thanks sifu

=edit=
ah yes that's exactly what i needed, furthermore reference towards the GODLIKE engine
only thing left would be to co-relate them with the mappings

This post has been edited by Quazacolt: Feb 17 2014, 12:43 PM

can i say, twin cam enjin still got room to improve efficiency at the xyz rpm? so they implement vvt

ermm...

40k km ?
50k km ?

yes there's a LOT of room for improvements and as you can see from the wiki references linked, there are at least FOUR modes to play around on the timings!

the possibilities could be huge if not even endless

DOHC engine advantage over SOHC ..

bigger surface for each Valve..
separate control for intake and exhaust cam ..

relate it to the squeezing effect ...
Bigger surface u will have problem during low end .. air fuel mixture lazy to move into the combussion chamber ..

(macam u take LRT .. if non peak hour .. u relax and walk in .. peak hour .. u kepit sardin also wan forcce in)
Non peak hour --> U DUN SQUEEZE IT
Peak hour -> U SQUEEZE iT

DOHC due to the larger surface is avantage during the high rev .. more surface .. more air can go in .. where else SOHC already choke itself .. not enuf air and fuel ..

SOHC -> LRT 100 meter long .. but only one door open at 1 meter wide..
DOHC -> LRT 100 meter long .. but open 2 door at 2 meter wide ..

so during peak hour .. u push me .. i push u .. into the train if we are running on SOHC
but if non peak hour ... we just walk in steadily..

Now DOHC ..
NON peak hour .. NOT many ppl .... but pintu buka besar besar ... sure all walk slowly into it .. (slowly mixture no gooding) ..
so ... DVVT / VVTI / MIVEC ... instead i buka the pintu 2 meter when the LRT stop .. i buka the pintu before the LRT STOP (sounds funny ) .. so when the time i stop .. ppl will start rush in bcoz i gonna close it faster ... lolzzzz ..

Not a very good example.. but hope u get it .

thanks a ton! that's basically addressed the DOHC question.

so the twin cams work on the exhaust and intake independently (as the previous god engine have actual picture illustration as well) as opposed to the older days of lifting/low or high cams (ala older vtec/campro etc).

understanding ok ya?

means want to shorten the station stopping time?

VANILA DOHC engine @ no DVVT or what so ever ...

u can change the intake cam to one kind .. exhaust cam to another kind (neglect the tuning part for now) ..
but SOHC u cant .. its 2 in 1 .

And when u ADVANCE THE SOHC timing .. the exhaust timing will follow .. lolz .. (SAME GOES TO VANILA DOHC) .. but if u got DVVT .. the oil chamber can shift the timing of each individual cam accordingly .

cam timing u can change to advance or retard.. BUT STILL the DURATION IS THE FREAKING SAME.. just early open or late open the valve... (take consideration of the vacuum effect) ..
Lift is totally a different monster... when VTEC kicks in .. or older Mivecs .. or older VTTi .. (toyota celica last version got) .. its like changing the car to HIGH CAM suddenly when it kicks in .. the DURATION of the valve open can be changed .. and the opening of the valve can be bigger too .. by pushing the valve deeper in.

QuazacoltDon't mention mivec kick in jo, later let other ppl laugh

i see, so what happens if we advance everything altogether at earlier timings? that would mean that you would not have low end power/acceleration, right? further more at low speed, air ram effect would not be achieved and if you squeeze the intake (and and loosen the exhaust?) that would mean the engine will be starved right?

got some ideas churning up in my head but i think best if this is taken offline whenever you're free hehe

so lift is like the train open door bigger, while VVT control when the open the door? correct?

oh..that one read liao since archonixm mention tappet noise..

that's very layman buttdyno feel ma... not everyone also can be technical (even myself also failed at at being technical ma )

later too technical jor, like YAB professor jayraptor, NO ONE understand lerh

Exactly

from (exaggerated ) understanding, lift is like the train throw away the doors and and then pick it back up when the passengers are in.
or eh the train transform into monster and start doing train driftings.

vvt can have control when to open/close the door, and how big it wants to close/open (squeezing effect as explained?)

Stop staying in the carburator days please..
Its electronic control d..
I can choose at low rpm low load this setting
Low rpm high load this setting
High rpm low load this setting and etc

yes exactly! hence the endless possibilities on playing around the settings

btw how does the engine determine speed? (eg: low speed high load)
from the mapping tables which has 0-100% (i assume that is throttle position?) and rpm, so that means rpm is the sole determination of speed while load is the throttle?

Nope
Load vs rpm

load is determined by how much the transmission is "dragging" the engine?

essentially rpm is the by product of throttle so throttle positions is irrelevant in the ecu mapping, that understanding ok?

Oh..paiseh ah...odo at 55k km..