pluto wrote:panic-mechanic wrote:Ok then once more. The management system on the polo gti, Golf 4 gti and all the ones using the same motor is a system that measures The volume/mass of air going throught the intake pipe - in other words it has a MAF (Mass airflow meter). It then adds fuel for that amount of air that has passed the intake. Now if you back off the throttle - the current BOV - Recirculating valve will pass the air from in front of the Throttle body - back to in front of the turbo to be recirculated because fuel has been added for it. The reason for the BOV/Recirculating valve is to drop the pressure between the turbo compressor side and the now closed Throttle body so it can increase turbo life and reduce wear. - Ok so far?
NOW - if you blow that air off to atmosphere - which non recirculating BOV does - which gives you the funky whoosh sound - then the management has added fuel for air which does not reach the motor - making it go rich for a moment. This constant rich for a moment situation causes small amounts of extra fuel to run down the sleeve everytime you lift your foot off the throttle after boost and in the long run it cuases bore wash - which means increased wear on your sleeves and shorter engine life. It also sometimes can be the cause of backfiring in those motors - which means unburnt fuel finding it's way into the exhaust and burning there - also not a healthy situation.
Ok so if you bought this car new and you do it early in it's life and you sell it by 100 000 km you might not notice this but at some point the next owner is going to have a kaput motor while the others are still going nicely.
Oh and if somebody tells you the lambda sensor will correct this - tell him to shove it up his arse - lambda sits in the exhaust and will see that rich spike by the time you have your foot on the throttle already again and well after the fuel has washed down the sleeve already - then it will go and try to make it leaner - so now you are under full power again and the management pulls back the fuelling making it lean for a moment - ALSO and even a worse thing. The raw fuel in the exhaust will also kill the catalytic converters in short itme if you care about such stuff.
But hey - it sounds tit
Cheers for that Panic , finally !
Do you agree that it helps with the spool up as well so that lag is kept to a minimal ...
The dv for the 1.8t motor is a vacume opperated valve that will be
open under normal idel conditions or full closed throttle i.e when gear chainge and decellaration.
The air-mass meter will register the bypassed air on idel as this is when
the dv is open.Yes the dv is open when the gears are chainged etc but for brief moment in time so this will not effect the air-mass.The same goes for decleration as this is when the ecu shuts off the injectors and they don't inject any fuel.[thats why fuel consumption on mfa drops to zero]
Genrally when the atmospheric valve is fitted to the 132 kw motor it will affect the idel as the car has added fetuares that the 110kw motor does not have.This can also have a effect on the running of the car as the air-mass has new learnt values and sometimes has a tendancy to get confused thus sending it into limp mode.With a chip this can be sorted out with the usual power gains.
The 110kw motor is not as sensitive as the 132kw motor.It can affect idel at times but i have not seen them go into limp mode etc.The mapping for these motors are diff to that of the 132kw.Yes once again a chip will sort out the small issue with the usual power gains.
This is not set in stone but more of a guide line.The cars do differ from each other and some will be affected others won't be affected.
There is no set rule or path in this matter for anyone to follow.
It always boils down to what does the customer want and what is his choice.
, there are some success story's of drive by wire cars, but more of them don't like it. I took a chance because my DV was on its way out, and if the Forge valve did not work the Split way, i could just put it to full divert. But mine work's fine in split mode 
