BASIC ENGINE ADJUSTMENTS
Throttle
Position Sensor Adjustment (Green and Black wires)
To maintain optimum performance of your 5.0L
check the setting of the throttle position (located on the top of the throttle
body). Accurate adjustment will provide smooth idle and good acceleration.
Using a digital volt meter or a multi meter with the ignition key in the
"on" position; but with the engine off, voltage should read between .997-.999;
1.1 to 1.25 for supercharged cars. Adjust (elongate the slots if necessary)
the sensor to obtain proper setting by loosening the mounting screws and
moving the sensor side to side.
Ignition
Timing
Most 5.0 Mustangs are delivered from the factory
with the ignition timing set from 4-10 BTDC (Before Top Dead Center). Stock
is 10. With premium fuel, start at 13-14. If you have no detonation, increase
upward. Timing is free horsepower and will run better up to 19-20 of timing.
Camshaft
Installation
o When installing a flat tappet cam (non roller)
it is important to install new tappets or lifters, valve springs and retainers.
o When installing a roller cam, '85 and up H.O. blocks, you don't have to change the lifters until 40,000 miles unless the lifters show wear. Also, if your motor has high mileage or if you are changing to a cam with very high lift, change your valve springs.
o Always match the lifters and tappets with your cam.
o Always match your parts. One of the biggest mistakes is the installation of a cam that is too big (too much lift and duration).
o Flat tappet cams must use prelube before installation. Roller cams are made from steel billet and only require a generous coating of fresh engine oil.
Transmission
Maintenance
We suggest changing the fluid in a T-5 transmission
at least every 10,000 miles, more often if the car is driven hard. It requires
less than 3 quarts of Mercer-Dextron automotive transmission fluid - nothing
else can be used. You can use synthetic Mercer-Dextron. Synthetic
fluid has been found to reduce transmission temperatures.
Cylinder
Head Torque
When tightening head bolts, torque the upper
bolts (near the intake manifold) to 80 foot/lbs. and the lower bolts near
the exhaust manifolds to 72 foot/lbs. When you tighten the intake manifold,
this tends to generate a lot of upward pressure on the heads. The additional
tightening of the upper bolts compensates for the upward pressure. Be sure
to coat head bolts or studs with non synthetic oil before installation.
Roller
Rockers
The selection of rocker arms will be dictated
by the type of camshaft and heads. Any 5.0 worth its weight should use
roller rockers. Stock rockers are adequate at best. They are designed as
1.60 but seldom are. Stock rockers vary in ratio from 1.45 to 1.66 and
flex too much. When installing roller rockers, be sure to remove the valve
cover baffle on the right hand side of the valve cover. And shim the rocker
arms if necessary.
***ADJUSTMENTS
Silencer Removal
One of the easiest modifications you can make on an '86-93 5.0 Mustang
is to remove the air cleaner silencer as soon as you get the car. The air
silencer is located behind the right hand side fender. Removal allows increased
air flow to the engine. Also, install a K&N air filter as it will be
the last filter you buy and will increase performance.
Keeping Cool
A cooler engine produces more power. The stock 5.0 Mustang thermostat
is rated at 192 degrees, which is fine for most. Installing a 180 degree
thermostat will cause the engine to run slightly richer thus producing
more power. Don't install a thermostat cooler than 180 degrees or remove
it altogether. This will prevent the engine from reaching proper operating
temperature and performance will suffer.
Adjustable Fuel Pressure Regulators
Fuel starvation with modified 5.0 Mustangs is a common problem. By
installing an adjustable fuel pressure regulator you'll be able to increase
pressure from the 38-39 lbs. factory setting up to 55 lbs. (if needed).
Fuel System
One of the most commonly overlooked upgrades is the fuel pump. When
changing intakes, heads or injectors, depending on modifications, the pump
will need to be changed to a 110 lph or 155 lph. If you use a super-charger
of nitrous, a 155 lph pump will be minimum. Depending on boost levels or
nitrous levels, a 190 lph pump may be required. When upgrading the pump,
it's recommended to change the regulator to an adjustable type with a gauge
so exact fuel pressure can be set and monitored.
Exhaust Improvements
One of the most restrictive elements of a stock 5.0 Mustang is the
factory exhaust system. With all the dimples and bends in the factory headers
and pipes, unnecessary back pressure is created in the exhaust system.
Installing headers and a performance exhaust system will not only make
your Mustang sound better but also the performance gains are quite noticeable.
Ignition
When supercharging your mustang, it is necessary to upgrade your ignition
system. With the high boost levels, a stock coil cannot keep up with the
requirements to properly fire the increased mixture. A MSD multiple spark
box will be required along with a high performance coil (like a Motorsport
or MSD). If you have a lot of modifications (cam, heads, intake, injectors,
and NOS or a supercharger) the addition of the Motorsport RPM extender
can increase the power output dramatically by increasing air/fuel ratio
and RPM limit.
***DRIVETRAIN IMPROVEMENTS
Shifters
Installing an after market shifter, such as a B&M or a Hurst, is
the best preventive maintenance you can perform on T-5 transmission. The
adjustable positive stops prevent over shifting and bending the shift forks.
When installing a shifter be sure to properly adjust the positive stops.
Incorrect adjustment will result in the transmission "popping" out of gear
or bent shift forks.
***SUSPENSION IMPROVEMENTS
Dieting Time
Mustangs are very weight conscious. Removing any unnecessary weight
will only help performance. Hint: Try removing the insulation under
the carpeting in the hatch area on hatchback models. This is usually about
15-20 lbs.
Strut Removal
When removing stock McPherson struts make sure you have the proper
"slotted socket' to hold the upper shaft in position. It's available through
Craftsman and other leading tool manufacturers.
Front Suspension Alignment
Most Mustangs are delivered from the factory with the camber set at
0 degrees or slightly negative. Ideal setting is - 3/4 to -1 degrees for
aggressive street driving. This will reduce the "feathering" effect commonly
seen on the outside edge of the tires while improving handling through
corners.
Lowered Mustangs
Many Mustang owners like to lower their Mustang for improved handling
and appearance. As with anything, there is a right way and a wrong way.
Cutting the stock springs will certainly lower the car but handling will
suffer. We suggest installing after market springs made specifically for
this purpose. Several varieties are available and directly replace the
stock springs. Lowering a Mustang more than 1-1/2" lower than stock is
not recommended without major suspension modifications. The stock suspension
geometry is not designed to operate at that level.
Chassis Stiffening
If you drive your Mustang on a regular basis, consider installing sub
frame connectors. Not only will they stiffen the chassis (reducing body
flex), but some sub frame connectors support the floor pan at the seat
mounting area which has been known to stretch and tear over time. A strut
tower brace and lower chassis brace will reduce flex and stiffen the front
suspension (keeping the front end tighter during cornering).
STEERED STRAIGHT
Increasing steering accuracy is easy on lowered Fox Mustangs with a
simple bushing change
Taken from June 1993 Super Ford article by Earl Davis
What is bump steer and where does it come from? Bump steer is not the
name of a new carnival ride although it could describe the way some people
drive. Bump steer is the term used to describe the steering misalignment
or geometric inaccuracies resulting from suspension travel.
Okay, so that doesn't exactly make the concept of bump steer clear
in your mind. Think of it this way. Bump steer is any unwanted toeing in
or out of the front wheels as the suspension is compressed or extended.
It is caused by the geometry or relationship, between the steering linkage
(rack, tie rod ends) and the suspension (especially the steering knuckle,
upright or whatever you want to call the piece where the tie rod end attaches
to the suspension). If the steering and suspension move in different arcs
(and they always do, somewhat), then the distance between the center of
the steering system and the suspension will vary. That forces the wheel
to toe in out as the steering alternately "lengthens" or "shortens." Then
the car does not steer accurately during cornering.
Lowered cars usually suffer from increased bump steer because the suspension
geometry has been changed where the rack has been lowered in relation to
the centerline of the spindle. To help remedy this problem we offer offset
rack bushings for '79-93 models or the 1990-93 tie rod ends for 1979-89
models. Either solution works equally well by itself but not together.
(Source: Mustangs Unlimited)