Originally Posted by jspecracer7

Well I wouldn't call it a myth. But inside the tank are metal "walls" that trap a certain amount of fuel inside of them so that you don't go lean under hard cornering. Problem is that if you have little fuel in my tank, then that little bit of fuel left inside the walls probably won't do anything.

Originally Posted by Rotary Experiment Seven

Drill a hole in the fuel pump assembly cover and install a 90 degree bulkhead fuel fitting. Earls makes them, or you can use something less expensive from a hydorlcs store. Secure the 2nd pump along side the first with some hose clamps. You're going to have to play around with the positioning of the pumps to get them to fit right, especially the way the sock filters point. At this point you can chose to run a new fuel line for the 2nd pump, use the existing vent line as a 2nd feed, or t the two fuel pump outlets together and use just the stock feed line. The stock feed is pretty small, and I like to keep the vent to prevent fuel vapor smell, so I like to run a new line. The problem with this however, is that it is more work to add another hard line, and running a soft line the length of the car can be dangerous. In your case I would probably just T the two pumps together. Makes it alot simpler. Some people run a pump for each fuel rail, but that becomes a real pain and I don't see much benefit in it. The stock wiring is barely adequate for a single pump, so you need to upgrade it. The stock setup also runs the pump at 9 volts (if I recall correctly) and then steps it up to 12v via relay under load. The best way tp get power in my opinion is if you already have the battery relocated in the bins or trunk. Run a power wire to the pumps. I forgot what guage I used, but it was at least twice as thick as stock. You also need to incorporate a relay into this. Don't use the starter relays alot of people use. They click loudly as they cycle and are not designed for extended use. Gotham usually has the proper ones in stock. Other than that, make sure any hose you use is marked as fuel injection hose and for high pressure. The other cheep stuff will burst over time. Also, solder and heat shrink. everything. I don't trust the crimp connectors for critical applications like fuel.

Originally Posted by apneablue

Thanks Ihor...I am no electrical wizzard so excuse the stupid question...But what part does the relay play in this and why would it be bad to just hard wire the pumps to the battery with a fuse?? I guss they would always be on then

Originally Posted by jspecracer7

Well I wouldn't call it a myth. But inside the tank are metal "walls" that trap a certain amount of fuel inside of them so that you don't go lean under hard cornering. Problem is that if you have little fuel in my tank, then that little bit of fuel left inside the walls probably won't do anything.

Originally Posted by jspecracer7

The stock fuel tank is already setup so that you don't have to worry about fuel starvation during hard cornering. That's why there's that metal thingy (for lack of a better word :LOL inside the tank.

Originally Posted by rx7tt95

I have a 1995 RX7 that was built in December of 1995. Technically it's a 2006. There are a few differences between my car and other 1995 models (and before) such as the ABS system. Another is that I have very little issue with fuel starvation at anything other than an empty tank. I should take a picture of the inside of the tank and will if I have a chance...I have a white plastic "tub" or baffle system which keeps fuel around the pump. Anyone else have this in their car? I heard Mazdaspeed sells an add-in baffle and I'm wondering if that's what is already installed in 96+ 7's.

Originally Posted by rx7tt95

I have a 1995 RX7 that was built in December of 1995. Technically it's a 2006. There are a few differences between my car and other 1995 models (and before) such as the ABS system. Another is that I have very little issue with fuel starvation at anything other than an empty tank. I should take a picture of the inside of the tank and will if I have a chance...I have a white plastic "tub" or baffle system which keeps fuel around the pump. Anyone else have this in their car? I heard Mazdaspeed sells an add-in baffle and I'm wondering if that's what is already installed in 96+ 7's.

Originally Posted by rx7tt95

Well they're relatively inexpensive and you'll have two sets of wires, one for each pump. In the end, it'd be more reliable to have two relays instead of splicing everything together. One might overtax a single relay as well. I purchased my relays from RadioShack along with the 25A inline fuse holder. For the relay's power source, I disconnected the stock fuel line wiring leading to the tank and used that. No need to go all the way up to the stock relay.

Originally Posted by FCNAred

one thing to consider running two sets of wires to the back, is that if one pump dies on you, the car will still run but when you boost if you have them in parallel, fuel goes to one rail only and you might pop. If you run one set of wires, the pumps die and the car doesn't run at all, saving you an engine. Just another way to look at it.

Originally Posted by rx7tt95

For the FPR, the stock unit is fine even for two Walbro pumps. I don't think it would have trouble supporting 450rwhp. It does 400rwhp just fine. I use an Aeromotive FPR, their new "compact" unit which only features one inlet/outlet as that's all I need. It's a whole lot smaller than the dual inlet unit.


As for the filter and related lines, they're fine to hold the pressure (that's regulated by the FPR and how much boost you're running) but the fuel filter should be changed every 30K minimum as it's essentially the Miata filter and can clog quickly. If you're running lots more fuel through the system, I'd recommend changing it sooner. I'm very surprised no one in the aftermarket industry has come up with a better solution (a kit) to move a larger fuel filter to an easier to service location. Might be down to lack of room.

Originally Posted by apneablue

Form what I understand, people are doing the relocating to the rear rebar just by the tank. I had Gotham relocate mine....Basically it's the filter strapped to the rebar with 2 large hose clamps. I think if you go through the trouble of changing the filter in the stock location you may as well relocate while you are at it.

Originally Posted by RotorMotor

oh, also... is it the Fuel Pulsation Dampener, or the Fuel Pressure Regulator that everyone keeps on going on about is a MUST to replace as they will "catch your car on fire."

PS if one does go w/ an aftermarket FPR, what is the propper pressure to set it at? (sorry its off topic but i was just wondering.)