2003 Baja - What is this tube?

[ebbsspeed]

I'm doing an engine replacement in a 2003 Baja, bought a 2003 Outback long block and replaced the head gaskets, timing belt and idlers, tensioner, water pump, valve job, etc. on it in preparation for the swap. today I discovered that the drivers side head on the Outback motor is different than the Baja. On the Baja there is a steel tube that runs from the back side of the head to the intake manifold. On the Outback head, the casting boss is there, but it has not been drilled or tapped. Can someone tell me what this tube is for and whether I can run the Baja with the port on the intake blocked off? This is a non-turbo motor, but I think this tube might have some function on the turbocharged versions of the Baja that were built in later years. Maybe some kind of extra crankcase ventilation that deals with the extra blow by under boost conditions? I now wish I would have gotten an intake with the Outback long block that I bought, but that's water under the bridge. Any help or suggestions appreciated. I really don't want to have to have another head rebuilt and remove all the timing belt infrastructure, etc to replace the head.

[naru]

Sounds like an EGR tube.

This may help http://www.ultimatesubaru.org/forum/topic/137829-using-a-non-egr-engine-in-subaru-with-egr-exhaust-gas-recirculation-valve/

[wtdash]

+1 on the EGR. And you'll need to run the Baja's IM w/the EGR so it doesn't throw a CEL. You can try my EGR - work around shown in the link above, but I don't know anyone who's yet tried it on a '99+ Subie.

 

Otherwise, you can CAREFULLY drill and tap that boss on the OB block.

 

I'd be surprised if the OB is actually an '03, but maybe your Baja (or the OB) is CA-spec vs. Fed-spec?

 

GL,

TD

[ebbsspeed]

So what would be the issue if I just plugged the tube fitting but left the EGR valve in place? Longer warmup times and a bit less mileage?

[wtdash]

Everything I read says that it doesn't affect the way the car runs it's merely an emissions piece but do some more research on that.

Edited April 24, 2016 by wtdash

[lmdew]

I have the same thing going on.  I put a 2002 engine into a 2003 Baja.  I picked up the correct intake manifold from CCR in Denver (Thanks, Rick).

 

I'm planning on drilling another hole in the air box, about the same place as the intake temp sensor but on the other side.  I plan on using the same rubber grommet at the temp sensor and a plastic hose fitting from Ace Hardware to connect a hose to the EGR pipe.  I'll cut the EGR pipe so I can slide a hose over it and onto the hose fitting. 

 

All I need now is the correct EGR Pipe.  The threaded hole on the intake is larger than the normal EGR pipes on the 95-99 engines.  Anyone have a spare?

[kamesama980]

Long story short it reduces knock, reduces NOx (emissions), and improves mileage minutely at part throttle (basically any steady speed cruising). I mapped it out on my Firebird and it was a box roughly 1200-2500rpm and 2-10% throttle or something like that (a few more conditions to be met but that's the idea). I imagine the Subarus would be similar but a much wider window of operation since we see 3krpm by 70mph (vs the Firebird doing 90 and change at 2k rpm). 

 

EGR ought to be ported to the manifold to work right. it *can* work ported anywhere in the intake but works much better after the throttle for the pressure differential. The PCM won't be calibrated for your setup and will likely still throw a CEL because it says "EGR valve open" and expects X change to the MAP sensor but gets Y. Similar to the Firebird (again) throwing an "EGR low flow" code once in a while cruising around 50-60mph: is has a very open exhaust so there's less backpressure thus a different pressure differential between the exhaust and intake thus less EGR flow than expected.

 

All that being said, most people see very little difference after removing EGR.

[ebbsspeed]

I figured I'd post an update on what I did, since it seems a lot of posts end up hanging in thin air, with no update as to how a problem was resolved. I ended up doing what lmdew is planning in post #6. Initially I plugged the EGR port in the intake, but when driving it any time I came to a stop or did a slow shift the engine would die, so evidently the EGR circuit does provide some air to the intake beyond what the IAC valve does when the throttle is closed. There were no codes, no check engine light, just died. It would restart immediately and idle OK. I cut the EGR tube, drilled a hole opposite the intake air temp sensor, put in a grommet and a 90 degree push-in elbow, connected the EGR tube to the elbow and all is well. I haven't noticed any drivability issues at all. One difference I did notice between the two intakes , one with EGR, one without. The ERG intake tubes were full of black sooty residue, while the non-EGR tubes were spotless. I assume that this is due to some exhaust gases being fed back into the intake tract via the EGR valve.