Jump to content
SAU Community

Recommended Posts

Wow, wait till aftermarket ECU tuners get their hands on that and can play with variable compression from 7.0:1 to 18.0:1. On top of varying fuel and boost already.

I wonder why they're using the whole separate rod and piston driven off the crank to control the compression instead of an electric device with a rod and piston driven off that. Maybe it makes too much mess around/external to the head

They indicated it was a 100% mechanical setup so thats probably why. I wonder what they use to move the actuator that adjusts compression. That is one awesome technology. Now if they can make it strong enough to handle some real power!

didnt play the you tube vid as this computer seems to get viruses from you tube all the time ,VCR is old technology . . was reading about an old test engine used in TAFE,. . . .they could raise the compression of the engine by lifting the head closer/further away from the pistons, not sure how they did it but it was within the grasp of first year students

this is true ^^, if this engine design makes it into regular production cars it will be interesting to see how durable it is compared to the current crop of engines, good to see some new devolopement coming out as there doesnt seem to be a lot going on with manufacturers (apart from hybrid tech) lately

that is neat. the end of it though makes things more interesting as they mention VVT and forced induction. overall someone had a bright idea to make an engine more efficient. that certainly does that. also like the comparison vs hybrid.

Not really a new concept, Saab did this in 2000 and unveiled a motor that had a tilting head which varies the CR. Haven't heard anything since then.

The geared conrod method is different, Saab probably patented the tilting head.

Wonder how the intrinsic strength of both solutions stacks up...

Not really a new concept, Saab did this in 2000 and unveiled a motor that had a tilting head which varies the CR. Haven't heard anything since then.

The geared conrod method is different, Saab probably patented the tilting head.

Wonder how the intrinsic strength of both solutions stacks up...

it would be good if it was out soon on cars, you would be able to have the ecu read the octane of the fuel in the tank and adjust the CR too suit , , ,run anything from cats piss ULP to E85 (and anything in between)without having to lift a finger

  • 3 weeks later...

Nissan's version is better if you look at that tiny gear wheel below the piston that has to take alot of force you can tell that's a potential weak point. Plus nissan's version suits a reciprocating motion better.

http://www.nissan-global.com/EN/TECHNOLOGY/OVERVIEW/vcr.html

Yeah it's old technology - another way to do it is to set up the head with high comp ratio and use psid controlled valves to dump pre combustion fuel/air mixture into exhaust. It's wasteful and not good for the environment, plus adds too much plumbing around the engine.

  • 1 month later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Not noticeably. Arguably, the catless turbo is going to work harder in a different direction, as it will spool up faster, go to higher speeds more easily. Only if it was tuned in the original condition. If it was a stock tune, using the AFM before and after the cat/dump change, then no, no retune needed. If the car is running on a MAP sensor, then it might well benefit from a retune. It might even run a little dangerously without a retune, but it could quite easily be fine.
    • We had this blend that uses 98RON + 10% Ethanol which brought it to 100RON. It's no longer available anymore unfortunately.
    • Does it make a difference in your turbo having a shorter life if you have a cat converter as it causes that back pressure versus less/no back pressure with a decat? (Not sure if this is accurate) Also slightly different question if you went from a oem cat to a decat or vice versa will it require a tune? I heard if you change the dump pipe onwards it requires a tune?
    • No. Have only gotten as far as contemplating the task of having to put in the required fairly heavy wiring and fusing to run it (along with the big alternator), and preferring not to. But otherwise, it would be nice to have a little extra freedom as to exactly where the compressor is located and free up some space around the exhaust side of the engine.
    • Following from this in a related by not closely-related sense... Because I was buying a bunch of other GKTech stuff, I got some rear subframe collars. The history that leads up to this is: 25+ years ago the car arrived into the country with stock subframe bushes. At some point shortly thereafter I added Whiteline pineapple rings, set up neutral, and it improved the rear end behaviour. Well, it is my vague memory that I was happier with it with them in. Less axle tramp on launches, generally better, etc etc. ~2012 it got a new non-HICAS subframe with new stock bushes. No pineapple rings. I reckon that ever since then I've been dissatisfied with the axle tramp. Recently I've been f**king around a lot with all aspects of the suspension. One contemplation has been to relocate the rear lower control arm front mount points (and do the other things needed to make that work) to improve longitudinal rear grip by getting rid of some of the stupid anti-squat that Nissan ladled into the R32. But.... before doing that I thought I'd put some collars in. And.... The collars are good. The rear sounds a little bit different, but there has been no significant increase in NVH coming up into the body. In terms of rear behaviour - expansion joints on long sweeping elevated freeway ramps that would sometimes cause the rear to jiggle around a bit, no longer seem to do so. It appears that jamming chunks of metal into the gaps in the rubber so they can't move much is a really good thing. And the launch behaviour and general forward traction situation seems to be greatly improved too. It's impossible to be really sure, because the tyres are completely shagged - they are freakishly willing to let go right now. But as an A-B test with the same tyres it certainly seems to grip up a lot better. Highly recommended to anyone who still has stock bushes.
×
×
  • Create New...