325 throttle body,AFM and manifold onto a 320

[mrLEE30]

I have read the various threads about the bigger throttle body etc but is it possible to simply swap the entire throttle body, AFM, airbox and inlet manifold from a 325 onto my 320? would that result in an increase of power or do i have to grind away at the standard inlet manifold as it seems to say in the atricles??

cheers fellas

mrlee

[Andy_magic]

I've looked into this and you really need to grind away the manifold intake.

It's probably easier to get the 325i maniflold too, with the added bonus of painting it black while its off.

I've seen people saying that they have ground the manifold out with it still on the car, by stuffing a greasy rag (really greasy to catch all the swarf) down the throat of the manifold.

For the sake of a few $$ I would get the gaskets and take it off. Do a proper job.

[Andy335Touring]

Only trouble with putting a 325 manifold on a 320 head is that the head ports will be smaller than the ports on the manifold so the air flow will hit a nasty step.

I'd stay with the 320 manifold unless you are going to open the ports up on the head.

[mrLEE30]

Good point andy cheers mate, i was always under the impression that the inlet size on the 320 was partly to blame for the sluggishness at low rpm, i believe they are already too big for an over square engine thus creating slow gas flow, and why it only gets going at 3k+, i would imagine that would mean increasing the inlet port size may make this worse? Ya know anything about that or am i talking out me arse??!!

mrlee