Fuel Rail Pulse Dampeners

[Dan McNarry]

I have been trying to find good information on a source for fuel rail dampeners and so far all I've come up with is the following from the AEM web site......


"Many vehicle manufacturers use a pulse dampener to reduce the pulsations in the fuel rail caused by the opening and closing of the injectors (a dampener also reduces the noise of the injectors). In applications where a new fuel system must be installed, a fuel pressure dampener is integral to ensuring consistent fuel flow to the injectors. AEM fuel rails have a provision for a pulse dampener. The dampener assembly part numbers are:

Honda PN: 16680-PE7-661 Dampener
Honda PN: 16705-PD1-003 Inner Gasket
Honda PN: 90428-PD6-003 Outer Gasket
AEM PN: 2-602 Fitting for Rail "

Has anyone out there sourced and or used dampeners from the auto wreckers? If so, what did you use and how'd it work out? I am running a v-8 with custom made fuel rails. I was hoping to incorporate a dampner in to each fuel rail at the point where the fuel lines connect.

Thanks,

Dan

[Dan McNarry]

My engine is a 390 Cadillac. I made my fuel rails out of 1.25" square aluminum bar drilled out to .5" id. I am using a Ford F-150 high pressure pump and 30lb injectors. My idle pulse width is 2.0ms. My fuel pressure gauge needle fluxuates quickly between 35 and 40lbs. When I shut the engine off it shows 38lbs. The car runs really well but I don't like the constant clicking of the injectors. I also get a small irregular flutter in the exhaust note at no load idle. I have rebuilt the distributor and am using a Pertonix II breakerless ignition with an MSD ignition and MSD spiral wound ignition leads. I think the problem is the fuel rail fluxuations I am seeing on the fuel pressure gauge. Bottom line is I would like to find a solution that doesn't cost $110.00 USD per side!

Thanks,

Dan

[PSIG]

... I am running a v-8 with custom made fuel rails. I was hoping to incorporate a dampner in to each fuel rail at the point where the fuel lines connect. ...

Are you having pressure issues or a noisy regulator?

David

[PSIG]

Oops - crossed in the mail. You can diagnose by adding (temporarily only!) a few feet of R9 or better rubber EFI fuel hose near the rails as a pulse damper. Alternatively a Tee'd-in upright EFI fuel fiter (used is fine) with the outlet plugged to trap air can be used for the same purpose. Might save you a trip or $ to find factory ones just to test with...

David

[Mk1rocco]

Old water cooled VW's (pre 89) with CIS fuel injection used what they called a fuel accumulator for that purpose, they were usually located somewhere near the external fuel pump.

[Jack]

All you need is the same device as is used for water hammer in house plumbing. Install a dead end pipe vertically upward adjacent to the fuel rail. Just a simple capped tee with a short extension upward should do. The air trapped within the dead end will work great as a pressure snubber/damper. This gives the incompressable liquid a place to move into during the pulse smoothing out the spikes.

Alternatively, as described earlier, try some Injector rated hose before and/or after the rail. That might just do it.

Jack (Mechanical Enginerd)

[Dan McNarry]

Wow! An embarresment of riches. I'll try the vertical capped tee deal. I'll have to go and get some plumbing parts but should be able to test it out soon. The fuel filter thing sounds good too but I have space limitations on my driver side fuel rail. My power steering pump is right in the way. I will likely have to put my vertical pipe in just before the 90 degree fitting that goes in to my fuel rail. If you are at all curious about my set up you can see it at the web site in my profile. Just click on project photos and scroll through.

Thanks,

Dan