fuel pump relocation

[Harpo]

Currently my fuel pump is mounted above the passenger side trailing arm. I plan on relocating this to the front. I have a 74 that was built in 12/73

1) Can I reuse my fuel pump?

2) I presume that I will just run a new dedicated switched power to the pump from the fuse box

3) Why are there so many fuel pump brackets and which one should I use? (74 and later - 911.608.105.01) - (73 and earlier 901.356.505.03)


Thanks


David

[Harpo]

Bumping back to the top

[Jonny042]

There are a number of fuel pumps and also crossmembers, so depending on what you have will dictate what bracket you might need. Pretty sure any pump good for CIS will work, including your original if it's in good shape.

Why relocate the pump? Just being the devils advocate here but it's been in the same spot for 45 years.....

[ossiblue]

Originally Posted by Harpo

Currently my fuel pump is mounted above the passenger side trailing arm. I plan on relocating this to the front. I have a 74 that was built in 12/73

1) Can I reuse my fuel pump?

2) I presume that I will just run a new dedicated switched power to the pump from the fuse box

3) Why are there so many fuel pump brackets and which one should I use? (74 and later - 911.608.105.01) - (73 and earlier 901.356.505.03)


Thanks


David

Yes, you can reuse your fuel pump if, as others have said, it is in good condition. Running a new dedicated switched power to the pump will also work.

As far as the bracket, I'm not familiar with the parts you listed, but there is no bracket or place for a bracket on the 74 front crossbar. You will have to fabricate or adapt a bracket of some design to fit the pump to the cross member.

As far as to the "why" of moving the pump, the rear location has two distinct disadvantages. First, the pump is forced to "pull" fuel rather than "push", which makes things a little more difficult for the pump. Second, and probably most important, the rear location puts the pump close to a high heat source from the engine which, again, puts unnecessary stress on the pump.

[Harpo]

I want to replace my fuel lines. It seems prudent to move the pump at the same time. While I'm a firm believer in the if it ain't broken don't fix it I only want to order new fuel lines from boxter GT once.

Secondly the current location of my fuel pump may interfere with my new rear sway bar.

[E Sully]

Yes, you should use the original pump if you relocate it, as long as the pump is in good condition. I have the rear mounted pump on my 1973.5, and at one time fabricated a bracket to relocate a Carrera pump for a 3.2 Carrera engine to the crossmember for the swap. You can remove the fuel pump wire on the fuse panel and run a new feed to the front crossmember from there.
Honestly I see no need for it. The original setup has never given me a problem. I understand the arguments, closer to the tank, no engine heat, etc. However it has never given me an issue in the rear. I would suggest instead to perhaps use an aftermarket heat shield for the pump if you think you need it. My original pump has over 100,000 miles and still works well.
In early 911's, -'71 bracket 901 356 505 01 used support 901 341 013 03. Later post 74 cars, Aluminum crossmember 911 341 013 10 can use later pump support 911 608 105 01. Both these options would require quite a bit of work and replacement crossmembers. Also, as you note, custom fuel lines.
If you decide to follow through, you should make a custom bracket to fit the current crossmember, as I did for the Carrera fuel pump in my swap.

[Steve@Rennsport]

Originally Posted by Harpo

I want to replace my fuel lines. It seems prudent to move the pump at the same time. While I'm a firm believer in the if it ain't broken don't fix it I only want to order new fuel lines from boxter GT once.

Secondly the current location of my fuel pump may interfere with my new rear sway bar.

Personally, I'd agree with what you are doing. Fuel pumps do far better when they push, rather than pull.

The main reason Porsche relocated the pump to the front was to prevent the vapor lock issue that plagued many of these in hot weather. With the left side HE valve just inches away, the pump and associated lines would cook the fuel into a vapor during heat soak so the best fix was to remount the pump up front in a far cooler location.