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FPR and FMU questions for my 95 non turbo

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inferno617

15+ Year Contributor
50
0
Jan 29, 2006
Southampton, Pennsylvania
I have a 95 which has the rare fuel rail set up. I am looking to eventually turbo, but right now i am putting on my OBX fuel rail. I have put my stock FPR on the end of the obx fuel rail. ( the 95 has it set up with it placed into the end of the stock rail) I am looking to hook up a after market FPR. I'm not sure how the after markets work. I'm guessing they run off of vacuum. If so i should be able to just hook it up to my stock FPR, right? Another question. I know if you have the 96-99 you need to install and FMU when using the OBX rail because i hear the fpr is at the tank. Do I have to install as well? I have no problem putting one on. I just do not want to put it on and wind up not needing it. And what is the best to get, 12:1?
 
85552d1216568173-installing-s-fmu-450cc-injectors-fuelsystemswfmu.jpg

Why do you need an aftermarket FPR? When using the 12:1 FMU setup, all you need is your stock FPR and the FMU.
Another question. I know if you have the 96-99 you need to install and FMU when using the OBX rail because i hear the fpr is at the tank. Do I have to install as well?
I'm not too sure what you're asking here. Please rephrase.

Late '96 and up will have the FRP back by the tank. The FMU has to be after the FPR in the fuel lines. It doesn't matter where any of these things are physically, as long as they're setup like one of the setup's in the diagram you'll be fine.
Yes, a 12:1 FMU is what you would want to use.
 
that diagram really helps a lot, thanks. What i was really asking is, how i should hook up an adjustatable aftermarket fpr to my obx fuel rail? The pic shows what i have right now. It has the return and the 95 fpr inside of it. If i want to get the adjustable fpr, should i take this whole thing off and make the end of the rail go to the new fpr then return to the fmu then tank?
 

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I got myself confused. Lets try again.

The stock FPR that you have installed in the rail will work with what you have now. Later on when you add the turbo, you will need to install the FMU on the return line. In your picture, the top right barbed fitting is your return. Somewhere after that is where you need the FMU intalled.

In the meantime, if you want an adjustable FPR, just remove your old one and put the new one there. I doubt the adjustable one will allow you to bump up the pressure enough to run a turbo. If it does allow you to go that high, I think you would go through fuel pumps every other week. No need to have a ton of pressure if you are not using it. The FMU allows the pressure to build when and only when you need it.
 
i understand the FMU setup. I just want to know if i will need an adjustable FPR or if i can put it on now and save myself the trouble while i have everything apart. For the turbo i will need an adjustable FPR, right?? I do not see how I will be going through fuel pumps.


Another thing I placed my 255 walbro in and was hoping to go turbo sooner and I ran into economical issues. Do I have to switch back to the stock or can I use an adjustable FPR to maintain stable fuel pressure?
 
The FMU is adjustable, but it does it on its own. The more boost, the more fuel pressure it creates.

Going through fuel pumps isn't an issue right now.....scratch that thought.

Your stock FPR will keep the fuel pressure where it needs to be with a stock engine. You might have a pump that can deliver more pressure, but the FPR will only allow so much.

Only reason I could see you wanting to go with an aftermarket adjustable regulator is if you had a chipped car with aftermarket exhaust, intake and lower temp thermostat.
 
Look at the diagram that rstare posted (nice diagram, by the way LOL. That's all you need: just a 12:1 FMU; a Walbro 255lph HP fuel pump; and the stock FPR. You can safely drive around with just the Walbro and FMU installed and not the turbocharger. The Walbro fuel pump will not overrun the stock FPR. You do not need anything like a 1:1 AFPR until you have some sort of electronic means of controlling the fuel injectors.
 
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