-
Stage 1 nozzle
is 10 gph and triggers @ 4 lbs. boost.
-
Stage 2 nozzle
is 13 gph and triggers @ 13-14 lbs. boost
-
Readjusted bypass
valve slightly to keep the pump just short of cycling.
-
Total flow is
now 23 gph. or .817 oz./sec.
-
Fuel pressure
at 45 psi. ( Will experiment with FP further)
-
RESULTS
From
a dead
stop there is NO KNOCK during boost rise through 24 lbs boost.
At the 2-3
shift there are 2 knocks spaced approximately 1 second apart.
No additional
knock recorded through 90 mph.
Part throttle
acceleration the "flat spot" in the middle appears to be gone.
Max retard
recorded was .5 degrees.
Outside temperatures
50 degrees.
Similar results
were obtained with an outside temperature of 30 degrees but 3 knock
counts
occurred during the initial boost rise (1st gear). No additional counts
were recorded during the run- not even at the 2-3 shift. This was with
a mix of denatured and methanol and 50% distilled H2O.
Update
9/7/00
Well, I apologize for the lack of new information through most of the
summer
months. Not many significant changes to the system lately but there
were
a few items to note. I had to use a Red Armstrong 108 chip (for
bluetops)
for a while and earlier testing and tuning showed excellent results. I
then purchased the Thrasher 108 chip and installed it but had to retune
a bit. Also, the much higher temps during the summer changed the way
the
car performed -but nothing major. The system has performed effectively
now from temps down near 15 degrees to as high as the mid 90's. I also
added a quality fuel pressure gauge to the gasoline fuel rail. The old
crappy gauge had been right on though!
My latest setup is dialed in to turn a 13.5 GPH nozzle on at 6 lbs of
boost
and then turn on a 10 GPH nozzle on at 16 lbs of boost. You might
notice
that I now have the larger nozzle turning on first, and that I am
turning
on the second nozzle at a slightly higher pressure than previously!
This
seems to work well at eliminating knock at part throttle and medium
boost
levels. It also works well in eliminating initial knock during sudden
increases
in boost. Also, it seems to work well without producing any of the
flutter
effect (drowning the motor) at boost levels between 15-20 lbs. This is
done using the Thrasher 108. I also have a boost valve from McMaster
supply
that is adjusted so that the wastegate does not see any boost pressure
at all until approximately 16-18 lbs. Spoolup is very quick especially
from a cruise. It is a bit slower from a dead stop- probably for the
following
2 reasons. One, I have the fuel pressure set for 48.5 lbs which is
higher
than the 45 recommended by Thrasher. Since the Thrasher has an open
loop
idle w/o O2 feedback and correction this is a little rich. Secondly,
the
Thrasher does not exit this open loop mode until the vehicle
speed
sensor starts producing a signal. In addition, I have a 145 MPH speedo
with a gear reducer so that VSS signal probably starts pulsing just a
tad
later than a car w/o the reducer. I'm guessing that all this may
contribute
to a slightly slower spoolup from a dead stop. I believe it will take
about
3 seconds to reach 20 lbs boost from a dead stop. If the car is in
motion
(even at less than 10 MPH) it takes 1 second for the boost to reach 25
lbs. That's pretty quick and no exaggeration at all!
The only other development has been along the lines of experimenting
with
different types of alcohols and mixture ratios. I firmly believe that
methanol
has the biggest kick in the pants of any of the alcohols. When methanol
gets injected power bumps right up! I've also increased the ratio of
alcohol
to water and believe the following mixture works best (at least for my
car, my fuel pressure, and my total alcohol quantity). I am using 60%
denatured
alcohol, 10% methanol (drygas), and 30 % H20. Denatured sells for
$6.49/gal
here and methanol drygas sells for .48-.50 for 12 oz. That works out to
about $5.00/gal for the methanol. I just found something called solvent
alcohol by Sterling. It is methanol in 1 gal. cans and sells for $4.99
at an Ann & Hope store. Methanol contains 50% oxygen and ethanol
(denatured
alcohol) contains 35% oxygen. I believe this is why the methanol has
more
kick for my setup. That extra oxygen helps to lean out my mixture
(which
I tend to have adjusted on the richer side). My car has always seemed
to
want a richer mix than most to run without knock. Both are the same
octane-115.
Maybe another car with different fuel pressure and air flow could be
tuned
to get a kick from denatured alcohol with the 35% oxygen content being
enough to make it lean and mean. I haven't tried this methanol yet but
I'll probably try a mixture of 70% methanol and 30% H20 to see how it
goes.
If you can use the 60/10/30 mixture you might be better off over the
long
run because the methanol is more corrosive to pumps, etc. I don't
believe
it's all that bad though when it is diluted to 50-70% with H20 but
thats
just my opinion.
With the 60/10/30 mixture I am seeing less than 1 degree retard and
that
only happens for 1 frame at the bottom of the run (and I don't always
get
that). I'll try to update on the results of the 70/30 methanol mixture
later.
One bad thing to note (but not too bad): I lost a street race to a
Mustang
several months ago. At the time I was still dialing in the Red A chip
in
and had my boost set at 21-22 lbs. He had M/T street strip tires and I
had 245-60 Dunlop full street radials. He had race gas- I had 93 octane
and my alcohol. It was my first and only street race. He had done this
many times before. He also had a slightly shorter distance to travel
since
his lane was on the inside of a very long slow curve. He took me out of
the hole by 1 1/2 car lengths. I left with no boost. We ran almost dead
even and I lost by less than 1 car length. He had run 13.0 @ 105 at the
track (I saw the time slip) the day before. I had run 105 mph at the
track
on race gas earlier in the spring. Our cars seemed to make nearly
identical
HP and everyone enjoyed the race. He was not an obnoxious guy- in fact
a real gentleman. I can't lock my convertor up because I guess I
need to replace the solenoid. That would have been enough to beat him
by
1-2 car lengths and my valve springs have about 150,000 miles on them!
He also told me (after we raced) that he had about $12,000. in the
motor
alone! So I guess it wasn't all that bad. I will make the repairs
eventually
and get my revenge.
I plan to purchase DirectScan in the near future to enable tuning more
precisely with the increase in data available. Maybe I can squeeze a
bit
more out of the motor before I add a TH downpipe and other possible
upgrades
to my basically stock motor. When I do get Dscan I may attempt to
increase
the boost level even higher if it is feasible. Haven't lost a head
gasket
yet!
UPDATE 11/13/00
I took off the upper plenum and replaced it with a spare I had that I
ported
out more than the one on the car. I opened up the inlet area and took
out
the egr port. I radiused the lower front edge to help air get to the
front
cylinders. For all the previous testing I had a 1/2" aluminum spacer
plate
installed below the plenum. This spacer plate protruded into the plenum
area on all 4 sides by approximately 3/8". I made this several years
ago
and estimated its width by comparing a spacer plate in a magazine add
that
showed the plate and the plenum gaskets. The one pictured appeared to
be
a little wider than the gasket widths so that's what I made. It may
have
helped low end torque but probably limited top end HP. So I reshaped
the
inside of it so that it is now flush with the inside edges of the
plenum
and intake manifold. However, I left the protusion in the rear only. I
did this to try to help limit direct air flow to the rear cylinders. I
did a crude test of the plenum on a bench by blowing a puff of smoke
into
the inlet and observing the direction that it exited out the bottom.
Without
a small ridge at the back the air did not make a 90 degree turn out the
bottom. It was less than 90 degrees by a substantial amount. In other
words
it directed air towards the back of the intake. I tried the same test
with
just a 1/4 obstruction at the back and the air made the full 90 degree
turn. Very little obstruction was required at the rear to make a
significant
difference in the direction that the air exited the plenum. Of
course
this was a totally unscientific experiment so you can take it with a
grain
of salt. It was significant enough for me to stop me from eliminating
the
3/8" overhang at the rear of the plenum spacer- besides the fact that I
already had blisters on my hands from hand filing the sides and
front
of the spacer! I used a huge 3" X 20" file to enlarge the insides of
the
spacer at the front and sides. I also bell mouthed the front and rear
of
the throttle body but I did not touch the throttle plate area.
I also had an intermittent problem with my MAF sensor for several weeks
before I found the problem. I located a used MAF from Bob Borelli. It
was
off Mo Vaugn's former GN and is now owned by his cousin Clarence.
Clarence's
car has run 9.90's but is getting a big buck 400 c.i. Chevy motor
transplant-oh
well.
After making the above changes to the air intake I had a problem
running
25 lbs boost without knock. It seemed to be more prone to knock retard-
although not too bad. I seemed to be getting KR between .5 and 3.5
degrees
but also in more frames. I had been running a 12gph first stage nozzle
with a 10gph second stage nozzle successfully before the changes. I
tried
2 more lbs fuel pressure but it didn't seem to help much. I then tried
using a 12gph nozzle in the second stage but it didn't improve the KR
much
and I was getting too rich on the alky evidenced by the steam coming
out
the exhaust! Maybe an 11 gph would be better. With the 12gph it would
start
the fluttering scenario and drivability at less than full
throttle
suffered. So I now have the 10 and 12gph nozzles back in the car and I
put in 2 more lbs of fuel pressure. I also turned the boost back down
to
22-23 lbs. I now get about .5 degrees KR at the beginning of the run
and
none at all after that. This is probably a more sane approach for
street
driving anyway but I'm sure I may try to tweak it back up again. I may
try to either raise the boost another lb. at a time or I may leave it
alone
and try to lower the fuel pressure again to see what direction it goes
in. It feels pretty safe right now and I may have backed away from the
edge just a little.
My guess is that I may be flowing a little more air for any given
amount
of boost pressure than I was before. At least I hope that is what
caused
the car to be more prone to knock at 25 lbs than it used to be. Even
throwing
more fuel and alky at it didn't seem to eliminate the knock to the
levels
before I opened up the intake. It may be that my alky setup is just
about
at its limit for the amount of air my car breaths and the 93 octane
fuel.
Another thing that may have happened is that the gas may have changed
for
the colder weather but I didn't have that problem last winter.
Everything included in this update includes the use of a mixture of 35%
methanol, 35 % denatured alcohol, and 30% H20. I settled on this
mixture in recent months as being best for my application. I may
experiment
further by increasing the H20 % or by increasing the ratio of denatured
to methanol. I think I backed away from the edge enough to try
experimenting
with a higher % of H20 again. That's it for now.
Installation
Pictures
Picture 2
Picture3
Picture4
UPDATE 12/29/00
