I am pretty new here and hoaping that some one could help me, I am bying an alfa spider 1750 tbi and I intend to tune up the engine and the exaust system, I turned to romeo feraris in milano and they preposed to change the turbo charger for a beter perfomance and to put a ecu unit, and an exaust system upgrade estimated power from 200 bhp to 260 bhp.
my question is if they change the turbo charger by a biger one will i have power loss on litle rpm and is soo how can i avoid this and bring my car to the best tuning result.
it's pretty much the upgrade on the Giulietta QV (the Giulietta also has different injectors).
The engine should support it pretty fine, and if properly done you should not feel much more lag: the Giulietta QV has not much more lag than the 200bhp 1750.
I'm concerned just about a couple of things: The QV has 235 Bhp, which are delivered, afaik, in overboost mode (i.e. you can have 235 bhp but for a limited amount of time, when needed), so, unless it's on overboost too 260 bhp feel to me quite optimistic.
The biggest concern i have anyway is not on the engine, but on the gearbox, which on the 939 1750 is at its torque limit.
The Giulietta has a different gearbox which support more torque... having the mentioned bhp by keeping the same torque level is indeed possible, but i think it would mean to push the engine up to 7K or more, which a turbo unit might not like much.