Thread: T28/T25 Downpipe Question..

whoa, there is a lot of bad info in here.

well if there is a bunch of bad info here then why dont you correct it instead of making a useless post that benifits nobody

Because I do not want to spread information that I am not sure of, unlike many of those in this thread. Reading through, it was clear that there were contradictions and incorrect assumptions being made. My post was useful in that it pointed out these obvious errors so hopefully no one takes what is said in this thread as factual.

Things I DO know:

All T2 housings should be the same (IIRC) so it doesn't matter if you are running a T25, T28, or GT28RS.

Almost any change in manifold will cause a change in the position of the turbo and require a different downpipe.

Any difference in O2 housing will also require a different downpipe.



Things I DO NOT know:

How the Bluebird, Avenier, and GTI-R manifolds differ.

How the Bluebird, Avenier, and GTI-R O2 housings differ.

T2 housings? which housing you talking about compressor or turbine?
Because not all T2 housings are the same, yes teh Avenir and Bluebird are as far is A/R is concerned. But the T25 turbine housing from the Avenir/Bluebird do not have the same exact bolt pattern as the RNN14 T28 turbine housing nor the S13 T25 turbine housing.

All the AWD turbo manifolds (T25/T28) place the Turbine housing and CHRA in the same exact place.

Like everyone should know the Bluebird/Avenir use teh same o2 housing.

The Gti-R housing is totally different.

So yes they both require a different downpipe. Downpipe selection soley depends on which o2 housing you are running as long as your running one of the factory cast iron turbo manifolds from either a Avenir, Bluebird, or GTi-R.

The manifold just differ in running lenght and the o2 housing just differ in clocking and angle.

Yes but to make things clear you can use any of the o2 housings on a gtir t28 turbo, a bb t25, and a rwd t25. You will have to enlarge 1 hole a slight bit on the o2 housing and the gasket for correct fitment. This also applies to gt2871's.

-If you have a t25 o2 housing get a t25 downpipe, if you have the gtir t28 o2 housing get a t28 downpipe.

-The bb manifold offers the least ammount of clearance out of the factory ones and may require grinding of the block depending on turbo choice.

-The gtir manifold will work with a t25, and t28 without having to grind the block, and depending on what size compressor cover you are running will work with a gt28 or gt2871r without having to grind the block. If you have a to4b cover with the smaller inlet clearance is tight but will work without grinding.(this is from my experiences having owned 2 gt2871's) If you have the larger t04e compressor cover you will need some grinding due to the inlet being larger.

I have never used an avenir manifold so i cant speculate on that.(someone fill in info here)

I have also never used a vet manifold so i cant speculate on clearance, but from what miko said it offers the most clearance of the factory cast manifolds that work with fwd.(feel free to add info and or correct me if i am wrong.)

still full of BS, I feel sorry for anyone trying to make sense of this

We are talking about turbine housings, why would I be talking about a compressor housing

Lets clarify it then, I posted in here about having to grind my block a little to fit my disco potato on an avenir manifold. I have picture proof! lol.

Not really if you know how to read. LOL There is some wrong info in the thread but if you read through completely there is some good info in this thread.

I have had 2 blue bird set ups, 1 gt28 set up and 2 gt2871r set ups. Now i have a custom ihi ball bearing set up where nothing was a bolt on affair.

I only commented on things i have done on my nx and turbo set ups i have put on other peoples cars.

Feel free to put forth some useful information If you have any to apply.

We all know you can make the turbine housing fit with a little hole widening but if you wanna know what fits without having to do any of that just look at what I posted, simple as that everything I wrote I personally have done it.

Heres is a little more proof from Nisssan fast with regaurd to o2 hosuing gaskets:

RNN14 etc etc etc o2 housing gasket part # 14445-26E00
Fits all the following turbine housings/o2 hosuing:


U12,U13,W10,W11,S14 etc etc etc o2 housing gasket part # 14445-79E00
Fits all the following turbine housings/o2 housings:


Buy both those part number for the o2 housing and compare and you'll see that just 1 hole doesn;t line up but its only off a couple millimeters.

This picture is proof.

If your placing a Gtir housing on a t25bb one of the hole is off by some millimeters.

t25 turbo / t25 02 housing = needs a t25 downpipe.

t28 turbo / T25 02 housing = needs 1 hole expanded alittle, needs t25 downpipe

t28 turbo / GTIR 02 t28 housing = needs GTIR downpipe

So down pipes

T25bb j pipe wont work on gtir downpipe.
T28 j pipe wont work on T25 downpipe.

So unless your cutting flanges on your down pipes these wont work with each other.

Now as far as Exhaust manifold goes. All GTIR, Bluebird, Avenir manifolds pretty much place the turbo in the same location thats if your using stock FWD Nissan turbo's (t25,t25bb,t28gtir).