Re: pitching in a V6 3.0 on my 156 2.5 V6
firebird, 190-200 wheel BHP comes out to about 230-240 at the engine for a manual car.
you need to use the 2.5 injectors as you will still be using your 2.5 ECU. the ECU from a 166/GTV wont work due to ancillary connections. ive been running a 3L with 2.5 injectors for ages now and its been fine. fueling's spot on. use the 2.5 throttlebody too, tho i think its the same one on the 166.
however, to get the fueling spot on, u might need to do a remap. i have the normal 2.5V6 remap from squadra, mated to the GTA 45mm intake runners, and fueling is spot on. cant comment on other remaps as i've never tested others. Angel Tuning might even be able to work out a custom map for and that'd be even better.
what year is your 2.5V6? there are subtle differences between V6s pre-02 and post-02 - mainly in some of the rebreather tubes, the oil catch can (post-02 doesnt have one), and the location of the engine ECU - so just keep that in mind.
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