I switched my Turbo from the T25 Garrett to a 16g TDO5. I have been having to get my car beyond 3500 RPM before boost actually begins.
Is this a problem or is this normal before boost?
Should it kick in a lot sooner or am I doing something wrong?
Is there something that I am doing incorrectly or do I need different sensors and other components to go along with the turbo swap?
The TDO5 16g flows a lot more air than a T25 (520cfm vs. 405, according to this ), so you should expect it to be laggy. On the plus side, once you get higher in the power band, you should be making more power. If you haven't upgraded your fuel injectors (and possibly your fuel pump) you should keep a close watch on your A/F ratio, as if you exceed your injectors' flow rate you'll run lean and that's not a good thing. You can probably find some good advice on some Eclipse-specific forums.
An otherwise stock 2g Eclipse 4g63 with a 16g is going to be around 3500 RPMs just as you've seen. You really need to get it tuned for the new turbo. To take full advantage you'll also need to upgrade to at least 550 injectors, with some sort of fuel control, and add a boost controller of some sort. Replacing the upper IC pipe is supposed to help some with the lag, but I've never done a before/after test myself on that piece.
