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VarioCam Plus
How did Porsche give the 2007 987 Base 5 more HP (245 vs. 240 for the 2005 & 2006)? It this the result of VarioCam Plus?
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To my understanding vario plus means the valve lift is continously variable which is present on 2003 and newer boxsters. Pre- 03 boxsters used a selonoid that worked more like an on off switch. 03+ cars used a infinately variable "stator" that varied valve lift up to 45 degrees I belive. Jim AKA MN boxster knows more on this than I maybe he could tell you. I would imagine the new hp increase is due to better breathing and ECU changes for the 2007 2.7L boxster.
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Actually, I believe it is from Variocam Plus...
Previous Boxster models, including the 2005 and 2006, just had variocam. That was a variable valve timing system. Variocam Plus, taken from the 997 and more directly from the Cayman. also incorporates variable valve lift; I think it has two different lift maps, one high one low. That seems to have generated the slight increase in grunt. Presumably, there were programming modifications int he ECU to take advantage of the increasing range in valve lift. The torque curve seems to have flattened out a little more, even though there's not a whole lot in terms of peak values (based on my drive of a 2.7l Cayman this weekend) and most sginifcantly, there's an impressive increase infuel economy, judging by the 23/32 EPA rating for the Cayman.
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John Y...how did you like the Cayman base?
I've seen a few of them but have not had the opportunity to drive one. BTW, the fuel economy increase was pretty significant--20-23/city; 29-32 highway. A 10%+ bump which is pretty significant.
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There seems to be some confusion on this topic. Earlier posts mentioned 987's had vario-plus. Jim said in an ealier thread that the lift is variable in 987's. The only change I'm aware of is the major one that happened in 2003. Here is some info I found.
Hi, VarioCam's job is to increase/decrease Valve Overlap to maximize Torque and Power. In the past, selecting a Cam was always a compromize between these two. By Advancing/Retarding the Valve timing, you can increase Torque, Power, and lessen Emmisions. Retarding the V Timing in the Low-Mid Ranges increases Torque, while Advancing the V Timing at Idle and Low RPM Range increases Power and reduces HC Emissions. There are 2 versions of VarioCam on the Boxster. Only on the Latter version is the adjustment Continuously Variable. The 1st version - '97-'02 used an Electric Solenoid which Advances the Intake Cam 13°, the limit of this system is that it is either ON or OFF at a pre-set RPM controlled by the DME. The 2nd version - '03-'06 eliminates the Solenoids and uses an Oil-filled Stator. This allows for infinitly variable V Timing within a 40° Range. This is where much of the HP/Torque gains are had over previous MY. Also, a Synchronizing chain between pairs of Cams is eliminated probably eliminating a 1-2 HP Parasitic Loss. Happy Motoring!... Jim'99 |
Well, I think Jim '99's info you posted was correct - because unless I'm missing somethin, it talks exclusively about Variocam - all about variable valve timing, not lift, on various models through 2006. The '07s, as I understand it form the literature, have added variocalm Plus - which allows a couple of different lift maps for the cam, as ewell as valve timing. Hey, I don't even HAVE a POrsche (yet! :) ) but in essence what the new system allows is not only varying when the valves open and close and how long they stay that way, but now, Variocam Plus also varies how much they open.
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Mike, I liked it a lot...
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Anyway, I really love the Caymans' - I think they are probably the sexiest thing on the road right now - I like them enough to consider unloading both my cars and foregoing the Roadster experience I was planning to continue, going from the TT to the 987, as I mentioned in another thread. I think with a Boxster, I could be very happy with the 2.7, because that car is fundamentally about the Roadster experience, and raw power and speed are less important to me in that context. It's about all the things you can see/do/feel/smell with the top down that you don't with the coupe. PLus, going Boxster would allow me to keep my GTI as a daily driver, which is probably alot more practical. If I go Cayman, I think I'd need the power of the S to keep me entertained, and I'd have to unload both cars for $$ reasons, plus the Cayman is probably more able than the Boxster is (IMO) to fill the dail driver role. Other notes on the test drive, to get back to your question: salesman mentioned there was a recall on the bump stops for the hatch - they were not allowing the thing to shut properly somehow, and the hatch rattled quite a bit, even with a metallic clang over rough stuff. Seems to be an 07 Cayman only issue. No biggie. The stock 17s were quite a nice ride handling compromise, and certainly enough to handle what the 2.7l can throw at the chassis, IMO. Love the look of the Cayman S 18s, but they may be overkill on the 2.7l, and even take away some of the cars fluid handling feel, I fear. Probably why they are OE on the S, not on the 2.7... :) On a related note, I also found that insurance is only a little higher than for my TT, and that Cayman's are only slightly more expensive to insure than Boxsters, at least with GEICO. So that is a plus for me... My final thought on the car came a day after the drive - you could argue that the Cayman, especially the 2.7l, is the closes thing to an old-school Porsche sports car; it's very compact, relatively light, does not have overwhelming power, huge running gear or AWD or turbocharging or anything like that; and lastly, it's a car that is fundamentally about the agility, responsiveness and fun of it's chassis. That's my 2 cents. So what should I get????????????????????????????? :cheers: |
One question for you guys who bought your Boxsters new - how much do Porsche motors loosen up during (and after) the formal break-in period?
The engine on my 2.7 05 Base felt noticeably faster and more responsive at 20,000 miles than it did at 2000. The fuel economy also improved noticeably. In my experience, the changes weren't that apparent until the 15k-20k mark. |
"My final thought on the car came a day after the drive - you could argue that the Cayman, especially the 2.7l, is the closes thing to an old-school Porsche sports car; it's very compact, relatively light, does not have overwhelming power, huge running gear or AWD or turbocharging or anything like that; and lastly, it's a car that is fundamentally about the agility, responsiveness and fun of it's chassis. "
I agree with this, nice observation. My ONLY beef with the smaller Cayman is the price. Lots of money for a nice simple car. To me, simpler should be cheaper, but then I am a cheapskate too! |
[QUOTE=Brucelee.
My ONLY beef with the smaller Cayman is the price. Lots of money for a nice simple car. To me, simpler should be cheaper, but then I am a cheapskate too![/QUOTE] And I agree with that! they are pricey, and at the end of the day I still don't buy the Cayman over Boxster pricing structure...the one I drove had the preferred package, metallic paint and sound package plus and stickered at about 52,900, I think. Also, the SPP sounded fine to me, at least in the accoustics of the Cayman. I suppose a Boxster top down may be another story, but I had been curious to check out the quality of the various Porsche sound systems, with my own relatively undemanding ears, since they are discussed alot here. I don't think I would need the Bose in a Cayman. |
[QUOTE=SD987
The engine on my 2.7 05 Base felt noticeably faster and more responsive at 20,000 miles than it did at 2000. The fuel economy also improved noticeably. In my experience, the changes weren't that apparent until the 15k-20k mark.[/QUOTE] good to know, thanks! |
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Yes you are correct. VarioCam is just a phase shifter - shifting the phase and duration which increases/decreases Valve Overlap, but it doesn't do a thing to the Lift. VarioCam Plus also varies Valve Lift. Also, on VarioCam, only the Intake Cam's (2) Phase is shifted. But, remember, this is the mechanical timing only. It is the DME which synchronizes this timing with the Spark and Injector duration to take advantage of, and maximize, this mechanical variance. The DME has different programming throughout the MY and is mostly responsible for the HP gains at the center of this inquiry. Hope this helps... Happy Motoring!... Jim'99 |
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