When GM introduced the C4 back (seems like an eternity), in 1984
they forever changed the industry benchmark for high performance
automobiles. In 1984 the C4 was declared by the media as being
the most technically advanced automobile on the planet.
The 1984 rock hard racing suspension and GM's first attempt
at fuel injecting the L98 via cross-fire injection gave way the following
year to a more refined and streetable version of the C4.
The radical redesign of a car within the first year of a new
platform introduction is almost unheard of. GM was forced by its customers
to fix its mistakes and by 1986 most of the production bugs had
been worked out.
The C4 emerged as a true world class performance
machine and forced most of the traditional hot rodders to go back
to school and relearn a new language. That language was until that time
reserved for computer nerds and rocket scientists.
Times have changed and the C4 has taken a back seat. The C5 and now the
C6 like all new toy's get the most attention. Well, C4 owners take
heart because a properly set up L98 or LT1 will stand head to head
with the new kids on the block.
The L98 and LT1 were designed as street machines. The C4 power curve
is right where you need it. The power is emphasized in the lower rpm ranges
(1500 - 3500 rpm) hey folks this is where you live on the street.
I don't care what Porche owners or anyone may tell you,
the fun factor of a high performance street machine is directly
proportional to low end back snapping torque.
In stock form the L98 puts out an amazing 350 lbs of torque that comes in
under the 4400 rpm. Net horsepower was rated at around 250,
that's net horsepower, if the auto industry was still using the
gross horsepower rating system, like it did in the old days,
the L98 would be rated at around 300 horses. Thats nothing to sneeze at.
The first time we got a chance to actually do some serious work on a C4 was back in
1986. Until that time we followed the time honored formula for hot rodders:
- Slap on a set of long tube headers and a 2 1/2"
dual exhaust system with a x-over pipe - Install an Edelbrook hi-rise intake
manifold with a Holley carb - Port the heads - Slap in a 3/4 cam - Modify the timing curve by
messing with the weights in the distributor -Install 4:10 gears and hold on.
There were no computers to mess with on C3's, no fuel curves, no sensors
no exotic fuel injection parameters. What you saw is what you got.
A gas guzzling, bad tempered, bad ass machine that was hard to handle at high speed,
tended to overheat and would not idle. It was a straight line rocket sled from Hell.
In short a thing of beauty for a hot rodder. It had to be babied and tended to on an almost daily basis. The plugs had to be inspected,
cleaned or changed out after a few weeks of semi normal driving. If you couldn't afford
to install stainless steel brake cylinders, bleeding the brake system was a daily event.
Yes we have come a long way baby.
In 1986 a customer brought in his
spanking new C4, he told us he wanted more power. We knew then that it was no longer
business as usual. At the time we were lucky enough to have a very good friend
who was a head mechanic at a local Chevy dealership. He had just completed
a six month GM sponsored course that was dedicated to the new C4.
We convinced him to moonlight with us and at the same time pass down
the new Holy Grail of GM C4 performance knowledge.
What we found was that you could meld old school hot rodding tricks with
the new rocket science. The C4 in stock form was a revelation, it delivered
incredible performance and at the same time was actually a real car.
By that I mean it could be driven on a daily basis in all kinds of
weather. It didn't break down,or overheat. It stopped and handled unlike
anything that Chevy had ever mass produced.
A spanking new out of the box C4 was an impressive package for the mid 80's. Remember
high performance was just emerging from the dark ages of tight emission and cost controls.
The American auto industry had just come to the realization that in order to survive
it had to offer something that was previously unheard of, "Quality".
GM actually performed quality control testing on the new C4. This the first time
a major US auto manufacturer did not use its customers to quality test its vehicles.
A new C4 could do the quarter mile in about 14.2 seconds, 0 to 60 came in at
around 6.3 seconds. Those were respectable numbers in 1986. Of course respectable
is not what new C4 owners wanted. They had just paid top dollar for an American icon
and were not enthusiastic about to getting dusted by four cylinder Porche's.
The Solution
Like its predecessors the C4 will respond to the traditional hot rodding formula:
Intake + Exhaust + Ignition + Gears = More Power
The difference with this new computerized marvel is that after the mods are
completed the car can still be used as a daily or long distance driver.
You won't even have to listen to your wife complain about how you ruined your car.
With some planning and coordination the C4 will easily slip into the mid
thirteen second 1/4 mile bracket. Computers are a wonderful thing, when high performance
modifications are planned around sensor operating parameters the end result will be a very
civilized and reliable touring machine. A machine that will deliver the same rocket sled acceleration
of former Vettes while at the same time delivering a very streetable ride while getting 25+ MPG.
If you are the proud owner of a C4 wo is just a little tired about constantly
being told that the C5 is the only way to go, listen up.
Upgrading the performance level of a C4 is pretty easy, with a little patience your
car will keep up with and in most cases dust off unwary C5's. The majority
of C5 owners are yuppie types that really never do much to their cars
other then put gas in them. I hope I didn't piss off anybody
with that last remark. Hey if you are a C5 owner and you are reading this, you
don't fit into the, "I only put gas in my car" category and have probably ordered
our ,(shameless plug)
Corvette Performance Modification Manual
Seriously, if you want to increase your overall driving experience with a C4 or C5 for that matter
take a look at our manual.It will guide you through all modifications to the major systems in your vehicle.
It will also help you to make some sound decisions on the road to more horsepower
while saving you money and the aggravation associated with mismatching
performance parts.
