Thoughts about period looking MPFI

[Foghorn]

Fellas,

I have been thinking about changing from a carb to fuelie for some time now. My current set-up is a KC 482, flat-top pistons and a hyd. roller cam, Ebok 76cc heads that Keith massaged slightly, Blue Thunder high-rise intake and a QT 780 cfm vacuum secondary carb. 480/475 rwhp and Q. I just returned from a 1400 mile road trip and netted 14+ mpg...

All I have been reading indicates that converting to a well-sorted fuel injection can/will equal 10% more power and better economy. That and I need a winter project to keep me occupied.

I want to maintain the correct appearance under the hood, and I want as close to equal length runners as I can get, off of a common plenum. The appearance piece means either a single or dual quad set-up (as you all know, the 427s didn't come with webers). The common plenum is so that the cylinders all have access to the same air so the software has a consistent base to meter the fuel, and the equal-length runners just makes sense to me....

I have narrowed my thoughts to two choices. One is already on the market in several variations, that being the single quad MPFI kit from either FAST or Edelbrock, or using a combination of hardware from Edelbrock and Holley run by several options of software: Ebok, FAST, Holley, Megasquirt, etc. This is the easiest route. It maintains close to the period correct appearance (never mind the fuel rails), has a common plenum, but doesn't do much for equal length runners.

The other option I am considering will require a bit of fabrication on the hardware side, but will still be able to be managed by one of several software options.

I am thinking of starting with a tunnel-wedge medium-riser dual-quad intake from Dove, modified with the injector bossses for MPFI, dual throttle bodies, and run by either a Holley Dominator ECU or a FAST XFI (probably Holley ATT, their user interface is easier to understand).

I was thinking it might be possible to weld the injector bosses on the bottom and hide the injectors and fuel rails inside the V of the intake. Two limiting factors would be the physical space required due to the length of the injector/fuel rail x 2 fitting between opposing cylinders and extra bracketry to support the fuel rail since gravity will be working in a direction other than straight down through the injector body.

Using this intake gets me pretty close to equal length runners and a relatively large common plenum, as well as preserving the period correct appearance.

Please fire away with what you guys see as issues going forward. At this point it is just an idea rattling around in my head. I appreciate all opinions, so long as it's more than just "that's the dumbest idea I have ever heard".

Also, I would need to contract out the fabrication work on the intake, if there are any parties interested enough to offer a quote.

[ERA Chas]

I think you should contact Hogan Racing Mnifolds and just run these questions by them. Expensive, but they'll fab anything you want.

[olddog]

Two issues with mounting the fuel injection under the intake:

1) If there was a fuel leak it would go into the oil, likely destroying the engine (might save a fire that destroys the car, on the other hand). I do not know if the oil would attack the O-rings that seal the injector in the bungs.

2) The injector bungs should aim the injector at the intake valve. Cannot do this from underneath. At light loads the injector sprays fuel onto the intake valve before it opens. The hot valve boils the fuel, so that all the liquid changes phase into a gas. This give more complete burning of the fuel for better MPG and cleaner emissions.

I do believe that with a some ingenuity, the injectors and fuel rails could be inside the intake manifold. Inside is not necessarily in the air-stream, rather machined into the aluminum. This would require the design to be in pieces, such that you would disassemble it to get to the injectors and fuel rails.

[Foghorn]

ERA Chas: Thanks for the gouge. I checked the website. Nice stuff, and the price definitely reflects it!

Olddog: Thanks for the observations. The tunnel wedge intake is an air-gap design with a removable bottom plate to close up the lifter valley when the intake is installed. I envision the injectors external to the intake, just mounted on the underside of the runners, still pointed at the intake valve.

Here's a linky to a picture of the intake manifold:
http://www.carlsfordparts.com/parts_...ure%207_14.JPG

I may have to settle and have the injectors on the top of the runners. Hiding them in the middle may be beyond the point of diminishing returns....

[olddog]

I wasn't aware of a FE 8V air gap manifold. You may be able to do what you want. Injector open/close speed may be impacted by the angle it is mounted. It may impact tuning parameters.

Take a look at MassFlow. They are selling 4V setups along this line. They are also selling a new ECU under a different company name. It uses more current Ford sensors. It may have a provision to use 2 mass flow sensors on an 8V set up. I cannot remember for sure if it was them or someone else. This system is worth a look. Even if you don't like it, you should get a lot of ideas.

I like EFI, but it is costly to convert a car from carb to EFI or visa versa. Unless there is a problem you are trying to solve, you may spend a lot of money and time sorting out all the problems you create along the way.

There have been dyno tests of an engine with carb and EFI swaps that showed the carb made more power. Barry R told me of one test he did some years back. You may be able to find that thread. I'm sure there can be many factors, and the results will varry, but I would not assume EFI will make more power.

[Donunder]

Expecting a 10% increase in power might be a stretch, but the lower rpm torque increases can be staggering. Sounds like an interesting project!

[Keithc8]

I do not believe there will ever be room to put the injector under the intake and get the fuel rails on. It would also not have them in the right position. You could weld the bungs on top in the normal spot and it would work fine.
The easiest thing to do is use the Edelbrock single plane intake that already has the bosses made into it. Use the throttle body and injector size best suited for the application. We have done these with the Fast stuff before and it works pretty well.
Now you could use the tunnel wedge intake with two throttle bodies that had the injectors made into them like a 2X4 set up and run regular air cleaner for a 2x4 set up. We have welded the bungs into the intake before on the small block and big block stuff before they were available. Kind of depends on the look you are wanting and the budget you want to spend. Let us know if we can help.
Thanks, Keith

[Dumpling]

I have seen an intake such as you envision.

It was for a SBF, was a crossram, with the injectors mounted on the underside of the runners.

The fuel rail was one length, with the injectors mounted on each side as needed.

That means if you took the fuel rail and stood it on end, there would be alternating injectors sticking out from each side.

The machining obviously would take an expert.

I also believe that there was not just an access plate under the runners, but full access to the runners from below (the spider mounted to a valley plate adapter.

You might consider a TB system, with the injectors mounted to the throttle bodies. That would more closely mimic a standard carb 'look' if you don't want injectors and the fuel rails showing.

[blykins]

Going to EFI for a project, or just to gain experience is one thing, but you will absolutely not gain 10% power by going to MPFI. You're talking about picking up approximately 60 hp at the engine....an't gonna happen.

[Michael C Henry]

I have never gone to the my cars limit, I have always backed out, but I have thoughts. I have that intake manifold in a 427 replica, and I realizeit was designed for a great big Galaxy. The engine sat with a rear down incline for oil drain back and to get the coolant thermostat as the highest point and lots of hood clearance. Back then, 900 CFM or larger carbs were not heard of. In my replica the engine sits almost flat that puts my carbs at a front down incline and I have a pair of 600 CFM Holley carbs with a pair of trimmed down S&H air cleaners. I feel the air cleaner are restrictive and still leave marks on the underside of the hood. I would rather have a free flowing manifold (maybe a slight air gap), carb base sits flat with my engine , multiport fuel injector bosses (probably custom made)The carb base being level probably wouldn't matter with multiport fuel injection. If it could made to look old school the better. I'd put a large single throttle body and cover it up with a big air cleaner. The old sidewinder intake starts sounding better all the time. OR, how about a large air door with ram air ducting from the front air ducts on the body. At any rate the whole system would need to be planned together because working with the old always calls for compromises. I find myself trying to reuse something that I have that doesn't really work with the new. Money and labor are always a concern.

I'm preparing for retirement and everything on this car works beyond my limits. My old stuff probably has no resale value to anyone else as my heads and intake are milled to fit with each other on a standard block. Lots of work has been done to the heads and intake and It started as 11.5 to 1 compression ratio., It's probably slightly higher now. Buying the best pump gas and adding stuff has worked so far. It sits in the garage and is ready to go at a moments notice to go farther than I can afford to buy gasoline. I don't want to turn it into a virtual boat ( a hole in the water where you pour money)

[Torrance55]

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