Intake Manifold with Port EFI--All single plane?
03-10-2014, 02:25 AM
#1
Melting Slicks
Thread Starter
Intake Manifold with Port EFI--All single plane?
My reading on single-plane vs. dual plane intake manifolds seems to indicate that dual-plane manifolds are more streetable--better low end and mid range--over a wide range of operating conditions and that single plane manifolds are at their best when going fast and faster. But that's when using a carburetor. (or throttle-body injection?) Unless I've missed something, thought, all the aftermarket port fuel injections systems, when packaged with a manifold, use single plane manifolds. Does the idea that dual-plane manifolds are better in street driving go out the window with dry flow, when the manifold is flowing only air until you're almost at the cylinder head, as in port EFI systems?
03-10-2014, 08:22 AM
#2
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St. Jude Donor '07
my .02...
dual plane intakes are better for street because the intake runners are longer and somewhat smaller, thereby raising the air flow speed and increasing the ram effect of the air/fuel mixture... (and, again IMHO, that is the 'secret' of the rochester FI..., the ram effect). remember, the rochester was 'dry' air too....
i would pick the dual plane.
Bill
dual plane intakes are better for street because the intake runners are longer and somewhat smaller, thereby raising the air flow speed and increasing the ram effect of the air/fuel mixture... (and, again IMHO, that is the 'secret' of the rochester FI..., the ram effect). remember, the rochester was 'dry' air too....
i would pick the dual plane.
Bill
03-10-2014, 11:18 AM
#3
Race Director
Single plane manifold like the Vic Jr, are used because you can get all the injectors mounted at the same level,and position.
You could probably do that with a dual plane, but it would take a lot more work, as the injectors all have to be at the same level for the fuel rail, and then you would probably have to slightly alter the injectors programming for the injectors on one plane vs another, as one set of injectors would be hanging in the air flow, and another set of injectors, would be recessed up into the injector sockets.
Since it is port injection, you do not have a fuel distribution issue, so in that case, the dual plane offers no advantage.
OTOH, due to reversion, a dual plane would be preferable. You can google what a dual plane has advantages, it has to do with the cylinder firing order,a nd what four cylinders are connected to each plane.
You will find you need to richen up the mixture in the ~2200 RPM range with a single plane manifold to overcome the reversion effects.
Ideally for EFI, you would want a single runner crossram type manifold, but you would need to make a common vacuum "can", that connects all the runners together to use the MAP feature.
Doug
You could probably do that with a dual plane, but it would take a lot more work, as the injectors all have to be at the same level for the fuel rail, and then you would probably have to slightly alter the injectors programming for the injectors on one plane vs another, as one set of injectors would be hanging in the air flow, and another set of injectors, would be recessed up into the injector sockets.
Since it is port injection, you do not have a fuel distribution issue, so in that case, the dual plane offers no advantage.
OTOH, due to reversion, a dual plane would be preferable. You can google what a dual plane has advantages, it has to do with the cylinder firing order,a nd what four cylinders are connected to each plane.
You will find you need to richen up the mixture in the ~2200 RPM range with a single plane manifold to overcome the reversion effects.
Ideally for EFI, you would want a single runner crossram type manifold, but you would need to make a common vacuum "can", that connects all the runners together to use the MAP feature.
Doug
Last edited by AZDoug; 03-10-2014 at 11:23 AM.
03-10-2014, 11:49 AM
#4
Safety Car
You want a single plane intake manifold for a sequential-multiport efi system. The fuel is being injected directly above the intake valve in a timed manner and thus the physics that apply for a carb or single point injection system are not the same here. I've used the mass-flo efi system, which is a sequential-multiport efi system, several times and it works incredibly well.
Last edited by 65silververt; 03-10-2014 at 11:53 AM.
03-10-2014, 01:45 PM
#5
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St. Jude Donor '07
Single plane manifold like the Vic Jr, are used because you can get all the injectors mounted at the same level,and position.
You could probably do that with a dual plane, but it would take a lot more work, as the injectors all have to be at the same level for the fuel rail, and then you would probably have to slightly alter the injectors programming for the injectors on one plane vs another, as one set of injectors would be hanging in the air flow, and another set of injectors, would be recessed up into the injector sockets.
Since it is port injection, you do not have a fuel distribution issue, so in that case, the dual plane offers no advantage.
OTOH, due to reversion, a dual plane would be preferable. You can google what a dual plane has advantages, it has to do with the cylinder firing order,a nd what four cylinders are connected to each plane.
You will find you need to richen up the mixture in the ~2200 RPM range with a single plane manifold to overcome the reversion effects.
Ideally for EFI, you would want a single runner crossram type manifold, but you would need to make a common vacuum "can", that connects all the runners together to use the MAP feature.
Doug
You could probably do that with a dual plane, but it would take a lot more work, as the injectors all have to be at the same level for the fuel rail, and then you would probably have to slightly alter the injectors programming for the injectors on one plane vs another, as one set of injectors would be hanging in the air flow, and another set of injectors, would be recessed up into the injector sockets.
Since it is port injection, you do not have a fuel distribution issue, so in that case, the dual plane offers no advantage.
OTOH, due to reversion, a dual plane would be preferable. You can google what a dual plane has advantages, it has to do with the cylinder firing order,a nd what four cylinders are connected to each plane.
You will find you need to richen up the mixture in the ~2200 RPM range with a single plane manifold to overcome the reversion effects.
Ideally for EFI, you would want a single runner crossram type manifold, but you would need to make a common vacuum "can", that connects all the runners together to use the MAP feature.
Doug
runner length/size is important for low end...Bill
03-10-2014, 01:54 PM
#6
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St. Jude Donor '12
Single plane manifold like the Vic Jr, are used because you can get all the injectors mounted at the same level,and position.
You could probably do that with a dual plane, but it would take a lot more work, as the injectors all have to be at the same level for the fuel rail, and then you would probably have to slightly alter the injectors programming for the injectors on one plane vs another, as one set of injectors would be hanging in the air flow, and another set of injectors, would be recessed up into the injector sockets.
Since it is port injection, you do not have a fuel distribution issue, so in that case, the dual plane offers no advantage.
OTOH, due to reversion, a dual plane would be preferable. You can google what a dual plane has advantages, it has to do with the cylinder firing order,a nd what four cylinders are connected to each plane.
You will find you need to richen up the mixture in the ~2200 RPM range with a single plane manifold to overcome the reversion effects.
Ideally for EFI, you would want a single runner crossram type manifold, but you would need to make a common vacuum "can", that connects all the runners together to use the MAP feature.
Doug
You could probably do that with a dual plane, but it would take a lot more work, as the injectors all have to be at the same level for the fuel rail, and then you would probably have to slightly alter the injectors programming for the injectors on one plane vs another, as one set of injectors would be hanging in the air flow, and another set of injectors, would be recessed up into the injector sockets.
Since it is port injection, you do not have a fuel distribution issue, so in that case, the dual plane offers no advantage.
OTOH, due to reversion, a dual plane would be preferable. You can google what a dual plane has advantages, it has to do with the cylinder firing order,a nd what four cylinders are connected to each plane.
You will find you need to richen up the mixture in the ~2200 RPM range with a single plane manifold to overcome the reversion effects.
Ideally for EFI, you would want a single runner crossram type manifold, but you would need to make a common vacuum "can", that connects all the runners together to use the MAP feature.
Doug
Just easier to plumb
