FPR
 

Hello all,

So I am finally up to date and might be starting an S52 swap now. My car is a 96 with an M44 with OBDII. I know my car does not have the FPR mounted on the car, it is on the rail. I also know that the S52 does not have the FPR on the rail, rather on the body. The real question is what are doing for the FPR? Are we just setting it inline with the fuel line and securing it to something or do I buy the bracket that BMW uses to hold it to the body and then place it somewhere in the engine bay? I am not aware of what I have to do with that. Also regarding my car not having ASC, the OBDII M3s with an S52 had ASC will that be a problem with my car? I am planning on purchasing DME, EWS, Harness and Motor with accessories all together and also Jim's swap manual. Any help will be greatly appreciated.

You can either get a fuel rail with the FPR mounted on it or mount one under your car. BMW_Hatchback had to mount one under his car. It's not that difficult either way. You definitely want to mount it properly, don't just have it hanging.

Thanks for the rapid response cooljess76. Well I would like to install it the most affordable but done right way. I wasn't aware that their is a fuel rail for an S52 with the FPR mounted on it, Can you point me in the right direction? I am leaning towards mounting it in the engine bay and this would be the best scenario since I know a vacuum line goes into it, this way I wouldn't have to run a vacuum line all the way to the back of the car, unless I am missing something?

It doesn't have to be from an S52. Check realoem.com for M50, M52, S50 and S52 fuel rails. They changed them over the years, and make note that some fuel rails have both inlet and returns towards the rear of the rail while some have the inlet on the rear and the return on the front. Also note that if you use an OBDI fuel rail, the OBDII fuel rail cover won't line up with the bolt holes. But if you plan on doing an M50 intake manifold upgrade, an OBDI fuel rail and fuel rail cover would be ideal.

Interesting. What would be the best fit for my car? One that both lines are in the same spot which is the one I have now on the m44? Are all the fuel rails interchangeable thought out the 6 cylinder engines?

Sure, they're interchangeable. However I think the OBDII ones have the Schrader valve on them and the OBDI ones don't. I have both without FPR's mounted, I'll take a pic for comparison.

I am searching through realoem.com and I cannot find fuel rails with the FPR mounted on them?

Here's a few pics. I have an M50 manifold on my S52, you could note the larger runners, it's a popular upgrade. I didn't want to use my S52 fuel rail cover or cheesy brackets to make an M50/S50 fuel rail cover work, so I opted to use an M50/S50 fuel rail and an M50/S50 fuel rail cover. The cutouts on the S52 fuel rail cover will not fit over the wider runners on the M50 manifold.

You could also see that the S50 fuel rail has an inlet on one end and an outlet on the other end. My S52 fuel rail has a pipe welded to it which makes the inlet and outlet both on the back end. This means I'll need to run a longer fuel line to reach the return outlet on the front of the fuel rail.

You can also see that the S52 fuel rail has a schrader valve on the front of it. I don't know what this valve is for, but it's capped and never gets used, so I don't need it.

Now you're going to be looking for a fuel rail with the FPR mounted on it. I can't remember what year they relocated the FPR under the car, but obviously you'll be looking for one that pre-dates that. Keep in mind, the S52 fuel rail cover may not bolt up to the fuel rail if it comes off of an OBDI car. But if you plan on doing an M50 manifold, it doesn't matter you could just use an M50 fuel rail cover.

http://www.realoem.com/bmw/showparts...69&hg=13&fg=15

Got it. The only thing is, I dont want to swap the manifold at least not as of now. So the only solution based on what I have been gathering is that the rails with the FPR mounted on them are from either S50, M50 which are all OBDI cars. The real question is, will the S52 manifold, and fuel rail cover work with the S50/M50 fuel rail?

The manifold will work just fine, but you'll need to fab up or purchase brackets for the fuel rail cover if you want it to fit. You can always just mount a FPR under the car.

Hmm, right now it looks like im considering mounting it under the car or use the same bracket that goes under the car somewhere in the engine bay and just run the hoses to the engine. It seems it is a bit more cost effective this way, any ideas? BTW I still follow your build thread, awesome project you have going there!

I'd hit up BMW_Hatchback aka Cedric. He ran into the same issue and I believe he did just what you're speaking of. Shoot him a PM, he's on here daily and I'm sure he'll offer a lot of helpful advice.

just FYI, it's where you hook up a fuel pressure tester