Austarion

How many vacuum ports would be required when converting to multipoint?

I have a plenum which is in a state of butchered and before welding it back together I need to think about vacuum ports for things. I assume MAP/MAF sensor, boost gauge, PCV. What else? The plenum previously had 2 big ass brass nipples on it as well as the stock one coming off one of the runners...not sure the brass ones will be going back on if I can help it.

Thanks.

On top of what you have listed, ports for boost controller and brake booster.

I'm guessing I'll use the stock one on the runner for the brake booster.

What is this boost controller you speak of? The wastegate line at the moment runs off the turbo outlet. Or will an aftermarket computer have a line from it to control the wastegate? (so I block the current one and instead use a line from the plenum....I suppose this will read different than straight off the turbo as any losses in cooler pipe etc are bypassed) I haven't dug around much yet into computers and what they can and can't control.

Alspos wrote:I'm guessing I'll use the stock one on the runner for the brake booster.

What is this boost controller you speak of? The wastegate line at the moment runs off the turbo outlet. Or will an aftermarket computer have a line from it to control the wastegate? (so I block the current one and instead use a line from the plenum....I suppose this will read different than straight off the turbo as any losses in cooler pipe etc are bypassed) I haven't dug around much yet into computers and what they can and can't control.

Computer does not control the gate. Your boost control is fine ,mine comes from the plenum so that is /should be slightly better as it is getting the actual pressure at the head after any loss of pressure due to any flow restrictions by the cooler and pipework If you are going to have MAP/SPEED DENSITY then you will meed a nipple/connection for the sensor

Add one for fuel pressure regulator. And another for a BOV.

On my MPI manifold I've managed to get rid of the ports you get on some of the mitsubishi throttle bodies and just using the ports available on the manifold.

All these are in the plenum:
Large port for the PCV valve from the rocker cover (this is the special one that runs in the casting down to the gasket to the head)
Large port for the brake booster.
Small port for the BOV.
Small port for the fuel regulator.

If you need it: Map Sensor, EGR, dizzy, boost gauge.

For the wastegate actuator it needs to be pre throttle body.