Identifying Hoses

[Lee Baldwin]

My donor is a 2007 WRX. I have a few hoses that I am not able to identify. I checked the forums and figured most of them out but I have a few left. I am pretty sure "B" is the vacuum port and "A" and "C" look like coolant intake or exhaust but not for sure nor do I know where they would connect. "D" is a mystery. Thanks in advance.




901C52BF-2C3E-4A9A-A443-BCC1F1254630_4_5005_c.jpegFC65CBA8-2485-4FFC-B5B7-BD0AD43056AF_4_5005_c.jpegE6F70EF8-E97C-40D5-99BC-5E086D9FB728_4_5005_c.jpeg

[lpmagruder]

I've got mine running with a 07 donor as well so I can check when I get home. Your pics came in pretty small so it's a little hard to make out.

A looks like part of the PCV system, if it's leading to the left valve cover that's what it is and it connects to the PCV 1-to-2 hardline that goes in front of the intercooler, this hose here:
A.png

B I'm having trouble with, I "think" that's where the brake booster attachment is but low certainty on that. If that's the case, it was a nipple threaded into a BSPT threaded hole and I ordered a plug off of McMaster (unless you're doing a power brake setup)

C I am not finding a photo in my gallery that has that area but I suspect that may be another leg of the PCV system, check and see if that goes to one of the 2 nipples on the top of the right valve cover; If so, that's what it is:

C.png

D I think is also in my first picture, that went to the bypass valve. On my motor it had a T attached to it that I think went to a boost pressure gauge in the car, not sure if that was stock location or not since my donor car was significantly modified.

[Lee Baldwin]

Sorry about the low res. Here are some better ones.

Pic1.jpegPic2.jpegPic3.jpeg

[lpmagruder]

Thanks that's much better! I'm more confident now on what I listed already, A is definitely PCV, you can see where it connects to the valve cover. I suspect you'll find C is the same. Those top 2 nipples on each valve covers are part of that system. The rest of the system is a maze under the intake manifold, that took me a while to figure out since the previous owner of my donor had hacked it all up and put some sort of catch can in. There's a good video to reference here: https://www.youtube.com/watch?v=mO9mxDUDUDc

Still pretty sure B went to brake booster, if it's a nipple with a hex on it then that's it. It was definitely a BSPT and not the more common NPT so keep that in mind if you go to plug it.

[Lee Baldwin]

Thank you very much "Ipmagruder".. It's so nice to be able to post a question and get responses like this. I just bought the BSPT plug so thanks for confirming that. That is a sweet video explanation of the PCV plumbing. I'll need to watch it 7 times to understand it fully . Lucky my WRX was not modified.

[Lee Baldwin]

I've got mine running with a 07 donor as well so I can check when I get home. Your pics came in pretty small so it's a little hard to make out.

A looks like part of the PCV system, if it's leading to the left valve cover that's what it is and it connects to the PCV 1-to-2 hardline that goes in front of the intercooler, this hose here:
A.png

B I'm having trouble with, I "think" that's where the brake booster attachment is but low certainty on that. If that's the case, it was a nipple threaded into a BSPT threaded hole and I ordered a plug off of McMaster (unless you're doing a power brake setup)

C I am not finding a photo in my gallery that has that area but I suspect that may be another leg of the PCV system, check and see if that goes to one of the 2 nipples on the top of the right valve cover; If so, that's what it is:

C.png

D I think is also in my first picture, that went to the bypass valve. On my motor it had a T attached to it that I think went to a boost pressure gauge in the car, not sure if that was stock location or not since my donor car was significantly modified.

Here's a dumb question.. In "D" what is the bypass valve part of?

[lpmagruder]

Not a dumb question! The Subaru vacuum/turbo/PCV hoses can be a complete rats nest until you've worked on it for a bit and get your bearings.

When the throttle slams closed while you had boost pressure like during shifting it will open and dump pressurized air back into the turbo inlet pipe, so you don't have ~13psi of air pressure bearing against a closed throttle plate. Similar to a "blow-off valve" but it keeps air that has already been metered and accounted for by your MAF, in the intake system instead of dumping out to atmosphere and causing a temporary rich condition.

[Lee Baldwin]

Not a dumb question! The Subaru vacuum/turbo/PCV hoses can be a complete rats nest until you've worked on it for a bit and get your bearings.

When the throttle slams closed while you had boost pressure like during shifting it will open and dump pressurized air back into the turbo inlet pipe, so you don't have ~13psi of air pressure bearing against a closed throttle plate. Similar to a "blow-off valve" but it keeps air that has already been metered and accounted for by your MAF, in the intake system instead of dumping out to atmosphere and causing a temporary rich condition.

Thanks for the explanation on the purpose which is very helpful (I'm a pre-emissions carb guy....). What does that pesky "D" tube plug into?

[lpmagruder]

It should connect to the smaller nipple on the bypass valve mounted to the front of the intercooler:
bpv connection.png

I had to replace the tee with a straight fitting and another length of hose. You might also want to keep a tee here for a boost indicator. I may do that eventually but for now I just have a straight fitting.

[Lee Baldwin]

It should connect to the smaller nipple on the bypass valve mounted to the front of the intercooler:
bpv connection.png

I had to replace the tee with a straight fitting and another length of hose. You might also want to keep a tee here for a boost indicator. I may do that eventually but for now I just have a straight fitting.

Thanks again. I ordered my donor from Wayne/VCP and ordered his water intercooler so I did not get the OEM air to air intercooler (so no hard lines etc). I'll have to see if there is a similar valve on the water cooler setup.

[Lee Baldwin]

There is a tube that is capped and I marked it with a letter "F". What is that tube used for and why would it be capped? Is that normal? Thanks again.


pic5.jpg

[lpmagruder]

That's the bypass valve tube, goes to the turbo inlet pipe. I'm not sure if the AWIC uses a recirculating valve or just vents to atmosphere, if it's venting to atmosphere you would keep that securely blocked, though recirc is better.

The smaller line near it is the "control" line for the bypass valve and that big one is the actual air path.

[Lee Baldwin]

I found another hose that I missed earlier. There is a hose that comes out of a hard tube out of the side of the turbo outlet. The hose marked with a "G" is not connected to anything so I am curious what what this should/did connect to. The other hose "H" goes to what appears to be a some sort of valve that is switched. I am also curious what this is used for. After spending 2 hours researching I figured that I would ask again... Thanks again

pic6.jpg

[lpmagruder]

G should connect to the wastegate actuator, that silver cylinder on top of the turbo with a linkage connected to the wastegate. It almost looks connected in your photo so it should be right next to where it connects. H is the wastegate solenoid and one of the things in the engine bay you'll need to mount somewhere and wire in that's not part of the main engine connector like most the rest of the engine connections.

Here's a helpful image for that system:

07subaruservicebulletinrk2.jpg


With the motor out of the car it's a great time to remove as much as possible that you know you don't need (A/C pump, power steering stuff if there's any dangling on there, top motor mount, air pump system + block off plates: https://www.kstech.biz/subaru-air-pu...x-sti-lgt-fxt/ , Do your heater core bypass, TGV deletes if that's your flavor, any other engine mods you might want) and then tracing these lines gets a lot easier without as much clutter.

I spent a lot of time in this phase going through all the vacuum lines and checking for problems, I found a lot of lines that were cracked and either leaking or weren't far from leaking. For under $100 you can get all the hose you need plus extra and in the process you'll learn a lot about the plumbing.

[Lee Baldwin]

Excellent and thank you again. Great advice about spending more time on the engine before it is installed. I am planning on adding Vintage Air so keeping the A/C pump and following AZ Pete’s thread. My 818 won’t be raced…. Interesting about the Air Pump delete. If I am not concerned about gaining some HP is it worth removing? I am using the stock harness and ECU. I live in IL but doubt I will drive the car in the winter when it is cold. Looks like I need to find a place to mount the pump if I keep it.

[lpmagruder]

The air pump is for cold start emissions, it's also a really common failure point on the WRX. It's not going to hurt your power or anything but most people remove it for wiring simplification and engine de-cluttering. There are guides around written for the WRX that show how to do the delete, there's one sensor as part of that system you do need to retain.

I'm in the KC area so depending on where in IL you are, you might not be too terribly far away. Let me know if you're ever in the area!

[idf]

This thread may be of use to you. https://thefactoryfiveforum.com/show...lifying-the-EJ There is a sensor in the air pump circuit for ambient air pressure which you need to retain.
Should you decide to delete the TGVs, don't try to remove the associated wiring. Just tape off the connectors. Ask me how I learned this.

[Bicyclops]

This thread may be of use to you. https://thefactoryfiveforum.com/show...lifying-the-EJ There is a sensor in the air pump circuit for ambient air pressure which you need to retain.
Should you decide to delete the TGVs, don't try to remove the associated wiring. Just tape off the connectors. Ask me how I learned this.

What's the gotcha? I'm getting close to starting up and I have deleted a whole buncha wiring including the TGVs.

Ed Holyoke

[idf]

When I deleted my TGVs I also decided to delete the associated wiring and connectors. I'm not sure what I removed that I should not have but afterward the car initially ran poorly with some backfiring. I drove about 1/4 mile and after a big back fire it would not longer start. My tuner told me he tells his customers not to delete the wiring. I ended up installing a new engine harness and taped the connectors over. Now runs great. There must be some interconnections in there that are needed even without the TGVs. Perhaps this could be sorted out by looking at the wiring diagram while deleting, but I did not do this.

[Lee Baldwin]

Great suggestions. I took off the intake manifold last night and that is not for the faint hearted. I took it off so I could drill and tap the "Wayne" belch barb for letting the air out of the cooling system. Now that I have the intake off it sounds like I should replace the hoses as the donor motor had 100K miles on it. I looked at the hose kits and it looks like most kits give you hoses that I wont need (ie radiator). Assuming that I keep most of the systems in place is there a suggested hose kit to buy for the engine that would give me what I need? I am bit scared taking off a bunch of emissions stuff and having to reprogram the ECU but maybe I will regret this down the road.

[lpmagruder]

Good move, I found out about that mod after I already had the motor in and it was a huge pain to get the air out of the cooling system.

For the vacuum/PCV hoses I just measured the various diameters used and ordered bulk hose, I think I used https://www.siliconehose.com/ or some similar website. They won't be molded to the exact contour like OEM hoses but that didn't cause issues for me. While you're under the manifold might as well do the fuel rail lines too. Maybe they fixed it on the 06+ but the earlier turbo motors would develop a fuel leak in the rubber hose that linked the 2 fuel rails and that required removing the intake mani to get to.

You're going to want to tune/reprogram your ECU regardless, Subaru motors are really picky to changed conditions and it's in quite a different setup than its OEM config. It runs/drives with the factory map but you won't want to drive very hard and for very long on that map and you're going to get like 15 random codes mostly related to emissions, a lot of them related to components no longer on the fuel tank/evap side of things. If you don't disable the codes you know you don't want, you won't have a functioning CEL for any "real" codes.

I use the Tactrix setup: https://www.tactrix.com/ If you want to spend a ton more money you can get the Cobb one.

[Lee Baldwin]

Great, I will change the rubber hose that connect the fuel rails as well. I will go with the Tactrix for reading/updating the ECU. That looks like a good setup for a Subaru. I'm pretty good with electronics so hacking the car should go right along with my other hobbies.... I did manage to break some of the harness connectors since they are brittle. Should I just tape/zip tie them now or try and find replacement connectors?

[lpmagruder]

If you know you'll be using any connectors that are broken you can get replacements from https://iwireusa.com/

If you're not sure, I'd hold off until you get to the wiring phase. The OEM harness is a beast and I think you end up trimming away more than half of it, good chance if some random connector is broken it's one getting removed anyway. The harness hacking was my least favorite part of the project, I'm glad that's behind me :-)