Ok, well after a lot of servicing still having problems with the lowend torque. The problem was started with a non-spooling turbo. We have changed the solenoid valve and it seems it is quite good but there is still smt wrong with the lowend torque. There is no error on the service computer. I dont know if the problem was because of I've gutted the downpipe. There is no catalitic converter in it.I though it'd gain performance but no!I lost the lowend torque. Would gutting a downpipe makes any performance loses at low end torque? Any experiences, inputs would be appricieated.
Cheers
edit: Does anyone knows which turbo does my car use? Can I upgrade it to bigger ones like e400cdi? Would it be possible to remapping after upgrading to a big turbo? or should I really need to remap it? When is the spool time of my turbo, and where it gets the maximum boost?
If you want faster spool up times you will need turbo(s) with less inertia. Usually what people do is go to a dual turbo setup. This will decrease the lag. But I think you will have a hard time finding turbos that will fit your bill. A bigger turbo doesn't mean more boost. As a matter of fact a turbo too large will give you less boost. Your engine won't produce enough exaust gas to spin the turbo.
Your turbo will produce maximum boost at max turbo RPM which will correspond to the load your engine is under and the RPM of your engine. However, your waste gate will limit the boost by bypassing some exaust gas around the turbo.
With some engineering one ought to be able to fit the VNT turbo from a 270 CDI. The variable venturi should significantly reduce the turbo lag at the bottom end. I've considered this a few times, but I've just got too many other things to do.