Multiple Throttle Bodies Query

[NicholasY]

Hi

Im planning on converting a 4 cylinder 1.8l fiat engine over to fuel injection. The car is used as my everyday car.

I am wondering whether using a single throttle body with a common plenum, or individual runners with quad throttle bodies would give better driveability and mid range performance.

When using multiple throttle bodies how is the intake vacuum connected? Does the map hose connect to the four intake runners, or just one? Is the air temperature sensor placed in one runner and the temp assumed the same over all inlets?

Thanks,
Nicholas

[wysiwyg]

depends on how you decide on the implementation. my engine originally had EFI but I converted to webers (quad throttle). now i'm doing MS and still employing the carbs as ITBs. you can decide to get your VAC from just one runner, i did but before MS i also added balance pipes - small hoses attaching all 4 runners so in effect it 'averages' the MAP
fo NA motors ITBs definitely has advantage over single throttle bodies, just dont go too big else your low end engine response may suffer.
also my air temp sensor is mounted on the backing plate of my air filter, just beside one of the velocity stacks

[Fii]

What if I plan to use individual air filters for each of the runners? Where do I place the IAT sensor? Would it be ok to put it on the metal plate between the filters or the readings will be way off there?