I have a question as to which size A/R housing I should run. I understand that a smaller A/R housing will allow the turbo to spool up faster minimizing turbo lag but limiting top end spool. And a large A/R housing will flow better at top end improving top end HP but spool a little slower down low. When I bought my STS kit I upgraded to the GT-76 knowing that I was planning on swapping to bigger cubes eventually and didn't want to upgrade the turbo later. To hold me over STS fitted me with a .68 A/R housing on the GT-76 so that the 5.3L wouldn't have such a hard time spooling it up. My forged 6.0L is done and finished and should be getting swapped begining of April.
STS said they would provide me with the new A/R housing, either a .96 a/r or a 1.15 a/r. I understand the .96 a/r is rated for 5.7 to 7.0L. But wasn't sure what I'd be looking at with the 1.15 a/r. I hope to be pushing 20lbs of boost and my question is which a/r housing would best suit my application. Thanks and sorry for the long winded question.

 

I think you answered your own question.. If you want to get off the line quick then stay with the smaller housing.. If you want top end go with bigger one...

 

I'd wouldn't put anything bigger then a .96 on it.

 

Just wasn't sure if I was missing anything. I was thinking about keeping with the .70 a/r for a while and make some Dyno runs with the .70 then switch out to the .96 and see how different the numbers look.

 

Yes, please do that. I just upgraded to the GT70 for my 408 build because I did not want to have to much lag. I only plan on runing 15lbs though. If your results show that the GT76 is not to laggy I may just go to that one as well.

 

Just run a 1.08 A/R housing. I hear they work good......

 

I bet they do but this is primarily a DD/street truck. On the track I could see going that big but I'm worried if I go to big I might be paying for it on the street.

 

I would stick with the .96

 

I built a 408 for a customer and upgraded the turbo to the GT76 with the .96 A/R. The truck runs great all around. I can't image you would benefit from the 1.15 any where but the race track at a greater sacrifice day to day.

Mark

 

Yeah that's the general consensus so I think I'm gonna stick with the .96 a/r housing. I'm going to run the turbo on the .70 a/r housing for a little while to see how she runs.