Stromung Parts

[99SUS SFD]

So as I understand it, my BD has 2 cats. If I were to buy the Stromung high flow cat found on boxer4racing, it only has one cat. This will cause problems, right? Or does the second O2 sensor fitting on the high flow cat eliminate this problem?

I'm thinking about getting the Stromung midpipe to bolt up to my SPT axle back, then eventually getting a high flow cat and headers.

[d1giPhux]

I've been wondering this same thing.. since I'm in the same predicament.. except.. both cats on my car have gone bad right now...

So i'm wondering if i can just replace both cats with the stromung cat pipe, or if i would need anything else in order to hook it up?

Also.. what is the diff between that pipe and the 'Random Tech Dual hi-flow cat pipe'.

If you dont want to get a CEL.. which pipe would be the best to buy to replace both of the cats? Also.. where do you get the 02 sensor spacer to help with this problem?

[99SUS SFD]

If I wanted to replace my cats with something that was high flow, and my only option was to drop over $500 for the Random Tech system to avoid CEL's, I'd say screw it and stick with stock.

From the description of the Stromung, it says the pipe has both connections for the O2 sensors. So maybe it has the spacer already?

[decke48]

three issues
1)if you live in a state that looks at how many cats you have at inspection you need two cats or you get a $500-1000 fine.
2) po402 cat below efficency has a chance of popping up. to fix it you need to buy a rear O2 spacer http://rallitek.com/rao2sesp.html
3) if you car has rear o2 before the second cat you will need to buy a o2 wire extender http://shopping.lightningmotorsports.co ... 716&page=1 (http://shopping.lightningmotorsports.com/customer/product.php?productid=782&cat=716&page=1)

other then that you shouldnt have a problem with it

[99SUS SFD]

Typically my inspection station just plugs into the OBDII port, checks my lights and e-brake, and everything is set. They've never gotten under the car to count my cats.

I'm not sure where my second O2 sensor is. I guess I'll just have to crawl underneath it and find out.

[d1giPhux]

^ same here.. i'm looking for a cheap way to replace both of the cats on my car.. the stromung looks like the best option.. but only has 1 cat.. whereas the rand. tech pipe has 2.

here in NH.. they dont look under the car.. they just plug the obd2 scanner in and scan for CEL's.

also.. where do you get o2 spacer?

the bd's seem to have the 2nd o2 AFTER the 2nd cat correct? I will know soon.. since I'm bout to go pick my 2 dead cats up from the shop :lol: .. that sounds funny.

[99SUS SFD]

If it's after the second cat we may be ok.

From boxer4racing's description:


High flow cat pipe for RS, Legacy, Baja and Forester. 304 stainless with high flow cat. Bosses for both O2 sensors 2.25" piping gives a 6 to 10 hp increase. The perfect piece to complete a full stainless header back system for your naturally aspirated Subaru. Up to a 9% gain in fuel economy when combined with the Borla headers.

So it sounds like it avoids the CEL issue by allowing the second O2 sensor to still be connected.

I would think you could technically put in 4 cats as long as that second O2 sensor is at the end of them.

[d1giPhux]

Got an email back from the guys at boxer4.. this is what they said:

'Yes it does replace the entire cat-pipe from the header to the mid-pipe. The Random has two cats but it can still throw the PO420 like the Stromung due to the higher flow. No additional parts are needed unless you want to replace the springs bolts and the graphite gasket where the mid-pipe hooks to the cat-pipe. The Stromung comes with the gasket at the header. The graphite gasket and spring bolts are reusable if they are in good condition. '

So I'm assuming.. either one of these pipes may throw the CEL code.. and probably will.. the only difference is that one of the pipes (rand. tech) has 2 cats (like stock) as opposed to the 1cat stromung pipe.

Also.. for o2 spacers.. i found this post on subymods about building your own:

http://www.scoobymods.com/forums/showthread.php?t=5468

Any whos done this have anymore info if the o2 spacer trick works?

[99SUS SFD]

Hmm interesting. I'm going to look around about that P0420 code to make sure it doesn't affect any performance of the car, especially if it negates any of the positives of the Stromung. I can easily turn the light off using the Scangauge.

[d1giPhux]

Yeah.. you can turn the light off.. however.. when you go to get your car inspected.. it might pop up.. i think thats why people try to actually get rid of the problem. The CEL itself does not cause any problems.. so i've read.

[Huffer]

Guys, you are rehashing old information.

If you have a Federally manufactured vehicle then you can use either the Stromung or Random high flow cat - they will replace the entire catalytic section. They have bosses for the O2 sensors.

You will want to purchase an O2 spacer for the REAR O2 to lift the sensor out of the exhaust path enough to avoid triggering the PO420 code.

The code is clearable, but will return within 100-200miles...it is easier to install the spacer from the beginning.

Done and done. Now do it!

[d1giPhux]

Yes.. we know we are re-hashing old info.. but it helps us understand a bit more... and btw.. when you say federal (took me a while to figure this out).. you could just have said '49 state'.. aka.. any state but cali.

Also found that cool DIY on the scoobymods page for making your own spacer.. but. do you know anywhere to buy them for cheap anyways?

[Huffer]

The o2 spacers cost $25 from boxer4racing or rallitek.

If you don't have a drill press handy, just buy one that's made up. They're well made.

[99SUS SFD]

I know, I was just trying to better wrap my mind around it and convince myself to do it and it'll work.

That's probably what I'll do, just buy the spacer from boxer4racing. That way I know it'll work, haha.

[d1giPhux]

the guys over at boxer4 said the o2 spacer only works for like 95% of the people in getting rid of the CEL.. if you cant get rid of it.. know anything else you can do? or are you basically screwed at the inspection station?

[Huffer]

95% is a lot digi.

If it doesn't work for you then you can try putting a resistor in-line with the O2 sensor to give a false emissions reading)...the only reason the CEL is triggered is because of the amount of flow... higher flow detected outside of parameters = CEL.

[99SUS SFD]

I wonder if clearing it with the Scangauge would fool the inspection station?

[d1giPhux]

hmm, yeah, might be a good idea to do both at once.. that way you dont have to pull the whole damn thing off again.. but.. i think the spacer SHOULD work. Didnt you have that PO420 code for a long time yourself? I remember seeing it in SOMEONES sig.. for the longest time.

[99SUS SFD]

No wasn't in mine. I only threw a CEL once and that was for something that came disconnected when I installed my intake. Cleared the light with the Scangauge.

Well I guess there's only one way to find out. I'll order this thing in the winter when I get my firefighter's pay.

[Huffer]

It was mine. I installed a semi-hi flow cat on my BD and it triggered the PO420. New O2 sensors. Never installed the spacer because I left it too late and the rear O2 seized up on me.

[99SUS SFD]

Oh gotcha.

Digi, are you going to do the install yourself?

[d1giPhux]

I need to get something on my car soon.. so i'm really looking for the cheapest option.. i had the shop take the cats off.. but they want WAYYYY too friggin much for a couple of new cats and keep telling me its 'illegal' to weld some universals to a pipe for me.. not sure why.

And huffer.. yeah, i figured it was ur sig.. i saw it there for forever.. what do you mean you left the sensor too late? just didnt have time to put it in when u installed?

[Huffer]

I didn't buy the spacer when I fitted the cat. I bought it after. 1 winter and the O2 had seized up, making it impossible for me to get out with handtools.

[d1giPhux]

yeah.. i should definitely get the spacer when i do it then... i wonder if the shop will want to install the damn thing for me.. or if i should just do it myself.. they seemed pretty keen on 'illegal things'... they would probably tell me it was illegal or some shit.. who knows. Only prob with the stock one was.. looked like it was a huge bitch to get to some of the bolts from the ground at least..

[99SUS SFD]

That's what I'm thinking about too. I've got jack stands so hopefully that'd help.

[dplacencia]

I have the stromung single cat and haven't had a problem.

[99SUS SFD]

Cool, good to know.

What else do you have for an exhaust set up?

[dplacencia]

Cool, good to know.

What else do you have for an exhaust set up?

Borla headers, Stomung cat, Stomung mid pipe, Stomung Axel back. Best sound ever out of an NA. People think I have a turbo but it's all NA baby. :grin:

[99SUS SFD]

Nice. I got half way through your rides thread (cool to follow it step-by-step btw) and was looking for an audio clip. You don't happen to have one, do you?

I'm thinking once all is said and done with mine I'll at least have Stromung hi flow cat, Stromung mid pipe, and the SPT axel back. Headers I'm not so sure about.

[dplacencia]

No sound clip here. The axelback is that extra kick. I would not change my exhaust for nothing. it was very expensive but worth every penny.

[d1giPhux]

Do you have the o2 spacer on your stromung single cat? I really want to put this in myself.. but looks like some of the bolts are in WICKED hard to reach places.. yet.. i dont wanna shell out another $80+ for someone to do it. :/

[Huffer]

You did suspension on your car - exhaust is no more or less on the difficulty scale.

[99SUS SFD]

Yeah I still haven't crawled under there to investigate myself. I emailed the guys at boxer4 to ask if they sold the O2 spacer as I didn't see it on their site.

I also asked about installation difficulty.

[99SUS SFD]

Turns out boxer4racing doesn't have the O2 spacers needed.

I think this would probably work.
http://yhst-49187380673845.stores.yahoo ... 2sesp.html (http://yhst-49187380673845.stores.yahoo.net/rao2sesp.html)

[Huffer]

^^ that's the one.

[d1giPhux]

You did suspension on your car - exhaust is no more or less on the difficulty scale.

True.. in fact.. i would say its easier.. if i could fully extend my arms.. however.. being on your back and trying to get to the tight spaces in there.. looked pretty damn hard to me. I guess I'll give it a try once i decide what I want to get.. hmm.

Also.. anyone know how loud the stromung makes your exhaust? Would it be wise to replace the o2 sensors at the same time.. or what? How much do these range for? I saw some on ebay for $25 or so.. but not sure if they are the right ones..

The guy at the exhaust shop told me that my 'engine was running lean'.. and thats what 'caused the problem'.. so now im just paranoid. I'm pretty sure he was just making shit up trying to get me to buy into their bullcrap.. cause when i started questioning him, he got all defensive.. but.. now im paranoid.

[Huffer]

Subaru's tend to run rich, not lean.

What exactly is the problem with your car? You have a leaky exhaust right? Or has the cat crumbled?

If a mechanic cannot give you a straight answer without getting defensive, then they cannot be trusted. It's not a difficult business.

[99SUS SFD]

Also.. anyone know how loud the stromung makes your exhaust?


I'd say it depends on what you have on there now. I'm going to be doing the Stromung cat, midpipe, and bolt it up to my SPT, so I'd imagine it'll sound a lot like Kris' (which sounds good IMO)

http://s256.photobucket.com/albums/hh18 ... 000296.flv (http://s256.photobucket.com/albums/hh183/Kris_ktg/Pics/Video/?action=view&current=P1000296.flv)




Would it be wise to replace the o2 sensors at the same time.. or what? How much do these range for? I saw some on ebay for $25 or so.. but not sure if they are the right ones..


When I did my cat and back exhaust on my Jeep, it was recommended that I replace the O2 sensors. I also had 100k+ miles and as far as I knew they were original.
I wouldn't go with eBay sensors, I'd go straight OEM from the dealer. You may pay more for 'em but that's worth it IMO. I bought OEM Jeep ones when I did mine and they were like $50 a piece.

[dplacencia]

When I did mine I reused the same O2 sensors and did not use a spacer. i've had no problem here. :wink:

[d1giPhux]

Subaru's tend to run rich, not lean.

What exactly is the problem with your car? You have a leaky exhaust right? Or has the cat crumbled?

If a mechanic cannot give you a straight answer without getting defensive, then they cannot be trusted. It's not a difficult business.

Yeah.. i don't trust them at that place.. first time there.. wont ever go back.. he said both of the cats were burned up in the inside.. but.. they dont look like they are to me? just looks like the weld busted on one of them.. but.. maybe i should take some pics.

Also.. why not go with ebay sensors.. i think most of them are pretty decent companies anyways.. i really doubt it would make a huge diff.. would it?

[winston856]

Just grab yourself the stromung track pipe, you'll love it : :grin:

[99SUS SFD]

Also.. why not go with ebay sensors.. i think most of them are pretty decent companies anyways.. i really doubt it would make a huge diff.. would it?

When it comes to stuff like that, I'd rather have the piece of mind to go with OEM rather than dick around with them. I'd rather replace something once and get it done with rather than having to do it twice.

[d1giPhux]

Just grab yourself the stromung track pipe, you'll love it : :grin:

I don't think the inspection station will think the same! LOL. I might just go with an OEM one... its $270 shipped as opposed to the $350 for the stromung.. and if I'm going to sell my car.. I don't really want to lose more money anyways.

Now i need to figure out why the guy at the shop said my cat 'melted' down.. not sure if the previous driving around with a hole in it had something to do with this.. or what.

[99SUS SFD]

I didn't even think of that. If I was trying to sell my car, then my mind owuld already be made up. I'd spend as little money as possible for the replacement.

[d1giPhux]

so yeah, no i'm trying to figure out if the cat really is 'melted'.. it doesnt look like it to me. The rear / 2nd cat seems to have a broken pipe.. but the other doesnt seem to look too bad at all...

When I took the car to the subaru shop before hand.. i asked them about my 'exhaust leak'.. and they told me it was coming from the second cat.. so it already had a hole in it. One day, i took it out and was beating on it around the highways for fun.. and yup.. looks like the hole got bigger! :lol:

But still.. i think this second shop, the exhaust shop.. was just lying to me. The other cat doesnt even look like it has any problems.. and doesnt look 'melted down' to me... i dont even know how they could tell.. they didnt even take the heat shields off the fucking thing!

https://sl-i.net/FORUM/images/imported/2008/09/cat1-1.jpg

https://sl-i.net/FORUM/images/imported/2008/09/cat2-1.jpg

I just dont wanna replace it and have to deal with this shit again...

[99SUS SFD]

Duct tape.

[d1giPhux]

HAHA.. it may work.. lol! :P

i just edited my post above... anyone know what i might be able to check so that I can be sure my car isnt going to melt down the next cat? Even though.. i really dont think these are melted.. as stated in last post.

[Huffer]

1. You can't tell the condition of a cat looking at it from the outside.

2. That's a major break and you do need a new pipe. Is that the front or rear cat?

[99SUS SFD]

I'm almost drunk enough to go ahead and order the midpipe now even though I don't need it. :grin:

[d1giPhux]

1. You can't tell the condition of a cat looking at it from the outside.

2. That's a major break and you do need a new pipe. Is that the front or rear cat?

Yeah, I know you cant tell the condition from looking at the outside.. which is why I'm wondering why they told me it was 'melted'. I looked down the pipe with a flashlight and it does not look 'melted' to me.. in fact.. the only thing i can see wrong is the giant break in the pipe.

Also.. anyone know how i can tell if an oxygen sensor is bad or not? I wasn't getting any cel lights or anything before the pipe broke.. so.. I'm assuming they are still good? I should probably get new ones.. but I'm broke as hell right now.. and dont want to spend another $150 if i dont need to.

ebay has some universal beck / arnley replacements for like $25.. just dont know how reliable that company is.. as long as they have the same amount of wires however wont they pretty much work the same? I noticed that some companies sell universals that replace either upstream or downstream.. i should probably stay away from these correct?

also.. thats the rear pipe.. the same one the subaru shop said had a small leak before hand.. so... i'm assming by driving it around, and driving it a bit hard.. just made the hole bigger and broke the pipe...

okay.. im done asking a million questions..

[evan55]

Borla headers, Stomung cat, Stomung mid pipe, Stomung Axel back. Best sound ever out of an NA. People think I have a turbo but it's all NA baby. :grin:

I have the same setup besides the cat, do you have a resonator on yours? I'm trying to decide if i should add one in.

[d1giPhux]

anyone have info bout my o2 sensor questions? thanks.. trying to figure this out soon..

[Huffer]

If you buy OEM-type PLUG N PLAY replacements they will be about $80 each.
If you buy the cheaper versions then you will have to either a) crimp and connect or b) solder the wires yourself.

If I do that again, I am spending the extra $30 to save myself time in the long run when my crimp job comes undone, and then my resoldering as well.

This one has the plug:
http://www.oxygensensors.com/showpictur ... ey=1305504 (http://www.oxygensensors.com/showpicture.php?&sensor=234-3091&pkey=1305504)

This one doesn't:
http://www.oxygensensors.com/showpictur ... ey=1305504 (http://www.oxygensensors.com/showpicture.php?&sensor=250-23000&pkey=1305504)

If you don't get the sensors with the plugs attached/wires terminated, you will have to cut your original plugs (measuring of course), and attach them to your new sensors.

Bottom line: buy the ones with plugs already attached.