Miata Mailing List: September 1994, Message #60
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   From: Herb Samuels 
Subject: Re: Comparing turbo/supercharging sustems
   Date: Fri, 2 Sep 1994 19:50:30 -0400

This in response to the turbo/supercharger post.  The following 
is a slight editing of a post that I send in several months ago.

I have a BBR turbo and am very satisfied with it.  It has just the
right amount of power (in my opinion) about 155-160 hp and lb-ft of
torque and the torque comes on at relatively low RPMs. There is no
question that there are turbos which can generate much more power.
The power was kept at the 155-160 range because Mazda U.K. had to
warranty the conversion the same as the stock car (3 years, 60,000
miles) so the boost was electronically limited to 7 lbs.  Since the
power is not overwhelming, the stock suspension does not have to be
modified.  Nevertheless, the car is reasonably fast.  I've newer
tried 0-60 mph since I have no need to stress the engine.  However,
the 50-70 mph marks in 4 th gear are 4.5 to 5 sec (depending on the
ambient temp) while the stock is about 8.5 sec.  The 50-70 for 5 th
gear is even more impressive at about 5.5-6.0 seconds (again depending
on the ambient temp because of the intercooler) while the stock is
about 12 seconds. This difference is due to the large amount of
torque which comes on at relatively low RPMs.  Surprisingly, gas
mileage is unchanged at about 28 mpg.  The turbo is both water and
oil cooled and the timing is controlled by a BBR ECU which connects
to the Mazda stock ECU.  The BBR turbo is approved for use in all 50
states.  The derivability is excellent and there is virtually no turbo
lag. There is a switch which attaches to the BBR ECU which is 
mounted in the armrest/storage compartment which alters the timing 
so the engine can use 87 octane (with slightly less power at very 
high RPMs) instead of 92 octane.

Would I recommend a BBR turbo to others.  The answer is yes.
However, it makes sense to check out the other options available
in the U.S. since there is always the specter of concern that if
there is a problem  that it make take time to obtain parts (check
with Al Staats at the Performance Buyers Club for other turbos that
are available and with Miata Magazine for a Miata Supercharger).
The fact that the BBR is made in England is probably the reason that
BBR will never sell the most turbos for the Miata in the U.S.or
Canada.

In addition, the engine has to be removed to install the BBR while
the other turbos and the supercharger do not require an engine
pull.  From my point of view  if the BBR turbo is installed correctly
(which is not difficult for someone with some experience to do) there
is very little to go wrong.  It contains a water and oil cooled turbo
and an oil cooler as well as an auxiliary ECU which controls boost
and protects the engine from overboosting.  In addition, it also
controls the timing as a function of RPM and has an intercooler. 
Whatever you buy try to drive a Miata with that conversion before you
get any after market changes.  I drove two BBR conversions before 
I decided  to go ahead with it.

P.S.  I recently spoke with Ken Brittan of BBR who told me that they
should have a turbo kit for the 94 Miata's very soon.  Unlike the
turbo conversions for the 90-93s, the 94 conversion will not require
removing the engine and will give more horsepower than with the 
previous models.

Herb Samuels