Difference between early and later tip turbines

[Jeff M]

The first tip turbine I ever drove was a '74 DM with the reverse scoop. The tip turbine was pretty loud, and was slower to spool up and down than later ones I drove which had the dual air cleaner inlets rather than the reverse scoop. These had a higher pitched turbine and were quicker to spool up.

Anyone know why these sounded and drove differently?

[j hancock]

I don't know of any differences but there probably were some changes over the years.

Keep in mind that the "spooling up" of the tip turbine is a function of bleeding some pressure from the engine turbo to spin the turbine fan. The tip turbine then would help push air through the air to air exchange to cool it before the intake manifold.

There may have been a restriction keeping the tip turbine from getting all the air it needed.

Running through the air cleaner kept the air to air exchange cleaner than than the hood scoop setup when working in a dusty environment.

The later tip turbine system also included water cooling in addition to the air.

[41chevy]

Wasn't there two h.p. ratings also? 300 and 350?

[masterwelder]

I thought there was a 285 also?

[j hancock]

There were different HP ratings due to injector pump changes etc. 285 - early 350.

I believe that the actual tip turbine and CMCAC stayed the same until the water cooling was added.

[leversole]

Keep in mind that the "spooling up" of the tip turbine is a function of bleeding some pressure from the engine turbo to spin the turbine fan. The tip turbine then would help push air through the air to air exchange to cool it before the intake manifold.

Hey Ken...there is our answer!