Top Tips For Improving Performance
Muscle cars came from the factory with a high level of performance. However, to those
not content with factory performance, one can improve their muscle car's performance. More
power can be coaxed from the engine and/or that power can be harnessed and put into
forward motion more efficiently. Either approach will increase your car's potential.
8 WAYS TO INCREASE ENGINE POWER
Engine power can be increased by good tuning of the fuel mixture, proper ignition timing for the engine and fuel
combination you will use, properly adjusted plugs of the correct heat range,
a good dual exhaust system, a clean and efficient air intake system to
the carb, proper operating carb, and good engine condition. If the engine is to be
overhauled, do it exactly like the shop manuals specify. Relatively minor changes
in cam selection, fuel mixture, ignition timing and advance, rear end gear ratio,
compression ratios, and carb type can provide some performance increase without
substantially degrading driveability. However, large changes to any part of this balanced
setup will almost always cause a loss in actual measured performance. The advantages to
this approach include reasonable cost, noticeably better performance in normal driving,
and measurably quicker times at the drag strip.
1. INCREASE DISPLACEMENT
More displacement means more power because you can burn more gas during each revolution
of the engine. You can increase displacement by making the cylinders bigger. As
displacement is a function of an engine's bore and stroke, one can either increase the
bore (widening the cylinder chamber) or increase the stroke or both. Increasing the
bore is usually easier and cheaper.
2. INCREASE THE COMPRESSION RATIO
Increasing the compression ratio produces more power by creating a larger "explosion."
However, the more you compress the air/fuel mixture, the more likely it is to
spontaneously burst into flame (prior to the spark plug igniting it). The use of higher
octane gasolines prevent this early combustion.
3. STUFF MORE AIR INTO EACH CYLINDER
Increasing the amount of air (and therefore fuel) into a cylinder of a given size,
increases the amount of power from the cylinder (in the same way that you would by
increasing the size of the cylinder). Turbo chargers and super chargers pressurize
the incoming air to effectively cram more air into a cylinder.
4. COOL THE INCOMING AIR
Compressing air raises its temperature. You would like to have the coolest air
possible in the cylinder because the hotter the air is the less it will expand when
combustion takes place. The most common method is to draw cooler air from outside of
the engine compartment, usually through the use of hood scoops. Therefore, "Ram Air"
systems generally are design to draw in cooler outside air, rather than truly "ramming"
the air into the engine. In addition, many turbo charged and super charged cars have an
intercooler which is a special radiator through which the compressed air
passes to cool it off before it enters the cylinder.
5. LET AIR COME IN MORE EASILY
As a piston moves down in the intake stroke, air resistance can rob power from the
engine. Air resistance can be lessened dramatically by putting two intake valves in
each cylinder. Some newer cars are also using polished intake manifolds to eliminate
air resistance there. Bigger air filters or more efficient air filters (such as K&N Filters)
can also improve air flow.
6. LET EXHAUST EXIT MORE EASILY
If air resistance makes it hard for exhaust to exit a cylinder, it robs the engine
of power. Air resistance can be lessened by adding a second exhaust valve to each
cylinder (a car with 2 intake and 2 exhaust values has 4 valves per cylinder,
which improves performance). If the exhaust pipe is too small or the muffler has a
lot of air resistance then this can cause back-pressure which has the same effect.
High-performance exhaust systems use headers, big tail pipes and free-flowing mufflers
to eliminate back-pressure in the exhaust system. Dual Exhaust systems improve the
flow of exhaust by having two exhaust pipes instead of one.
7. MAKE EVERYTHING LIGHTER
Lightweight engine parts help the engine perform better. Most engine parts are made of iron -
which is cheap but heavy. Switching to Aluminum parts is a bit more expensive, but can reduce
engine weight by up to 100 lbs. In addition to losing weight in the best place (up front and up
high), lightweight engine parts results in a more efficient engine. For example, aluminum
pistons are more efficient because each time a piston changes direction it uses up energy
to stop the travel in one direction and start it in another. The lighter the piston, the
less energy it takes.
8. INJECT THE FUEL
Fuel injection allows very precise metering of fuel to each cylinder. This improves
performance and fuel economy.
9. KEEP IT IN TUNE
Even the most powerful engine will not perform if it is not properly tuned. Tuning an
engine is an art and involves fine-tuning the carbs, distributor, timing belts, and
other engine internals to achieve the best performance over the RPM band.
6 WAYS TO INCREASE PERFORMANCE
Increasing power is just one side of the coin. Optimizing the use of that power is the other.
Here are some tips to best utilize that power.
1. LEARN HOW TO DRIVE CORRECTLY
No modification to your engine or car will result in a greater performance improvement than
training your self how to drive correctly. Whether it is on the drag strip or through a
road course, driver skill is the most important factor between winning and losing. So
practice and constantly try to improve.
2. LOSE WEIGHT
Vehicle weight hurts all areas of performance: acceleration, top speed, and handling. Replacing
heavy pieces with lighter pieces or removing some pieces all together will greatly improve
vehicle performance. For every 100 lbs. of weight loss, your quarter mile time will drop by
0.1 seconds.
3. INCREASE TRACTION
For maximum acceleration, traction is key. Larger diameter and wider wheels and tires will improve
traction and greatly improve your launch times and thus quarter mile times. For drag strip
runs, consider drag slicks to maximize traction.
4. REAR END
Also consider the rear end for maximizing traction. Adjust your suspension to ensure that
the weight transfer upon launch cleanly puts the weight over the rear tires. Also,
adding a differential (especially a locking one) will defintely help your launch.
Performance differentials are usually in the 3.90 to 4.11:1 range.
5. BETTER AERODYNAMICS
The aerodynamics of the vehicle only comes into play at high speeds. However, for
truly fast cars, the right combination of functional spoilers (front and rear),
and underbody modifications that reduce the car's drag coefficient and increase
the downforce on the rear of the car will help. Note that on most street cars
(going less than 125 mph +), most body pieces just add weight and increase
aerodynamic drag, thereby slowing your car.
6. BETTER BRAKES
Don't forget stopping your car. Replace your tired drum brakes with disc brakes and/or
install performance brake pads. Never skimp on your brakes - they could save your life.
COMMON MISTAKES
Unfortunately, the usual approach to increased power consisting of installing a larger
cam, race manifold and carb, big tube headers, etc., will always degrade low end power,
and if you are really lucky, some increase of power may occur at the upper RPM range.
Unfortunately, to utilize it, you would then have to run your engine to top RPM in
every gear, because low-end power will always be lost with such changes. The engine
will no longer idle properly, will waste fuel, probably overheat, and generally be
difficult to drive in city driving.
Also note that there is no mention of light weight rods, light weight or other types of
trick pistons, super mega ignition systems, huge headers, big cams, race intake
manifolds, 1000 CFM carburetors, align boring, porting or even hardened valve seats!
These kinds of changes or modifications might help the performance and reliability
of high RPM race engines, but are not necessary and will not help performance on
stock type engines operated in the factory designed RPM range.
Remember, if you add something that doesn't improve performance, all it is adding is
weight and cost. 95% of body pieces fall into this category.
