Fuel Pump question

[soareyes]

I'm replacing my fuel pump and filter on my Birkin this weekend with new units. They are inline, mounted outside the fuel tank. I noticed that the old pump and filter are hooked up so the filter is inline after the pump, but I remember reading somewhere that it is best to put the filter before the pump so that it protects the pump too. Any opinions?

 

Thanks in advance!

[slngsht]

I've always had my filter before the pump.

[SR27.Seth]

Some fuel pumps have issues if any resistance is in the fuel line between the pump and tank- some pumps will suck and push- others only push. When we build the SR27, for the first tank of fuel I put a large micron, reusable filter before the pump and a regular small micron fiber type after the pump. After the first tank of fuel is used I pull out the pre-pump filter, because for 280+hp we need the full capacity of the fuel pump. I would say in your case- use two filters.

[11Budlite]

Hi Stan,

 

I agree with Seth. I run a small Russell screen-type filter (bottom center of pic) before the pump and a large capacity fine-filtering Canton Mecca (top center of pic) after the pump to protect the injection system in case of fuel pump failure. Here's a picture of the set-up on my Birkin:

 

http://www.usa7s.com/aspnetforum/upload/631193083_FUEL CELL-REAR END.JPG

 

Please note that the return line is not hooked up correctly in this old photo.

 

Bruce

[soareyes]

Wow, Bruce, that is a very nice (and clean) setup! Is the main advantage of using steel braided fuel line durability? While I was replacing my pump, I went ahead and replaced the 4 year old rubber lines as they were looking weathered, but I just used rubber again. The new pump solved my fuel starvation problem I was getting at higher revs.

 

Thanks Mazda, Seth, and Bruce for your help!

[11Budlite]

Hi Stan,

 

I always wanted to "play" around with braided line (and 1/4" and 3/8" stainless hard line with AN flares) and this was my chance to do it. I work at an o/h shop that works on jet engines so I see this stuff all the time. I picked up some good quality flaring and bending tools and had some fun learning to fabricate this stuff. I also came up with a simple (inexpensive) way to cut-off the braided line and assy the fittings which is one of the most PITA parts of the job. One thing I can say is the FI rubber line is a lot easier to work with and probably works just as well except for the abrasion performance.

 

Here's a description from Russell about the benefits of braided hose:

 

PROFLEX AND PRORACE STAINLESS STEEL BRAIDED HOSE

 

For maximum protection and reliability, more professionals and enthusiasts choose Russell ProFlex or ProRace performance hose. Constructed with a stainless steel outer braid that resists abrasion and corrosion, both have a Chlorinated Polyethylene (CPE) synthetic rubber liner with a nylon inner braid that will not collapse under extreme heat, yet is extremely flexible. Superior ProRace hose has the same features as ProFlex but with a specially formulated CPE synthetic inner liner that is embedded with a partial coverage stainless steel inner braid, then bonded together by a full coverage stainless outer braid for 50% more strength. Both types have these great features:

 

Stainless steel covering for a more attractive installation that is abrasion resistant

Temperature range of -40ºF to +350ºF for a wider variety of uses and routing

Compatible with all hydrocarbon and alcohol-based fuels, lubricants and additives

Available in a wide range of AN sizes to meet your needs

Use with Full Flow, Full Flow Swivel and Tube Seal hose ends

Use with AN adapter fittings in either Endura, stainless steel or anodized finishes

 

Bruce

[pierats]

Bruce, That is a nice installation.

 

Can you elaborate on the method you came up with for cutting the hose and assembling the fittings? I've had to make a few and it can be quite tricky!

[BobDrye]

On the suction side of the pump you are limited by vacuum. You only have so much vacuum, but on the pressure side you can size the pump to what ever you need. Almost all production cars now have the pump in the tank to eliminate the problem. On higher power installations measure the return flow of your system as the fuel returns to the tank. Do not under size your return line size. It needs to be the same size as your pressure side as the system doesn't use much fuel at idle. If the return line size is too small you will have excessive pressure problem at idle. This will result in either poor idle or not enough pressure under full power.

 

[11Budlite]

Hi Tom,

 

After many frustrating attempts at trying to get the socket (nut) of the fitting over the freshly cut hose, I decided to try the following. For AN-6 hose, I took a piece of 1/2" copper pipe, cut off a piece about 1-2" in length and then cut it lengthwise down the middle. I then put the two cut pieces of the copper pipe over the braided hose with the ends at the location where I want to cut the hose. I then put a hose clamp over the two copper pieces to hold them in place on the hose. I used a die grinder with a cut-off wheel to carefully cut the braided hose using the ends of the copper pipe as a guide. Then, you take the socket (nut) of the fitting and slide it over the hose end and the edge of the copper pipe which covers the cut end of the braided hose. The socket will slip over the copper pipe far enough to retain the braided end and then you can CAREFULLY release the hose clamp and take the two copper pieces off and slide the socket the rest of the way onto the hose. The rest of the assembly is easy after that....I always use the special lube and the soft jaw vise clamp to hold the fitting. When I was doing some AN-4 hose, I used the same 1/2" copper pipe, but had to cut a section out of the pipe for the reduced diameter of the -4 hose, and then had to form it around a steel rod to conform to the diameter of the -4 hose.

 

Since I tried this method, I've never had to re-cut the end of the hose because of fraying!

 

They have since come out with a product called a Koul-Tool which I believe does the same type of thing.

 

Bruce

 

PS: I can take a few pictures of the process tonight if you want.

 

 

[soareyes]

Bruce, I looked up the specs on the Canton Mecca filter and I see that it filters down to 1 micron. The Jegs filter I just put on is only rated to 40 microns. Should I replace mine with something that filters better, or is 40 microns acceptable? Thanks!

[pierats]

Bruce,

 

That is a neat trick! :hurray: Many thanks for sharing this info...I'm sure it will come in handy the next time I have a hose to make up.

[11Budlite]

You're welcome Tom!

 

Stan, I think the CM filter can use either a 1 micron element, or an 8 micron element for higher flow. If you're running carbs a 40 micron should be fine, but with injection I personally would want to use something finer. Maybe someone with more experience can give their point of view...

 

Bruce