Awesome Write up man!
Alright, so I decided to install a FPR on my Skyline last weekend.
After installing an up rated fuel pump into my R33 Skyline I decided that I might as well finish the fuel system with a new adjustable Fuel Pressure Regulator (FPR).
So here is a quick guide on installing a FPR. Should be the same for most cars. Only thing that might vary is the location for your FPR and which ports are fuel in/fuel out (consult your FPR manual to be sure) and honestly it’s not terribly difficult.
First, off you're probably wondering do I need an adjustable FPR?
So here is some info I found while researching:
The installation of an aftermarket fuel pressure regulator allows for the adjustment of fuel pressure to suit larger aftermarket injectors and other engine modifications. They are also necessary to regulate and flow increased volumes of fuel pumped by high flow aftermarket fuel pumps.
Fuel pressure regulator, which works with the fuel pump to maintain a steady pressure relationship between the fuel line side of the injectors and the intake manifold.
My choices were a Nismo, Sard, Tomei, HKS, or Turbosmart (TS) FPR. However, I wanted something that would bolt on easily and didn’t require running extra fuel lines all over the engine bay. So, ideally it would need to bolt near the stock FPR. All of the Japanese branded ones have a version that bolts onto the stock location and fuel rail, but they don’t have any ports for a gauge.
So, enter the Turbosmart FPR 800. In the end I went with the TS unit because they offered the FPR (with gauge ports), pressure gauge, and fuel rail adapter all for a basically the price of 1 nismo FPR.
The only extras I had to buy were fuel injection hose, 4 fuel fittings, and fuel clamps.
Fuel rail adapter. This thing bolts on to the factory fuel rail and gives you a 1/8th npt port so you can run any fuel fitting you need
First, you will be working with fuel, so don’t decide to swap out the fpr after having driving the car for an extended period of time. Also, you will need to add thread sealant to the fittings, so if possible let the car sit overnight so the sealant cures (if using liquid sealant). At least that’s what the instructions on the sealant package state.
Ok, remove the fuel pressure from your fuel lines. I just unplugged the fuel cap and pulled the fuel pump fuse, cranked the car and voila. I believe in some repair manuals, they tell you to crank the car, and then go remove the fuel pump fuse and wait for the car to stall and turn off. Either way, depressurize the lines.
Remove your old FPR. The RB25 apparently has 2 FPR, but the one we need to change is located at the front near the fuel rail.
Looks like this;
Fuel diagram. You can see how the FPR plugs onto the top of the fuel rail and a fuel hose. Very simple.
Where the FPR is located on the actual engine bay.
This fpr is held by 2 screws (marked in RED), be careful removing them. I stripped one and had to spend another hour drilling out the stripped screw. So, use properly sized screwdriver/ratchet or you might damage them.
Next remove the fuel hose or at least loosen the clamps. In my case I just loosen the hose clamps.
Next pull out the old FPR upwards and away from the fuel rail. You shouldn’t get very much fuel spilling out from the fuel rail, only a little bit. Once it’s out you will notice it has a rubber o-ring.
Normally you would replace this ring if you are putting a new fpr since it seals the FPR and prevents leakage. My TS adapter came with a new o-ring, so i was ok. Next came pulling the FPR from the fuel return line. This is where it can kind of get messy. Mine only pissed out a little bit of fuel, but it was enough to completely soak one of my hands. So, remove the hose (marked in blue)
So, once you pull the fpr and fuel lines you can start test fitting the new FPR. In my case I wanted it as close to stock location as possible. I noticed on my engine there was this metal brace conveniently next to the FPR location. So, I test fitted how the fpr would sit, where the gauge would go, rigged it so I could test close the hood/bonnet and make it close properly (very important! Don’t forget to close the bonnet at least once! Nothing worse than finishing your project only to find out it can’t clear the bonnet/hood!).
After some trial and error I realized I would need a bracket to bolt on the FPR to the engine, so I made a cardboard prototype. The red dots being where I would drill holes in order to mount the bracket to the car.
Next came finalizing the fuel lines plumbing:
The TS fuel rail adaptor comes with an O-ring and 1/8npt port. So I placed a 90 degree fitting on the npt port and connect that to the corresponding port on the FPR with another 90 degree fitting. Lastly, I run a straight fitting from the FPR back to the factory fuel line that connects to the fuel tank. Simple!
Take note and refer to your FPR manual as to where fuel IN/OUT ports are. On the TS unit the fuel rail port is on the side while the return is on the bottom of the unit, which worked out fine after mixing in some 90 degree fittings.
Kinda crude drawing, but you get the idea
So, after building my bracket I also sanded and paint it with high temp, silver paint to clean it up a little. I also went back to the FPR and permanently put the fittings on. I used liquid thread sealant so I let it cure overnight, just to be on the safe side. In the end I got this:
As you can kind of see the TS FPR comes with it’s own mounting bracket. I bolted that onto my own bracket which is bolted to the engine.
The last step was to connect the vacuum hose from the manifold to the FPR, but i wanted to check that everything works first, so I left it disconnected and started the car. No leaks! Almost, done.
Now I just needed to adjust the fuel pressure. Base fuel pressure on a Nissan RB25 with the vacuum hose disconnected should be around 43psi or 3Bar. When you re-connect the vac hose it will drop to around 34-37psi. So adjust the FPR by loosening the lock nut and then taking hex key turning it to raise or lower the pressure. With gauge install you can look at the pressure rise as you turn the hex key. So I set mine for 43psi, reconnected the vac hose and it dropped to 34psi.
Clean everything up and take it for a test drive! Done! Easy!
Results were good! Car no longer bogs down in the higher gears and drives smoother. This is mostly a reliability upgrade/mod.
Although, I did this on my Skyline, the principles are the same for any car.
Last edited by benelli; 13-06-2012 at 10:16 AM.
nice, im going to attack mine this weekend with the tomei type s fpr
i had a paintball company make mine as a prototype. i cant find an o ring for the adaptor tho
Thanks guys! I hope it can help some of you out.
Bawls, any local auto shop should be able to provide you with an o-ring just take the adapter to them. It just has to be fuel resistant or at least oil resistant.
awsome tech write up dude, im also in need of a pump and reg haha dieing to run some more boost, how much was your turbosmart FR with all the attachments out of interest, i honoustly didnt even know TS made regs
With everything it was about $220AUD (with shipping) shipped from USA + 11AUD for the fuel hose and fittings from local shop. Not too bad considering, it would probably run me between $180-220USD just for a Nismo or Sard FPR alone. I also didn't know TS made regs until i saw it on their website, so i decided to try it out mostly because of cost and it comes in blue, so matched my engine bay nicely
Last edited by benelli; 14-06-2012 at 04:43 AM.