3'' o2 housing into N1??

[9D9X]

Hey Guys,
Just wanted to run this by you. I have a 3'' o2 housing with a 46mm wastegate routed back in and N1 turbo back. The N1 as you know starts off at 2.5''. Do you think it is a big deal to have a 3'' o2 going into the 2.5'', do you think it will hurt flow or is it such a small distance that it may be fine...

Thanks

 

[bsbllfit7]

if u want a 3 inch downpipe go on ebay and get the cxracing downpipe, fits very well and is a true 3 inch all the way back, under 100 dollars too

 

[lq1driver]

its going to create a great deal of turbulance in the exhaust stream

 

[9D9X]

Did not see any for 2g awd...Really think it will cause that much turbulance being only 6in or so long.

 

[bsbllfit7]

Eclipse Talon 2G 95-99 GSX AWD Downpipe 3" Stainless: eBay Motors (item 350168890493 end time Jul-15-10 01:56:07 PDT)

there is one and there are MANY more on there

Eclipse Talon 2G 95-99 GSX AWD Downpipe 3" Stainless: eBay Motors (item 190411312111 end time Jul-29-10 17:15:00 PDT)

thats the same one i have, 3 inches allllll the way through and works perfect with the car, no areas are hitting or rubbing.

 

[9D9X]

Wow.. never saw that one. Still looks like it necks down at the flange to 2.5'.

 

[bsbllfit7]

i dont believe it does, it doesnt on mine atleast and i bought it from the second link.

 

[jp91gsturbo]

It will cause some turbulance but shouldnt be anything really to hurt performance. It's not like your going to gain 5hp from opening up a few inches of pipe an extra half inch.

 

[AK Maniak]

It will cause some turbulance but shouldnt be anything really to hurt performance. It's not like your going to gain 5hp from opening up a few inches of pipe an extra half inch.

uh thats not necessarily true.

 

[Zdrummer15]

It's rare to find a downpipe that doesn't neck down at the entrance because 3" o2 sensor housings are almost nonexistent. That being said, I doubt either of those ebay ones will be 3" at the entrance because that would not work well with nearly every potential buyer.

 

[bsbllfit7]

i can take a picture of my ebay downpipe, it is at the very smallest 2.75 but im almost positive its 3 inches.

 

[9D9X]

Well guys I also have a punishment racing 02 housing but I measured the inside of the bend and it was only 2'' max. Do you think that is better or what. Also have you seen this downpipe? http://www.heperformance.com/_images/part4_lg.jpg

 

[viprez586]

You do not want a bottle neck restriction in the exhaust system.
You can go 2.5" to 3", but do not go 3" to 2.5"

 

[9D9X]

Yea I know that. But I was just wandering because it was such a small distance of 3''. Don't you think the 2'' will be a bottle neck too being that close to the turbine.

 

[viprez586]

The turbine outlet is not greater then 2" i believe. So running a 2" internal diameter O2 housing is fine.
I too have a PR O2 housing, it's great, flows a shit ton more then any 1G or 2G ported.
Anything smaller after your O2 housing is bad. So you could run a 2.5" exhaust and then have a 3" noise maker at the end if you really want. But I'd think that'd eliminate the purpose of going with 2.5" anyway.
Go with 3" downpipe back end of story.

Nevermind just saw your running a FP green, I'm not sure of the outlet size then.

 

[EclipticalGS]

get a punishment DP, you'l be very happy with it i promise

 

[9D9X]

Only thing that sucks is that most of the 2.5" o2 housings are 2" at the bend. Do you think that hurts hp that much..maybe 5 or 10 at the most right.

 

[EclipticalGS]

it doesnt hurt HP, it affects flow which relitively can effect HP, use the 3" 02 housing, and get yourself a 3" Punishment-Racing Down-pipe. Its full 3".

 

[crazyquik22023]

I don't think it will really make a difference if you only have a few inches of the 2.5" pipe. I did the same thing on my car... I have a 3.5" O2 housing welded to the apex'i downpipe to the 3" exhaust.. I only have about 3" of the 2.5" pipe and it runs fine... I might gain a lil more power if i got rid of the 2.5" and changed it to 3 but i don't think its really worth it.

 

[9D9X]

Thanks guys for all the feedback. Please don't think I'm a ding dong, I've been working on dsm's for over 10 yrs now. I just wanted to see what everyones thoughts were. Most of the o2 housings like I said are only 2" max at the bend and the bend is so close to the turbine that maybe a larger o2 would let the turbine spool alittle easier, not having to overcome the wall of the bend being so close and the 3" o2 has such a small distance of 3". I know that on exhaust side you want small to big for flow and on the intake side I know that you want the ports of the intake manifold to be smaller than the head ports and the exhaust manifold ports to be larger than the exhaust ports in the head for flow. Just good to bounce things off each other now and then.

Thanks Again....