yauser

I'm still trying to find out what's the best a/r hot side to use on my Garrett Airesearch Turbo. This turbo is a t04b with a 4 inch cold side, and 2.5 hot side, and is good for 500hp. When I first bought it, it had on a 1.15a/r turbine housing. I remember switching to a .58 a/r, and it ran like sht. Then I went with a .81 a/r, and it ran better, but not to it's greatest potential. Now recently, I've been noticing that a lot of these similar turbos come with a 1.15a/r. Do you think this type of an a/r is actually required to run the smaller t04b turbo efficiently? Maybe if I did want it to spool faster, a .91a/r would have been the lowest I should go? Is that possible? I use to always think that any single turbo that's capable for us to use on our 2jz motors would be best with a 69a/r turbine housing. Correct me if I'm wrong.

I am going na-t in a few months, and would like to have on the right turbine housing the first time. I'm definitely not going back with the .59a/r, because it didn't run as good as the .81a/r. I currently have .81a/r on the turbo , but debating whether I should go with the .92a/r, which I also have available. Or maybe go back with the original that came with the turbo, 1.15a/r.

Update: TURBO IS NOW FOR SALE. IT WILL COST ME TOO MUCH TO HAVE THE RIGHT FLANGE TO BOLT ONTO MY DOWNPIPE. MY DOWNPIPE JUST HAPPENS TO HAVE A 4 BOLT FOR THE TURBO EXHAUST HOUSING. LOOK FOR MY THREAD ON THE FOR SALE SECTION.

TTSC3

The smaller hotside creates backpressure and will create a PEAK TQ spike, but will run out of breath up top, while the bigger housing will flatten the torque out, and probably give you a lower peak torque number. There's gonna be a limit where you will outflow that compressor though, so too large a backside will not really be beneficial. I can tell you right now that .68 is gonna be too small for a 2J no matter what. .8X is gonna be as low as you wanna go, with .9X being closer to where you wanna be. 1.15 is probably ok too, but for the meager top end gain you'll see, I'd probably stick with the .9X hotside, or maybe even the .8X, especially with the very small "B" compressor cover.

yauser

That's great! You know, I might just go back with the .92 a/r since the turbo originally came with a 1.15a/r. 1.15 has to be the recommended size for that particular or compressor, and .92a/r would probably be considered an upgrade for a slightly faster spool. What you said about PEAK TQ was probably what I was going through after using a .59a/r. Everytime I hit the pedal all the way down, nothing happens. It's as if the turbo is stuck or something, lol.. It doesn't happen with the .81a/r however, but still it wasn't too much of an improvement either. Also, I've seen several 2jz turbo owners use .58a/r as well as .68a/r with great results. I think it depends on the turbo they're using. My compressor is rather small, so I'm guessing it would require a larger a/r. hot side. Correct me if I'm wrong though. I've been always trying to figure this out.

yauser

Another question I have is whether my turbo is a t04b; I can't tell. It says Garrett Airesearch t04, so does that say a thing? I've been going through the Supraforums' MKiii section, and most of those t04b's are using .58-.89a/r's, so I'm confused again!