vvt and LIFT

[mr_desmo]

I wanted to start this topic because i feel this is the only technology missing from this hi tech engine....valvetrinic like bmw or variocam like porsche are two unbeatable systems. Continually variable lift so you have the perfect (most aggressive and most mild) cam for every rpm (THIS IS IN ADDITION TO VARIABLE VALVE TIMING OF COURSE)!!!! Tell me what you think!

[rays]

Those and VVT are the same thing with different names. They all accomplish the same thing

[mike25]

Originally Posted by rays

Those and VVT are the same thing with different names. They all accomplish the same thing

x2..and thats also what tends to make tuning a nightmare in accordance with the direct injection

[Mojave]

Then no wonder BMW did it, they have been so anti-tune

Originally Posted by mike25

x2..and thats also what tends to make tuning a nightmare in accordance with the direct injection

[scrming]

Originally Posted by mike25

x2..and thats also what tends to make tuning a nightmare in accordance with the direct injection

agreed...

but what I really want from a tune is to reduce the torque management a bit... firm the shifts up a bit... but leave the engine calibration alone.... no messing with timing, fuel, etc... that's what I'm looking for! LOL

[mr_desmo]

Originally Posted by rays

Those and VVT are the same thing with different names. They all accomplish the same thing

not the same thing at all ...both pink show both systems...we only have the continually variable valve timing (which is also found in hyundai accent); this is mainly for fuel economy and only have the timing in which open or close a valve... THE vvt and LIFT IS the capacity to change infinitely the cam profile (say you put a big cam in a ls3 is good for 70whp at 6600 rpm but you lose 20 whp at 3000 rpm....this permit you to have the mild cam at low rpm and the aggresive one at high rpm...)

With porsche the way it works(as in the pic) is that if you look at the cam lobe you have an hole in the midle and the more rpm you get a little finger in the middle act as the profile changer to push the valve a couple more mm to get more air in!!!

[scrming]

you want really cool and variable.. check out the VCR (variable compression ratio) engine!

http://www.mce-5.com/introduction/index.htm

[mr_desmo]

Originally Posted by scrming

you want really cool and variable.. check out the VCR (variable compression ratio) engine!

http://www.mce-5.com/introduction/index.htm

Very, very cool!!!You imagine getting all these systems in one car! The engine will be twice as heavy as before!!! cam in head, TWin VVT, dbw, direct injection, variable compressionetc......

[mike25]

It's porches version of vvt... They all work to accomplish the same goal which has to do with cam phasing

[HaveBlue]

Four-cam phasing
The 3.6-liter V-6 VVT DI employs four-cam phasing to change the timing of valve operation as operating conditions such as rpm and engine load vary. The result is linear delivery of torque, with near-peak levels over a broad rpm range, and high specific output (maximum horsepower per liter of displacement) without sacrificing overall engine response and driveability. When combined, direct injection and cam phasing technologies enable an unmatched combination of power, efficiency and low-emissions in gasoline V-6 engines.

Cam phasing pays big dividends in reducing exhaust emissions by optimizing exhaust valve overlap and eliminating the need for a separate exhaust gas recirculation (EGR) system.

By closing the exhaust valves late at appropriate times, the cam phasers allow the engine to draw the desired amount of exhaust gas back into the combustion chamber, reducing unburned hydrocarbon emissions. The return of exhaust gases also decreases peak temperatures, which contributes to the reduction of oxides of nitrogen (NO x) emissions. In tandem with the dramatic 25-percent reduction in cold-start hydrocarbon emissions brought on by direct injection, the 3.6-liter VVT DI V-6 surpasses all emissions mandates, and does so without complex, weight-increasing emissions control systems such as EGR and air injection reaction (AIR).

Source: Text courtesy General Motors