Best fuel delivery setup (FPR)
 

I am trying to figure out what the best setup would be for my turbo 1.6 with MegaSquirt. I read alot on these forums but I’m still not sure what I need. I have a built turbo 1.6 running 200whp and I plan to make more. But I want to make sure my fuel system is perfect, I have a DW255 fuel pump with 850cc injectors and I’m using the stock rail and old stock FPR. I want to replace my FPR but do I need a adjustable one? Or do I just need a stock replacement? My goal for now is 250whp on e85.

Your current setup will do 250whp easily. In fact, you're probably wasting your time (as well as the capabilities of a built motor) switching to e85 for only 250whp. However, those DW255 pumps have been known to overpower the stock FPR at idle and cause some idle AFR irregularities, so that might be a worthwhile upgrade. I'd go with an aftermarket AFPR because they aren't crazy expensive and look fairly good despite the fact you might not change base fuel pressure.

For reference, my setup: ID1050x, DW200, fuel pump rewire kit, Radium rail, flex sensor, fuelab AFPR, full AN lines in the bay, and a new fuel filter. All that is probably good for 300+ limited only by the pump.

If I didn't have an aftermarket FPR, I would be using the old trick of tapping the end of the stock rail for 1/8npt to install a fuel pressure sensor. I'm running into more and more fuel pressure issues with cars, I now always recommend a pressure sensor wired to the ECU.

That'll give you actual data as to what your pump and fpr are doing. The "old stock" FPR is a very simple device that doesn't fail easily, and I've installed a brand new aftermarket FPR that performed much worse than the original.

Gonna hijack here briefly -- I know MS3 has provisions for controlling fuel pumps (on/off, open, and closed loop). Does the addition of a pressure sensor warrant the use of open or closed loop with a PWM controller as opposed to on/off? Also, how would someone using MS2/1 go about this?

If you have a ms1/2, I don’t think you do anything. If you have an MS3, you could use it to PWM a solid state relay, yes. You don’t need to. I simply use it for monitoring, although that may change. Ideally, it would be part of the fuel calculation, so if pressure changes, your AFRs dont.