New Zealand Datsun Club

Hi Guys,

Just a couple of questions I have with the surge tank setup I am doing

1) The return/overflow from the surge to the main fuel tank - can this you a fitting at the bottom of the fuel tank? The only fittings on the tank apart from the filler are at the bottom.
2) How important is it to have the lift pump below the fuel tank? I have seen a few setups where it was slightly higher then the pickup at the bottom of the tank. I assume this is alright as the lift pumps don't get all upset about a little bit of air, and the air would just vent out of the surge tank and back into the main tank eventually. Just want to double check here. I am only talk a couple of centermeters higher then the fuel pickup

Cheers

To be honest I don't know a lot about them but logic would tell me for question 1, is the piping for the return going to be lower than the bottom of the tank at all times? If it is and you don't have a 1 way valve in there I think you'll just get petrol from the tank filling up the line? If there's a fitting in the bottom of the tank why not use that for the pickup?

2. Being that it's a "lift" pump I wouldn't think it has to be below the pickup, depending on the pump of course. I've seen low pressure pumps mounted in all sorts of places with no problems.

1- yea that will be ok as lon as its from the top of the surge tank.
2- that will be ok too. what lift pump are you running?

Are you going to run the return line from the engine back to the surge tank? i have seen it run back to the tank and the surge tank would run out of fuel after a lap at puke

DJZ wrote:To be honest I don't know a lot about them but logic would tell me for question 1, is the piping for the return going to be lower than the bottom of the tank at all times? If it is and you don't have a 1 way valve in there I think you'll just get petrol from the tank filling up the line? If there's a fitting in the bottom of the tank why not use that for the pickup?

There are two fittings on the bottom of the petrol tank. One will be used for the lift pump pickup, the other is what I am thinking of using for the surge tank to fuel tank return/overflow as there isn't another fitting in the top of the petrol tank that I can use.

fletch wrote:1- yea that will be ok as lon as its from the top of the surge tank.
2- that will be ok too. what lift pump are you running?

It will be from the second to top fitting on the surge tank, which is right near the top of the surge tank. It is a faucet style pump. Not 100% sure what it is. It was in my brothers starlet years back and excess to his requirements as they had fitted two lift pumps (which it really didn't need)

fletch wrote:Are you going to run the return line from the engine back to the surge tank? i have seen it run back to the tank and the surge tank would run out of fuel after a lap at puke

Yes, there will be a return from the engine to the surge tank. I was going to use the fitting on the very top of the surge tank for this. The next fitting below this I was going to use to return excess fuel from the surge tank to the fuel tank.

Heres my setup - has been running fine and had no surging etc and it used to surge heaps.



The outlet on the bottom goes from the surge to that Subaru filter and then out to the VL pump under the car which goes to the engine.

The pipe that you can see at the bottom of the original fuel tank is a banjo fitting and bolt that is bolted to the original drain bung hole, this travels around to that small filter and to the lift pump which is just mounted with its bracket to the fuel tank bracket (works fine at that height even with less than half tank)

if you look closely you can see two more smaller hoses that go around the back near the top of the surge tank - one is the return from the engine and the other returns to the tank - and we just used the original fuel outlet at front of tank.

In summing up the lift pump or facet doesnt mind being slighly higher and you can use the lower points in the tank for your return, because when it fills the low pressure will push fuel back into the tank. I also used efi fuel line everywhere just to be safe.

hope this doesnt confuse you but it give you an idea to work from - i was a bit daunting trying to work it out the first time cause you dont want to fry expensive fuel pumps - let me know if you want anymore pics etc

brocky41 wrote:Heres my setup - has been running fine and had no surging etc and it used to surge heaps.

Cheers man. Funnily I had a pic of your setup open on a tab already.

I'm getting pretty well sorted with it now. Been building a pump mounting tower thingee to hold the pumps and run the hoses through. Was too cheap to buy a $15 mounting bracket (read war department already at odds with my current spending).

Only thing I am trying to work out is whether I can put it in the boot floor on the side of the car that the exhaust runs. This dramatically reduces the amount of fuel line I have to run. The LVVTA guide says some stuff about fuel not being able to spill onto the exhaust, but realistically if the original fuel tank had a rupture it would be just as bad.

Has anyone put their surge tank on the boot floor on the same side as the exhaust runs and been certed fine? There is heaps of space between the floor and the exhaust so heat won't be an issue, also the surge tank doesn't sit directly above it.

Thoughts?

jeremiahnz wrote: Has anyone put their surge tank on the boot floor on the same side as the exhaust runs and been certed fine? There is heaps of space between the floor and the exhaust so heat won't be an issue, also the surge tank doesn't sit directly above it.

Thoughts?

I think the best setup is to use bundy tubing with flared ends instead of hose as much as possible going into the tank (or teflon-inner R14 hose) as rubber fuel line ALWAYS allows fuel smell to permeate, and both are far more heat resistant than rubber hose, ideal for keeping the certification jerks happy. Also, another good idea is to mount the tank and pumps underneath the car if possible - this keeps noise to a minimum, eliminates fuel smell inside the car, and makes routing the line from the banjo on the bottom of the tank and the high pressure line forward to the fuel rail nice and easy (important if you use bundy!).

PM me if you need a hand setting it up, I get all the hose and fittings cheap through work, made setting Brocky's one up a lot simpler!

There's actually a rule of thumb or something about not having any lengths of hose over 300mmm. But don't quote me on that.

broke wrote: I think the best setup is to use bundy tubing with flared ends instead of hose as much as possible going into the tank (or teflon-inner R14 hose) as rubber fuel line ALWAYS allows fuel smell to permeate, and both are far more heat resistant than rubber hose, ideal for keeping the certification jerks happy. Also, another good idea is to mount the tank and pumps underneath the car if possible - this keeps noise to a minimum, eliminates fuel smell inside the car, and makes routing the line from the banjo on the bottom of the tank and the high pressure line forward to the fuel rail nice and easy (important if you use bundy!).

PM me if you need a hand setting it up, I get all the hose and fittings cheap through work, made setting Brocky's one up a lot simpler!

Yes - I will be using bundy as much as possible. I'm planning on using that aluminum bundy which is meant to be pretty easy to work with. The rubber hoses are only around the surge tank setup, however no matter which side I put the surge tank on in the boot, the return from the surge to the fuel tank will have to go to the opposite side of the tank.

I don't think there is anywhere under the car the is going to give me a large enough cavity to safely mount the surge tank.