Our O2 housing is 2.5" throughout (our does not enlarge to 3" and then taper back to 2.5" though) as it is simply unavoidable for end users that wish to use a stock location downpipe. Our O2 eliminator (one piece o2 housing and downpipe) is 3" throughout...

 

Either I am misinformed or I would have to disagree slightly. I purchased a Works downpipe(3") that is a factory location pipe that uses a larger doughnut gasket to adapt a 3" O2 housing to it. You can use a stock O2 housing or 2.5" variety using the stock gasket. I could have benefited from a true 3" O2. I chose not to buy theirs(Works) 3" O2 for many reasons but I am still in search of the true 3" combo. Am I mistaken or is my situation somewhat unique as there aren't many that use this downpipe or am I misunderstanding you? Hey Chris...Any pics you could post up or send my way on the recirc MAP downpipe? I have yet to find any. Thanks.

 

I am not familiar with this particular works product sir, if they made changes to the downpipe flange and donut gasket the works package may very well be a third true 3" option...

You can find a terrible quality picture of an early prototype recirc downpipe here, I really need to get an updated one lol.

 

I am running the 02 eliminator downpipe/dump from MAP i have no complaints or issues at all. Great product in my opinion. They sound good, good performance, and little smell which is tolerable for sure.

 

And i have a friend who is running the regular 02 dump from Map as well, no issues. The piece is almost identical to the Shearer as well..

 

Thanks for the reply Chris. Not wanting to lead people the wrong way I will say that even though I have the Works downpipe I obviously didn't go with their O2 housing for several reasons. I like Works products but my reasons are opinion and not necessarily fact(except price) so I will keep them to myself. I think anyone in search of a true 3" combo have better options that are listed in this thread than the route I took. I now have to find a home for a downpipe and O2 dump that I feel is inferior. I hate buying things twice!! I am really looking forward to the day someone comes up with some comparison dyno results for the MAP O2 eliminator pipes and Shearer dump. Seems like we've been waiting years for some hard numbers.

 

The invidia is a true three inch 02 that is compatible with stock style downpipes. They use a custom slim copper doughnut in place of the fatty that works with 2.5 02 housings. Its a nice piece. You should check it out sometime.

 

I've got a stocking order of them coming in, I will be sure to take a look!

 

Ah, so the map dump wont work with Buschur's downpipe?? Is that right, or did I make that up lol

 

Heres a look at my custom jerry modded invidia 02. I prefer to use cast pieces on my car for reliabilty sakes. plus I believe they just work better in many cases. The invidia as it comes has a simple straight divider installed from factory. its straight, and short. pretty much a half *** effort at keeping the two paths separated. on the main flow side the flow would open to a larger than 3 opening and have to find its way back to a 3 inch opening into downpipe. buschur tested this piece and found it not to work as well as megan 02. I believe that to be true just looking at design. So I decided to take some time and improve on the design. I didnt take pictures before I started. It was used and dirty on inside so it wouldnt have photographed well. But basically I took some cardboard and kept trimming it till it looked like it would fit inside and make the flow paths what they should be. I then cut the piece from stainless u bend and welded it in. There was lots of welding and grinding. more welding and grinding. all in an effort to improve the flow path and re-entry point for wastegate flow. I think this will work well. The re-entry point is at the 02 sensor where turbulance already exists. I dont know why the meagan piece puts it right in flow path? There was also a big dip right before exit on the invidia. that dip was filled with weld and ground down. Then she was ceramic coated ready for action.

 

So 94AWDcoupe what you are saying is that if one would want to stick with a non-dump O2 housing that a ported Megan would be ones best bet unless one would want to try to modify an Invidia? Looks like you did a pretty good job on porting yours but I'm not so sure there are many of us out there that would have the skills to do that or would want to hassle with it. Seems like the quest for a 3" O2 outlet is futile. At least a proven one.

 

I just have a feeling that most guys running at about 25-27# on straight pump gas aren't really gonna see much diff between a well designed traditional O2, such as the Invidia, or a Titek vs. a poorly designed O2 dump.

On the other hand, a well designed O2 dump such as the unobtainable R/T Ernie unit, or the ultra-expensive Shearer piece will outdo a standard tubular O2, probably. They should perform better at boost levels above 30+ PSI. But, for the common man running under 27# there really is not going to be too much difference.

We can't generalize based on BlkCarbonEvo's experiences, as he is running a one of a kind custom dump at 32#, on Meth or E-85. Sure, given Mikey's particular circumstances, there was a significant powergain. But, I just can't see extrapolating for your average Joe, or Jane's Evo based on his experiences.

 

i dunno about recently but i had a qtp cutout an an ls1 camaro.....suuuuuuuucked. they get stuck and break all the time, it ends up becoming a manual cutout. Several friends have had the same issue. not trying to argue but i had to voice my opinion from experience. qtp cutouts were always unreliable and didnt last long. JUNK

 

On the Red Ill be running around 33psi all the time, never lowering my boost.

 

I agree. Any gains seen is because of changes to the housing itself, not the fact that it is a dump. I did it so I could have rock solid boost control with no creep on my Eclipse, not for more powahs. Its a stinky noisy evil thing I don't want on my Evo, though.