Fuel Injectors

2002_lincolnLS

2002_lincolnLS

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So I was wondering how the air assisted fuel injection actually works on the V-8?

Is there a vacuum line or is it air from inside the manifold, what is exactly is air doing to help the fuel injectors?

Also why does it cause problems with forced induction, if it is assited by air then logically thinking more air would mean more "assisting", I'm sure thats not how it really works though.


Simalar topic...

Are there any aftermarket Injectors that just so happen to fit our car, Kind of like mustang coils "fit" our car?


I did do a search, I didn't find much in the way of how it works... I did see something about putting mustang injectors on our car but is was a v-6 and there wasn't much info at all.
 
There's an air rail molded into the intake manifold that runs along the base of the injectors. There's a cross-over tube that connects both rails to the filtered intake air. It looks a lot like a fuel line. That tube plugs into the manifold in the middle. Do some digging around and you'll find it.

The manifold is under vacuum (generally), and the air rail provides air into the base of the injector that is at ambient pressure. So when the injector fires, fuel is pushed through the injector as normal, but air is also pulled through the base of the injector and mixes with the fuel. The theory was this turbulence would help mix the air and fuel leading to better combustion. It hasn't taken off, so it's fair to assume the idea isn't fully baked.

The first problem with using our injectors with forced induction is the base of the injector is strange - it seals at the bottom like normal, then has a separate seal for the air rail. If you use a custom manifold that doesn't have the air rail, then there will be a huge leak.

If you add forced induction AND plumb an air rail, you have to bad options:
1) plumb the air rail to ambient. The above ambient pressure in the manifold will push air and fuel into the air rail. Bad.
2) plumb air rail to manifold pressure. This will be a null effect, but turbulence between the air rail and the manifold might make things interesting.

So, in sum, just use standard injectors with FI.
 
Okay cool thanks,

now in a turbo aplication I wouldn't be changing the manifold around at all so would it be alright to use our injectors in that situation.
 
2002_lincolnLS said:
Okay cool thanks,

now in a turbo aplication I wouldn't be changing the manifold around at all so would it be alright to use our injectors in that situation.
Click to expand...

I've seen suggestions to just put a check valve in the air line between the IAC and the injector air rails. This should work okay as my understanding is that the air assist feature is mainly for at idle conditions.

Here's a little background on it...

http://books.google.com/books?id=14...e&q=lincoln ls air assisted injectors&f=false
 
Thanks Joe, I looked for some general Info on google, but didn't see much.. Of coarse I didn't really know what to look for.

Do you know of anyother other cars that use this set up that I could see what people have done with or have insight into this type of Fuel Injection, I'm going to nose around on google to see if I can find any.
 
2002_lincolnLS said:
Thanks Joe, I looked for some general Info on google, but didn't see much.. Of coarse I didn't really know what to look for.

Do you know of anyother other cars that use this set up that I could see what people have done with or have insight into this type of Fuel Injection, I'm going to nose around on google to see if I can find any.
Click to expand...

I think that some Toyota's do or did. (4runner maybe?)
 
2002_lincolnLS said:
now in a turbo aplication I wouldn't be changing the manifold around at all so would it be alright to use our injectors in that situation.
Click to expand...


one of the parts of going FI, is that to make more power you need to burn more fuel, a turbo only solves part of the problem by getting more air to mix with the fuel, you still need to get more fuel into the motor. now if your only using a real small amount of boost (an awful lot of money for not much gain) you may be able to get away with the factory injectors, but for any reasonable amount of boost, you will be way past the maximum duty cycle of the factory injectors. here in lies the real problem with the original issue, the common proper sized injectors wont work with the air assist system, so a good fabricator's easiest option, is to make a custom manifold, to be able to put a more standard injector (like a cobra injector) into it, and have enough fuel to not worry about blowing up the motor
 
joegr said:
Here's a little background on it...
Click to expand...

Isn't it great that a section of a book about general Ford control systems contains several pages of Lincoln LS exceptions?
Man, we got the special cars. :D
 
Loud LS, thats what I was trying to figuire out, was where does the issue come in when looking at forced induction type set up.

thanks guys
 
the other issue with the air-assisted injectors - is that there are not many options (sizes) available. So if you are adding more power - the turbo / supercharger will add the needed air but you will have to add more fuel as well - likely that means upgrading the fuel injectors to larger ones....

and trying to find larger injectors that are EV6 with the air assist is nearly impossible...
 
Quik LS said:
the other issue with the air-assisted injectors - is that there are not many options (sizes) available. So if you are adding more power - the turbo / supercharger will add the needed air but you will have to add more fuel as well - likely that means upgrading the fuel injectors to larger ones....

and trying to find larger injectors that are EV6 with the air assist is nearly impossible...
Click to expand...

what do you think the max boost with out getting new ones, would 5 pounds from a turbo be to much for our stock injectors or could I even hit 8, or is that out of the question? I just want to know everything I can before I even begin to tackle any kind of project like this.

thanks for all the help, guys.
 
If my math is correct.... I think you are pretty close to the edge with stock...

meaning at 252hp (stock) you need 18.9lbs injector (@100%) so at 85% (typical drive) you are into 22lbs... I believe the stock injectors are:
Ford XW43-9F593-CA, Ford XW4Z 9F593 CA, Motorcraft CM4934, Standard FJ297, Airtex 4G1234, Delphi FJ10533

12 ohm coil with the following flow rates:

Dynamic (2.5ms @ 100Hz): 25.32 g/min 32.88 cc/sec
Static (10ms @ 100Hz): 173.14 g/min 224.85 cc/min

if I am doing my math right -- 224.85 cc/min/10.5 = 21.45 lb hr.

Capture.jpg
 
so basically I can't go any higher with stock fuel set up. That blows, well Lincoln you have stumped me again with your lack of ability to take aftermarket parts... I'll figuire something out.
 
If you're spending the money going with FI, upgrading the injectors shouldn't be an issues, they wont be the ones breaking your bank in the FI set up.


Thanks for that info Quik, I tried finding out the stock injectors rating a little while ago and just gave up.
 
Alax7 said:
If you're spending the money going with FI, upgrading the injectors shouldn't be an issues, they wont be the ones breaking your bank in the FI set up.


Thanks for that info Quik, I tried finding out the stock injectors rating a little while ago and just gave up.
Click to expand...

I'm not worried about the injectors price, its the price of a custom manifold because of our goofy injectors. So the more I understand the injectors and the manifold the better, because when it does come time that I do this, I will be doing all my own work.

Quik, are the holes the arrows are pointing at the air assist ports.

Is it possable to plug the ports and install regular large injectors, or would that cause problems. (fuel running up into that air rail)

intake mani.jpg
 
Oh yeah, brain fart.

Sucks for you gen1 guys.

They are using cobra injectors for my ls. I think they only needed to build a spacer because the injectors were too long, but I'm sure it's way easier and cheaper than getting a custom manifold done.
 
are the injector plugs the same (electrical conection) between gen one and two.

also would it be at even feasable to mount a gen 2 intake manifold on gen 1 engine with a gen 1 tb, or is everything different, I mean the blog and such should be bassically the same, then I could use the cobra injectors and such.
 
yes - your arrows are pointing to where the air feed hoses connect to the air rail. the air rail is the 'tube' looking thing running across all the injector bungs.

the issue is one of sealing a standard injector tip to the bottom of the manifold - the air-assisted injectors have a much wider tip than a standard injector does. I could never get a proper seal with standard injectors (especially under boost).

I believe people have tried the Gen2 intake and it did not fit as the VVT heads are sized differently.
 
Why does everything on these cars have to be complicated? We gotta have hydraulic fans and air assisted injectors?
 
Quik LS said:
yes - your arrows are pointing to where the air feed hoses connect to the air rail. the air rail is the 'tube' looking thing running across all the injector bungs.

the issue is one of sealing a standard injector tip to the bottom of the manifold - the air-assisted injectors have a much wider tip than a standard injector does. I could never get a proper seal with standard injectors (especially under boost).

I believe people have tried the Gen2 intake and it did not fit as the VVT heads are sized differently.
Click to expand...

I'm sure you have thought of this but what about playing around with different sized o-rings maybe even have fatter ones made to fill the gap, I'm just trying to think out side the manifold here.
 
scjmc said:
Why does everything on these cars have to be complicated? We gotta have hydraulic fans and air assisted injectors?
Click to expand...

I know typicaly an engineers goal is simplicity, instead they thought lets over complicate everything on this one but make it look super good so people will buy em...


I love the car but man does it drive me up wall sometimes.
 
1LoudLS said:
not in the premium car market, its about who can cram the most fanciest high tech gizmo's in to the car to be able to sell it for more.
Click to expand...

I know, I feel bad for BMW techs when thier 7 series cars come in for service, I cant even imagine diagnosing an electrical isuue in one of those.
 
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