dual plane mpfi?

[rmccubbin]

Most of the custom mpfi set-ups I've seen are on single plane drag racing manifolds and I can't recall seing a dual plane modified in such a way. It IS feasable to outfit a dual plane with injectors and rails...right? I've got a SBO Edelbrock Performer RPM in mind. Any potential problems with such a setup over a single plane? Comments, advice, and feedback are welcome; thank you.

[Skip Fix]

I think the issues using a dual plane are angle of the runners into the port for injector/fuel rail clearance and different runner lengths for each port.

[Hammered]

I believe the main purpose of the dual plane design is to give the carb a strong signal at low rpms. No carb - no need for a dual plane.

[Samckitt]

I don't see why you would want to make a dual plane MPFI intake. All factory MPFI are basically a single plane manifold. Look at the GM TPI, LT1 & LSx engines. All are a sinle plenum with 8 runners, just like a single plane intake.

[Rolling_Thunder]

I believe the main purpose of the dual plane design is to give the carb a strong signal at low rpms. No carb - no need for a dual plane.

correct... because the carb does not need a good low end signal to pull fuel, there is no point to use a dual plane intake...

[68Formula]

The statements about carb signal are true. But it still will affect the RPM range at which the manifold is optimized for power because of runner length and plenum volume. Single plane carb-based usually have shorter/larger diameter runners with more "effective" (due to the plane being halved) plenum volume than dual plane carb-based.

EFI will be less sensitive than a carb as far as driveability, but still effects your torque curve.

[rmccubbin]

EFI will be less sensitive than a carb as far as driveability, but still effects you torque curve.

That's more to the point of what I am asking; the rpm/optimal power range of a particular manifold doesn't change with carbed to mpfi conversion, right...so if I had an option of converting a street dual plane manifold vs a drag racing single plane...I'd choose the dual IF it could be done since I won't be driving around at 4500 rpm routinely.

That's my line of thinking; I understand what you guys are saying about the design of the dual plane being based on the notion it would be carb fed...I wonder how converting a single plane designed for drag racing would behave on the street converted over to mpfi...

Thank you for the dialogue and input.

[GetMore]

I'd probably think about using a TPI setup instead of a dual plane intake, but that's me.

Generally speaking, a single plane intake is okay for EFI because the fuel is injected at the intake valve, so it doesn't have a chance to puddle like it could in a carbed intake.
You are correct in thinking that velocity will be lower at low RPM, and that you won't have quite as much ram effect to boost low end power, but the superior fuel distribution usually makes up for that.

As for the power range, I think the lower end of the scale is partially determined by the ability to hold fuel in suspension. Too large a runner will have too low a velocity and drop the fuel at low speeds. So, again, a single plane EFI system has less problem at low speeds.

As mentioned, most OEM setups have the runners all the same length. This "tunes" the intake pulses for a certain rpm and makes the cylinders all act the same (more or less.) I believe it is more important from an emissions standpoint than a power one. Having two different length runners would create two torque peaks, but neither one will be as strong as an equal length setup.

[RAMKAT2]

There are other factors that may determine the choice of intake manifolds, hood clearance being one of them. Some cars simply cannot get a tall single plane manifold, throttle body, and breather underneath the stock hood without cutting a hole in it and adding some type of hood scoop. I believe the dual plane would work fine for an efi conversion, as long as you still took the airflow limits of the manifold into account when choosing the engine components. Dual plane manifolds weren't designed for use with high rpm's like single plane manifolds, and with multiport fuel injection, the manifold will see dry airflow instead of wet airflow (above the injectors) so the dual plane will not be as succeptable to fuel /air separation while negotiating the varius turns in the manifold. You can always cut down the divider in the manifold for more airflow between both sides of the dual plane if you feel it is necessary.
I am going to be using a Poston dual plane manifold on my 455 buick EFI setup when I get farther into my 67 Riviera project, & since the motor is being built for torque instead of high rpm's, a dual plane manifold will work fine in my application. And it will fit under that looooong low hood without requiring a cutting torch. Later, Randy

[Hammered]

Welcome to the forum RAMKAT2. We (at least I) need to hear more about this '67 Riv' I've been thinking about another project and was looking at the '66 and '67s as good candidates.

[pdq67]

I would love to try to do what you are trying to do using a Hi-Tech Torklink Intake here.........

http://flowdesign.tripod.com/flowdes...ology/id6.html

It is like an old E-brock SP-2P dual plane that set up w/ really long "horseshoe" shaped " dual plane runners like a high-rise single plane!!

Think about how this configuration would build midrange T very well imho!!

pdq67

PS., and fwiw, this is about the ONLY NEW aftermarket intake design for a carb. that has come along in YEARS and YEARS!!!

[rockvillespeed]

the torklink's been out many years on the market - at least a decade.
bear in mind it's a race intake; probably won't do as well as a typical dual plane at low r's; these intakes are purported to not work real well; i think it's a neat idea and respect jim mcfarland a lot, but these just havent caught on for some reason.
professional products has a poncho intake that's port efi and dual plane (not that this means a thing; they're not exactly innovative)

[Alaska442]

There is a new air gap style duel plane out for the 455 olds. it has bosses cast into it for FI.
Its a china made product but quality looks good from what I have heard.
The name escapes me at this time - Patriat or huricane canr remember.
Check some olds sites like realoldspower and im sure you will find it.
Nathan

[camcojb]

I don't think you'll find much love for the Chinese rip off of Edelbrock manifolds on the car boards.

Jody

[Alaska442]

Jodie, Nobody else makes a air gap for olds v-8 350 or 455. It is not a rip off as this one had to be designed from scratch.
Prfoessinal products is the name and there is one on ebay now under oldsmobile air fuel delivery.
Im not a big fan of nock offs but this manifold is one of a kind design.
Nathan

[Fuelie Fan]

This question has been asked many times, do a search.

2 issues: airflow dynamics and fuel flow dynamics

As mentioned above, airflow dynamics are largely independent of fuel metering type (carb or efi, ignoring cooling effects for now). Runner length, runner diameter, and plenum volume(s) all affect how pressure waves act within the intake manifold. A "dual plane" intake, if you've ever noticed, is not simply a single plane with a divider; certain cylinders are paired according to their firing order. This is all in search of getting favorable pressure wave action. I'm not going to get any more into the theory here, look up "helmholtz resonators" if interested. Point is, these effects occur whether or not it's efi, so an intake that is listed in the catalog as "idle to 5500" will give you power in that band.

fuel delivery is another issue. As some have correctly pointed out, carb'd intakes must be designed (some would say greatly compromised) to provide effective fuel transport. Race single plane intakes somewhat ignore that, and so for lack of a technical term they suck on the street, especially at low rpms. People have found that with EFI and the lack of fuel transport issues, some driveability can be regained. They then wrongly assume that with EFI the intake design doesn't matter. But, the runners (unless stated otherwise) are still tuned for higher rpm performance, and you are still giving up low end torque (Albeit not as much) to an intake designed for low rpm performance.

To counteract what someone else said, OEM efi and dual planes are not mutually exclusive. Take a look at the Viper's intake design. Two plenums, each feeding five cylinders. Single versus dual plane, runner length, runner area, plenum volume, etc are all design variables that can be tweaked to achieve the desired torque curve on modern or older engines alike.