V70 T5 Performance

[Engineer]

Originally Posted by jod t5

whats that gary?, that you cant bolt a mbc on a me7?....i would say so cos bypassing the bcs on me7 will react badly....? that s what ive always understood....
cheers
jod

Torque demand not mbc

Well it is Christmas

[Nuisance]

Originally Posted by Engineer

Ain't they all torque based control systems and it's just that Freds and his mates cars are easily fooled or am I talking motronic 4.4 only?

Been up the pub.

Well yes they are in a roundabout sort of way.

It's just that the ME7/9 works on an electronc "torque request" system. That's the only input the driver has to the engine. Where as the Motronic 4.4 has no control over the quantity of air entering the engine, as that's the drivers input. The 4.4 HAS to respond to the drivers throttle input, it HAS to fuel to match what air the driver is dumping into the intake it has no choice. So an MBC will force it to reply to the greater quantity of air.

The ME7/9 can do what it jolly well likes, because all it gets from the driver is a voltage. (from the potentiometer on the throttle pedal) It has 100% control of all engine functions, and can adjust them regardless of what the driver is asking for. So adding an MBC will not force the ME7 to fuel the extra boost, all it will do is close the throttle till the readings from the sensors are back in specificaion. The only way you can really up the boost on an ME7 is to change the specification.

That is how I managed to drive a car (not lightly) with a wastegate jammed shut for 10,000 miles without the slightest damage to the engine.
Try that on a 4.4......

[Engineer]

ME7 systems do indeed control the cylinder air charge which the Motronic 4.3 / 4.4 can’t do, however they are all torque electronic engine control systems and not sort of as you put it. Hence 90% the same engine control sensors.

So to quote that the latter can’t run an MBC because it is torque on demand controlled is therefore misleading hence my posts, for sure a jammed actuator could be catastrophic for these earlier systems but normally they don’t, the spring just suffers fatigue and gets loose thus loosing air charge pressure the diaphram failing is also rare they normally only become a problem when they have been badly adjusted / modified in this condition. Which is why, you should replace them.

I know you are really impressed with your control system J and rightly so but to put down pre-ME7 engine controls because of your experiences is unfair as properly maintained and tuned they are very reliable. It never ceases to amaze me that people tune high mileage cars and expect the secondary engine components to respond without complaint

Cheers