View Full Version : in tank fuel pump vs in line

12-07-2004, 01:10 AM
Which one sould I get for my sr20de 510? How hard is a in tank assembly to weld in? MIG? I know the inline ones can be noisy.

12-11-2004, 03:47 PM
Use a 300zx fuel pump! Its easy, just cut out 300zx pump along with some extra material and cut a hole in the 510 tank to accomidate the pump and housing. Make sure you clean out both tanks prior to cutting and welding or you go boom!!!! It would be nice to install some baffles in the tank while your in there.

12-31-2004, 06:00 AM
An inline 280z or 280zx fuel pump works nicely for non turbo efi nissan 4 cylinder engines. It can supply more than enough fuel for a nicely modified sr20de or ka24de. If you pull it from the donor Z car with the rubber insulator bracket it fits perfectly under the rear seat shelf underneath the 510. Just need to drill two holes to bolt it in. The rubber insulator keeps it nice and quiet.
Then you need a few brass reducer fittings from the local autoparts store to get it to mate up to the stock 510 fuel tank. Make sure you get the feed line to the stock feed off the tank though. A lot of people mate the feed up to the bigger hose connection on the tank and have fuel starvation problems cuz it feeds from a 1/4 way up the side of the tank.
I also like to run a nice big fuel filter in between the tank and the pump to act as a fuel surge tank.


12-31-2004, 02:40 PM
Thanks for the info guys

01-01-2005, 11:52 AM

Do you have any pics of what you described. This is where I am at in my swap. And want to go that route.

01-01-2005, 11:42 PM
Sorry man, don't have any pictures. Let me spell it out a little bit better.

On the gas tank there are two hose connections for fuel lines. One of them is blocked off on 70-73 models, it is used on 68-69 models as the carb had a return line. The other connection is used for the fuel feed line. The feed one is the smaller of the two. It is a 1/4 inch connection. The normally blocked off one is a 5/16 connection, and it just empties to a hole right inside the tank which is a good quarter way up the side of the tank. The 1/4 inch feed line actually picks up fuel from right off the bottom of the tank. You need to use that one to feed the fuel pump. You can use the other bigger one for the fuel return line from the fuel rail. What happens here time and time again with 510 efi swappers is they use the bigger hose connection for the feed line cuz they think it will be better, and then they end up running out of gas with over a quarter tank left.
Now once you get the 280z/zx fuel pump you will notice it has like a 1/2 inch feed connection on it. You need to adapt from 1/4 to 1/2 inch to get from the tank to the pump. What I usually do is get the guy at the auto parts store to let me look at the fuel filters and use a fuel filter as an adapter. I was actually able to find a quite large one that had a 1/4 inch inlet, and a 1/2 inch outlet. You can use any low psi fuel filter as it is before the fuel pump, so it doesn't need to be efi pressure spec. Of course you can fudge the line sizes a little bit with rubber hose if you need to. Keep the lines short though and make a smooth down flowing transition from the tank-filter-pump.
I have also used some brass couplers to make an adapter to go from 1/4 to 1/2 inch, so if you don't want to run a filter back there it should be easy.
For the fuel return line you can use the factory charcoal canister vent line from the front of the car, or just add a new fuel feed line and use the stock 1/4 inch feed line as the return. 68/69 chassis cars have two lines in them allready.
Oh and btw... some people think the 1/4 inch 510 fuel line is to small to use as a feed. It has been made to work fine on quite a few KA24DE 510 swaps without any ill effect or fuel starvation problems. Those 5/16 lines on the 240sx chassis have some pretty nasty crease bends in them that probably neck them down further than the smooth bends on the 510's 1/4 inch line. Don't make em like they used to.

Danny Youngs

01-02-2005, 09:14 AM
I damaged the 5/16 return line putting in the tranny, since I need to run a line, I am thinking of just running 2 5/16 so I can bring them in the engine compartment where I want them. The line coming up in the front pass side is way up there. But I have only run hard pipe once a long time ago, so I am still contemplating the difficulty of it. Where did you mount your filter if it is before the pump?


01-05-2005, 05:52 AM
Well if you are gonna run two new lines to/from the front of the car you are set then. That is the best possible route.
As for mounting the filter.... You don't have much space to work with in the back of the car. If you get a small filter you can mount the pump and filter side by side on that rear shelf under the car. If you get a big one you just sort of have to suspend it somehow in between the tank nipples and the pump. It's just a matter of finding a properly sized one and finding some way of securing it. You can use zip ties pretty easily, or look for simple metal band fuel filter brackets at the junk yards. You can usually attach those to pretty much any metal piece using a drill and some screws.

01-05-2005, 08:27 AM
I would run the biggest lines you can and have 2 filters. one just after the fuel tank and one after the fuel pump and running larger lines will help in preventing any starvation under heavy loads.

01-22-2005, 08:38 AM
So I ran new hard lines, not hard at all, but a nice inline pump new is around $100. So I thought, I can just modify the 240sx in tank pump to work in line? It looks as if it might work, but there are two pinholes on the pump that might use the gas for pump lubrication? Is anyone familiar with this?

01-25-2005, 10:00 PM
The stock 240sx in tank pump will not work as an in line, The two small holes besides the out line spit fuel back in the tank when the pump primes and/or builds too much pressure. Back to looking for an inline pump. Walbro has an inline 190 Lph for around $120 I think, And their 255 Lph unit could be used as well.

01-26-2005, 08:48 AM
A 240SX pump will work, but you would have to buy the 255LPH and then cut a big hole on top of your tank then weld in the 240SX unit (the whole unit including sender) then you would have to modify the pick up tube the correct length of the datsun tank. You might just want to get the correct in line pump if your going to do it properly. I would also pay close attention to the flow and pressure rates, especially if your going to modify your SR.