From: (John & Dianne Brigstocke)
Date: Fri, 22 Dec 1995 22:06:31 -0500

Since popular request seems to be to post SC experiences to the list
here is my offering. ( i.e. pardon the bandwidth) If you read this, be
aware that I am thoroughly convinced that driving a boosted Miata
correctly set up will convert any Miata enthusiast.  It's just what is
needed and most everyone on this list seems to want.  That's not to
say there are no problems to sort out but most are well handled.  My
point of view is from having installed a Sebring/Eaton/Downing
Supercharger on our 1.6 L 93, with ABS, PS and NO AC last spring and
having a blast since.

I first read about it in the MCA mag (Fall 94, pg 50) when they did a
piece on the installation. Then I said 'too many MSU's' (money at that
time) for a year or so then after that time I couldn't resist anymore
and besides the co-driver said 'ok' too.  I called Jim Goodroe at
Downing/Atlanta for more info.  He was very helpful answered my
questions like:

Can I install it myself? - yes.  

It wasn't difficult and took all day about 6-7 hours.  Most time spent
reading installation manual prior. The manual is good but didn't cover
the main problem I had which was the power steering pressure switch
connector interfered with the drive belt idler asssembly. I had to
modify the connector to get clearance - took about 45 mins.

Does the kit fit on a car with no AC (we don't need air up here) and ABS? - yes.  

In reality the kit does fit but the new drive belt provided for cars
without air was too long. I called Jim and he acknowledged this but
had sent the ill fitting belt anyway since they didn't have any other.
A standard correct length belt is NOT made (in 4 ribs).  I had to by a
6 rib belt locally and cut off 2 ribs. Since then Jim indicates a
special run of belts is being made by Gates and they will be available
soon.  I am still waiting 8 months later.  BTW, the cut off 6 rib belt
works fine.  The ABS brakes have additional lines near the location of
the SC intake elbow that have to be bent gently to clear but after
bending the clearance is fine.

How does the clutch stand up? - fine but consider Centerforce on replacement.

The stock clutch has enough grip except for very aggressive standing
starts at high rpm - but that's hard on the rest of the driveline so I
avoid this.  Have 50k Km (31k Mi) on clutch without problem - inc 15k
Km with SC. I plan to upgrade tires next summer to 195/50 or 55/15 so
maybe the extra tire grip will tell.

Does kit pass Can emissions? - don't know but has 50 state CARB cert.
In CAN this means it's better than what we need.

While we're on Can, how does the SC like winter temps? - some installs in BC
and Ontario without problem.

I was concerned with cold start problems and start-up driveability as
well as controllability (?) in ice-snow?  Now after proper adjustment
of fuel pressure-regulator pressure, from factory set psi of 70(!!!)
to low side of spec at 46psi, the start up, driveablity and ice-snow
control is the same as stock.  I was considering by-passing the SC for
winter but after FPR adjustment all is fine.  Only negative here is
that initial startup rpm (with warm idle set at 950 as spec'd for SC)
is momentarily too high for me - right up to 2200 then back to 1500
idle within 3-4 secs.  With warm idle set lower (850-900) the start
rpm is 15-1600 then 13-1400 idle, but then the warm engine idle
recovery problem creeps in.

A replacement thermostat is provided (160 deg F vs stock 187) which I
used in the summer but have put stock one back for winter because of
reduced heater output.  Will switch again in spring.  (just like the
Mini-Cooper S I used to have way back!)

What fuel required? - didn't ask this question but spec is 93 octane
with timing at 10 btdc, 92 at 8 btdc.  With additional MSD timing
retarder (retards 3 deg per psi over 4 psi, max 6 deg), other fuel
could be used or timing advanced with 92-93 Octane.  I am currently
running MSD device with 87 octane at 10 btdc and no audible detonation
in city rush hour and using 91-92 octane when elsewhere. (93 not
available conveniently all places)

Can I stay with standard exhaust? - yes, but replace stock with better
when required or you want too.  Will open up top end more.  Still have
original exhaust, other items have my MSU's - wheels, tires, skirts,
racing costs.  Plan on exhaust later.

Can't remember what else I asked but Jim sent a 5 page descriptive
summary which was helpful.

So the installation went pretty well with no other surprises and it
started and ran well right away.  Took a while to get the idle right
(seems we all have this problem now and then) and there was an idle
metallic rattle which appears to be the strait cut gears used in the
SC drive internally that still remains.  Can't hear it off idle but
under sustained boost the SC whines - perhaps at least partly the

Only other area was that clearance between exhaust manifold(stock)
heat shield and bottom of repositioned throttle body was too small
(1/16 inch).  I adjusted up but then SC hit hood diagonal brace so I
had to juggle a little to optimize - now clearance is 3/16 and seems ok.

At the same time I installed a NACA air duct from Brainstorm, a
vacuum/boost gauge and sump oil temp gauge.  The engine definitely has
more power in cool weather as expected but I don't know how the duct
affected this since installed together.

I have since installed a fuel pressure gauge under the hood to monitor
the FPR performance. The set pressure has not changed since set to
46psi at 0 in vacuum 6 weeks ago.

PERFORMANCE: I still have 185/60-14 stock tires (Yoko 376?) that break
free easily in first and second. (new tires when snow disappears)
Times might be better with new tires and more agressive start.  0-100
kKm (62.5 mph) is easily less than 7 seconds with 2500 rpm starts.
50-70mph in 5th is less than 8 secs.  50-70mph in third is less than
4.5 secs.  Best characteristic is the increased torque across the
range making it drive much the same as stock but DOES IT PULL!,
especially over 3k rpm.  It's difficult to get caught off peak at too
low rpm in traffic as increased torque is available all the way down
as far as you want to go.  No low speed lugging here!.

Everyday driving is easier if you choose to use lower rpm changes. No
longer necessary to keep rpm above 3000 for good response (unless you
want lots of fun! and have the room.
Using boost raises noise level - predominant whine.  At highway cruise
noise level is no different.

Gas mileage is worse - who wouldn't use it!  Still around 10 L/100 km
avg (Canada again!).  Highway cruise mileage is similar to stock.

Reliability: no problems other than FPR adjustment required. 

Being good Canadians we usually go south in the winter for spring
break.  Jim Goodroe suggested earlier that we stop around at the shop
in Atlanta, see the SC unit, a Miata with SC installed and SC
production. We did that in the spring prior to purchase and Jim gave
us a personal tour of the shop. We saw the milling machines working on
some castings and was generally impressed by the quality of the
operation, the parts of the SC and the Eaton unit.  Recommended to any
interested party.  (Went to spend more MSU's at Brainstorm right after)
p.s co-driver still loves it -  "car goes like stink"
John & Dianne Brigstocke
Unionville, Ontario (Canada)
93 SE Black/Tan