An Idea
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From: B'ham, WA
An Idea
I've decided I'm going to put a banjo bolt in place of my PD, but I don't like the idea of the pulses not being dampened. I'm thinking that putting one of these on the line going to the secondary fuel rail to help soften the pulses, with the other end attached to return. Watcha think? 
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Joined: Mar 2001
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From: Twin Cities, MN
It's fine if the fuel pulsates. RETed (GOD of FC's) said it's ok.. so it'll be fine. I just JB Welded mine shut too after it burst.
Lots of info in this thread : https://www.rx7club.com/forum/showth...ight=pulsation
this is what RETed said :
Lots of info in this thread : https://www.rx7club.com/forum/showth...ight=pulsation
this is what RETed said :
The damper is designed to get rid of or minimize pulsations due to having only two fuel injectors per fuel rail. In theory it's a good design - it's purely there to keep fuel flow consistent when the fuel injectors are firing.
In actuality, removing the PD does not affect fuel delivery - that's all that matters. With a fuel pressure gauge, you'll see the fuel rail pulsations (if you've got the FP gauge sensor installed on one of the rails) increase, but this still doesn't affect fuel delivery.
This is based on my experience tuning an FC on the dyno with an A'PEXi S-AFC before&after PD removal - the fuel requirements were still the same before&after, which in my book means nothing harmful was done with the PD removal.
Now, what does this means? It could be that the stock fuel rails are large enough to handle the added pulsations from the PD removal. It could also be the stock rubber fuel hose is also helping dampen the pulsations. Bottom line, PD removal doesn't affect fuel delivery - which is what we were after.
Welp, taking into consideration that ANY PD will leak and catch on fire, I'd rather take the banjo bolt option anyday...
Good luck!
Ted
In actuality, removing the PD does not affect fuel delivery - that's all that matters. With a fuel pressure gauge, you'll see the fuel rail pulsations (if you've got the FP gauge sensor installed on one of the rails) increase, but this still doesn't affect fuel delivery.
This is based on my experience tuning an FC on the dyno with an A'PEXi S-AFC before&after PD removal - the fuel requirements were still the same before&after, which in my book means nothing harmful was done with the PD removal.
Now, what does this means? It could be that the stock fuel rails are large enough to handle the added pulsations from the PD removal. It could also be the stock rubber fuel hose is also helping dampen the pulsations. Bottom line, PD removal doesn't affect fuel delivery - which is what we were after.
Welp, taking into consideration that ANY PD will leak and catch on fire, I'd rather take the banjo bolt option anyday...
Good luck!
Ted
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Joined: Mar 2001
Posts: 171
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From: Twin Cities, MN
Um.... the PD is one VERY common point of failure on the RX-7. It breaks lose inside (rubber diaphram) and fuel is let loose over the exhaust manifold 
!
This has been the reason for hundreds of our cars going up in flames, injuries, deaths, and being totalled. However, Mazda is being a little bitch weasel and not taking any responsibility for their FAULTY design. Almost every fuel injected car has a PD, but only our ****-*** ones fail this often...
PLEASE, everyone either use another car's PD (like a Mazda MPV's) and relocate it somewhere in the fuel line... anywhere. Then weld up or bolt shut your PD. Or if you are cheap (like me) then you should just weld or bolt your PD, as a PD is not necessary on these cars.
Newer other car PD : $35-$50 (optional)
JB weld : $3.87
Banjo Bolt : ~$8-$10
Totaltd RX-7 : $$$$$
! This has been the reason for hundreds of our cars going up in flames, injuries, deaths, and being totalled. However, Mazda is being a little bitch weasel and not taking any responsibility for their FAULTY design. Almost every fuel injected car has a PD, but only our ****-*** ones fail this often...
PLEASE, everyone either use another car's PD (like a Mazda MPV's) and relocate it somewhere in the fuel line... anywhere. Then weld up or bolt shut your PD. Or if you are cheap (like me) then you should just weld or bolt your PD, as a PD is not necessary on these cars.
Newer other car PD : $35-$50 (optional)
JB weld : $3.87
Banjo Bolt : ~$8-$10
Totaltd RX-7 : $$$$$
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What R U thinking self?
Joined: Mar 2002
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From: Stockton, CA
but what about higher fuel pressure?
"It could be that the stock fuel rails are large enough to handle the added pulsations from the PD removal. It could also be the stock rubber fuel hose is also helping dampen the pulsations." -Ted
Does this still hold true with Walboro Fuel pump? I figure it will give a bit more pressure that maybee the stock setup will not handle without a dampner.
any idea's on that?
"It could be that the stock fuel rails are large enough to handle the added pulsations from the PD removal. It could also be the stock rubber fuel hose is also helping dampen the pulsations." -Ted
Does this still hold true with Walboro Fuel pump? I figure it will give a bit more pressure that maybee the stock setup will not handle without a dampner.
any idea's on that?
Former Moderator. RIP Icemark.
Joined: Apr 2001
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From: Rohnert Park CA
Originally posted by dre_2ooo
Mazda is being a little bitch weasel and not taking any responsibility for their FAULTY design. Almost every fuel injected car has a PD, but only our ****-*** ones fail this often...
Mazda is being a little bitch weasel and not taking any responsibility for their FAULTY design. Almost every fuel injected car has a PD, but only our ****-*** ones fail this often...
It is a relitively common thing for cars designed in the mid eighties.
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