I went out to the Hangar last Tuesday to start installing the intercooler. Well, at least to fit a few tubes and hoses, then hold up some parts and make plans.

As I took the air discharge tube off the compressor, I noticed the whole turbo compressor & bearing assembly wiggling around on the turbine housing!

I checked all the mounting bolts and clips, everything was tight.

So I took the turbo off the engine, and realized that I probably cooked the turbine housing. I did see EGT excursions to 1800F. What's worse, I had a new turbo blanket. I think a heat shield would have been better, so some cooling air could pass over the housing, but still block radiant heat.

Bummer.

So I decided to go with Plan B: I ordered the bits and tube bends to switch to naturally aspirated operation. I'm keeping the exhaust header that the turbo sat upon, and replacing everything else past the bottom of the firewall, to the new pipe & muffler I recently added.

I'm retaining the ability to 'Go Turbo' later, but I've become curious about what the turbo must boost to equal full throttle of 'Naturally Aspirated'.

I did build and have been running a tuned intake manifold. The exhaust won't be a tuned header, but it is pretty good, possibly better than the stock exhaust reactor and a whole lot lighter. It has port discharge nozzles (reversion cones) EGT probes and a gentle sweeping shape. Plus it's proven strong while carrying the weight of the turbo beyond 1800F, and it passed inspection. I trust it.

So I hope to run it, find the performance satisfactory, the fuel consumption significantly reduced, and use 87 octane ethanol free mogas instead of 92. (low compression rotors)

Also, I can advance the timing to the NA spec.  

Anyone see a problem or have advise?