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It seems like this is either the cure for the common turbo, or an engineering nightmare. It has a "control shaft" with an electric actuator that kicks the crank up or down depending on what compression ration is commanded.
The map suggests it varies from 8:1 to 14:1. Someone told me this is going in the next gen 240sx, but I've not found any proof of that yet. Of course there are also claims of greatly increased efficiency and reduced vibration. We'll see!

Thoughts?

Definitely a neat idea, but its basically replicating what a turbocharger does. I'd be interested to see the efficiency comparison between one of these engines and an efficient turbocharged system.

Reliability could be a problem, the more moving parts and engine has the more points of failure you introduce. I'd rather have to deal with a blow up turbo than my variable crank arms, losing a bearing.


-Chris

This technology is used in conjunction with a turbo - high CR off boost at low rpm and light load, and low CR in boost at high load.

I wonder what would happen if you combined this with some vtec...

Silver Z wrote:I wonder what would happen if you combined this with some vtec...

You'd get Chuck Norris


1989 Z24 Convertible - Dust Covered
2006 tC - Dust Covered, but driven more

Haha, I'm sure it will employ some kind of variable valve timing or whatever nissan uses these days. I think they should add direct injection. Something like a 2.4L VVT direct injected variable comp ratio w/ something like a GT30r pushing about 300bhp and 300ftlbs from about 2k rpm And it would still get 40mpg. And last 200k miles no problem.

Yea i'm a dreamer.

Saab worked on the technology years ago. Neat concept.

Craig Lewis wrote:Saab worked on the technology years ago. Neat concept.

Yes I actaully searched and saw your post before I made mine to make sure no one already discussed nissans tech. Saab doesnt take full advantage of the performance aspects of this technology. IMO....

I forsee a lot of failures with that kind of system.

I recal that Saab's system had a variable height head. Obviously an invitation to issue.

Variable compression certainly might have some valuable benefits. But I wonder.

Considering the low ball tech of the SBC and what it can be achieved with it. Why bother with all this complexity.

Nissan always tries weird sh*t like this and it usually works for them. ATESSA ( Skyline GT-R AWD system), Super HICAS (four wheel steering), and the "Magic Brake" (sensors detect object proximity in front of you and slow you down accordingly) are all at least tested Nissan tech concepts. I imagine they'll make this work somehow. It'll either make it into a new SX/Silvia, Fairlady concept, or part of the GT-R V-Spec.


2010 Honda Fit LX

Atessa was a good idea, and it worked well, but it needed about 12 years to get it juuuust right.
Hicas wasn't a bad idea, but it was bad execution and bad timing. 4wsteer is great on road cars that you want to keep planted but they were putting that on 240/180's and Silvia's. RWD + 4WS made the steering feel... odd...(I don't know how else to explain it. My GF's old 240 had it, and I test drove a 300ZX with it) However, pairing it up with Atessa was a great idea for road courses. Placing it in RWD cars wasn't a good idea, but if it had been in FWD cars, there'd be a lot more advantage.

This one... I don't know.. I'd like to see it happen but I'm not going to lay money on it just yet.