Jump to content
LegacyGT.com

Help Needed: How to install aftermarket Fuel Pressure Regulator (FPR), 08 Spec-B


Recommended Posts

Looking around the forums and internet I haven't found a clear explanation of completing a fuel pressure regulator (FPR) install. I have a 2008 Spec B, stock FPR is not holding pressure correctly (reveled after testing), and I would like to install an aftermarket adjustable FPR like the ones found on ebay. Seems simple enough to do myself (saving paying a shop an arm and a leg), but I've never done it before. I can provide pictures if needed. If anyone could direct me to a good tutorial or could explain it out for me, that would be appreciated.
Link to comment
Share on other sites

You may want to PM m sprank for help with that, or GTTuner.

 

I sent you a link with some help too, enjoy the vacation pic's.

305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD).  CHECK your oil, these cars use it.

 

Engine Build - Click Here

Link to comment
Share on other sites

  • 2 weeks later...
  • 1 month later...

So while I was looking at some of my vacation pics from this year, I got to thinking about some diagrams I had seen regarding the factory fuel system.

 

On two adjoining pages, the diagrams have the return/supply lines reversed.

 

(See first two attachments)

 

 

 

Which then prompted me to do a bit of looking, and I found THESE instructions for installing an aftermarket FPR into a GR STi, and they reference using a "balance hose" to connect to one side of the FPR, and the feed line to the other.

 

So this leaves me to wonder (see third attachment), what do the engine-side return and supply lines connect to, and what does the firewall-side supply line connect to?

fuel_1.jpg.58f068b28d82a72d77be92b1bf954950.jpg

fuel_2.jpg.737c9c4c2b20bc1d89e4246cb6e9d113.jpg

fuel_3.jpg.6d21d4edf4544b28c88f17e050a64ab8.jpg

Link to comment
Share on other sites

  • 4 weeks later...

Revision and update:

 

.: The fuel supply line is the upper one on both the firewall and engine side.

.: The evap hose is in the middle.

.: The return line is the lower one on both the firewall and engine side.

.: On our cars, the fuel pressure regulator regulates pressure on the return line.

.: When using an aftermarket FPR with dual inlets, one of the inlets must be capped off.

 

 

 

How the FPR should be routed (either inlet will work, as long as the other is capped):

 

http://i.imgur.com/ULxZ9.jpg

 

 

 

 

 

How mine is mounted and routed (using -6AN SS hose - the return line wasn't hooked up in this picture):

 

http://i.imgur.com/h5m27.jpg

Link to comment
Share on other sites

^^^Nice clear explanation, thanks.

I'm assuming in it's stock form, a return line comes from each fuel rail then hits a tee of some form and is turned into one line which is then sent as the return line? I could be wrong, I'm just trying to visualize it in my head. If so, could you run a line back from each rail to the inputs of the reg instead of plugging one hole?

This isn't for my application, I'm just curious. Thanks.

Link to comment
Share on other sites

  • 8 months later...

Time for an update...

 

 

(And thank you to KCWagon for his help and pointers!)

 

So the SS lines I was originally running in this setup began allowing ethanol to permeate them, and the in-cabin smell was pretty strong. Thinking that this shouldn't be happening since the lines I opted to use were PTFE-lined, I bought some different SS hose from the same local vendor, but this time went with lines that were "coated," thinking that this might help to mitigate the odor. It did, for awhile, but then the smell came back again after a couple months.

 

Since I had to disconnect the lines and remove the FPR while doing the STi MC/booster swap, I decided to also revise the under-hood fuel system at the same time. The new look and setup are much cleaner, but only time will tell whether it stops the permeation issue or not. I should also note that I've since replaced the nitrile O-rings at all the ORB fittings with Viton ones. We'll see if this helps as well, since the nitrile ones looked pretty degraded when I removed them.

 

http://i.imgur.com/fNJHaZB.jpg

Link to comment
Share on other sites

It's an Aeroquip fitting, 15117. 5/16" fuel line quick disconnect on one side, female -6AN thread on the other. The AN side of the fitting is designed to be used with an ORB fitting rather than a traditional AN male. (It's too deep for most AN fittings to seat the flaring properly.)

 

Fitting: http://www.summitracing.com/parts/aei-15117

 

ORB Union Adapter: http://www.summitracing.com/parts/aei-15606

Link to comment
Share on other sites

I have been gathering the parts to swap my FPR as well and run a similiar setup as you but I noticed you didn't plumb in the the factory pulse dampeners near the FPR as recommended in other swaps. Have you noticed any hesitation or stumbling like others have said? The factory set up seems to run them on the feed and return but adapting a -6 AN hose(3/8 id) to factory dampeners (5/16 id) is impossible. Did everything tune ok and stay smooth?
Link to comment
Share on other sites

My first iteration of this setup included both pulse dampers, which did nothing to cure the hesitation issues. (Which on my car are fairly minor to nonexistant anyway.) The second iteration included doing the longer return line, coiling it up, etc. etc., which also did nothing for me.

 

 

 

Should you choose to implement the pulse dampers in your setup, you can adapt an AN fitting to them in one of two ways:

 

.: Slide a tube nut and sleeve onto each end of the damper and then flare the tube end

.: Use a hard line -6AN tubing adapter for 5/16" tubing

 

 

 

I will grab a picture of the latter setup to post here in awhile when I get to the shop to show you how I implemented it on my first go-around.

Link to comment
Share on other sites

I am also having a lean issue around 5300 rpms and the tuner can't seem to figure it out. Currently have DW 65c fuel pump and DW 740cc injectors and they are telling me to go top feed with id1000's but don't really want to spend another $1000 to guess at a problem. Have you corrected the hesitation? Making me crazy.
Link to comment
Share on other sites

I'd say unless you're starting to max out your IDC at that RPM, larger injectors will not solve your problem. Have you watched your fuel pressure to ensure it's not dropping when you're seeing the lean condition? Have you checked to make sure you're also not getting a voltage drop at the fuel pump?

 

There's a HUGE thread on here about how shitty our factory FPCM is.

 

 

 

Like I mentioned, the hesitation issue really isn't that prevalent in my car. I get it a little bit, but I had the same issue on my 09 STi and since it's not dramatic I've learned to "drive around it," if that makes sense.

 

 

 

 

EDIT: Who is your tuner? If it's not Cryo, have you asked him to take a look at it for you?

Link to comment
Share on other sites

I have been using MAC Autosport in Parker. They come recommended and I was new to the area. My hesitation is really only under light throttle as he tuned around the issue but ultimately I would like to fix it.
Link to comment
Share on other sites

Not sure if related...but I had odd hesitation in my former WRX. The "tuner" had de-capped the stock injectors so that they would flow more. This resulted in an altered spray pattern that shot fuel directly at the TGV plate/wall inside the TGV housing.

So fuel would hit that wall, then drip down into the intake port/intake valve. When I eliminated the TGV and ported the TGV housing, the problem went away and no more stumbling and better gas mileage.

It took me a long time to figure this one out. I had replaced all the fuel lines, aftermarket regulator (from Radium Engineering, which worked really well) and even put in aftermarket fuel rails (cant remember what brand....YXYZ or something like that). But in the end it was crappy spray pattern not spraying in the right place and not atomizing the fuel.

 

I would definitely not upgrade the injectors unless you are bumping up against 90% duty cycle or more. If not, then it is some other issue. Maybe something like my weird spray pattern issue.

 

MONEY SAVING TIP:

To adapt -6AN to the 5/16 quick-connect fuel ports, you can use Russell p/n: 644113 which is MUCH cheaper than the Aeroquip version posted earlier.

And its held on with a screw in retainer, not a plastic clip.

http://www.summitracing.com/parts/rus-644113

Link to comment
Share on other sites

Those Russell bits are nice - they were second on the list if the Aeroquip fittings leak or don't work. What swayed my decision was that I liked the idea of being able to quickly disconnect them using my fingers if needed. They don't even require the tool.

 

 

 

Sent from my SCH-I535 using Tapatalk 2

Link to comment
Share on other sites

  • 2 months later...
Time for an update...

 

 

(And thank you to KCWagon for his help and pointers!)

 

So the SS lines I was originally running in this setup began allowing ethanol to permeate them, and the in-cabin smell was pretty strong. Thinking that this shouldn't be happening since the lines I opted to use were PTFE-lined, I bought some different SS hose from the same local vendor, but this time went with lines that were "coated," thinking that this might help to mitigate the odor. It did, for awhile, but then the smell came back again after a couple months.

 

Since I had to disconnect the lines and remove the FPR while doing the STi MC/booster swap, I decided to also revise the under-hood fuel system at the same time. The new look and setup are much cleaner, but only time will tell whether it stops the permeation issue or not. I should also note that I've since replaced the nitrile O-rings at all the ORB fittings with Viton ones. We'll see if this helps as well, since the nitrile ones looked pretty degraded when I removed them.

 

http://i.imgur.com/fNJHaZB.jpg

 

Hey buddy,

 

Very nice setup :)

 

I had a question, did you need the fuel rail adaptor - TS-0402-1001

 

Cheers jack

Link to comment
Share on other sites

Permeation is a problem for sure in rubber hose.

Gates makes a hose called BARRICADE that has a special lining built into it that*almost completely* eliminate permeation.

http://www.gates.com/brochure.cfm?brochure=12468&location_id=5348

 

The problem is that is pretty much suited only for beaded stem connections with a hose clamp. To use -AN fittings, I dont think this hose would work because I dont know if an approved -AN hose-end that can attach to this hose.

 

So, that leaves 100% PTFE teflon hose. This hose is made from a extruded PTFE core tubing that is wrapped in stainles steel braid. It is not as flexible as rubber hose, but it is compatible with ALL FUELS and alcohols and has ZERO permeation.

For PTFE hose assemblies, I go straight to Techna-Fit for the best prices and best service, and they ship:

http://www.techna-fit.com/ourhose.html

You tell them what size, length and end fittings and they crimp up a hose. Yes, crimp. That is the best way to attach end fittings to PTFE hose. There are removable end fittings, but they SUCK to assemble.

Here is a selection of various PTFE hose ends techna fit offers:

http://www.technafitstore.com/category-s/1849.htm

 

I use PTFE on all performance builds, it is hands down the most trouble free "install and forget" hose, and it is not over priced.

 

FWIW: This place has some pre-fabb'd -6AN hoses in stock:

http://www.radiumauto.com/-6AN-PTFE-Teflon-Hose-Assemblies-P267.aspx

 

Just thought I would share because I have a lot of direct experience fighting permeation and the haunting "gas smell".

 

 

 

Time for an update...

 

 

(And thank you to KCWagon for his help and pointers!)

 

So the SS lines I was originally running in this setup began allowing ethanol to permeate them, and the in-cabin smell was pretty strong. Thinking that this shouldn't be happening since the lines I opted to use were PTFE-lined, I bought some different SS hose from the same local vendor, but this time went with lines that were "coated," thinking that this might help to mitigate the odor. It did, for awhile, but then the smell came back again after a couple months.

 

Since I had to disconnect the lines and remove the FPR while doing the STi MC/booster swap, I decided to also revise the under-hood fuel system at the same time. The new look and setup are much cleaner, but only time will tell whether it stops the permeation issue or not. I should also note that I've since replaced the nitrile O-rings at all the ORB fittings with Viton ones. We'll see if this helps as well, since the nitrile ones looked pretty degraded when I removed them.

 

Link to comment
Share on other sites

  • 1 month later...

Aracheon, nice setup! Just found this thread while researching FPR. I'm getting some pretty major "dripping" around my OEM FPR and thought this would be a great time to put in an aftermarket FPR. I really like your new setup and would like my pro-shop to copy your design and parts used. Was wondering what fuel line/hoses those are and if you solved the permeation issue with those new lines? Those lines look pretty beefy!

 

Thanks for the help!

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.



×
×
  • Create New...

Important Information

Terms of Use