Quote:
Originally Posted by Dimis
What I was hoping someone could tell me is what do I need to do to ensure I can create suitable and consistent vacuum pressure for reading MAP having Brake boost, to have a street-able, and easier to tune EFI system.
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I have the manifolds shown above, on a 427W small block. It's a large plenum with plenty of reserve. With a moderate cam, you'll get a balanced vacuum signal just like you would with a single plane carb manifold.
The deciding factor would be your camshaft. A moderate to mid level cam will create a strong signal off idle. If you have a big cam, you will probably need a reservoir for the power brakes, just as if you were using a single carb on a single plane manifold.
I also have EFI. Because my cam is gigantic, I don't get much of a vacuum signal. My primary fuel and ignition maps are based on TPS and RPM. And then I supplement those maps based on vacuum. As my vacuum drops, it adds in a bit of fuel, and takes away a bit of timing.
It's an excellent system and a real joy to drive. And the looks are just killer.