AFC position

Big Blue24 said:
What does the jig do?
Click to expand...

Lets you test the plate and AFC as they would work together on the truck. You would be surprised what you find. It's about passing the plate not bottoming the AFC out, they can be far from the same thing.
DSC00997.jpg


Damn to slow on the draw again :kick:
 
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Has that AFC been worked over? My foot will pass the plate by at least 5mm with the AFC full rearward.
 
cbtoyz said:
What I was getting at is if you correctly modify your AFC, it will not limit rack travel in any position, forwards or backwards. You can put it in any position you like. The AFC jig allows you to tune your AFC off the truck, you can set the foot height, see what pressure the arm begins to move, and what pressure it stops at, how far it moves, when the gov arm will hit the fuel plate, ext. It is useful for tuning, and modifying the AFC.
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Gotcha. My dumbazz missed that before. Thats what I was looking for this whole time.

Anything to do for full AFC travel besides the washer and grinding the foot?
 
cbtoyz said:
Has that AFC been worked over? My foot will pass the plate by at least 5mm with the AFC full rearward.
Click to expand...

Nope, completely stock arm with stock 215 spring. Just shows why the AFC should be modified.

madmikeismad said:
Gotcha. My dumbazz missed that before. Thats what I was looking for this whole time.

Anything to do for full AFC travel besides the washer and grinding the foot?
Click to expand...

Don't grind the foot if you can help it. Grind the barrel instead. That way you have better control of your bottom end fueling and still get full top end travel.
 
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White Knight said:
Nope, completely stock arm with stock 215 spring. Just shows why the AFC should be modified.



Don't grind the foot if you can help it. Grind the barrel instead. That way you have better control of your bottom end fueling and still get full top end travel.
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How do you grind the barrel?
 
White Knight said:
Nope, completely stock arm with stock 215 spring. Just shows why the AFC should be modified.



Don't grind the foot if you can help it. Grind the barrel instead. That way you have better control of your bottom end fueling and still get full top end travel.
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I call the part that actually slides on the shaft the "foot." I guess thats what I heard it called (probably by mistake) the first time, and I just stuck with it. I'll make a mental note to stop that starting now.

I never really understood why it mattered which part you grind on. Either way, it's all one solid piece, and will allow the foot to clear the rack's path. All I can come up with is so that you can keep the foot smooth.
 
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bsmith said:
What I meant is which part is the barrel? The top piece of the foot?
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the part that is a cylinder. it slides on the shaft in the afc.

You need to take 1/8" off the front(towards radiator) of the barrel.

The reason not to grind the foot(where the gov arm rides) is because it angles backwards to pull fuel out as rpm increases. I had a foot that had been cut straight up and down, could never tune smoke out correctly from idle to 3500 rpm because of it.
 
It's more than just one piece. It's not just about getting maximum fuel, it's about controlling fuel presentation, it makes a big difference. One reason you don't want to grind the foot is that it allows more fuel throughout the entire boost range which is often unwanted with big power components. Grinding the barrel only allows more rack travel at high boost, where you want it.

Here's a post by Smokem showing where on the barrel to grind:
Smokem said:
AFC lever
AFC013.jpg

Removing 0.100" from the marked area will provide full travel.
Click to expand...
 
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White Knight said:
It's more than just one piece. It's not just about getting maximum fuel, it's about controlling fuel presentation, it makes a big difference. One reason you don't want to grind the foot is that it allows more fuel throughout the entire boost range which is often unwanted with big power components. Grinding the barrel only allows more rack travel at high boost, where you want it.

Here's a post by Smokem showing where on the barrel to grind:
Click to expand...





Thanks. I saw that pic but didn't know it was called the barrel.
 
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mathews8pt said:
the part that is a cylinder. it slides on the shaft in the afc.

You need to take 1/8" off the front(towards radiator) of the barrel.

The reason not to grind the foot(where the gov arm rides) is because it angles backwards to pull fuel out as rpm increases. I had a foot that had been cut straight up and down, could never tune smoke out correctly from idle to 3500 rpm because of it.
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Thanks. Is it hard to take apart? I've only changed the gov springs, haven't fully torn into it.
 
White Knight said:
It's more than just one piece. It's not just about getting maximum fuel, it's about controlling fuel presentation, it makes a big difference. One reason you don't want to grind the foot is that it allows more fuel throughout the entire boost range which is often unwanted with big power components. Grinding the barrel only allows more rack travel at high boost, where you want it.

Here's a post by Smokem showing where on the barrel to grind:
Click to expand...

Here we go again with the "fuel presentation" term.:hehe::hehe::hehe:
 
White Knight said:
It's more than just one piece. It's not just about getting maximum fuel, it's about controlling fuel presentation, it makes a big difference. One reason you don't want to grind the foot is that it allows more fuel throughout the entire boost range which is often unwanted with big power components. Grinding the barrel only allows more rack travel at high boost, where you want it.

Here's a post by Smokem showing where on the barrel to grind:
Click to expand...

Ohhhh, I definitely didn't think of that lol. I'm glad I ask questions before I just go and start cutting stuff.
 
joni1013 said:
what would happen if you took too much off the barrel?
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The large washer becomes the stop once you've taken ~0.100" off the barrel. Cutting more off doesn't affect anything.

Washer bottomed out...

DSCN0020.jpg


Barrel is no longer limiting the travel...

DSCN0021.jpg
 
npe3484 said:
The large washer becomes the stop once you've taken ~0.100" off the barrel. Cutting more off doesn't affect anything.

Washer bottomed out...

DSCN0020.jpg


Barrel is no longer limiting the travel...

DSCN0021.jpg
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In that 2nd pic, is that as far as it will go?

I get my barrel to touch the housing and I haven't ground on it yet.
 
In that 2nd pic, is that as far as it will go?

I get my barrel to touch the housing and I haven't ground on it yet.
Click to expand...

That's the point of grinding the barrel. After you grind enough off of it, it will no longer be the limiting object of rack travel. The pictures show that after you grind the barrel the washer becomes the limiting factor. Notice how the washer is hitting the afc housing and the barrel is not.
 
Always wondered if it's ok to change to a slightly smaller washer. Is there a chance the AFC rack will get hung up if you let it go too far?
 
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