-2013, 11:28 AM   #11
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Quote:
Originally Posted by thstone View Post
Aha! I found the exact conditions:

When the ignition is switched on, the electromagnetic valves of the camshaft adjusters are supplied with positive potential. If the engine is started, the control unit applies ground to terminal 25 (camshaft adjuster for cylinder line 4 - 6) and to terminal 52 (camshaft adjuster for cylinder line 1 - 3) if the following conditions are fulfilled (VarioCam activated);
1 - Engine oil temperature between -3C and 133C
2 - Engine speed > 1,300 rpm
3 - Throttle opening > 5%
or
1 - Engine oil temperature > 133C
2 - Engine speed > 1,480 rpm
3 - Throttle opening > 3.9%

Variocam is deactivated by the DME control unit if: engine speed > 5,120 rpm"

This sounds like the 2003 & up VarioCam which has infinitely adjustable cam timing & 3 timing chains.
My previous post was about VarioCam actuation for 1997-02 engines with 5 timing chains which I believe is what the OP has. This actuation has 1 step cam adjustment that occurs between 2200-2600rpm depending mainly on oil viscosity & wear of the parts involved.
To illustrate the inevitable wear problem, I think of the parts as a brake shoe against a dull chainsaw, hydraulically activated. Each time you force the brake shoe against the chainsaw it wears. If you cruise in the activation rpm range, you risk multiple activations & deactivations, leading to accelerated wear.

The updated wear pads seem far superior in wear resistance. On a good dyno graph it's easy to see which pads the engine has due to the smoother cam adjustment transition.
My apologies to Meathead for not answering your question more directly. I type slow & try to address multiple issues simultaneously.
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Old 11-12-2013, 10:16 AM   #12
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So.....The DANGER ZONE is between 2200-2600 rpm. That sucks! My daily drive consists of 10 miles averaging 50-55mph and 2 miles with 5 stop lights. In 5th gear 50-55 mph puts me directly in the Danger zone. In 4th gear I'm going to be over 3000 rpm. I don't mind going over 3000 rpm but in such a short distance it don't think the engine has had time to substantially warm up (I don't like to exceed 3000 rpm before engine is warm).

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