"But I guess the other question is if it improves things with a bigger throttle body, why don't OEMs do it?
As the manifold would also accept the 65mm TB maybe the GDI is tuned to allow this larger TB on higher horsepower engines"
I think the answer might be that the n/a GDI crate engine as purchased by Mr Morgan for the Plus 4 is used in very few standard production applications -- just a Mazda saloon produced in Thailand I underestand. It is also now ending production.
The engine is essentially the same as the turboed GTDI Ecoboost motor, which is used in very many Ford and some Mazda applications. This motor, now in its second incarnation, uses the bigger 65mm throttle body and is the one currently in
Possum, the 2014 Plus 4, now putting out 260 bhp.
