So I THOUGHT this was a run-of-the-mill Volvo turbo. The standard T3 .42/.48. When I was replacing the head studs and timing belt with Dad today I just happened to notice the markings on this turbo. Take a look and tell me what you think.










.42 cold and .63 hot??


JP

 

Volvo T3 with a Tbird exhaust housing?

 

That would be a standard 1.93" minor, 2.56" major T3 turbine with a 45 trim compressor wheel. Regardless of which A/R exhaust side you use (.48 or .63), it still has a max of 25 lbs/min on the compressor side. The turbine itself is actually larger than the T3 with a 60 trim compressor wheel but is still a 57 trim. The 60 trims have a 1.92" minor and 2.32" major giving them a 68 trim. Either way, your compressor wheel will still measure 1.59" minor and 2.37" major and is still only good for 25 lbs/min max.

Big difference between the 45 trim and a 60 trim:

 

So WHAT trim is it? 45 or 57? If I DO convert the .60 T-Bird comp. housing I will probably gain more than the .48 exhaust ones correct? More of an ability to make more whp, correct? I never heard of a .42/.63 only the .42/.48. Does this make it any better or worse or different?


JP

 

57 trim turbine, 45 trim compressor wheel. The exhaust housing doesn't change the compressor wheels ability, only your engines ability to make more power within the given rpm range. The 45 trim wheel is still only capable of a 25 lbs/min max and the 60 trim is still only capable of 35 lbs/min max regardless of which exhaust housing you use. 25lbs/min is roughly 380 CFM and 35 lbs/min is roughly 530 CFM. Don't get confused and think that the 45 trim is good for 380 CFM and the 60 trim is good for 530 CFM. Those numbers are absolute and the max that they're good for, not the number that they're practical for, which is much lower.

 

LOOKS like a regular TB03. Did it come off a 2.3 sohc?

 

great, more lag with the same airflow...sweeeet.

 

That's exactly what came to my mind. Weaksauce. I get the housing swap I should be alright. Regardless, he says the exhaust has no effect on whp so I'll always be laggier. I hit 3rd gear full spool (10.5psi) at 3700rpm as of now.


JP

 

how do you figure? a larger a/r on the turbine side will reduce backpressure at higer rpm and boost levels and does help contribute to more whp. if it didn't why would there be larger ones? we could all just run .1 a/r turbine sides and have instant spool.

 

Huh? Too big for the little compressor side so it's not used to it's "potential" to create more whp. You are correct. Dad and I finished up today and ended up (Praise God) the housing/WG went on smoothly (thanks to everyone and Stevemode for bringing this idea to my attention) so we permantly put it on minus the flapper being wired open. NOW, maybe it might be used to more efficency having a larger compressor housing on. Before it still flowed the same amount of air and being a larger A/R it was just st00pid because it was the same power with more time (lag) to get there. SixSick6 said it nicely, but it's a little hard to grasp at first rather than a simple: "Hits the same only later." Now just hurry up and wait to get a re-tune.


JP