Guest Anonymous Posted December 18, 2000 Share Posted December 18, 2000 Any suggestions for a pump? I know I told Scottie to get an in-tank pump, but I don't want the time/labor/expense of using one Good external pumps? I've heard all sorts of horror stories about various aftermarket pumps, and definately don't want to grenade anything with a crappy one. What about the 240 fuel lines? I assume they are 5/16 like most nissans? That should be plenty large enough shouldn't it? Does a 73 240 have a stock return line? I have a metal line in the engine that is not hooked to anything... Looks like a return line, but it's probably full of all sorts of crud. I'd like to avoid running a new line, but if I have to, what size? 3/8? Or is 5/16 big enough? I'd like to use 5/16 just to keep everything the same size if possible.... And any suggestions on a good pressure regulator? I will have a stock l28t regulator, is it sufficient? What pressue does it run at? If it's not good enough for around 400ish horsepower, anyone got reccomendations on a good one? And what's a good pressure to run? 30 psi? 40? 50? ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 18, 2000 Share Posted December 18, 2000 Not sure why you think an external pump is not a good thing. I guess I could go into theories about which components are better, but I prefer to tell you what I know works from experience. You can go with a fuel cell or rear sump in the tank. I used a Bosch external pump which I had in my spare bin for the 911 and when it crapped, I went with a Pierburg from Corky Bell. This is what my buddy is also using. Quiet and can flow 70+GPH. For the fuel lines I recommend .5" or -8 feed and the original 5/16" feed as the return line. I am using -8 braided hose and my buddy ran a .5" aluminum line. We both used custom fuel rails with an SX FPR. How much pressure you run depends on the injectors. Some injectors, like the factory units are rated at 36# pressure and most aftermarket units are rated at 43#. More pressure and the inj flows more, less, etc. E.g., my buddy is running 600cc injs rated at 43#, but he runs them at 36#. I ran the SVO 36# injs and ran them at 43# pressure. Both worked as we had big mph numbers for what we were running. The stock FPR is a 36# unit and is not adjustable. Sure you can "crush" it and get more pressure, but it would be 20+yrs old. If you plan on running 420cc injs, almost certain they were rated at 43# pressure,so if you used the stocker at 36#, the injs would flow less. E.g., if the 420cc injs were rated at 43# and you ran them at 50#, they would flow 453cc. If you ran them at 36#, they would flow 384cc. If you are thinking 400ish HP, the only component of the original fuel system you should consider using is the original 5/16" feed line to be used as the return. ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 19, 2000 Share Posted December 19, 2000 A rear sump in the tank? You mean like for drag racing? Huh? ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 19, 2000 Share Posted December 19, 2000 The rear sump is a must for drag racing, but believe me, with that kind of HP making the Z squat, any kind of hard acceleration with less than 1/2 tank is asking for trouble. EFI tanks have baffling and combined with the rear sump, you should have it all covered. Scottie Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 19, 2000 Share Posted December 19, 2000 Enlighten me more. I don't care about drag racing. I also don't want to remove the tank and have to find someone to weld on it. ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 19, 2000 Share Posted December 19, 2000 I am not certain you want to attempt installation without pulling the tank and making sure it is thoroughly clean and dry before welding. Here is what it looks like: I am sure someone on the forum has done this and can enlighten you. When patrick did his, he pulled the tank, had it welded and plumbed in braided hoses and AN fittings from the sump to the hard lines. ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted December 19, 2000 Share Posted December 19, 2000 I added one of those to my tank. My tank was empty for 10 years, so I didn't have a problem welding it on. But if your going to do it to your tank, take it off and have it flushed out first! ------------------ http://members.tripod.com/~SnowSurfer/mikekz1.html Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 19, 2000 Share Posted December 19, 2000 What about a surge tank? Were I going to remove the tank I'd just use an in-tank pump... I neither can, nor do I want to, weld on a fuel tank. I wouldn't trust my life to my own welding on anything! Also scottie, you say 'sure someone has done it' and it sounds like you didn't do it.... What did you do? ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com [This message has been edited by Morgan (edited December 19, 2000).] Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted December 19, 2000 Share Posted December 19, 2000 I ran the stock 71 tank and finally gave in and bought Mikelly's RCI aluminum fuel cell. If my stock tank level was low I had to be cautious and avoid hard acceleration. At the track I had to make sure I had at least 8-9 gallons in the tank. Does not sound so bad until you realize I only race with 112-octane at $5.50/gal. Ever heard a high-HP turbo motor at full song suddenly have no fuel? The other frustrating problem I had with the stock tank was the fumes, despite taking out the tank and replacing all the lines and having a metal vent tank. I am talking about gasoline fumes, not exhaust fumes. I suppose an in-tank pump would work supplemented by a surge tank, but that seems like a mod no easier than the other. ------------------ Scottie 71 240GN-Z http://www.mindspring.com/~vscott911/gnz.html Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 19, 2000 Share Posted December 19, 2000 A surge tank seems easier to me, and comparable in cost. Bolt it in with an extra fuel pump and a few hoses and you're good to go, right? Removing the tank and having stuff welded onto it seems like more of a PITA to me than popping in a surge tank. Am I missing something here? ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
Drax240z Posted December 19, 2000 Share Posted December 19, 2000 Ross C and I had thrown around the surge tank idea in emails. I'm gonna build one for myself I believe. (unless a cell falls on my lap) We think you could get by without using another pump, and just have gravity feed the surge tank. (which should hold about the volume of a coffee mug, IMHO) This does mean that the surge tank needs to be lower than the actual tank, or at least right at that level. My car has a foot of snow over it right now, I haven't checked the logistics of this yet. ------------------ "Gimme Fuel, Gimme Fire, Gimme that which I desire" -Metallica Drax240z 1972 240z - L28TURBO transplant on the way! http://members.xoom.com/r_lewis/datsun.html http://members.home.net/drax77/newpage.html Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 19, 2000 Share Posted December 19, 2000 I'd love a fuel cell, but it's more time, effort, and money than I want to expend right now. Perhaps later once it's in and running nicely. I think it should be bigger than a coffe mug, more like a coffe can I was thinking! I doubt gravity feed would work unless the line to it from the tank was really big, you can't get much lower than the bottom of the fuel tank anyhow. I was thinking a decent pump from summit or wherever meant for big carbs - lots of flow, low pressure, and they can be had fairly cheap. Even a gimpy $20 auto zone generic fuel pump would be adequate I bet, but I don't want to test this theory! ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted December 20, 2000 Share Posted December 20, 2000 An idea I've heard of but never seen done is a surge tank up front. Use a standard carb pump to fill a tank up front with a float of some sort to prevent overfilling. Then in that tank run a regular EFI pump with a return to that tank. Maybe put that tank where the battery sits stock? Anyway, with such a small volume up front even if th erear loses fuel pickup you'll have your fuel up front. Hard to explain but can you visualize what I'm saying? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 20, 2000 Share Posted December 20, 2000 Maybe I'm showing my stupidity, but what's the difference in where the surge tank is located? Up front, out back, high, low, whatever, it's all the same. I like front though, maybe put it and the pump where the battery goes? That keeps your expensive fuel pump out from udnerneath the car and all that good stuff too. And keeps the pressurized plumbing shorter so leaks are less likely and easier to find if they occur. I think I'll do it that way unless someone has some logical reasons not to? ------------------ Morgan http://z31.com/~morgan/s30 http://carfiche.com Quote Link to comment Share on other sites More sharing options...
TimZ Posted December 20, 2000 Share Posted December 20, 2000 quote: Originally posted by Morgan: Maybe I'm showing my stupidity, but what's the difference in where the surge tank is located? Up front, out back, high, low, whatever, it's all the same. As long as you are using a pump in the rear to move the fuel to the front surge tank, then that should work fine. The weight of the column of fuel in the line will create a pressure head toward the rear under hard acceleration, so the rear pump is a necessity to prevent starvation of the surge tank. The best setup that I've seen uses a low pressure pump to fill the surge tank, and a ~5psi pressure regulator in the surge tank to keep it pressurized. This keeps a positive pressure at the inlet of the high pressure pump, and will go a long way toward eliminating cavitation at the high pressure pump's inlet. I haven't checked, but I'd bet that at 5psi, the stock FI pump would be able to flow enough to keep the surge tank fed. It's nice and quiet, and you might already have one lying around, depending on what car you started with. Quote Link to comment Share on other sites More sharing options...
Owen Posted December 20, 2000 Share Posted December 20, 2000 I second that, in fact the book from JTR, TBI/TPI swapping suggested something like that. A low pressure pump to feed the resovoir and a high pressure one after it to feed the engine. I may do this later as I am using a '75 260Z EFI tank on my '73 240Z and an SX fuel pump. Are there any rules on where the pump can be mounted? Mine is outside cuz I though mounting it in the trunk would cause problems. Owen ------------------ http://www.homestead.com/s30z/index.html Quote Link to comment Share on other sites More sharing options...
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