o2 Housing help ..

[Rollinukwn]

ok soooo heres the deal .. 90 awd 5-speed

2g mani and my buddy is gonna build me a custom exhaust from the 02 housing to the rear bumper all 3" mandrel bend tig weld stainless ..


What o2 housing should i go with ..? Im looking for a 3" exit on the o2 housing is that over kill ? the turbo will be a 16g for now then later a 20g with the works...

The plan for the muffler is the straight threw bullet muffler.

 

[brian9397gsx]

you could go with either a 2g or evo3 but im unsure if either is a 3" exit. either way your gonna have issues with boost creep with a 3" down pipe

 

[Zdrummer15]

Most o2 sensor housings you'll find will only have a 2.5" outlet at the largest. For a 16g, you should be fine. If anything you'll be better off with a 2.5" o2 housing because of boost creep.

 

[JusMX141]

Im looking for a 3" exit on the o2 housing is that over kill ?

Considering there are many other popular turbos with much more airflow potential than a 16G using a 2.5" o2 housing (GT30R, PTE SC6031E, etc.) then yes, I believe it's overkill.

If anything a 3" o2 housing on a 16G will render the stock internal gate useless and murder your ability to control boost properly.

 

[hurricanecris24]

I would pick up an stainless steel o2 dump housing from punishment racing so you don't have boost creep with that 3" exhaust

 

[ReYnd]

There's very little need to upgrade beyond a 2G oxygen sensor housing until you are laying down some serious power. I'm talking... enough that you've probably long abandoned Mitsubishi exhaust components, bolt patterns and all.

I'm not even sure the 2G housing provides any more flow than its 1G counterpart, I just prefer where it places the sensor. The Evo III housing is quite a bit bigger. I'm unsure on fitment for the 14b, but reason suggests it will bolt right up to at least the Evo III flavored 16g. Its outlet flange angle is also different from the 1G/2G angle, so keep that in mind as well if you want to give it a shot and are fabbing up a downpipe.

But keep in mind that exhaust gases are a lot hotter and moving faster just as they leave the engine. Their density increases as they cool, which is why you start opening up the exhaust from the muffler forward instead of working front to back. Someone smarter than me can probably explain it more eloquently if that doesn't make sense.

 

[mandrigues]

If you get a external wastegate you will be able to control boost creep a lil better, you would have to go with a biger turbo and you could get an o2 that has a flange for a waste gate, just a thought for you if you are worried about boost creep but I wouldnt if you are planning on running only like 300hp. stick with a 2.5 internal wastegate when you have that 16g

 

[2GbTalonGuy]

I don't get why he would have to worry about boost creep with a 3" turbo-back exhaust. Isn't boost creep casued by not enough exhaust passing through the waste gate? With that logic I would think that opening the exhaust up after the turbo world help with the boost creep problem. Can someone please clarify?

 

[hurricanecris24]

I don't get why he would have to worry about boost creep with a 3" turbo-back exhaust. Isn't boost creep casued by not enough exhaust passing through the waste gate? With that logic I would think that opening the exhaust up after the turbo world help with the boost creep problem. Can someone please clarify?

I don't think so I'm not to sure how the whole theory goes. I was running my e3 16g on stock boost with all stock exhaust then I upgraded my whole exhaust system by adding a 3" dp and cat back my boost was creeping to 20+ on stock wastegate boost the way I fixed it was by putting my stock cat back on

 

[2GbTalonGuy]

There's something there I'm not getting. Reason I ask is because I picked up a 3" cat eliminating DP for dirt cheap ($75) so I wouldnt be able to just throw a cat back on to fix my setup. Would installing an External WG setup on my car help? I only plan on running a 14b to start with (when I get the engine put back together and finish up my project)

Sorry OP, I don't mean to jack your thread...

 

[Rollinukwn]

Yah i also thought boost creep was by having a smaller exhaust and the air flow now leaving fast enough..


I guess the 3" exaust is a no go then .... but i will only run the 16g for a few months and then grab the 20g . I guess 2.5 should be ok .... i just thought while i have someone who can make the whole setup do it 1 time and be done .


And also i hate the sound of a 02 dump...

***** soo the stock o2 housing and 3"dp should be ok then ... no boost creep right ?

 

[JusMX141]

I'm not even sure the 2G housing provides any more flow than its 1G counterpart

It doesn't.

The 2G housing simply has a slightly larger wastegate passage from the factory which some say offers more boost creep protection....however, a ported 1G o2 housing is equal to a ported 2G housing in every way; so if you're porting a housing, it literally does not matter which one you choose.

I don't get why he would have to worry about boost creep with a 3" turbo-back exhaust. Isn't boost creep casued by not enough exhaust passing through the waste gate? With that logic I would think that opening the exhaust up after the turbo world help with the boost creep problem. Can someone please clarify?

Yah i also thought boost creep was by having a smaller exhaust and the air flow now leaving fast enough..

You don't understand boost creep, apparently.

Summed up, exhaust flow is going to take the path of least restriction. If your exhaust system flows insanely well, the exhaust is going to want to continue to pass through the turbine housing instead of exiting through the wastegate hole, adding further airflow to the turbine wheel which generates more air pressure on the cold side, creating an uncontrollable boost situation.

Therefore, a larger-than-necessary exhaust is a bad thing if you're going to be running 18psi or below; an area where boost creep normally is an issue.

 

[2GbTalonGuy]

You don't understand boost creep, apparently.

Summed up, exhaust flow is going to take the path of least restriction. If your exhaust system flows insanely well, the exhaust is going to want to continue to pass through the turbine housing instead of exiting through the wastegate hole, adding further airflow to the turbine wheel which generates more air pressure on the cold side, creating an uncontrollable boost situation.

Therefore, a larger-than-necessary exhaust is a bad thing if you're going to be running 18psi or below; an area where boost creep normally is an issue.

Ah, Ok. That makes sence. Thank you for clarifying that jusmx.

 

[Rollinukwn]

It doesn't.

The 2G housing simply has a slightly larger wastegate passage from the factory which some say offers more boost creep protection....however, a ported 1G o2 housing is equal to a ported 2G housing in every way; so if you're porting a housing, it literally does not matter which one you choose.




You don't understand boost creep, apparently.

Summed up, exhaust flow is going to take the path of least restriction. If your exhaust system flows insanely well, the exhaust is going to want to continue to pass through the turbine housing instead of exiting through the wastegate hole, adding further airflow to the turbine wheel which generates more air pressure on the cold side, creating an uncontrollable boost situation.

Therefore, a larger-than-necessary exhaust is a bad thing if you're going to be running 18psi or below; an area where boost creep normally is an issue.

Sooo ... If i stay with 2.5 o2 housing to the back of (no cat) a bullet muffler think it should be fine then... ?

 

[JusMX141]

None of us can answer that for you, but it's a better start than a giant o2 housing and a giant exhaust system- neither of which your setup will put to good use.

 

[Rollinukwn]

None of us can answer that for you, but it's a better start than a giant o2 housing and a giant exhaust system- neither of which your setup will put to good use.

i thought a 20g 22-24psi was a fair amount of boost.

Im just gonna go with a tubular 02 housing 2.5 inch and a 3" exhaust and go from there ...

 

[JusMX141]

i thought a 20g 22-24psi was a fair amount of boost.

That's a fair amount- probably around 40-42lb/min of airflow on a proper setup....however, if you're planning your build on what you'll do eventually, you must deal with the consequences that it may cause currently- the biggest of which being uncontrollable boost.

Im just gonna go with a tubular 02 housing 2.5 inch and a 3" exhaust and go from there ...

Sounds like a plan to me.

 

[2GbTalonGuy]

Justin, do you know if somebody makes a (preferably stainless) 2.5" o2 with a flange to fit a 3" DP? I have been looking and cannot find one.

 

[JusMX141]

Almost all downpipes available for our cars are necked down to 2.5" at the o2 housing in order to fit stock and most aftermarket o2 housings. The only way you'll find such a thing would be in a pair where you'd get the o2 housing and downpipe as a setup....nobody is going to build a downpipe or o2 housing alone which fits less than 1% of the DSM population.

 

[1G Boy]

i have an ebay o2 housing just an o2 dump it was like 89 bucks or somthing but ive had no problem with boost creep and i am running the new fp68hta and i belive it is only 2.5"inch....

 

[Rollinukwn]

ill post pics soon.