3" o2 housing and downpipe

[volkerding95GSX]

Hello,
I have a 16g turbo and I am looking for a o2 housing/downpipe to compliment my "3 HKS catback. I'm not worried about being street legal, so I want my downpipe to eliminate the cat. Also, I would like the o2 housing to be 3" as well as the downpipe.

My question is if anyone knows where to get a 3 inch o2 housing that bolts to a 3 inch downpipe that eliminates the cat converter? Everything I can find that is 3 inches has a 2.5" entrance. I know the turbo side of the o2 housing has to be 2.5" but I want everything else to be 3" after that. Lastly, I drive 95 AWD, so that makes this all more difficult to find. Any ideas?

 

[tjbiker031]

Honestly i dont believe anybody makes an o2 housing with a 3inch outlet. I know they make down pipes with a 2.5 inlet and a 3inch outlet.

 

[SexyDSM95]

I have been searching for years. Without getting something custom/fabricated I highly doubt you will find one. One of the DSM gurus I go to explains it that most aftermarket DP's taper to 2.5" at the flange.

Lastly, I drive 95 AWD, so that makes this all more difficult to find.

Can you explain this question a bit? What's more difficult to find? I have a 95' GSX and the only issue I have found was finding a 95-96 transmission.

 

[JusMX141]

Why do you want it to be 3" starting right at the turbo? Afraid the 2.5" setup will not boost creep enough for your liking?

 

[volkerding95GSX]

Why do you want it to be 3" starting right at the turbo? Afraid the 2.5" setup will not boost creep enough for your liking?

1.I want a 3" turbo back because an exhaust is only as free flowing as its narrowest component. 2. The o2 housing I want will have an external wastegate that eliminates boost creep.

Here's what's I have: (flange size)
Turbo(2.5") 2.5" o2housing (2.5") 2.5"downpipe (2.5") 2" Cat (2.5") 3"exhaust.

Here's what I want:
Turbo(2.5) 3" o2housing (3") 3"downpipe (3") 3"exhaust.

Pretend I'm stupid and can't answer rhetorical questions. Is this out there or not? and how much do you think the 2.5 flanges counteract performance?

I have been searching for years. Without getting something custom/fabricated I highly doubt you will find one. One of the DSM gurus I go to explains it that most aftermarket DP's taper to 2.5" at the flange.


Can you explain this question a bit? What's more difficult to find? I have a 95' GSX and the only issue I have found was finding a 95-96 transmission.

You can ignore that, not important. I was just finding more 3" gst downpipes than for the gsx. Thanks for the help

 

[BigBeans]

Forced performance tested 2.5" vs 3" O2 housings, and there were no real differences below 540whp, IIRC.

 

[LunarEclips]

contact Road Race Engineering. They can fab one up if you really want it. Kinda pointless to me though.

 

[LiquidX]

Remember that hot gasses have higher velocity than cold gasses. The exhaust is hot enough right after the turbo that the 2.5" won't be a restriction until you get to some high HP numbers. If you have 2.5 after the down pipe, then yes that will change your performance as the exhaust is a lot colder there than 2" post turbo.

As stated 90% of aftermarket o2 housings are 2.5"-3" tapered. You can get full 3" v-band housings for like $5-600. Lot's of pie cuts to make a good flowing one anyway.

 

[dsmdeliveryboy]

I have a RRE 3" o2 housing, undivided mitsu flange with a vibrant 3 bolt flange

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Running it on a fully ported FP18G

 

[JusMX141]

1.I want a 3" turbo back because an exhaust is only as free flowing as its narrowest component.

Then why stop at the o2 housing? Pull the turbine housing off and have that baby hogged out to 3" right up to the turbine exducer.

2. The o2 housing I want will have an external wastegate that eliminates boost creep.

Right, because all externally-gated setups have no issues with boost creep.

http://www.dsmtuners.com/forums/bolt-tech/355504-still-boost-creep-after-external-wg.html

http://www.dsmtuners.com/forums/newbie-forum/329445-boost-creep-external-wastegate.html

http://www.dsmtuners.com/forums/turbo-system-tech/265096-crazy-boost-creep-external-gate.html

Is this out there or not? how much do you think the 2.5 flanges counteract performance?

They're out there, but nobody feels they're necessary. Even when Curt Brown's 1G made 499 AWHP and cut a 10.33 using an off-the-shelf Evo III 16G (the highest HP and ET on an Evo III 16G to date) he was also using an Evo III o2 housing.

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So unless you're planning on going faster than 10.33 or making over 500whp with your 16G, I think you'll be fine with what you consider to be too much restriction.

 

[jimmythesaint]

http://i648.photobucket.com/albums/uu205/jimmythasaint/DSCI0010.jpg

Dont know if you can see it or not, but thats my exhaust. Full three inch all the way back from the turbo. One solid piece with no bolt up between an O2 housing and downpipe.

 

[Rollinukwn]

Then why stop at the o2 housing? Pull the turbine housing off and have that baby hogged out to 3" right up to the turbine exducer.


Right, because all externally-gated setups have no issues with boost creep.

http://www.dsmtuners.com/forums/bolt-tech/355504-still-boost-creep-after-external-wg.html

http://www.dsmtuners.com/forums/newbie-forum/329445-boost-creep-external-wastegate.html

http://www.dsmtuners.com/forums/turbo-system-tech/265096-crazy-boost-creep-external-gate.html



They're out there, but nobody feels they're necessary. Even when Curt Brown's 1G made 499 AWHP and cut a 10.33 using an off-the-shelf Evo III 16G (the highest HP and ET on an Evo III 16G to date) he was also using an Evo III o2 housing.

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So unless you're planning on going faster than 10.33 or making over 500whp with your 16G, I think you'll be fine with what you consider to be too much restriction.

What mani or cast header is that one ?

 

[Rengar18]

STM: FP DSM CAST RACE MANIFOLD

Fp race manifold. One of the best manifolds offered for our cars for the price.

 

[9!'clipseDOHC]

What mani or cast header is that one ?

Forced Performance.

 

[whyadsm]

sorry but I have to ask ( cant find my answer anywhere) Does the stock 2g o2 housing bolts right up to the evo 3 16g turbo?

 

[talontsi18]

sorry but I have to ask ( cant find my answer anywhere) Does the stock 2g o2 housing bolts right up to the evo 3 16g turbo?

Yes it does.

 

[JusMX141]

sorry but I have to ask ( cant find my answer anywhere) Does the stock 2g o2 housing bolts right up to the evo 3 16g turbo?

The bolt pattern is the same, but the outlet of an Evo III 16G is almost 2.5" where the inlet of a 2G o2 housing is around 2"....so plan on doing LOTS of porting.

 

[Army4g63]

http://i648.photobucket.com/albums/uu205/jimmythasaint/DSCI0010.jpg

Dont know if you can see it or not, but thats my exhaust. Full three inch all the way back from the turbo. One solid piece with no bolt up between an O2 housing and downpipe.

So I guess I'm confused. You didn't bolt up the DP to the o2 housing? Is it welded? Or (this is a stretch) V-Band?

 

[JusMX141]

One-piece....o2-eliminator style, which is the worst aftermarket part design I've ever seen. Last time I worked on a car with one of those I had to pull the turbo to drop the oil pan.

 

[Moonlight GSX]

I know it maybe figured out already but there is a 3" custom O2 housing from FP themselves, only problem is finding a V-Band connection downpipe... that's what I'm looking for.