Manaz wrote:The ECU controls boost on a Liberty. It's generally pretty good once tuned properly (it's rare to see people using third party ECUs on Liberties), though there are a few people (myself included, mine isn't fitted yet) who have opted for the Pierburg 3-port boost control solenoid (it gets driven by the ECU, but does require different tuning) for more accurate boost control (rather than faster boost).
Even with the stock tune, you should see a difference just by switching between I, S and S# modes with the SI-Drive...
+1 to the 3 port and a decent tune. I had one fitted and a revised tune loaded by Matt only a couple of weeks ago. Factory ECU, intake & turbo, 3" turbo back exhaust and we had 14.2psi at 2100 r.p.m. while road testing the tune. Although not a scientific measurement, at 2200 rpm it "feels" like its pulling the way it did at 2600 rpm before the 3 port was fitted. The difference is particularly noticable in the in-gear acceleration (on the highway overtaking as an example - most of my km's are on the highway) which happens considerably quicker now. My summation based on cost vs benefit its a no brainer.