conedodger Posted September 23, 2012 Share #13 Posted September 23, 2012 I use fuel injection rated hose and the return line to the tank... Link to comment Share on other sites More sharing options...
5150 will Posted September 27, 2012 Share #14 Posted September 27, 2012 Long story, but I'm putting a L28 converted to my ZTherapy carbs into my 71 from an '83zx. I was planning on using the Carter pump above and I was wondering where I should tap my power from? Also, should I mount the pump near the tank? Don't mean to be a hijacker..... Link to comment Share on other sites More sharing options...
Lazeum Posted September 27, 2012 Share #15 Posted September 27, 2012 you should install it close to your tank. In front of the tank fuel sender, you'll see 2 holes tapped on your car. You should use those 2 holes with M6 screws to install the pump. In the fuel sender harness, you'll find a green wire hidden you should use for the pump for +12V. It was a wire made for fuel pump from Datsun connected to ignition switch already. Other wire has to be grounded somewhere on the Z body. Support provided with Carter pump worked well with r180 mustache bar but I switched to r200, I had to custom build a new support. If you add a fuel pump, either add an inertia switch (found mine in junkyard) or a oil pressure cuttoff switch (280zx have one). You need to make sure your pump will stop working in case of accident. and while you're at it, change all the fuel hoses going from the tank to the pump and then from fuel hard line to carbs if it is not done already. This is how my inertia switch looks like - it can also be a thieft prevention device. Mine is behind passenger seat. Link to comment Share on other sites More sharing options...
5150 will Posted September 28, 2012 Share #16 Posted September 28, 2012 Matt, Thanks so much for the info. All my lines are new. I'll try to locate the oil pressure cutoff switch since I still have the ZX I removed the engine from. Any idea where it is located on an '83 zx? Link to comment Share on other sites More sharing options...
Lazeum Posted September 29, 2012 Share #17 Posted September 29, 2012 it is the oil pressure sender that is having such feature. It is right next to your oil filter. Link to comment Share on other sites More sharing options...
Zedyone_kenobi Posted September 30, 2012 Author Share #18 Posted September 30, 2012 Well today in a bid to remove some restriction of my fuel system. I removed my holley fuel regulator. It was cranked all the way out anyway, and all the RX7 pump could muster was 2.75 psi. I am running dead headed. My question is, what is the minimum amount of fuel pressure a set of DCOE's need? I have not seen a minimum, I have read they like lots of fuel and should not have more than 5 psi, but what is in fact a good number. Reason I ask is this. I installed my holley inline filter in place of my old regulator. I figured more filtering was better (since I already have a pre-pump filter installed as well) if the pressure drop through the filter is small. Well with the filter installed the most I can achieve now is 2 psi on my fuel pressure gage. That was with the car NOT running, just sitting spinning the pump dead headed to the fuel rail. I am not sure 2 psi is enough pressure. I am going to remove the holley inline filter right before the fuel rail and see if it was contributing to any of the pressure drop. With it dead headed at no flow, I would not think it would matter one bit. I dearly love how quiet my new pump is, but wonder if it is up to the task of fueling my carbs. Link to comment Share on other sites More sharing options...
240260280z Posted September 30, 2012 Share #19 Posted September 30, 2012 Most seem to set it at 3.5psi but I have seen it recommended as low as 2.5psi. Link to comment Share on other sites More sharing options...
Lazeum Posted September 30, 2012 Share #20 Posted September 30, 2012 My Mallory 4070lp pump is having a pressure of 2.5psi. I cannot get much more than that (whereas it is given for 4psi)I just remember that I've also changed my fuel filter with a inline glass unit I can disassemble, maybe the pressure limit comes from filters, flow anyhow is good. Link to comment Share on other sites More sharing options...
Travel'n Man Posted September 30, 2012 Share #21 Posted September 30, 2012 I'm at 3.5 psi - no troubles at all with my Carter at any RPM. The only time I can really hear my fuel pump is at initial start up when I turn on the key.......no switch-er oo for me. Link to comment Share on other sites More sharing options...
Zedyone_kenobi Posted September 30, 2012 Author Share #22 Posted September 30, 2012 (edited) Yeah, my Carter could easily hit 3.5 psi as well, but the noise it made was just plain crazy. I am going to experiment a bit with the fuel line. The real reason I am messing with this, is that I want to run a return line back to the tank. I know it may not be totally necessary, but I like the idea of not having stagnant fuel in the fuel rail. When I built the rail I tapped both ends and bought AN fittings to make a return circuit. However, I need to get the fuel pressure back up, as when I add a return line, the pressure will drop a bit. I am going to use the fuel restrictor orifice that was on the OEM SU fuel rail.From doing more reading, it would seem what really matters is the amount of flow. Pressure is of course not negligible, but if you can supply enough volume, then the webers are usually happy. I have no data to back this up, just words of advice from various weber threads on numerous other automotive forums. Edited September 30, 2012 by Zedyone_kenobi Link to comment Share on other sites More sharing options...
conedodger Posted September 30, 2012 Share #23 Posted September 30, 2012 I run my Webers at 2.5lbs. I have never experienced fuel starvation at all. Now, we'll see what Keith Franck says on the 14th of October. I may end up having to turn it up or down... I doubt down.You can give your fuel pump a bit of help by running a smaller return line than your feed line... Link to comment Share on other sites More sharing options...
Zedyone_kenobi Posted October 1, 2012 Author Share #24 Posted October 1, 2012 Totally agree but I am only getting 2 psi with it dead headed. My return line is smaller since I am using OEM sizes. We will see what happens Link to comment Share on other sites More sharing options...
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