better cheaper pulsation dampner
07-02-07, 05:27 AM
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better cheaper pulsation dampner
I am working on a friends S4 NA. I already replaced the dripping PD with a banjo bolt, and put the car back together. I am not entirely comfortable with no PD.
So here is the idea:
http://www.matronics.com/fuelchec/dampener.html
an all stainless PD t'd into the fuel line between the engine and fuel filter, out away from heat, and it looks in the picture like its probably leakproof even if the dampening where to fail. And it should be seeing as its made for aircraft.
And the best part, its only 45 dollars.
any thoughts?
So here is the idea:
http://www.matronics.com/fuelchec/dampener.html
an all stainless PD t'd into the fuel line between the engine and fuel filter, out away from heat, and it looks in the picture like its probably leakproof even if the dampening where to fail. And it should be seeing as its made for aircraft.
And the best part, its only 45 dollars.
any thoughts?
07-02-07, 01:27 PM
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For a fuel PD to be useful, it has to be close to the injectors. Mazda put it on the fuel rail for a reason. I've seen people running that PD. Works pretty good. wasn't on RX-7's though.
07-02-07, 02:12 PM
#6
Yeah that thing is pretty useless, the stock PD is a rubber diaphragm.
Now if someone made an adapter for the stock pd to go above the fuel filter, that'd be more useful i thinnk. The main issue is the fact that the fuel leaks onto the exhaust afterall.
Now if someone made an adapter for the stock pd to go above the fuel filter, that'd be more useful i thinnk. The main issue is the fact that the fuel leaks onto the exhaust afterall.
07-02-07, 02:31 PM
#7
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Reply to basic questions from the dealer:
"The Pulsation Dampener we sell is manufactured by FloScan, the transducer company. It is essentially a 2" stainless steel sphere with a 1/2" NPT female fitting welded to the bottom. It works on the same principle that the faucet air hammer works, using the higher compression characteristics of air vs fuel.
I don't know what the maximum pressure rating is for the device. It is typically used in carb and injected installations where the pressure is 5-50 psi or so.
I have had a couple of customers use it in injected installations, but typically pulsation issues are more related to low-pressure carb installations.
About the only failure mode would be if the fitting became unwelded from sphere. If this were to occur, there would be fuel leakage."
"The Pulsation Dampener we sell is manufactured by FloScan, the transducer company. It is essentially a 2" stainless steel sphere with a 1/2" NPT female fitting welded to the bottom. It works on the same principle that the faucet air hammer works, using the higher compression characteristics of air vs fuel.
I don't know what the maximum pressure rating is for the device. It is typically used in carb and injected installations where the pressure is 5-50 psi or so.
I have had a couple of customers use it in injected installations, but typically pulsation issues are more related to low-pressure carb installations.
About the only failure mode would be if the fitting became unwelded from sphere. If this were to occur, there would be fuel leakage."
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07-02-07, 02:37 PM
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Why does the PD have to be close to the injectors, the "circuit" where pulsation is taking place is between the pump and FPR.
I believe I have seen stock cars have a single PD on one rail, with a whole lot of tubing and fuel rail between banks of cylinders covering more actual length than the distance between the fuel inlet at the rats nest and the FPR
I believe I have seen stock cars have a single PD on one rail, with a whole lot of tubing and fuel rail between banks of cylinders covering more actual length than the distance between the fuel inlet at the rats nest and the FPR
07-02-07, 02:42 PM
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here is the company that makes it, 30 dollars
http://www.floscan.com/html/blue/acc...ail.php?aid=98
and just to show that the Rx7 isn't the only car with PD issues
http://auto-recalls.justia.com/conte...NNER-2003.html
http://www.floscan.com/html/blue/acc...ail.php?aid=98
and just to show that the Rx7 isn't the only car with PD issues
http://auto-recalls.justia.com/conte...NNER-2003.html
Last edited by slo; 07-02-07 at 02:52 PM.
07-02-07, 03:04 PM
#11
(Terraplane)
Google-Pulsation Damper. It is used to smooth out pulsations caused by pumps or opening/closing valves. Ever hear of water hammer?
Because fluid is not compressible, it can virtually be mounted anywhere in the line, although it is often located by the pulsating source, Injectors.
It has a diaphragm in it and sealed air on the other side charged to a particular pressure. It acts just like the Mazda unit except the Mazda unit has a spring, I think. Typically the charge pressure is somewhat less than the operating pressure to work most effectively. I would be curious if it has worked for high pressure fuel injection applications.
This not a bad design, just one that has been miniaturized and targeted for fuel applications.
Closed minds, concrete thinking, UGH!
Because fluid is not compressible, it can virtually be mounted anywhere in the line, although it is often located by the pulsating source, Injectors.
It has a diaphragm in it and sealed air on the other side charged to a particular pressure. It acts just like the Mazda unit except the Mazda unit has a spring, I think. Typically the charge pressure is somewhat less than the operating pressure to work most effectively. I would be curious if it has worked for high pressure fuel injection applications.
This not a bad design, just one that has been miniaturized and targeted for fuel applications.
Closed minds, concrete thinking, UGH!
07-02-07, 03:10 PM
#12
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UMM...........Looks useless, Im running a banjo bolt!! I dont see what the big fuss is about a banjo bolt replacing the PD, my car runs fine or better w/o the PD........Thats my 2 cents!!
Chris
Chris
07-02-07, 03:20 PM
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this isn't a debate about PD vs banjo bolt, this is wether or not a cheaper PD that should be leakproof would work, and what configuration it would need to be installed.
07-02-07, 03:46 PM
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07-02-07, 04:02 PM
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07-02-07, 04:05 PM
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07-02-07, 04:27 PM
#20
This is just stupid, if there were an easy cheap replacement for the PD, it would've been found by now since the car is 20 years old, and we'd all know about it, and if someone WERE making something, theyd probably come tell us about it, am I right?
07-02-07, 04:41 PM
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What's the point??
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LOL, after doing a bunch more research I finally learned the complete reason behind what you said. My apologies. Feel free to correct me on anything else too since I really just want to learn as much as possible. 
Other RECENT thread:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/quick-pulsation-dampner-663131/
Other RECENT thread:
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/quick-pulsation-dampner-663131/
07-02-07, 05:05 PM
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ive heard that subaru has the PD mounted like that too.
07-02-07, 05:19 PM
#23
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Pulsation dampers are easy to come by at any junk yard in plenty of vehicles in the mazda fleet. Look on the fuel rails and you will find that the same exact PD is used throughout multiple model lines and generations so finding a barely used one is easier than ordering from mazdatrix. I know for a fact that the mazda 2.0l FS-DE engine uses the same PD, it is not a part unique to the rotary.
07-02-07, 05:35 PM
#24
(Terraplane)
Ted, your right about the system not being closed, (recent thread). Me being a "pump guy' immediately associated this problem with a closed system.
However, pulsation must be there, hence the OEM damper. I've read of some guys even seeing pressure fluctuations on their pressure gauge.
Larger injectors, more flow and the stock return line diameter would add to higher back pressure.
I use the damper and this has never been an issue.
The theory still holds, if there is pressure fluctuation this type of damper could reduce it or you could even increase the return line diameter to reduce it.
However, pulsation must be there, hence the OEM damper. I've read of some guys even seeing pressure fluctuations on their pressure gauge.
Larger injectors, more flow and the stock return line diameter would add to higher back pressure.
I use the damper and this has never been an issue.
The theory still holds, if there is pressure fluctuation this type of damper could reduce it or you could even increase the return line diameter to reduce it.
07-02-07, 05:38 PM
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