Something I want to share

[woo]

It has the same as the T20SED

but how about in comparrison to the C20sed that is in my 98 leganza??

[Nubira2.2]

I cant tell you I havent seen a C20SED they dont como to PR

Any body has Top View pictures of a C20SED and a T22/T20 SED

[GsiTurbo]

It has the same as the T20SED

but how about in comparrison to the C20sed that is in my 98 leganza??

Both motors use same blocks, so no diference there. Change in the code letter (C vs T), comes from fact Australian motor meets different emission systems, and possibly slightly different compression.

Tom

[MMamdouh]

DAEWOO cars run rich in open loop, beeing too rich is bad

what does "running in open loop means??

MMamdouh

[Audacity Racing]

closed loop means that the ECU is monitoring all the systems and is controlling the air/fuel ratio of the engine.





open loop means that the ecu is running the car off of a pre-programed map, with no adustment to the the ratio.... this means that you can be rich or lean without any control over it because the ECU hasn't switched over to closed loop.

[MMamdouh]

aha... so tht means we are inherently running rich, any O2 sensor problems will cause us lots of trouble and we can afford to have better breathing at the same level of fuel feed... right?

MMamdouh

[Audacity Racing]

well, in order to get the car to closed loop, your o2 sensors have to be operating correctly. the things that makes the car switch back and forth is the temperature of the engine/exhaust. in order to get a really good reading of air/fuel, the o2 sensor has to be hot (hence the o2 heater circuit failures). if your o2 sensor never gets hot enough, or your thermostat decides to die, you won't be in closed loop combustion, which is horribly inefficient. they use extra fuel on the pre-programmed map in an effort to keep you from leaning out and also to heat the system quickly.

[Nubira2.2]

When the car is in close loop it regulates the AFR using O2 sensors. The ECU wants the AFR to be stoich (14.7:1).

In open loop the AFR is adjusted from the readings of the MAP and TPS sensors

[MMamdouh]

so our cars operate in an open loop... whats the O2 sensor for then?

MMamdouh

[Audacity Racing]

it operates in both. the car starts in open loop and closed loop is achieved after the oxygen sensors heat up and the engine temperature is normalized.

[Nubira2.2]

It changes back to open loop at a certain point determinated by the ECU you can see when using a OBDII scan tool

When you are tuning specialy in turbo cars you need to know that point

If you reach Full boost in close loop you will have problems

[Audacity Racing]

It changes back to open loop at a certain point determinated by the ECU you can see when using a OBDII scan tool

When you are tuning specialy in turbo cars you need to know that point

If you reach Full boost in close loop you will have problems

this is true because the engine cannot fully control the fuel flow in closed loop... theoretically, you could push infinite fuel/air on a closed loop system which would in fact flood the engine or lean it out if boost is applied

[Nubira2.2]

in a simple way to explain

In close loop the AFR will be controlled with the O2 sensor

In open loop the AFR will be controlled with the MAP sensor

[MMamdouh]

now i am begining to fell that i am stupid

now closed loop control can't control the engine indefenatly... why use it then? we should be all using open loop control but thats not the case either

i suppose 'cause open loop is an inaccurate control and closed loop is not effecent in the long run then you need to flick between the two methoids to keep the control at its optimim... right?

if i got this wrong then i guess i am defenatly tupid.

MMamdouh

[Audacity Racing]

you got it right, tard