I plan to eventually buy a Turbonetics TC78 once I get my "turbo debacle" sorted out. I believe I have found the shop I will buy from, now I just need to pick the turbine housing size.

It will be a stock LS1 346 short block through a 4L80e and a 9" rear end. I was thinking .96 A/R for now, with the option to buy a larger housing if/when I redo the stock motor and go for more cubes. My hot side plumbing has an undivided T4 flange on it, and I wasn't sure at what point they go to divided housings.

They told me that the could upgrade me to the larger "T" compressor housing for about $40, and that it was only slightly larger than the "TC" (I want to say I was told about 1/2" in overall diameter). Sound right? My hot side was originally built to accommodate a Master Power T70 while keeping the radiator in the stock position (which I've already planned to go to a vertical for other reasons) so if it's much larger than the MPT70, it might be too close to my crank pulley.

Thoughts?

 

bigger man... trust me

with an auto you want atleast a 1.15

 

Yes bigger housing for sure. There is a thread in this section about a group buy on bigger housings for the tc78 I'm getting in on it going with a 1.52 ar on my ls2

 

I swapped out a t-76 for a mpt70 and it fit almost exactly the same, you should be fine.

 

Good deal - question though...why did you go down in compressor size?

Guess I'll scrub the idea of the .96 then.

 

I just got my TC78 with a .96 a/r...why bigger for the auto though? Does boost fall off early? I have an auto with the Yank SS3600

 

Because you are going to have alot less lag with how the autos load the turbo. So you can afford to go with a bigger housing and make more power.

 

with an auto, lag between shifts is not an issue so your better off with a bigger housing,which will allow the engine to breath and keep making power at the top end.

The smaller housing will spool slightly faster but will fall over sooner at the top end due to backpressure.

 

@ SPRAYED 01 and Johnv,
Thanks for the input, it does make since. I will probably look into the 1.15 a/r housing then.

 

look at the uprade thread we are trying to get as many people as we can to get in on the group buy more people = less money...

a/r 1.15,1.3x, 1.5x and down pipe size 3, 3.5 and 4 inch...

something to look in to if you are buying a new one anyway get in on that good deal...