You are right Scott, that is a much better turbo, though I doubt you were experiencing compressor stall at power settings you would want to use on the ground.  I also fly with the TO4E-50, but have used the 60-1 in the past with good success.  And yes, your turbine housing should be as big as you can reasonably fit.

Dave Leonard

On Tue, Oct 29, 2013 at 2:41 PM, Scott Emery <shipchief@aol.com> wrote:

Here is a pic of my 13BT powered RV-8. I've already blown & rebuilt the engine, now I've learned from ground running and forums that the 60-1 turbo with .81 A/R housing was not good in 2 ways: the compressor was too large and the turbine housing too small. The resultant increase in exhaust Back pressure rising too rapidly with boost pressure. This held back any hoped-for power gain. Also, the compressor seems to have been on the verge of stall, with fluctuating boost pressure during tethered power testing.
The pictured TO-4E has a 50 trim compressor & 1.30 A/R turbine house. I did run it briefly before I had to return to work, it ran very lean. I'll be reprogramming the EC-2 during the next run. This forum & Ross Farnham over on the Vansairforce were big helps getting me researching in the right direction.
Possible future intercooler location is along the Charge Air pipe on the left side. The hot jacket water pipe will need to be relocated.

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