[BEECHFRONT]

I have been looking at changing to efi mostly for the benifit of not haveing to mess with carb adjustments and quick starting in cold temps etc... mostly for a street car, looking for a simple easy bolt on efi

been researching

fast ez efi and the Powerjection III ,

both suppose to be self learning and the powerjection III also says it can be tuned with laptop

powerjectionIII also says (coming out soon no fuel return required)

any body have any experience with this efi?


http://www.retrotekspeed.com/products/powerjection-iii/

 

[BEECHFRONT]

here ia a sema video on it
http://www.youtube.com/watch?v=Kty_JzA3MZY

 

[MikeMalibu]

Funny, Bill, I was just about ready to post the same question. The one difference I see between the designs is the electronics (ECU). The FAST product has a separate unit, whereas the Powerjection has the ECU built into the body, which means less wires to route. I read through both manuals and both seem easy to install. I have no experience working with EFI and would like to hear other's opinions.

 

[Xtreme70SS396]

Take a look at Vince's kit (new) he's got for sale:
http://www.chevelles.com/forums/showthread.php?t=293671

 

[Doug F.]

Funny, Bill, I was just about ready to post the same question. The one difference I see between the designs is the electronics (ECU). The FAST product has a separate unit, whereas the Powerjection has the ECU built into the body, which means less wires to route. I read through both manuals and both seem easy to install. I have no experience working with EFI and would like to hear other's opinions.

A big difference between the two is where they inject the fuel. The powerjection does it above the throttle plates, the EZ below. Makes a difference in the distribution and atomization.

 

[vrooom3440]

And to add a bit of "why you should care"...

We probably all know that liquid fuel does not burn so well. We really need fuel "atomized" or turned into a generally gaseous state. In a carb this transition occurs over several steps:

1. at the initial mixing of air bleed air with fuel (on the main circuit the emulsifier holes).
2. at the introduction of emulsified fuel into the low pressure high velocity air flow of the booster venturi.
3. somewhat at the turbulence of the throttle plates and intake runners/ports.
4. at the heat of the intake runners, ports, valves, and combustion chamber.

The atomization process it assisted by heat and greatly by pressure changes. In a carb this is atmosphere to vacuum, or a maximum of 14.7 PSI a bit above 0 PSI (I will use 0 PSI for simplicity in explaining the concept). In an EFI system this is injector pressure to the pressure where it is injected. For multi-port EFI you are looking at 40 PSI to 0 PSI.

Above the throttle blades you have 14.7 PSI or very close to the same as the injector pressure. Below the throttle blades you have a lot less so you get better fuel atomization.

But it is probably less of a differentiator than you would think... because above has the heat of the throttle blades to assist atomization. Above also may get better distribution from the throttle blade atomized fuel as it is better able to make turns under the throttle body (less mass per unit == less inertia).

 

[brngrhd]

A big difference between the two is where they inject the fuel. The powerjection does it above the throttle plates, the EZ below. Makes a difference in the distribution and atomization.

that is very good info i did not know that but it will make a big difference to me when i choose a system...... the one thing that i do like is that the powerjection system takes boost.

i would really like more info on the new holley system

 

[BEECHFRONT]

And to add a bit of "why you should care"...

We probably all know that liquid fuel does not burn so well. We really need fuel "atomized" or turned into a generally gaseous state. In a carb this transition occurs over several steps:

1. at the initial mixing of air bleed air with fuel (on the main circuit the emulsifier holes).
2. at the introduction of emulsified fuel into the low pressure high velocity air flow of the booster venturi.
3. somewhat at the turbulence of the throttle plates and intake runners/ports.
4. at the heat of the intake runners, ports, valves, and combustion chamber.

The atomization process it assisted by heat and greatly by pressure changes. In a carb this is atmosphere to vacuum, or a maximum of 14.7 PSI a bit above 0 PSI (I will use 0 PSI for simplicity in explaining the concept). In an EFI system this is injector pressure to the pressure where it is injected. For multi-port EFI you are looking at 40 PSI to 0 PSI.

Above the throttle blades you have 14.7 PSI or very close to the same as the injector pressure. Below the throttle blades you have a lot less so you get better fuel atomization.

But it is probably less of a differentiator than you would think... because above has the heat of the throttle blades to assist atomization. Above also may get better distribution from the throttle blade atomized fuel as it is better able to make turns under the throttle body (less mass per unit == less inertia).

Steve, if you had to pic between the fast ez efi and the Powerjection III on a 383 stroker what one would you pic?

Bill

 

[rianbechtold]

The powerjections don't look that great in person. None of their pics really show it but the "bowls" that cover the injectors are like skirts. IDK, it just looks alot cheaper in person.

 

[vrooom3440]

Interesting question and I had to go browse their web sites and get more information.

I see what Ryan was saying about the Powerjection units. They have some bottom side pictures on a prior generation. The fuel bowls really are just cosmetic covers. And it still has pretty much all of the usual wires coming out.

By comparison the TBI part of the Fast EZ EFI looks a lot cleaner in it's own way, it just looks more functional.

Reading through the install docs, both are wide band based which is good. Both are fuel only units, which is a bit of an issue to me. There is a lot of advantage to being able to tune ignition across the map rather than the simple mechanical/vacuum advance setup on non-computer controlled setups.

While admitting personal biases I also have to admit I prefer multi-point injection over throttle body injection. Both of these units are TBI and will have some degree of unequal air and fuel distribution. With MPFI the air flow may vary but not so much the fuel flow. Gets you a step closer to beneficial evenly balanced cylinder operation.

The Powerjection uses a laptop for tuning while the Fast EZ EFI uses it's own custom control panel. This a good news/bad news kind of thing. There is a lot more hardware capability to work with a laptop so they can do things you just cannot do with a small control panel. Then they are bulky and not exactly optimized to in-car use. That is where the little custom control panel is cool. You could velcro that sucker down someplace and be fine.

Both units claim to allow mounting the EFI computer in the engine compartment. This can be a lot more convienient than having to mount it in the cabin and pass the wiring bundle through the firewall.

I think in the end I prefer the Fast EZ EFI. I think injection under the throttle blades is better since it puts fuel into a low pressure zone for better atomization. I wish it had a PC option, but for what it is the control panel offers some compelling tradeoffs. I also think the documentation on the Fast was superior. So if I were spending $$$ that is where I would send it.

 

[BEECHFRONT]

Steve, thanks for the indepth input, I can get over 400.00 off the fast ez efi through summit for a short time, and that was the unit I was leaning towards

Bill

 

[jerryanderson]

Anyone got a program for a 383 stroke for a powerjection 3