Newbie here with exhaust issues

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pieceofjake12
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Newbie here with exhaust issues

Post by pieceofjake12 »

Hey guys, bought my 2004 Baja back in September. It had a hole in the exhaust when I bought it and now it has gotten significantly bigger. Im looking to fix it or just replace the whole thing, only issue is I'm not sure how to do so. Rockauto doesnt seem to have the exhaust system kit, and I'm not exactly sure how to fix it. Any help would be appreciated, thank you!
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Guacamole
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Re: Newbie here with exhaust issues

Post by Guacamole »

Hey there. Before we dive into this, is your 04 a Sport or Turbo? Rockauto has all the exhaust parts for the Sport, but not the Turbo. That said, if the Cats are not throwing codes, DO NOT REPLACE THEM!!!
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Re: Newbie here with exhaust issues

Post by pieceofjake12 »

It is a Turbo and is not throwing any codes.
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Re: Newbie here with exhaust issues

Post by Guacamole »

Well being a Turbo definitely makes things more complicated. But fear not! The parts can be found... just not all in the same place or category.
So, one thing to point out about the Baja Turbos: the entire drive train is identical to the Gen-2 Forester XT (2004-2007) drive train. As such, other parts that are linked to the drive train (such as the exhaust) are 100% compatible to the Baja Turbo.
As for the Baja, everything behind the rear axle is proprietary, but almost everything from there forward is shared with another platform (mostly Legacy).
Now to your predicament: exhaust.
All models and years of the Baja share all but one of their exhaust parts with another platform. The headers, cats, gaskets, and midpipe are all straight from the Legacy. On the Baja Turbo however, the headers, cats, and gaskets are all shared with the Forester XT, while the midpipe is still from the Legacy. The muffler on both the NA and Turbo Bajas is proprietary, but is from what I understand shared between the two models and is compatible for all years.
So, if you want to do a full [minus the cats] exhaust replacement, you can get Forester XT parts for everything IN FRONT of the midpipe. The midpipe can be pulled from a Gen-3 2.5L Legacy (2000-2004). The muffler will need to be from another Baja, or an aftermarket from Bosal. No one else (to my knowledge) produces this part. The hardest parts to find will be the headers, as not too many manufacturers produce them.

Now with that all said, is it really a full exhaust replacement you want?
Where and how big is said hole in the exhaust?
The most common exhaust failure is right at the flex joint where the rear cat pipe and midpipe meet. The engineers designed the joint to be in the exact spot that gets splashed on from the gunk kicked up from the tires. The gasket inside the flex joint is a metal mesh gasket, and at this point is probably rusted to hell and back and will crumble to dust when pulled just like the one in my 06 Sport did.
Phew!

P.S if you haven't already since it's a Turbo, pull that pesky mesh filter in the banjo bolt
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Re: Newbie here with exhaust issues

Post by BajaTim »

I (2005 turbo) went to a local custom
muffler shop and the mech bent all needed pipe (from catback - is that midpipe?) and was about to put on a muffler when I said to you have one in stainless - he did (but it’s a bit louder - still passing inspection here in MA) - cost: $340?? $325?


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Re: Newbie here with exhaust issues

Post by joedavex »

Resurrecting an older post rather than starting an new one because the info from Guacamole is invaluable. Thank you for posting the details on which years match up across models.
My 2004 turbo Baja has severed the midpipe between the 2 resonators. I'm debating about taking it off and trying to weld it back together or rather just getting a new midpipe.
subarupartsandaccessories.com lists the midpipe https://www.subarupartsandaccessories.c ... AE170.html for $416 (I'm not going to buy it, just looking at it for photo reference) but it doesn't look like my midpipe.
My midpipe more resembles the the midpipe listed at RockAuto for the 2004 Legacy 2.5 (non-turbo). https://www.rockauto.com/en/moreinfo.ph ... 8&jsn=1108 Walker 56243.
What has been other's experience with the exhaust? Does it match the Subaru spec?
My hesitancy with taking it off and welding is that I just took an impreza off the lift after welding a hole in the midpipe and it's still leaking a little through the patch I put on, not feeling the desire to fail another pipe. I probably will take it off tomorrow though since any repair is going to start with the removal of it.
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Re: Newbie here with exhaust issues

Post by mike-tracy »

I have used Walker exhaust pieces before. Fitment isn't as good as OEM, but can be made to work satisfactorily.

The bigger issue is factory turbo exhaust pipe is 2.25" whereas Subaru put 1.75" piping on 4 cylinder non-turbos. So even if you made it work, you'd be choking your engine.

If you can, I'd see what an exhaust shop can do for you. They don't usually cost too much and are quick.
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Re: Newbie here with exhaust issues

Post by joedavex »

Thanks mike-tracy, I hadn' thought of the difference in diameter.
I'm going to pull the pipe off today and see if either I can repair it or as you suggested possibly take it to a muffler shop and have them repair or make a new one.
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Re: Newbie here with exhaust issues

Post by Guacamole »

Brand new part if you want to pay and arm and a leg :lol:
https://www.subarupartsdeal.com/parts/s ... ae170.html
I DID actually purchase that exact Walker midpipe when mine fell off- AVOID WALKER LIKE THE PLAGUE. There were more holes in the new pipe than my old pipe, one being nearly an inch long along a weld seam. Quality like that is either accepted by their QC department or the department is nonexistent and their welders just don't care.

If it's broken at a weld joint, cheapest option is to saw off the welds, sleeve a pipe and re-weld.
If it's broken at the flange, you have three options:
1. replace the entire pipe with a new one
2. cut the flange off and weld a new flange
3. and this is only if the flange flaring is intact but the screw holes are gone- get some split flanges and mount them behind the original flanges and bolt those suckers together (something like this: https://www.amazon.ca/Nickson-Industrie ... B00AZWSGX6)
My solution on my NA when it went:
Image

I ended up getting a new midpipe but re-used the split flanges at the flex-joint:
Image

...but you get the picture.
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Re: Newbie here with exhaust issues

Post by joedavex »

Thanks Guacamole.
I tend to agree on the Walker, unfortunately the selection is limited.
Mine is broken between the first and second resonator, about a foot past the cat.
IMG_20211216_110149.jpg
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After grinding off the bolts for the front and rear flange i managed to get the midpipe out and cleaned it up. My plan is to get 2.25 OD pipe and slide it inside the existing pieces. Sorta like this picture but the piece of pipe I have is 1.875, this is just for demo.
IMG_20211216_181859_BURST001_COVER.jpg
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My plan is to weld it to the front resonator which has plenty of meat to weld to and then simply put an exhaust clamp on the pipe by the second resonator. This gives me the added benefit of not having to be perfect aligned in rotation or length, I'll have a little wiggle room.
Up until last week my local subaru dealer gave a discount if I ordered online and then picked up in store, used to work out great. I just jumped online to order the gaskets, etc I need and they are now charging MSRP. I did find another Subaru dealer in CT,Dan Perkins in Milford CT which has competitively good discounts online. I'll drive the hour tomorrow to pick up the parts and hopefully get it together.
Unfortunately my son had to have his OBW towed home tonight so I have another project for tomorrow also, do some diag on that and repair.
IMG_20211216_213930.jpg
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Thanks again for the help, I'll post some completed pics after I reassemble.
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Re: Newbie here with exhaust issues

Post by Guacamole »

joedavex wrote: Thu Dec 16, 2021 8:41 pm
Had to break in the worst possible spot!
Excellent approach. The only thing I would suggest is before you weld it all together, re-assemble it on the vehicle with the connecting pipe installed and put a screw into it on both sides of the pipe (or weld one side and bolt the other) so you know exactly how long to make it + positioning when you're welding it off the vehicle. You can either leave the bolts installed in the final product or weld over the holes.

While you're at it since you're already going the mile- I'd suggest you might as well beef up the flex joint since it's looking like the bolts are barely holding it together. Could probably do what I did and use split-flanges and re-use the original flange screw holes with just extended bolts (the springs are probably still good, I was lazy and decided to "un-flex" mine, seems to not be a problem)(also, if you go this route, the bolts will need to be inserted from the cat through to the downpipe, NOT the other way). The flex joint gasket is probably sawdust at this point too so definitely replace that not only to stop the leaks but also helps your airflow. The mesh one I originally went with on mine rotted out in a few months so definitely get the solid steel one.
I actually had to get Walker gaskets (lol, after I just spent almost an entire post dumping on them), and it might be tricky finding the right one.
Walker says this one doesn't fit a 2006 NA baja but it's the one I put on there (it fits) and is still in there: https://www.amazon.com/gp/product/B000CQDK9K/
Measure the outer diameter of the pipe that the gasket is supposed to sit on and choose from there, this one is 2.56" inner diameter but I have no idea if these specific gaskets are the same on the Turbos since the outer pipe diameter is different. (Let me know the measurement if you go this route please)

Looks like you have your work cut out for you!

EDIT: I managed to actually find a (albeit small size) full diagram of a Turbo cat-front exhaust system, save this for your records because this is incredibly hard to find! (And this picture if off a now-dead blogspot but the images are still archives)
turbo exhast sytem.jpeg
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Re: Newbie here with exhaust issues

Post by joedavex »

Alright, the Baja is back on the road.
Guacamole, thanks for the valuable info and the pic of the exhaust, I've downloaded and saved.
We both had the same idea on the pre-fitting before welding and a good thing I did. I ended up stretching the new pipe another 1/2 inch more than my initial measurements indicated.
Here's the final product welded in and clamped on:
IMG_20211217_141320.jpg
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I even went ahead and reweded the heat shield onto it, I'm guessing since it's right below the driveshat carrier bearing it's there to keep the rubber from failing.
IMG_20211218_140856.jpg
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I went to Subaru direct and got the bolts and gaskets I needed.
Here's the parts list and prices for what I got, I didn't want to try to figure out what equivalent parts were.
Quantity Product Stock Number Price EA
1 Catalytic Converter Gasket (Rear) 44022AA123 $19.17
2 Flange Bolt Exhaust Pipe. . NO.1. NO.2. 44059AA010 $4.39
2 Spring Exhaust Pipe. . -1Y. 1Z-. 44044AA010 $5.09
1 Exhaust Pipe Connector Gasket 44011AE01A $4.01
2 NUT 802008270 $2.84
2 FLANGE BOLT 010510307 $2.00

Total ended up being $51 after discount.

Here're are the dimensions for the Donut gasket:
donutgasket.jpg
donutgasket.jpg (1.13 MiB) Viewed 1579 times
1/2 inch tall
3/16 inch thick
2 7/8 inch wide overall, about 2 11/16 inside diameter.

For the flange gasket the dimensions are:
2 1/16 inside diameter
3 5/8 center to center on the bolts.

For some reason I can't add any more images to this post so I'll add another post with installed images.

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Re: Newbie here with exhaust issues

Post by joedavex »

Final installed pic of the repair:
IMG_20211219_132504.jpg
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One thing that needed work with a chisel and screwdriver was cleaning the Cat pipe to have the donut fit over it. Also cleaning the other side of the flange where the donut rides.
IMG_20211219_130600.jpg
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The new repair has zero leakage but I am getting leakage at all the flange points (including the downpipe to Cat connection which has not been touched.

It is not overly loud at all and without being under the car you probably wouldn't notice it so I'm letting that go (for now, until the next exhaust failure).

Thanks for all the help and support everyone! If anyone has questions please don't hesitate to ask, I'll be able to hold the memory of the job for a little bit :)
Now off to replace the broken timing belt on the OBW, keeping my fingers crossed that the valves aren't bent.

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Re: Newbie here with exhaust issues

Post by Guacamole »

Great work and thanks for the info!
Good luck with the OBW
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Re: Newbie here with exhaust issues

Post by jpv74 »

Guacamole wrote: Mon Dec 03, 2018 6:03 pm Hey there. Before we dive into this, is your 04 a Sport or Turbo? Rockauto has all the exhaust parts for the Sport, but not the Turbo. That said, if the Cats are not throwing codes, DO NOT REPLACE THEM!!!
Hey Gauc.....I am a newbie with a Subie as well. My car has a JDM 2.0 installed by the previous owner but it is not dialed in yet. The car boggs down in second gear and jumps to overdrive when climbing hills. I took it to a Subie shop and they are telling me they think the cats might be clogged but cant say definitively. They ran it with no exhaust and felt it was peppier with more air flow. We decided I would order a cheap cat section of pipe off of Ebay and just try to see if the performance improves with a new but cheap aftermarket double cat section of pipe. I personally dont think it will resolve my issues but willing to throw a couple of hundred in the pot to give it a chance. So now my question.......you say Dont replace those cats!!!! Educate me please.....mine have 183k on them.....might be partially clogged.....keep em or replace em? thanks
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