Ok, here's a little draw up of what I've been cooking at. Need some feed back though. If anyone has questions comments please let me know, this isn't just 7 related, but I'm doing it because as far as I know, the RX7 has the most difficulties with this. Please have as many people as you can contact take a look at this, if you can find any flaws in the design please let me know. I'm gonna have a machine shop make of these babies at the end of next month. but I want it to be as close to perfect as possible.

 

oh come on, someone has to have a bloody comment!

 

DAMN IT PEOPLE SAY SOMETHING!!!

 

SUX

 

What does the pulsation damper do? I'm a bit of an armchair engineer, if I knew that I could make an educated guess.

 

I think it's a good Idea the PD in my car failed and almost cost me the whole car!

 

The PD reduces the pulsations often accomponied by the fuel pump. This helps so that you don't get random spurts of fuel being sent to the injectors, and then having a lapse of fuel. The pulsation dampner evens this out so the injectors get a constant steady flow, provided that the fuel pump continues. The problem with stock pd's is there is a screw inside that often comes loose and fuel can leak out, if the fuel reaches the exhaust manifold it can ignite and set your engine bay on fire. I'm not sure if I can fully understand and comprehend your design. Maybe if you made it more descriptive and if you labeled everything better that would help.

- Steiner

 

I think its moot. The FB SE has 2 pulsation dampers, and the one on the rail is the one that causes the fires. Just throw it away and get a 12x1.25 banjo bolt and throw it in. The damper on the fuel pump works fine. Your design looks like it would cause restrictions, and doesnt seem to have a 'diaphram' or spring that would help dampen then pulsations..

 

Why does everyone seem to think that the screw falling out has something to do with it (PD) leaking? It has absolutely nothing to do with it. If you've ever removed the plastic cap over the PD, and rev your engine up, you'll notice that as fuel pressure increases, the screw is pushed out with the diaphragm.


ANYHOW, the best (and more simplistic) design would be a plunger with a spring behind it. Just like the stock diaphragm mechanism, sans diaphragm and pre-tentioner screw, but with a neoprene plunger that won't rot, and a spring.

OR you could just ditch the whole setup and replace it with a banjo bolt since the FPR also has a dampening effect.

 

Would it be easier to remove the pulsation dampner and use a unit that is not mounted to the intake plenum?

Whaddabout a better fuel pump that provides a steadier flow of fuel. The PD is a response to a fuel flow problem, instead of fixing a suboptimal solution, fix the initial problem.

 

The pressure from any fuel pump is going to have variations in it.

- Steiner

 

Wow this topic lived longer than I thought. I just think everyone is on the right track but different fixes. I know Im scraping the PD and the stock fuel pump and going with upgrades. U can put a nice FPR on the return line. Most FPR's also dampen the fuel flow (or act as a damper), and with a return style fuel system like ours, Im not really sure fuel pulsation is a big problem as long as the fuel pump can keep up and the fpr is working correctly.

 

thanks for the good inpunt, I'm gonna work on it some more.