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Discussion Starter #1
I was looking at what I can only assume is a fuel pressure regulator (00 M900). One large hose in, one out (one on the side, the other on the bottom). There's also a nipple up toward the top of this thing, that has no hose on it. On a car, id say this would be the vacuum source for the regulator. Only, this has no hose on it. Should this be open to atmosphere? I looked around and didn't see a vac. hose thats the size to fit this nipple. Don't get me wrong, the bike about tears my arms off if i want it to, but this strikes me as odd. Anyone have any input?

Kevin
 

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>Should this be open to atmosphere?

Yes. Ducati uses an off the shelf pressure regulator which might use a vacuum or pressure hose to alter the fuel pressure in another application.
 

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Discussion Starter #3
>Should this be open to atmosphere?

Yes. Ducati uses an off the shelf pressure regulator which might use a vacuum or pressure hose to alter the fuel pressure in another application.

Really? How can it regulate pressure with no vacuum source though? Im inclined to think that my bike is indeed normal, but it still doesn't make a whole lotta sense to me.

Kevin
 

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There is a spring in there. The pressure is regulated against the spring pressure. The hose is used to raise the pressure on turbo charged cars. You can also raise the pressure by hitting the bottom with a hammer. Something the tuners do when Dyno tuning. Evo makes an adjustable one with a screw in the bottom that pushes against the spring.
 

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Discussion Starter #5
There is a spring in there. The pressure is regulated against the spring pressure. The hose is used to raise the pressure on turbo charged cars. You can also raise the pressure by hitting the bottom with a hammer. Something the tuners do when Dyno tuning. Evo makes an adjustable one with a screw in the bottom that pushes against the spring.
But there still needs to be a vacuum source to change the pressure. All the non turbo, fuel injected cars ive owned have a vacuum source to the top of the regulator. If you pull that hose off, fuel pressure shoots way up because the spring you spoke of is keeping things closed up (there's no manifold vacuum to counteract the spring) In that situation, you get one pressure all the time, no matter the operation conditions.

Kevin
 

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Fuel pressure is constant (regulated by the spring), that vacant "teet" is a vent.

Jeff
 

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Discussion Starter #8
Fuel pressure is constant (regulated by the spring), that vacant "teet" is a vent.

Jeff

So the fuel mix is changed only by altering the injector pulse duration? Ive never seen a FPR that didn't hook inot the inake somehow or another. Looks like 980SSP does know what he's talking about. Thanks all.

Kevin
 

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If you've seen any of Alex's stuff, you'll know that if the time ever comes when he doesn't know what he's talking about, none of us will be able to tell ;D ;D
Looks like 980SSP does know what he's talking about.
 

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Discussion Starter #12
Well, since its been over 3 years since I posted this initially, I've learned a little.

I've also heard of AO :)

Kevin
 
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