Turbine housing help if y'all please!

[blkt72]

OK, I bought this turbo about 3 years ago and spent the last 3 years buying all the supporting mods. The turbo is supposed to be a Turbonetics T72 Q trim. SOB wouldn't fit on my header (hit against the shock tower) but it was an on center housing. I ordered a Q trim tangential housing and the thing is way too small. Here's some dimensions:

My turbine wheel major diameter is 3.231". The turbine housing they sent measures 3.144" and the old on center housing that I took off measures 3.552.

Is there something bigger than a Q trim? The turbo IS a T4 footprint. What turbine housing do I need?

Thanks in advance,
Nick

 

[dbsupra90]

yo nick-

3.2" major sounds like a GT-S. is the minor around 2.7"?
the 3.1" is right for a Q trim, so it sounds like you do have an S.
by the way, they do make a G trim. often found on the big pt101 turbos. 5" major haha.

 

[blkt72]

yo nick-

3.2" major sounds like a GT-S. is the minor around 2.7"?
the 3.1" is right for a Q trim, so it sounds like you do have an S.
by the way, they do make a G trim. often found on the big pt101 turbos. 5" major haha.

Thanks Dave. I'll get pics and all the measurements when I get home. Really need to figure out what this thing is. Thought it was a T72 Q trim, apparently not.

-Nick

 

[blkt72]

Pic is below, sorry in advance for the size. Gimp kept crashing and I couldn't resize it. I think I may have gotten lucky for a change in this build! Thought the turbo was a T72 like I said before but I'm pretty sure the turbo is actually a GT4294. Here's the measurements:

Turbine,
Major: 3.225"
Minor: 2.956"

Compressor,
Major: 3.699" (94mm)
Minor: 2.763" (70mm)

 

[jtamulis]

by my spec sheet its pretty close to a T-78/T88, and that q-trim is a hair
big. That's a big 800+rwhp monster.

 

[dbsupra90]

well how bout that a GT42.

GT42 56 trim

inducer-2.769
exducer-3.7

edit- forgot the turbine side numbers

inducer- 3.23
exducer- 2.96

however, my notes also say the turbonetics 76GTS use the same wheels as the gt42.

so, all things considered, i believe you to have a t'netics T-76GTS since the GT42 comes w/ a T6 housing. sure, the housing could have been changed. but i dont know why someone would opt for an on-center t4

i'll look around and let you know if i find out anything different.

 

[blkt72]

by my spec sheet its pretty close to a T-78/T88, and that q-trim is a hair
big. That's a big 800+rwhp monster.

800 my ass:icon_bigg Bigger!

 

[blkt72]

well how bout that a GT42.

GT42 56 trim

inducer-2.769
exducer-3.7

edit- forgot the turbine side numbers

inducer- 3.23
exducer- 2.96

however, my notes also say the turbonetics 76GTS use the same wheels as the gt42.

so, all things considered, i believe you to have a t'netics T-76GTS since the GT42 comes w/ a T6 housing. sure, the housing could have been changed. but i dont know why someone would opt for an on-center t4

i'll look around and let you know if i find out anything different.

Not sure, but what size turbine housing do I need? What trim and all that horseshit?

Turbo was originally on a MKIV, would an on center make sense there?

 

[dbsupra90]

im not sure what is available since its t'netics. i dont sell anything like that. all my stuff is pte built. now if you could run a real gt42 turbine housing thats different. however, the smallest t4 they make for that is a 1.01 a/r. it is very expensive and not easy to come by.
look and see if there are any numbers stamped on the chra or the old turbine housing. maybe that would help figure out some options.

 

[blkt72]

im not sure what is available since its t'netics. i dont sell anything like that. all my stuff is pte built. now if you could run a real gt42 turbine housing thats different. however, the smallest t4 they make for that is a 1.01 a/r. it is very expensive and not easy to come by.
look and see if there are any numbers stamped on the chra or the old turbine housing. maybe that would help figure out some options.

I'm fairly certain that it's actually a gt42. I'll get the #s off the turbine housing this evening and see if the CHRA has anything on it. All the T'netics stuff I found seems to indicate the q trim is as big as they ever made.

 

[dbsupra90]

my sheet says they made the S trim as an option.
to be honest, you will be better off if its a 76 for tubine housings. like i said, i still believe thats what it is. ive never seen an on center t4 housing for the 42. most of them are 1.15 tang t4 or a t6.
hopefully the machined stamps if any will help.

 

[blkt72]

my sheet says they made the S trim as an option.
to be honest, you will be better off if its a 76 for tubine housings. like i said, i still believe thats what it is. ive never seen an on center t4 housing for the 42. most of them are 1.15 tang t4 or a t6.
hopefully the machined stamps if any will help.

I don't know, the dealer I spoke with said Q was as big as they ever went. Here's what's on the compressor housing:

G A/R .81 M1 (The G might be a C, it's not real clear, The M1 is not very clear either). An observation about this casting, it's a lot cleaner than the T'netics casting I have, the T'netic's has ridiculous porosity and this seems to be a really clean casting. The flange that connects to the CHRA is a 4.5" OD V band flange. The DP flange is a circular 4 bolt flange with an OD just a hare under 5" and an ID of 3".

The center housing has this stamped on it:

First side, oil drain top:

A large stylized "A" (This is very clear, the left leg of the A is curved while the right leg is straight). Below that is G7 and then there is an arrow pointing down (oil feed flange is below this arrow, lol)

2nd side, oil feed top:

Arrow pointing down, then "AD".


On the compressor backplate:

Stylized A from above, IW, small "A", $, 661H


The $ symbol cracked me up.


Thanks Dave,
Nick

 

[blkt72]

Bump, any ideas Dave? I need to figure this turbine housing out ASAP.

Thanks,
Nick

 

[dbsupra90]

i cant find anything. im gonna have to call reinforcements.
perhaps in the meantime you could get a couple pics of the housings themselves? dont worry about the pics being poster size, that would prob help. if you want you can send to me direct. dbdave7 at yahoo dot com

 

[blkt72]

i cant find anything. im gonna have to call reinforcements.
perhaps in the meantime you could get a couple pics of the housings themselves? dont worry about the pics being poster size, that would prob help. if you want you can send to me direct. dbdave7 at yahoo dot com

Pics sent Dave, thanks for the help! If it'd help, I'd send you the turbo. I need to get this resolved.

Thanks man,
Nick

 

[blkt72]

Pics keep bouncing, What's your max message size?

 

[dbsupra90]

hmm i dunno. i know i have 1gig of space allowed.
maybe if you try to zip them and send that way? i know i have received pics in multiple mb before.

try sending a text message first to see if that goes thru. that way i know it isnt a filter problem.

 

[dbsupra90]

btw, what size turbine housing do you want? i might be able to get you one for a gt42 to try. but the a/r is gonna be pretty large.

 

[X-man]

The turbo looks like a GT4294. The T4 turbine turbine housing for the GT42 you sell Dave, like the one you guys got for me, should work.

 

[blkt72]

btw, what size turbine housing do you want? i might be able to get you one for a gt42 to try. but the a/r is gonna be pretty large.

Smallest one possible, I think it's 1.01 IIRC. Pics resent, sent them 3 pics at a time instead of all 10 (15MB). Thanks for the help Dave, I really appreciate it. This thing has turned into a pleasant surprise, but it's a real PITA right now. How do you tell if it's a ball bearing turbo?