2.5" exhaust, stock o2 housing, confused...

[Woodsy0]

Alright, I'm going to have a friend weld up a bunch of RRE exhaust pieces to make up what essentially will be a turbo back 2.5" exhaust set up. However, my o2 housing is stock, so the opening to the downpipe is obviously larger than the opening to the o2 housing it will be mated to. Now I'm still running a stock turbo with plans to upgrade later, so I don't want to buy a whole new O2 housing made to fit a stock turbo and a 2.5" exhaust only to upgrade it again later when I put in an EVOIII.

My question is this: Am I able to gasket match the o2 housing opening by porting? Or will it leave too little space for the gasket to mate? Basically, how do I go about mating this 2.5" downpipe to the stock o2 sensor housing?

Thanks,
Scott

 

[never2muchBoost]

You can bolt the 2.5" downpipe up to a stock 02 housing just fine, if You want to port the 02 housing outlet to 2.5" You can do that also. It really doesnt matter to be honest, but having it ported will help when You start to get some power in it. Just have it ported when you're putting your 16g on. You wont notice a difference with the t25.





Edited by 98RedGs

 

[LandoAWD]

u can bolt the 2.5" downpipe up to a stock 02 housing just fine, if u want to port the 02 housing outlet to 2.5" u can do that also. it really doesnt matter to be honest, but having it ported will help when u start to get some power in it. just have it ported when you're putting your 16g on. u wont notice a difference with the t25.

"u" is not "you.

DSMTuners is not AIM.

Don't type like that again. Thanks.

If this is confusing to you, next time before you post, read #6 in the red "Before you post" text.

 

[midnght]

Wow, it's been some time since my last visit.

Ok, first things first. It is ok to bolt the exhaust up going bigger as you get to the rear of the car. It is not recommended to go smaller from muffler to o2.

Basically, you can mate up parts in order of front to back like so:

---(o2)====(DP)ooooooooooooooo(catback)000(muffler)

From small (o2)to big(muffler)



Doing it the opposite way will work, but it will be working AGAINST itself.

 

[Woodsy0]

Okay, I was just worried that the o2 and DP would mate weird since there are different sized openings on the o2 outlet and the DP. I'm going to have to file the bolt holes on the gasket and DP flange to line up to the studs on the o2 to even have a chance of it fitting, but do I have to gasket match the o2 opening (port it open a bit) so that there is a good seal between the two? It just seems weird that I'd be mating together two pipes with different inside diameters.

Thanks,
Scott

 

[Mirage1]

but do I have to gasket match the o2 opening (port it open a bit) so that there is a good seal between the two? It just seems weird that I'd be mating together two pipes with different inside diameters.

You don't need to gasket match the two. But it would be a good idea if you have the tools. It would be even better if you could fully port the O2 housing.

Compared to running an 3" O2 housing with stock exhaust, your setup is great. That is what the other guys were trying to expain. You always want the exhaust the same diameter all the way or at least getting larger as you get closer to the end of the exhaust system.

 

[zachdeagle16]

Alright, I'm going to have a friend weld up a bunch of RRE exhaust pieces to make up what essentially will be a turbo back 2.5" exhaust set up. However, my o2 housing is stock, so the opening to the downpipe is obviously larger than the opening to the o2 housing it will be mated to. Now I'm still running a stock turbo with plans to upgrade later, so I don't want to buy a whole new O2 housing made to fit a stock turbo and a 2.5" exhaust only to upgrade it again later when I put in an EVOIII.

My question is this: Am I able to gasket match the o2 housing opening by porting? Or will it leave too little space for the gasket to mate? Basically, how do I go about mating this 2.5" downpipe to the stock o2 sensor housing?

Thanks,
Scott

Won't a stock o2 housing fit on an evo 3. If so you could just go ahead and upgrade o2 hosuings.

 

[oplix]

stock o2 housing does fit an evo 3. that's that i have.