Paul,

I've seen a lot of E-mails lately concerning the use of turbos with the 13B
for aircraft installations.  I may also look into this application for my
eventual use.  One concern I have, based partly on personal experience as
well as lengthy conversations with the Service Manager at the local Mazda
dealership, concerns the reliability of these turbos.

Due to the exhaust temperatures from the rotary engines, (1600 + degrees)
the turbos basically self destruct when used in the RX-7.  He told me that
they have had a number of 3rd generation RX-7's in, where the turbos AND
engines were in need of replacement, due to heat damage, in less than 30,000
miles.  True, this was somewhat attributed to driving around town
(Charlotte) where the heat doesn't get a chance to dissipate very well, but
wouldn't a belt driven supercharger be a better fit for aircraft use?  Belts
break and I'm sure that bearings could go bad, but the temperatures in the
supercharger would be around 1400 degrees less than the turbo.  If a belt
breaks and you lose the supercharger, you still have 170-180 hp available.
If you lose a turbo, you still have some power available, but you'll also be
losing a far amount of oil through the now damaged seals.

I've thought of just using a 20B, but the weight could be an issue, and it
would be nice to be able to get on top of most weather, with a supercharged
engine.

Dave Kuc

Yes the third gen's do crack but we have seen and heard of quite a few
ten year old 2nd gen 89-91 that are not cracked.  That is the one I 
recommend trying. I in fact have one. So does Dave Leonard.

I don't yet know how well it will hold up
in aircraft use so I am going to sneak up on it with modest boost
at first and a monitoring of the EGT (TIT) and turbine RPM.
Both NASA and Mecanair in Switzerland have done some dyno testing
with this turbo. Mecanair rated their engine at the stock 205 HP. 

Jim Mederer (Racing Beat) is using a much larger 
turbo on a 20B and  has a couple of hundred dyno test hours at 500 
to 900 HP range.

Paul Lamar
 
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