Engine Modifications
Allowing the Beast to Breathe!!
The drivetrain from the factory
is quite responsive and rugged but there is some room for improvement without
comprimising dependability, smog certification or comfort. The LT1 engine
in the B-Body is rated from the factory at 260 hp. I'm told that this is
basically the same block they were using in the 'vettes around the same
period. It is a 350 block with cast iron heads, roller cam, tuned port injected
and dual exhaust. Most noticable is the gear driven reverse flow water pump
and the Optispark Ignition system(distributor) that are driven off the front
of the engine which incidentely, are also the most likely items to fail.
Most guys that have done the usual
mods to improve performance short of getting inside the engine claim to
get around 300 hp. These mods include aftermarket air cleaner and intake
systems, cat-back exhaust systems, reprogrammed PCM (computer chip) to take
advantage of things like a 160 degree thermostat, throttle body coolant
bypass, gear ratios and premium fuel. This car was built for my wife to
drive daily so it will probably never see a dyno or the race track, I so
I'll never know for sure what ours is capable of. That's what my '66 Nova
is for, but I digress....
Don't get the wrong impression
though, this car gets driven hard, OFTEN!! We drive through a 15 mile long
canyon several times a week to get to our church and it has a great combination
of tight turns, sweeping curves as well as long straights and the wife has
just as much trouble as I do staying of the "go" pedal. The mods
I've done have made a definite difference in the "seat of the pants"
feel of the car. I did most of them in a period of less than a week so I
can't really say what helped most or was the "best bang for the buck".
It's important to note however that with all these mods in place, I averaged
23 MPG highway on a recent trip averaging 75+ MPH.
Our particular car came from the
California Highway Patrol. It my understanding that they sell most of thier
cars at around 100,000 miles. That was the case with mine also. Our car
had been involved in a front end accident prior to sale so it was not refurbished
and sold in sealed bid as most CHP cars are. It was sold to a private party
in Feb. 1998 with 104,000 miles "as is" with a salvage title.
I got it with 104,500 on the odometer. The prior owner had all new body
parts installed in place of the damaged parts and then lost interest. Whoever
did the work, did a great job lining up the fenders, hood and bumper. I
cannot say enough about the maintenence and upkeep of the CHP cars. I looked
at several police cars at auction as well as a few private party cars and
this car,even with the body damage was in superior condition. Something
else worth noting is that most CHP cars were not ordered with the G80 option
(Limited Slip rearend) or cruise control.
Clean-up
The engine itself had no leaks
with the exception of the oil filter adapter (which is common). The only
evidence of any other leaks were from the transmission cooler lines (which
is also common), but the previous owner had just replaced them all. Upon
further inspection I discovered that it also had a GM Goodwrench transmission
installed at some point which is a good sign because these transmissions
are prone to failure at any point beyond about 80,000.
I didn't need to use any type of
engine cleaner in the engine compartment. The car had already been painted
so I would have been really nervous if I had. Most of the dirt just wiped
away with a few rags. Then I sprayed the whole engine compartment down with
Formula 2000 (in the flourescent green bottle). That stuff worked wonderful!
I had heard about it from a guy preparing for a car show one day. After
it sat for a few minutes to soak into the rubber and plastic, I began wiping
to remove the excess. It made the entire engine compartment look like new
including the painted surfaces.
Repairs
I had to replace the water pump
as soon as I got the car put together. While the pump was off, I replaced
the Optispark cap and rotor since it is behind the water pump. From all
that I've read, it's not worth it to get anything other than a factory new
unit. I got a factory unit and it came with everything, including a new
thermostat and housing plus all the fittings already in place. I replaced
all the fluids when I got the car, since it was unclear how long it had
been since any servicing had been done on it. Everything looked good when
it came out. While I was at it I replaced the serpentine belt with a Goodyear
Gatorback belt. Another neat feature about the 9C1's are the hoses, which
are silicone(green) and designed to last far longer than anything else.
I replaced the center link and idler arm before I had it aligned. It's been
9 months and 10,000 miles including a road trip to Oregon and it's been
perfect and solid. I have a small sqeak to pinpoint under the car and that's
about it.
Exhaust
After driving it a week or so with
the Impala wheels and new paint, the exhaust note coming from the tailpipes
just didn't match the appearance of the car. I went to my local muffler
shop and had mufflers and the 2 1/4" pipes cut off from the mufflers
back. In thier place I had a pair of Flowmaster 3-chamber mufflers installed
with 2-2 1/2" aluminized pipes running the stock route with the stock
hangers to the back bumper with a slight down-turn similar to the stock
pipes. It gave it a noticable growl at idle but is not too loud throughout
the entire RPM range. There is a slight drone effect most noticable between
about 40 and 55 mph. Since it doesn't have a tach I can't nail it down exact.
Air filter and intake
(No pictures yet)
Then after looking into all the
options I decide to go the low-budget direction and install a drop-in K&N
air filter in the stock air box. Then I did what is commonly reffered to
as the "Home plate and first base delete" mod. It consist of removing
two of the plastic pieces that make up the intake system that goes from
the airbox to the throttle body. These are primarily air baffles that are
designed to reduce that "giant sucking sound" as Ross perot would
put it, but they also are suspected of reducing air flow to the throttle
body. In thier place are a few ABS plastic plumbing parts from Home Depot.
Covering the home plate opening I used a ABS clean-out plug for a sewer
drain. In place of the first base I used a pair of ABS 45 degree 4"
elbows glued together. I've seen it done a few different ways, but this
seemed to work fine for me. The ABS is already black and seems to be sturdier
that PVC which is what a lot of guys have used.
Fresh air "scoop"
Then I removed the stock air box
and began "lightening it" so to speak! Many of the aftermarket
units are designed to be cold air intakes so I didn't want to "swiss
cheese" the thing. I chose to open up the front completely and the
side that goes toward the fender. I noticed that there was a hole in the
fender for fresh air to enter the area around the PCM which is mounted right
below the airbox. After a little thought I decided to create a fresh air
intake of my own.
The plastic cowling that goes from
under the front of the driver's side wheel well to the front bumper was
broken a few inches short of the bumper from the accident so I cut it off
straight across and altered it so that it hung down a inch or two lower
that it should. Then I took a grinder to the bottom lip of the bumper and
ground it down just before the first curve upwards. This created a pocket
to direct air to the scoop I created which then pushes fresh air up inside
the area in front of the wheel well when the car is moving. It's only about
a foot wide and you can't see it unless you bend down and look for it. It's
right next to the SEO air deflector. Cool is good!
Throttle body coolant bypass
I also did the throttle body coolant
bypass mod which basically removes the coolant flow that was designed to
warm up the throttle body faster. By not having the coolant flowing through,
it reduces the throttle body temperature which keeps the air cooler that
is entering the combustion chambers. Cool is good!
B&M ShiftPlus Module
About the only other mod to date
has been a B&M ShiftPlus Module. This was a simple mod that goes inline
between two wires from the PCM to alter the way the transmission shifts.
It doesn't change the shift patterns at all, but just firms up the shifts.
I am really pleased with it except that it engages very abruptly from park
to drive most of the time. It has three settings; stock, firm and firmer
that are adjustable from a small switch mounted anywhere you like. Mine
is usually in the firmest position, which is supposed to extend the life
of the trans (probably at the expense of the u-joints or rearend). I got
mine through Summit Racing.
Back