MR.T

If I had to guess, the pulsation damper does exactly what it's says it does.....dampens pulses. It must be some sort of hammer arrester. That's a term we use in plumbing.
When valves (injectors) are quick/closing or solenoid type they slam shut, the water pressure inside of the pipe, or in this case the fuel inside of the fuel rail stop abruptly, causing a back and forth surge and varying pressure until the pulsing stops.
This surge would be very fast and almost unnoticeable in terms of performance. I would guess that if it did have an affect on performance, it would be more on deceleration instead of acceleration.

In plumbing we use hammer arresters to prevent the noise of hammering pipes inside of the walls, but they also have another use....protecting the integrity of the piping system. Soldered fittings have been know to blow apart, pipe shifting back and forth against metal or other hard items can develop holes from rubbing....etc. I would guess that a fuel system could be susceptible to the same failures.

As far as the screw, I assume it pushes down on a rubber seal that is spring loaded in some way or another.

shind3

If the screw is not required, why did they go through the trouble of using it in the design, using threadlocker on it during manufacture etc.?

bgoetz

I am not sure about this specific component, but in terms of Honda installing useless crap MANY different components come to mind. Some are required by emissions and basically are installed for no other reason than meeting a requirement. Others I am still not sure what the heck they are for, as the car is better without them (see CDV).

Slowcrash_101

I never said it's not required, quite the contrary I said it's meant to work with the screw. I'm also saying that the pulsation damper can still do it's job without the screw because all the screw does is limit the amount that the diaphragm can move. It still moves with or without the screw, if the diaphragm rips then you're in a mess. But the screw itself provides no sealing whatsoever.

jkelley

I never said it's not required, quite the contrary I said it's meant to work with the screw. I'm also saying that the pulsation damper can still do it's job without the screw because all the screw does is limit the amount that the diaphragm can move. It still moves with or without the screw, if the diaphragm rips then you're in a mess. But the screw itself provides no sealing whatsoever.
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I believe this is correct. I work with pulsation dampeners at a chemical industrial level used in conjunction with air-powered (double) diaphragm pumps. Essentially it's an additional flexible diaphragm that has positive pressure behind it (in this case). The surging of pressure from the pump firing generates head pressure at the time of cycle but dispenses after the firing stroke before the next firing stroke. This causes "pulse flow" (obviously?). The dampener basically is close to the point of head generation (very close to pump discharge typically) and absorbs some (never all) of the head pressure spike by flexing the dampeners diaphragm, absorbing the pressure. The pressure on the opposite side of the dampener's diaphragm is able to compress to absorb some of the discharge (process side) pressure, but then it re-equalizes that pressure from the positive pressure on the dampener diaphragm, non-process, side.

The screw (I believe) is a mechanical way of setting the maximum diaphragm flex/expansion distance. For my chemical applications, I have to "tune" dampeners by adjusting their size and positive pressure side (non-process) pressure. I believe these fuel rail dampeners are similar, but they are a mechanical limit on the flex distance of the diaphragm, rather than an air pressure limiting force on the back side.

I wouldn't even know where to start in figuring out how to set it on our cars, though.

street_ruler

read the rx7 thread people.


basically this is the same as what you put on the water line to your washing machine. it prevents "hammering" in the fuel system. it gives little surges a place to go and takes up a little "low points" when there isnt quite enough fuel to fill the space.


They can pop out and vent fuel everywhere. on most cars they have this readily accessible. however on an RX7 specifically its buried under the manifold facing away from the mechanic. at all angles. Its also more of a problem on an RX7 with the pattern of firing that the injectors see.

shind3

I never said it's not required, quite the contrary I said it's meant to work with the screw. I'm also saying that the pulsation damper can still do it's job without the screw because all the screw does is limit the amount that the diaphragm can move. It still moves with or without the screw, if the diaphragm rips then you're in a mess. But the screw itself provides no sealing whatsoever.
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You're arguing semantics now. If X 'can do its job' without Y, then one might say that Y is 'not required'...

Thank you. /thread