Ok so even with the AD100 pushing fuel to the stock frame rail mounted fuel pump i can watch the FP drop to about 50psi @ WOT. I have been looking around online and can get just the pump itself instead of the whole water separator and pump. Has anybody ever replaced the actual fuel pump instead of the whole rail mounted water separator/fuel pump?

This would be the fuel pump im talking about. rail mounted fuel pump

This one is a Racor unit. racor fuel pump

Out of the 2 i linked which one do yall think would be more reliable?

 

What's the rest of your fuel system consist of?

 

Blue spring upgrade, AD100, 155cc/30% injectors.

 

Stock banjo bolts? Are you still running up through the fuel filter on top of the motor?

If you're draining pressure now... I'd just buy a fuel lab or an A1000 pump to put in front of that AD100, eliminate the stock pump all together, and run that right to the heads directly, bypassing the filter on top of the motor too.

What size line do you have coming from your tank to your AD100? That might be a problem too. Does the fuel pressure drop still happen when you have a full tank? A sump would be a good idea too.

 

I have read that when a seperate regulated return system is put in the filter/regulator on the motor becomes unnecessary. Although you are going to have to do some plumbing in either stainless or braided directly to the heads to eliminate it. Further, I have read that some of these systems deliver better mpg at lower psi, lower as in below 50. Most of these users are AD2, so I don't know how much it relates to what you are doing.

A sump or low profile bulkhead fitting may be what you need. Both of these would eliminate the load created by sucking the fuel up through the tank. Mdub and I have gone rounds about which is better in the past, and until I get a bulkhead fitting, my opinion will remain speculation.

 

Good point Karl, a regulated return would be a good idea too, especially if eliminating the fuel bowl. You can use a RR with the fuel bowl too, but only one of them is going to be doing the regulating... so you could just stretch the crap out of the spring in the bowl to effectively eliminate that as a return, and let the good return do the work.

Karl I had read a couple posts about the lower PSI helping too, but it seemed to vary greatly. Some said they noticed throttle response improvement, others said they found no change, some said it was worse. I think for the time being I'm going to keep my pressure where it's always been at.


As for the fitting or the sump... eh whatever works I guess. The sump looks purdier!

 

Both the A1000 and fuel lab pumps only rate @45psi. How is that sufficient for a system that needs 60+-psi? And both are way out of budget for me so i guess ill just get the stock one.

 

The only thing I can come up with is that the aftermarket pumps have greater volume at lower pressures than the OEM pumps do. I base this on the only ones preaching lower fuel psi have an aftermarket set up.

 

I just dont see a pump only rated to 45psi being good for a system that needs at least +55psi to keep the injectors working. I think im gonna get a fuel sump and new stock pump.

 

It flows 700lbs/min at 45psi... it's adjustable. This pump is made for 1000+HP motors, it will be more than adequate. It would just flow less fuel at a higher pressure. It's all relative to what you're doing. It doesn't mean it can only do 45psi, it can do basically whatever you want, but flow will either rise or drop depending on pressure needed. This and the fuel lab are very widely used on high performance diesels everywhere. Base pressure on the A1000 is adjustable from 30-70psi from what I'm reading.