Feel that VarioCam kick in!

So, I have a friend that says, "Man you can really feel the VarioCam kick in around 4,000rpm!" I think he's wrong. It's my understanding that VarioCam is more of a low end feature that allows you to lug it in a low gear, say moving slowly in 2nd without bogging down the engine. I think he thinks VarioCam is like Vtec or something. Are we both wrong?

Variocam is like vtech from what I understand, it switches to more agressive cam timings at a specific RPM thus providing a noticible boost of power, I thought it was 5200 on the Cayman 3.4, not sure what it is on the Cayman 2.7.

VTEC has a hard cam switchover so you can definitely feel when it kicks in (6K rpm on the S2000 ). My understanding of VarioCam is that it's a more sophisticated system that continuously adjusts to optimal settings based on rpm. If that's the case, you shouldn't really feel it...the benefit is an engine that is strong across the powerband, not just in a 2-3K rpm window.

If your talking about Vario Cam it adjusts the valve timing all of the time. If your talking about Vario Cam Plus the valve lift is adjusted around 4000 to 5000 rpm. And that is the change that you feel.

Variocam is on the intake, Variocam Plus is on the exhaust . They both are variable in that they don't 'kick in' like Vtec (which uses a second set of cam lobes and is activated by a hydraulically actuated pin that engages a second set of rockers to switch profiles). Porsche uses the same cam lobes, therefore the lift and durations don't change but the timing of the valves vs piston positions do - which is accomplished by the little square things on the cam drive mechanism in the first post picture. I believe it is very similar to Toyota 's system. So you shouldn't be able to feel a definitive rpm that it 'kicks in' - unless it was programmed to come in aggressively - but there would be a difference in feel between it and a non Variocam motor. BMW 's newer system actually can vary valve timing, duration and lift which negates the need for intake butterflies thereby reducing intake system losses - it is electrically activated I believe. Then of course there is F1 which uses pneumatics and that is another story...

http://www.porsche.com/all/transitional/uk/pdf/cayman_MY07_gb.pdf p. 39 "VarioCam Plus combines variable valve timing with two-stage lift on the inlet side. ... Essentially, the system creates two engines out of one" Camshaft adjustment on the intake side (VarioCam) is now supplemented by valve-lift control, also on the intake side (Plus). http://www.carpages.co.uk/porsche/porsche_technical_highlights_25_10_02.asp Nothing about the exhaust side.

I stand corrected. Looks like the Plus actually adds the similar feature of Vtec in that a second cam profile is made available. I have seen Plus described as the exhaust portion of Variocam though, which seems to be in error. Gotta like this forum for info and sharp eyes!

The picture posted doesn't have the two-stage lift, only the variable valve timing. The different cam profiles are activated by concentric lifters in the valve tappet (the round cylinder thing at the top of the valve right above the spring). An electrohydraulically actuated pin in the tappet locks or unlocks concentric lifters in the tappet (the part of the round cylinder thing that touches the cam lobes) so different lobes are used. In a two-stage lift engine, you'd see a different cam lobe profile on the camshaft in the empty black spaces between the lobes that'd be activated by the alternate lifters. Page 31 of the Cayman brochure has a similar picture but with the two-stage lift feature. If you stare at it long enough, you can figure out how it works. --Andre

The PDF linked by chows4us has a picture of the Variocam Plus system including the two-stage lift. I've pointed out the alternate lobe and the concentric lifter. You can see how the concentric lifter when it's narrow (as it is on the picture) only touches the inner cam profile. When the green pin is withdrawn, the lifter is then as wide as the whole tappet, and the outer cam lobes are used. --Andre

Chow4us, Thanks for saving the day!!

End result is additional torque at the low end RPM that would otherwise be lower.

I don't know about any of the above, but I feel a flat spot around 3600 rpm. Anyone else feel this?

According to the power/torque curves for the Cayman S published in the sales brochure, the torque dips by 10Nm at around 3,500 rpm which would explain the flat spot. Marco

My understanding of the Variocam plus vs. VTEC thing is that Variocam is like Honda's I-VTEC and both adjust cam timing and lift. The original VTEC like the S2000 and my old Integra Type R just adjusted lift at a particular RPM like someone else mentioned. I-VTEC like is in the newer cars is closer to Variocam Plus.

There are some other great threads on this in the forum - try a seach on "variocam" ...great info in this thread here too...and yes I do notice a surge as apposed to a "flat-spot" at about 3000rpm when slight gas is applied and then acceleration rolls on at 2900-3200 - that is when I get a slight surge forward. Z

Agree with Marco, the CS looks more 'peaky' because it scales greater heights of torque, it starts almost at the peak of a 2.7 (at about 1750 rpm the CS has just about the maximum 270Nm or so of torque that the 2.7 has at 4400 rpm) - as the America's may say "there's no substitute for cubes" i.e. the extra 700cc gives some of that low down grunt. In terms of feeling a kick then maybe its tied to the sound but after 5000 rpm I 'feel' like I get a kick but maybe it's just the noise getting more interesting Torque curve is flat by then...

I have an S2000 in addition to my Cayman S . The S2000 has a sudden burst of power around 6000rpm. It's even more pronounced than what I've experienced in turbo cars. I don't experience anything even close to this in the Cayman . The Cayman S has a far smoother power curve. The sudden burst of power in the S2000 has caused me to break the tires loose and get sideways in the road a few times.

Moving to " Cayman Tech" brad

It seems like the flat spot is minimize or eliminate at 3000 rpm when the sport button is on. Maybe it is got to do remap of the throttle posistion. Anyway I drive with sport button on all the time.

I find that very hard to believe. The torque curve is the torque curve and it dont matter if that button is pushed, exists, or not. Unless magically the better throttle response change the power output of the engine ... doubtful. Sorry ...

Chow, You need to try the SC option in order get that feeling. I do not want to be rude but I don't see your car have that option installed. I agree that SC does not add additional power. I just like the non-linear feel of remap throttle position when the SC is on. I don't feel the flat spot and the rpm rise faster between 2900-3200