Varying performance 2.0T

[Dan F]

Bloody computers! Don't know what happened there!!

[Ross9]

Hehe, I thought it was just so informative you just had to say it twice :P

It's an interesting way for the ECU to work, so instead of measuring the pressure in the inlet manifold, and then fuelling and adjusting the timing to suit etc, the ECU works out what it must be from the inlet/exhaust temp etc? and then fuels from this calculated value?

Therefore if you keep the exhaust cool etc by having the air directed down over the turbo and exhaust manifold at the back of the engine, you trick the ECU into thinking its running less boost that it is, so it then bleeds a little more pressure off away from the actuator to raise the boost level a bit, and thus the car goes faster? I assume it uses an ECU controlled Solenoid that works a bit like a bleed valve in order to control the boost. Hopefully I understood everything correctly.

One more question then, say you were to remap the ECU, using a Unichip, will this calculate and control the boost in the same way and increase it, or do you need to use a bleed valve, or better, a Dawes Device style valve to control it. I ask, becuase say the ECU was set to run 1.1 BAR on the T4, if you had then to adopt cooling and "tricking" the ECU like I said above, would it then not increase the boost a bit, perhaps to a level the standard internals can not deal with? Very unlikely I know, but could this happen?

[Dan F]

>Hehe, I thought it was just so informative you just had to
>say it twice :P

:)

>It's an interesting way for the ECU to work, so instead of
>measuring the pressure in the inlet manifold, and then
>fuelling and adjusting the timing to suit etc, the ECU works
>out what it must be from the inlet/exhaust temp etc? and then
>fuels from this calculated value?

Correct. It uses a mathmatical model.

>Therefore if you keep the exhaust cool etc by having the air
>directed down over the turbo and exhaust manifold at the back
>of the engine, you trick the ECU into thinking its running
>less boost that it is, so it then bleeds a little more
>pressure off away from the actuator to raise the boost level a
>bit, and thus the car goes faster?

Yup.

>I assume it uses an ECU
>controlled Solenoid that works a bit like a bleed valve in
>order to control the boost.

Yes it does use an ECU controlled solenoid.

Hopefully I understood everything
>correctly.

Looks like you did. :)

>One more question then, say you were to remap the ECU, using
>a Unichip, will this calculate and control the boost in the
>same way and increase it, or do you need to use a bleed valve,
>or better, a Dawes Device style valve to control it.

Not sure about that one as far as the unichip is concerned, as I have no experience with them, but from what I recall the RICA chip (for example) takes the parameters that the ECU deems as its limits and increases them so for a given temp etc the ECU doesn't restrict, it lets the calculated boost go higher.
Standard boost on a T4 is 0.9bar (13psi) I had mine running on just a bleed at 1.1-1.2 (max) bar. There is a 'window' of boost levels that the ECU will accept. With just a bleed you push the system to the top of those limits. (So I assume at altitude my CEL would have come on, but I don't drive up mountains much, so it wasn't a problem).
It wouldn't do this for very long periods, but it gave enough extra shove to make a difference to 1/4 mile sprints for example.
The EMS2000 that the turbo'd x40s use compensates for climate and altitude as well, which is why the window is so large. If you alter whereabouts in that window your boost curve sits it will give you less overhead to accomodate climate or altitude change.

>I ask,
>becuase say the ECU was set to run 1.1 BAR on the T4, if you
>had then to adopt cooling and "tricking" the ECU like I said
>above, would it then not increase the boost a bit, perhaps to
>a level the standard internals can not deal with? Very
>unlikely I know, but could this happen?

Theoretically if you could supercool the inlet, exhaust and fool the ECU about the amount of air going in the engine (remembering it isn't just temp that can make it cut boost, if the amount of air entering the engine goes way up, it will deem that the engine is producing excess boost and lower it as much as it can) then you could get unlimited boost from the car until the engine blows up.
Remember too that power can be cut by the ignition, as is so evident when the DSA cuts in!!

Hope that gives ya something to munch on. ;-)

Dan.

[Ross9]

Much munching indeed, cheers Dan.

Had to wait till this morning to give it a proper read, last nights read over was passing through the haze of alcohol between the screen and my brain, lol.

Well got in the car this morning and the outside temp guage said it was 10C. Once the engine was warm I had a play with a BMW 3 series and a new shape Laguna. :):):):):):) }(

She flew. Pulled, and pulled and pulled. Very pleased - so I guess it was just the heat that was getting to the car (and the traffic james I tend to sit in now the Holiday season is over)

Stu

[Dan F]

:)

You have to remember that these cars are more designed for 'normal' motoring with a nice shot of grunt when you want to over take etc, than being outright 'go hard and long' sorts of cars. They are not really designed for long term harddriving as the temps will get too high for the design (lack of holes to allow heat to escape). More vents and holes will help loads in keeping temps down and giving a larger performance window before things get too hot.
Incidentally, I managed to get my 2.0Ts turbo glowing red hot very easily when I drove it hard, and once my T4 was tuned it glowed well too.

However even after very hard driving I have not managed to detect even a soft orange glow from the T5, so it must have a bit more headroom to utilise yet!

Later,
Dan.