About 2 days after my last article, I again put the
ëStealthí on the dyno. After numerous runs carefully enriching
the fuel map in very small degrees, I decided to do an
experiment. I first took the whole map and richened it by 10%.
Power fell off over most of the graph. Next I decided to lean it
out some. Starting with the same baseline, I went the way of
caution and leaned the whole map by 5%. Power and torque came
up a bit. I then went to 10% (total), and power and torque
increased with a peak of 30 ft/lb over the previous best
published readings!! Holy hidden horsepower Batman!
Even with this leaned map, the retard amount remained the
same. With the sensitivity adjusted to minimum, and no
detonation audible, we had a suspicion that with the increased
output of the engine, the knock sensor was starting to ëfalseí on
engine noise. John at J&S (manufacturer of the unit) was very
helpful and stated there would be no problem in reprogramming the
unit to reduce the sensitivity a bit. Currently I am eagerly
awaiting the reprogrammed unit.
The only ëbadí news is that I promised my girlfriend Julie
that I would quit playing with my car on the dyno as she feels
that the car had more than enough power even before I started
messing with it, and to concentrate on getting the d**n thing
painted. After you read the following adventure, you might
agree:
My first ëtest driveí since this last tuning session
occurred around the end of December. It was a late Saturday
night and I was warming up the car to put it back inside. I
decided to run the car up and down the parking lot just to blow
the gunk out (good excuse right?). On the first run, I found
first gear to be almost worthless as it would smoke the tires and
bounce off the rev limiter before I could even put the throttle
halfway to the floor. Easing into second gear would spin the
tires as soon as boost came up, which was rather funºit never
pulled like this before! On the way back towards the building
during the second pass, I decided to get into it a little past º
throttle in second again. This time the acceleration was even
more intense as the rear end drifted out to the right. I
countersteered and lifted right away as I was suddenly moving 50+
MPH and drifting towards one of the few cars left parked in the
lot. As I lifted, the rear caught traction and swung quickly to
the left (I was rather surprised as I have had this car sideways
a LOT and it has never swung so violently before). I
counter-steered again as I was heading towards the other of the
few cars in the parking lot!?. In a widening pendulum effect, I
went again to the right. And finally on the next swing to the
left, I waited until I was aligned with the center of the lot and
nailed the brakes. After a lengthy slide to a halt, I let out a
rather juvenile holler, and cautiously pulled up to the shop door
as about a half dozen friends looked on in disbelief, "Dude,
that was the coolest thing I have seen all year!". I donít know
about the ëcoolí part, but it definitely was an experience. A
brief look over the car revealed part of the cause of my
ëexperienceí a left rear tire with probably about 3psi of air
in it between the low profile of the tire and the light weight
of the car, it was hard to notice upon first glance. Time to put
the car up for the night...
In recounting my tale over the phone to longtime turbo guru
Corky Bell, he laughed for a moment then proceeded to give some
advice, I cringed a bit as I knew I had fallen short in his eyes,
"Steve, Iím a lot older than you are, and have been driving a lot
longer", oh boy here it comes, I thought, "there is one thing I
know, you donít want to die in a parking lot. You want to go out
in something much more spectacular, but not a parking lot".
After saying goodbye, I stood there a moment in shock, slow in
the realization of his statement. Itís good to know I wasnít he
only one.
I was fortunate enough, through some contacts in the San
Antonio Alamo Motorsports, to get some flow numbers for the mitsu
turbo I am using. The stock TD06-17C-8CM2 that is on the car now
flows 550 CFM @15psi. The upgrade TD06H-20G-14CM2 that I want to
use flows 650 CFM at the same psi. I canít wait to upgrade to
this unit as we just had a 2.0L Mitsubishi Eclipse Turbo produce
413 hp at the wheels with a hybrid TD05/06-20G turbo at 24psi
with some 116 octane race gas mixed in (remember, that converts
to over 500HP from a ërelativelyí stock 4 cyl)!! This was a
daily driver, although running at a more conservative 20 psi on
the street. It kind of pissed me off at first, having a 4 cyl
car best me by 100hp, but when I put that same compressor section
on my Z with 6 cylindersºhmmºBut Julie, just one more dyno run,
pretty please???
Iím afraid I was remiss in some thank-youís the last couple
of articles. I forgot to thank my very good friend and coworker
Larry for LOTS of help tuning the car as well as machining some
very trick stuff for the car including our killer strut tower
brace (which now sports a mirror polish thanks to Larry). And
thanks to Herve Oulette for a lot of good advice over the years
and helping me out of a ëjamí more than once.
I try to mention everyone involved in my endeavor as without
the support and involvement of friends, club members and loved
ones, there would be no point in it at all. Itís the interaction
and appreciation of peers that makes things worthwhile, whether
its cars, computers or stamp collecting. I hate to say it but
ëMadí Mike was right (that hurts to admit), but "itís not the
cars it is the people".
Well, Iím about dyno graphed out, so Iím sure everyone else
is. With power at a ëmore than adequateí level right now Iím
going to concentrate on finishing the car for a bit. Next month
weíll look at gauges, wiring and possibly some sound insulation.
And maybe a little more engine work...
