I have turbos I bought years ago 2nd hand. They were supposedly custom made hybrids with HP66 compressors and F1-65 turbines. I have measured and verified that these are indeed the wheels I have. The units had T3 housings machined out to accept the turbines. I dumped those and put on T4 housings.

Looking at the compressor covers, it appears that they are small covers (3" inlet / 2" outlet) that have been machined to fit over the HP66 wheel. The standard housing for the HP66 is a 4" inlet/2.5" outlet.

Would I see a benefit from going to the bigger compressor housing?

I'm making about 1200hp at 30psi.

Thanks

 

I would give Jose a ring to discuss.

 

It does seem that fitting smaller covers does reduce the efficiency or airflow of the actual units.

Most race type covers, or even most Borg Warner units that perform well, all have huge volutes. So there must be something in it.

But I'd say many are happy to sacrifice a little in order to actually be able to fit them into confined spaces.

Whether you'd need a new backing plate or not might be a problem though.