REFLECTOR: Re: Electronic Fuel Injection

[Chuck Harbert]

 Brian, I didn't know that you had a turbo on your Franklin. I'm interested 
in what you did to match the fuel flow with the turbo boost? I get the sense 
that you used a throttle body (s) with electronic fuel injectors, and then 
blow thru after the intercooler? Maybe you could explain your system to me, 
if you wouldn't mind. If you have any pictures, I'd like to see them.

The reason I'm interested is that I'm turbo-normalizing my IO-360 using a 
T-03 blowing thru a automatic fuel flow adjusting Bendix servo from a 
helicopter. Initially, I'll be using a manual wastegate, plus a overboost 
prv set at 34.5" (the helo servo was set up to handle up to 36"). I'm not 
using a intercooler, and the ignition will be handled by a Jeff Rose crank 
trigger driving a MicroTech ECU (which can also drive electronic fuel 
injectors) (Slick mag as backup). Eventually, I will add the electronic fuel 
injectors to the intake tubes, and turn the fuel off to the servo (which 
will be an emergency backup). I used the MT ECU on my previous AC engine and 
it worked well, plus it was reasonable cost. Check out their website 
http://www.microtech-efi.com/index.html, but don't tell them you are working 
on an AC, or they won't talk to you. This is a true sequential firing 
system. I've got the turbo setup almost finished and will install in the 
next few months.

You mentioned that you run 50 psi rail pressure which is great for 
atomization, but hard on electronic injectors which normally run 30-40psi, 
as I remember. Are these special injectors, or am I misunderstanding your 
system? I agree that normal AC carbs or servos are heavy and expensive, but 
I had a ECU failure and a forced landing that could have been prevented with 
a redundant fuel system.

Chuck H

 ------------------------------
>
> Message: 2
> Date: Mon, 2 May 2005 17:49:11 -0700
> From: "Brian Michalk" <michalk at awpi.com>

>
> I looked into this as well.  I called Ellison Throttle Body to ask about
> this specific arrangement.
> My fuel rail pressure is 50 PSI for the benefit of atomization.  They can
> make a throttle body that can take that kind of pressure, but a one-off
> wasn't cheap.  I'm also turbo-normalized, and for engineering reasons, 
> would
> need a blow through setup.  That also increased the cost.  The other thing 
> I
> didn't like was the plumbing.  I don't recall specifics, but after 
> learning
> how much weight and complexity it was going to take, I opted for a battery
> backed redundant system.
>
> On the Franklin, I was able to remove the MA-5 carb, which isn't a
> lightweight beast.  I removed the Tee manifold, and the cast intake
> manifolds.  Replacing them with .035 321 stainless.  The throttle body I
> replaced it with weighs very little.  I would guess about 1 lb.
>
> I was able to lose weight on the induction, but I gained weight in the
> turbo, intercoolers, and fiberglass.
>
> What we need is for someone to invent a reliable throttle body injector
> strictly for redundant uses.  Make it light, and mountable in any
> orientation.  Do all of this at the expense of fuel atomization, or
> efficiency.  It's a crutch that makes power until you can land at an
> airport.  It doesn't even need to idle an engine, which is where a lot of
> engineering work (and weight) goes in for a carb type system.
>
> I would have bought one of these if someone was selling them.