I have been looking around at the various 3" TB and O2 housing based exhausts. After my search I have came to the conclusion that there may be little or no advantage to getting an exhaust with the O2 housing built in. I plan to run the stock turbo and no plans of upgrading it. Furthermore after inspection of the O2 housing it is a really clean piece for being casted. It is pretty smooth and doesn't seem to affect flow more than 1-2hp. If anyone has dyno #'s or other information to support that a O2 housing built in the downpipe nets more HP than my decison will be made. Although if I cannot find support for this then I will buy a standard downpipe and exhaust.
I used the search function. So please look at this post as a way to save money or benefit from knowing if an O2 housing based exhaust really works.

 

I think the only disadvantage of the stock O2 housing (and any housing this short) is the potential turbulence of the wastegate exhaust as its merging back with the turbine outlet..

I think your assessment is probably accurate..

 

The primary issue with the Diamond Star 4g63's restricted O2 housing was boost creep with the addition of a larger intake and exhaust. Porting the O2 housing or replacing it was a recommended solution. ( I had an Evolution O2 housing on my 93 TSI Talon.)

Boost creep is not an issue with the EVO and therefore also agree with your conclusion.

Speedlimit...

 

I know on a DSM that a good O2 housing can yield 2tenths of a second in the quarter. Although if there is no supporting information that on a EVO that similar results are not possible then I don't see the purpose. Although turbulence will be minimal because because it is fairly smooth.

The only other advantage is that it will mean 2 less bolts and one less gasket, therefore making one less place to leak.

What I really want here is a vendor or shop to jump in here and speak the truth.

Thanks for the help!

 

The stock Evo o2 housing is less than 2.25 inches at the exit. Thats not big enough if you plan on producing good hp numbers.
The guys at Gtfabrications.com have a nice o2 with or w/o an external dump which I plan on buying soon.

 

That sounds reasonable, although is there any actual dyno #'s or track number somewhere that would support that this or any other O2 housing would really help performance.

Also if you were planning on getting the dump tube how do you plan to get the pipe routed...

Joe

 

I agree with most here the O@ housing isnt that bad sure it could be smoothed and port matched but I really dont feel its worth the effort. BTW to the other poster there Buschur/Vishnu/Dynoflash/AMS/ pruven all run the fastest evos with the stock o2 housing

 

have they run their cars with a upgraded O2 housing?
although i don't belive the O2 housing to make a huge "oh my god" difference in power, but looking at the inside of the stock O2 and comparing it with a 3" piece i think it would make a difference.

 

It should help spool up, at the very least.

 

OK guys. Here are some thoughts

2.25" vs. 3" is a big difference
The 3" unit will defintely help spool of the stock turbo
3" 02 Elim helped make 390whp on stock turbo
This way using a dyno dynamics 4WD dyno
Just because of the faster guys didn't use it doens't mean they couldn't have gotten faster if they did.



A 3" 02 elim downpipe is by far our biggest seller. It's what got us started. They are a huge improvement in the DSM world and one day it will also be the standard with EVO's

Basically if you paln on keeping the stock turbo and want to get it's full potential then get a 3" 02 elim housing or downpipe. You won't regret it because there is a lot of advantages to it.


Also the external dump will offer even greater advantages as well. Dumping the wastegate gases to the atmosphere will help control boost and you will acheive more power.

 

but if you get a O2 eliminator down pipe then that would mean everyone whohas a aftermarket DP has to go with the RNR product right? and sell off their aftermarket piece that they just got?

 

As far as I know RnR only sells the O2 housing built into the DP. You would have to sell your other inferior downpipe and upgrade to the RnR unit. As far as I know there are a few companies that make the housing only without the DP. Although the full unit is a much cleaner install.

 

Its much cleaner yet an inconvenience when it comes to removing the turbo. You have to remove the entire DP...
not to efficient if you ask me.

 

Like this

 

We also sell just the 02 sensor housing. With either an internal or external dump.