Rear Housing Options

[ARTZ]

Ok so couple of days ago I came to the realization that its pretty obvious my rear housing is the only thing holding my turbo back. I was talking to AVO about their rear housings wondering if I was going to experience any extra lag and they advised me that the excess back pressure cause by my 21u housing ( I believe its modded to .64) was possibly the cause of my lag so there would probably be no difference, sounds plausible right..

Anyway i scoured this forum for whatever info i could and noticed this..

here are my turbo specs..

GT3071R garrett ball bearing turbo

comp housing

0.50a/r

inducer wheel diameter 53.1mm

exducer wheel diameter 71.0mm

trim 56

exhaust housing

0.64 a/r

turbine wheel diameter 56.5mm

trim 84

here is Hks 2835 pro s turbo specs..

COMPRESSOR:

-Wheel- 56 Trim - 53.1 Inducer / 71.1 Major

-Housing- 100 Inlet / 50 Outlet - 0.50 A/R

TURBINE:

-Wheel- 84 Trim - 56.5 Major / 51.8 Exducer

-Housing- T3 inlet / Outlet spec:

Internal GT-Pro; 0.68, 0.87 A/R

Now the only difference is i have an 80mm inlet, hks has 100mm other than that they are identical except for the rear housing.

\

.I also then pulled out Hamishs old dyno chart (cause I knew he has the 2835 pro s) for a comparison and noticed this

Joes boost plot

My boost plot

Also identical topping at 19.8 and dropping to about 17.5. Now i was always under the impression the rear housing was the biggest deciding factor in the way a turbo holds boost but this kind of throws that theory and it seems it is all to do with core specs..I guess both can play their part in this though..So even though I already knew my rear housing was why I didnt make big power, i now realise how much power it could make with the right housing and there is no need to lose response for it, in fact I could gain some..

Now when i compared power graphs my turbo will ramp up power almost exactly the same till 3500rpm when full boost hits and the hks takes off ahead in leaps and bounds

heres graphs if your interested, remembering its the red line on his chart not the white which is e85..

damn you Joe getting black printouts that are impossible to read

Now I was going to tune for E85 for some extra grunt but whats the point when I can change my rear and make extra power still on pulp.

But , which housing would be the best choice..

1.Hypergear can mod me a 0p6 housing to suit

2.AVO .71, direct bolton ,

those 2 are the cheapest options or

3.HKS .68 will need new dump and front pipe, possibly a new WG actuator = $$

4. Garret housing, not sure whether .63 or .82 would be best and again, new dump and front pipe required

those 2 will possibly perform better but will cost twice as much and is the cost worth it?

Now the way I see it I have all supporting mods and all of these housings should make me 260-280kw, but which do you think will be suited best to my current setup? remembering I want to retain my response, get the best result for the best possible for the price..

Now I have pretty much made up my mind what I am going to do but am very interested to hear others opinions on what they would do In my situation..

Cheers

Dave

PS i know what your thinking, why am I going about this all ass about instead of just buying the right turbo to begin with. But hey, what can I say, I play my cards as they fall

[DaveO74]

I'm no expert but I'd go for the hks .68 setup IF you can source one. Stao's .86 will get you there but you will loose response.

Plus and somebody correct me if I'm wrong hypergears rears will still have the 6 bolt standard pattern yeh? Hasn't that been known to cause boost control issues, same as the AVO rear?

Yours is the 2835 kai yeh?

Edit: for a 2835 it seems pretty low power wise, I mean a gtrs makes around 250 and the 2835 is meant to be the next step up. You sure there is not something else afoot with your car.

[DaveO74]

Forget that last bit, just re read you have the 71r sorry

[ARTZ]

pretty sure there is nothing else wrong, my wastegate is only a 20psi actuator and im getting that at the manifold so not getting to much pressure drop through my cooler even though its a cheapy. A 200cpsi metal cat probably isnt helping but shouldnt be robbing to much power.

Apart from that everything is fine and dandy so pretty sure its just the rear housing, its just too small to flow a gt30 core successfully.

i got the turbo secondhand a year ago off an R34 so figured it had an 0p6 housing, I didnt even think to check cause I figured who would put a 21u on an neo engine

At the moment my biggest concern is not actually more power but i have been told the backpressure caused by the housing puts to much stress on the turbo bearings and burns them out especially if its pushing 20psi. Tao said hes had to repair a few so I'd rather fix the problem if I can rather than have a dead turbo

[zebra]

HKS housing would be best yes, also have a look at the .63 Garret housings, They arent the best things out there, but will be way better than the factory RB hosuing, just port the wastegate outlet and fit a bigger flapper.

You will need a new dump pipe though, or just modify the one you have.

Also re: OP6 hosuing on a R34, not all R34 GT-T's had the OP6 housing

[ARTZ]

really I thought they all had it, so which ones didnt?

[zebra]

Id would say it would be the earlier ones, which wouldve got the left overs from the R33 SII

[ARTZ]

that would make sense, stupid question.. The car I got it off was only pushing standard fuel system and making 220 on 14 psi so it hadnt been flogged stupid..If i put a better housing on it, it should be good for many kms yet..Atm kind of feels liek a grenade waiting to happen

[GTScotT]

Its actually a similarly sized turbo to staos ss range, I know he can make you a housing with ease as his bearing cartridges are also Garrett design.

I'm far from a fan of the Garrett internal housings, so, be it myself I would ask stao to build me a housing from scratch (not op6).

[ARTZ]

that could be what He was talking about when I spoke to him, he said he would make me one up, i was thinking he meant out of an op6. I Didnt think of that.. definately anothr option though. Where is Tao to shed dome light on this maybe I'll shoot him a PM

I do figure if I can get hold of a hks would be the best option as it delivers proven results and my tune is basically setup for it already and would just need some tweaking ,but for the price of stuffing around I could almost pick a whole turbo s/h with dump.. Theres been a few up for sale recently too, pity I didnt think of this before. Even if I could pick up a blown one ,I'll see what happens

[R31Nismoid]

A ported OP6 seems to realistically run outta flow around the 270-280rwkw marker. Sometimes people get more, but more often than not it's not the case.

I've never been impressed with AVO's housings for the price. They never seem to make the numbers vs response compared against Garrett.

A Garrett with ported gate/enlarged flapper - i concur is another option that could be reasonable... But you'll still get capped upper RPM as its smaller than the HKS.

[AngryRB]

A ported OP6 seems to realistically run outta flow around the 270-280rwkw marker. Sometimes people get more, but more often than not it's not the case.

I've never been impressed with AVO's housings for the price. They never seem to make the numbers vs response compared against Garrett.

A Garrett with ported gate/enlarged flapper - i concur is another option that could be reasonable... But you'll still get capped upper RPM as its smaller than the HKS.

just wondering, i have a highflow r33 turbo, uses a 2871r core 56trim, would i be best getting an OP6 housing or is there another housing HKS or Garrett????

i just want to try and get more top end if its within reasonable cost wise, the turbine is the 53.8 i think

whats the best housing to slap on??? would like to get upto 260-280rwkw??

[Harey]

As scott said get Tao to make you an exhaust housing up that has the same 6 bolt nissan rear. That way it will bolt straight up. I havent seen any problems with Tao's housings plus you can prob interchange between 0.63 and 0.82 for not too much extra changeover if you decide to change.

I would stick with his 0.63 housing to start with. The 0.82 housing is a large housing and you will definitely loose response.

[Harey]

just wondering, i have a highflow r33 turbo, uses a 2871r core 56trim, would i be best getting an OP6 housing or is there another housing HKS or Garrett????

i just want to try and get more top end if its within reasonable cost wise, the turbine is the 53.8 i think

whats the best housing to slap on??? would like to get upto 260-280rwkw??

Same recommendation get Tao from hypergear to make you one up in 0.63. I think 280rwkw is too high though for a 2871 core. Somewhere in the 250-260 would be all you will get. Some of the figures floating around have correction factors applied.

[R31Nismoid]

Ye you won't make 260-280

More like 240-260, anywhere in that range is normal.

OP6 housing really only seems to let you make an extra 10-20rwkw. Whole lotta cost for nothing IMO.

If you want 260+ - get a 3071/3076

[tridentt150v]

and make sure its a genuine 3071/3076 otherwise you will be back here with a long face and asking more questions about lack of power etc etc

[ARTZ]

ooo..my thread came back..

believe it or not I scored a HKS housing, i think its my best option and worked out about the same price as all the other options but I have no dump so I might have to invent one

Its only going to make whatever my clutch will handle though but will be interesting to see how much difference going from a crappy .64 to a quality .68 will make

...stay TUNED!!

[ARTZ]

and make sure its a genuine 3071/3076 otherwise you will be back here with a long face and asking more questions about lack of power etc etc

you mean like me

[tridentt150v]

lol.........

[discopotato03]

I belive HKS sell a version of the GT2835 called KAI which is like the GT Pro S version but using the T3 flanged GT 28 0.64 AR turbine housing off the T3 flanged 2530 and GTRS .

Surprisingly it is said to perform very similarly to the 2835 GT Pro S with the 0.68 AR turbine housing option .

The GT28 turbine housing removes all the hassles of the GT Pro turbine housings unique dump pipe flange and obviously takes all std and aftermarket dump pipes .

It could be entirely possible to pinch the turbine housing of a used T3 flanged 2530/2535/2540/GTRS and machine to suit the cropped GT30 turbine . What you wouldn't get is the port shrouded compressor housing HKS uses on these turbos and it must be woth having because they wouldn't have gone to the trouble of supplying it for no reason .

Ask Woolverine here because he's used a GCG Hi Flow/GTRS/GT2835 Pro S and knows a bit about this GT2835 KAI as well .

A .