by dapinky » Tue 21.05.2019, 20:47
Mountainman,
What you describe sounds a bit like 'turbo lag' - basically, when you open the throttle fully, a number of things happen - all of them are dependent on the throttle opening and the revs at the time....
The Throttle possition sensor (TPS) tells the ECU that 'more' is required from the engine, so the ECU will add fuel at the injectors (fairly instantanious) and accelleratrion ensues.
The turbo should only start to add boost once the engine is over 3000 rpm, and is a gradual application of extra 'oomph' up until the red line (or gear change).
Also, there are a set of secondary throttle flaps which open at full throttle (at something like 5500 rpm, but I cant remember the exact number) to allow extra air intot he system along with the extra fuel.
As all of these things occur at different times, and it takes a few fractions of a second for them all to catch up and allow smooth performance, there is often a bit of a 'dead' feeling when you first boot it, especially you are under 3000 rpm at the time (more noticable on a gear change than a steady run). until the boost request from the turbo catches up.
This can be minimalised with a dump valve, but can't be eliminated completely, as the turbo is a mechanical boost 'additive' and there are fluid dynamic considerations which can't be overcome.
Dave
Just the one now, but this one's mine! - and it will be finished eventually..... - but also temporary custodian of a project until it is finished enough for Angie to drive it
...oh, and a 2006 Freelander destined for the jungles of The Gambia - 4500 miles across roads, desert and tracks - what could possibly go wrong?