2.5" and 3" o2 housings

[AshTsi]

Alright, i've been looking to upgrade my exhaust to a full 3" system. I'm currently running a e316g, but looking to upgrade to a mitsu 20g in the near future. So i've been looking at 02 housings since from my understanding they are interchangeable this can be an upgrade that i can transfer to the new turbo. My question is i cant seem to find any 3" housings for a 16g is this because its to small a turbo for a 3" housing? Would a 2.5" housing be more than enough? And lastly can i bolt a 3"dp to a 2.5" o2 housing? If the 2.5" is enough for the 16g will it be enough for the 20g? i did a little research and im pretty sure 2.5" to 3"dp is fine but figured i'd throw it in with the rest just to make sure.

Thanks guys
~Ash

 

[Artago]

Alright, i've been looking to upgrade my exhaust to a full 3" system. I'm currently running a e316g, but looking to upgrade to a mitsu 20g in the near future. So i've been looking at 02 housings since from my understanding they are interchangeable this can be an upgrade that i can transfer to the new turbo. My question is i cant seem to find any 3" housings for a 16g is this because its to small a turbo for a 3" housing? Would a 2.5" housing be more than enough? And lastly can i bolt a 3"dp to a 2.5" o2 housing? If the 2.5" is enough for the 16g will it be enough for the 20g? i did a little research and im pretty sure 2.5" to 3"dp is fine but figured i'd throw it in with the rest just to make sure.

Thanks guys
~Ash

I don't know if a 2.5" will be "enough" but I would think so. I'm running the 2.5" O2 on a V-Trim. Regarding whether a 2.5" O2 will bolt up to a 3" DP, the answer is Yes. I have a 2.5" O2 I got from eBay and it bolted up to a 3" DP I also got from eBay.

This is the O2 housing that I got from this vendor:
eBay Motors: NEW DSM Stainless o2 Housing - Eclipse Talon 4G63 Turbo (item 150201854380 end time Jan-09-08 19:00:51 PST)

 

[Gstclipse69]

A 3" o2 housing is overkill for almost anything you can throw at it. I read this somewhere but I cant find the link to the page. 2.5 will be fine and will bolt up to the 3" downpipe as well

 

[AshTsi]

Alright, thanks guys i just wasn't sure. it just seemed like everywhere i was reading guys were running full 3" turbo back so i wasn't sure if i would be costing myself more $$ going with the 2.5" now and having to go to a 3" later

 

[DGajre777]

I say that you'll be fine with a 2.5" o2 housing. Here is a 3" one if you still want one, it is a V-band housing though. Blank

Your best bet would be to get an EVO o2 housing and porting it.

 

[DsmDave95]

as everyone has stated your best bet would be to go with a 2.5 housing for your setup wheter with the 16g or the 20g. good luck

 

[jaday]

So if a 2.5 O2 housing is good enough, what is the purpose of upgrading to a 3" exhaust system? Wouldn't the smaller area of the O2 housing be a bottleneck to the rest of the system... Just seems that if you do a 2.5 O2, having a larger system behind it would be someone pointless...

 

[DSMsOwnYourV8]

I don't think the 3" really matters on that side of the exhaust. An example is an Apexi Downpipe. The inlet is only about 2.5" but after the initial bend it thickens to 3" and still is rated at 10-25 horsepower, while I've seen Full 3" downpipes rated at only 10-16 horsepower. I may be wrong on this though... I do know that I probably wouldn't buy a $35 02 housing off of ebay. Ebay parts have been known to be cheap - you get what you pay for.

 

[Artago]

I don't think the 3" really matters on that side of the exhaust. An example is an Apexi Downpipe. The inlet is only about 2.5" but after the initial bend it thickens to 3" and still is rated at 10-25 horsepower, while I've seen Full 3" downpipes rated at only 10-16 horsepower. I may be wrong on this though... I do know that I probably wouldn't buy a $35 02 housing off of ebay. Ebay parts have been known to be cheap - you get what you pay for.

I got a eBay O2 housing for dirt cheap and the quality is 100%. No complaint. Stainless steel. Wicked clean welds. Please don't bash something if you haven't tried it. I have one and I love it. It's the best purchase I made. Now, that being said, I'd never buy a turbo off eBay.

 

[AshTsi]

Well see, thats why i was asking all those questions. i was just under the impression that if im running a 2.5" o2 whats the point of running 3" after that? is there somthing im missing? wouldn't the 2.5" o2 act as a bottleneck and restrict the flow? there isnt much distance that exhaust flows until it hits the downpipe so would it not even effect it being such a short distance?

I probably wouldn't buy a $35 02 housing off of ebay. Ebay parts have been known to be cheap - you get what you pay for.

I have to agree with Artago, i dont really see anything wrong with the ebay o2. Thats actually what im looking into buying. i bought a SS exhaust manifold from ebay and i have not had a single problem with it.

 

[turbosax2]

Our DPs have a 2 1/2" stainless steel first bend with a 2 1/2" stainless steel flex section. They then expand to 3" right after the flex section right under the oil pan area. Why start out at 2 1/2"? If you are running on the stock O2 sensor housing, even ported it is 2 1/2" inside diameter. When the exhaust gasses are hot, they flow better, 2 1/2" is plenty for the first 12". As the gasses cool , bigger helps. By going to 3" after the flex section, we allow this expansion and also allow for better clearance at the front where room is tight. From there they are a full 3" back to the Apex 3" flange with 14 gauge aluminized steel piping. We had some Apexi flanges laser cut out of thick 1/2" steel for a good seal and fit.

Eclipse Exhaust System Upgrades

 

[DSMsOwnYourV8]

I got a eBay O2 housing for dirt cheap and the quality is 100%. No complaint. Stainless steel. Wicked clean welds. Please don't bash something if you haven't tried it. I have one and I love it. It's the best purchase I made. Now, that being said, I'd never buy a turbo off eBay.

I simply said that ebay parts have been known to be cheap. From experience I have had ebay parts that I have bought, both crack and fail. IMO i would rather spend more money for parts that have been proven to perform and be reliable.

 

[AshTsi]

Another question... I've been looking at diff downpipes. would a full 3" bolt to the 2.5" o2? because im seeing alot of 2.5" inlet to 3" outlet downpipes. is the the combo i would have to go with? it doesn't make sence to me for a 2.5" o2 outlet to bolt right up to a 3" dp inlet.. or will that work?

 

[turbosax2]

Where have you seen a downpipe with a 3" inlet? Most are 2.75" or 2.5" inlet and then expand to 3".

 

[V8notENUF]

I got a eBay O2 housing for dirt cheap and the quality is 100%. No complaint. Stainless steel. Wicked clean welds.

I agree, I have the dump version of the o2 off of ebay, no complaints, nice welds, etc. comes with all gaskets and new bolts as well. Also I checked the feedback before the purchase and found next to nothing for complaints against them.

 

[Artago]

Where have you seen a downpipe with a 3" inlet? Most are 2.75" or 2.5" inlet and then expand to 3".

You can get a 3" in and out DP from eBay. You'll have to ask the seller if it's a 3" in and out. If not, move on to the next seller. I ended up finding a 3" in and out DP for $70 + shipping ($130 ish total).

Then I bolted the 3" DP to my 2.5" O2. Worked great. I also, cut and shortened the DP because we (in Canada) are required to have a Catalytic converter and have tough emissions laws.

You can get a 2.5" in to 3" out but you might as well go for the 3" in/out. It's the same price.

Tom

 

[AshTsi]

i still dont see how the 3"dp can bolt to a 2.5" o2 housing. wouldn't you have issues with gaskets? i mean those are two different sizes holes, but i guess if it works then that great. im just trying to make it make sence to me.

 

[Artago]

i still dont see how the 3"dp can bolt to a 2.5" o2 housing. wouldn't you have issues with gaskets? i mean those are two different sizes holes, but i guess if it works then that great. im just trying to make it make sence to me.

Yeah good point. I forgot to mention that. I got a gasket with the O2 and the DP, so I had two (one 2.5" and one 3"). One of them worked better then the other but I can't remember which. I think it was the 3" gasket but I'm not sure. Try it out and see what works better.

I just remembered... I have pics... Here is the link to my Picasa (Google) web album.
<table style="width:194px;"><tr><td align="center" style="height:194px;background:url("http://picasaweb.google.com/f/img/transparent_album_background.gif") no-repeat left"><a href="http://picasaweb.google.com/tomas.beblar/TurboO2Downpipe"><img src="http://lh3.google.com/tomas.beblar/RvwrbZYa2AE/AAAAAAAAE0I/kTxVjk61OJ8/s160-c/TurboO2Downpipe.jpg" width="160" height="160" style="margin:1px 0 0 4px;"></a></td></tr><tr><td style="text-align:center;font-family:arial,sans-serif;font-size:11px"><a href="http://picasaweb.google.com/tomas.beblar/TurboO2Downpipe" style="color:#4D4D4D;font-weight:bold;text-decoration:none;">Turbo + O2 + Downpipe</a></td></tr></table>