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http://www.rexnet.com.au/forum/index.php?/topic/80078-sti-raspec-c-in-tank-anti-surge-box-replica-for-less-than-30/
Look at the factory STi RA/Spec C anti surge boxes. What are they???
Spec C anti surge box
http://img349.imageshack.us/my.php?image=dscf00101ba.jpg
http://img306.imageshack.us/my.php?image=dscf00055iz.jpg
http://img141.imageshack.us/my.php?image=dscf00118kh.jpg
http://img349.imageshack.us/my.php?image=dscf00101ba.jpg
MRT's $447.87 version - http://www.mrtrally.com.au/shop/images/products/musse008ag.jpg
They are a square plastic fuel resistant box with a jacketed hole at the bottom rear for the pump intake pipe, a barbed prong up the top rear for the fuel return line to enter the box, and they have a uniquely shaped slice cut out of the front end which allows fuel slosh to escape the box only during braking g's, i.e. cut out of the box facing towards the front of the car. This makes sense as there must be an easy fuel entry point into the box but your engine won’t be demanding lots of fuel during braking g’s which will quickly empty the box on a near empty tank. You will notice that the box intake cut-out is on the right hand front side of the box so that during right hand turns, the fuel that is thrown left has maximum captivity in the enclosure. Right hand turns happen to be the most troublesome for fuel starvation with the standard tank setup. So It all makes sense.
The box has a snap on removable lid and the bottom of the box mounts flush with bottom of the tank for best pickup. The box is also a neat fit for the factory intake filter sock.
I wasn’t going to pay hundreds of dollars for that. Being a practical person - which you have to be to change a fuel pump anyway - I made myself a functioning replica for less than $30
Here’s what I did. I went to Jaycar and bought a 115mm x 90mm x 55mm diecast Alloy enclosure for $17.50. This is fuel resistant and wont leach anything into your fuel tank.
I carefully measured the distance between the bottom of the diecast box as it sat on the bottom of the fuel tank, and the fuel pickup pipe on the pump assembly. Using this measurement I drilled a hole a bit larger than the pump intake pipe through the bottom rear of the box. With the sock removed, I slid a short length of tight fitting fuel hose up this pipe to where the pipe will pass through the hole in the box. This acts as a jacket gasket to seal the pipe fairly well. It also stops the box rattling on the end of the pump intake pipe as it is vibration absorbent. It doesn’t matter that it’s not a perfect seal. It won’t leak fast enough to empty the box of fuel before the g’ force is over.
I then drilled a hole in the top rear of the box to match a thread ended hose barb that I bought from Bunnings for a couple of dollars. I screwed this in without needing to thread tap the hole (its only a thin walled box) and connected up a short length of fuel hose between this box barb and the tank return barb. You can use a small hose clamps here, i didn’t as the barb was tight fitting. This allows fuel return to ‘top up’ the box.
Then looking at the picture of the factory STi box, I filed out the unique wedge shape on the front right hand side of the box. This is easily done with the box lid removed.
To put it together, i forced the tight fitting jacketed pump intake pipe through the big bottom hole. I then Placed the sock on the end of the pipe through the top of the box. Then screwed the lid on the box and you now have yourself a fully functioning anti surge box that negates the need for an external surge tank. This has eliminated my entire near empty tank surge problems.
One thing the STi box has is a bracket that secures the box to the pump assembly. I found that the inlet pump hose that passes through the rear of the box was enough to secure the box due to the tight fit. I wasn’t worried, but you could make up a bracket out of a thin alloy strip to secure this better.
Look at the factory STi RA/Spec C anti surge boxes. What are they???
Spec C anti surge box
http://img349.imageshack.us/my.php?image=dscf00101ba.jpg
http://img306.imageshack.us/my.php?image=dscf00055iz.jpg
http://img141.imageshack.us/my.php?image=dscf00118kh.jpg
http://img349.imageshack.us/my.php?image=dscf00101ba.jpg
MRT's $447.87 version - http://www.mrtrally.com.au/shop/images/products/musse008ag.jpg
They are a square plastic fuel resistant box with a jacketed hole at the bottom rear for the pump intake pipe, a barbed prong up the top rear for the fuel return line to enter the box, and they have a uniquely shaped slice cut out of the front end which allows fuel slosh to escape the box only during braking g's, i.e. cut out of the box facing towards the front of the car. This makes sense as there must be an easy fuel entry point into the box but your engine won’t be demanding lots of fuel during braking g’s which will quickly empty the box on a near empty tank. You will notice that the box intake cut-out is on the right hand front side of the box so that during right hand turns, the fuel that is thrown left has maximum captivity in the enclosure. Right hand turns happen to be the most troublesome for fuel starvation with the standard tank setup. So It all makes sense.
The box has a snap on removable lid and the bottom of the box mounts flush with bottom of the tank for best pickup. The box is also a neat fit for the factory intake filter sock.
I wasn’t going to pay hundreds of dollars for that. Being a practical person - which you have to be to change a fuel pump anyway - I made myself a functioning replica for less than $30
Here’s what I did. I went to Jaycar and bought a 115mm x 90mm x 55mm diecast Alloy enclosure for $17.50. This is fuel resistant and wont leach anything into your fuel tank.
I carefully measured the distance between the bottom of the diecast box as it sat on the bottom of the fuel tank, and the fuel pickup pipe on the pump assembly. Using this measurement I drilled a hole a bit larger than the pump intake pipe through the bottom rear of the box. With the sock removed, I slid a short length of tight fitting fuel hose up this pipe to where the pipe will pass through the hole in the box. This acts as a jacket gasket to seal the pipe fairly well. It also stops the box rattling on the end of the pump intake pipe as it is vibration absorbent. It doesn’t matter that it’s not a perfect seal. It won’t leak fast enough to empty the box of fuel before the g’ force is over.
I then drilled a hole in the top rear of the box to match a thread ended hose barb that I bought from Bunnings for a couple of dollars. I screwed this in without needing to thread tap the hole (its only a thin walled box) and connected up a short length of fuel hose between this box barb and the tank return barb. You can use a small hose clamps here, i didn’t as the barb was tight fitting. This allows fuel return to ‘top up’ the box.
Then looking at the picture of the factory STi box, I filed out the unique wedge shape on the front right hand side of the box. This is easily done with the box lid removed.
To put it together, i forced the tight fitting jacketed pump intake pipe through the big bottom hole. I then Placed the sock on the end of the pipe through the top of the box. Then screwed the lid on the box and you now have yourself a fully functioning anti surge box that negates the need for an external surge tank. This has eliminated my entire near empty tank surge problems.
One thing the STi box has is a bracket that secures the box to the pump assembly. I found that the inlet pump hose that passes through the rear of the box was enough to secure the box due to the tight fit. I wasn’t worried, but you could make up a bracket out of a thin alloy strip to secure this better.
