FAQ Frequently Asked Questions
CMS Classic Mustang Shop FAQ
Basic Engine Adjustments
hier finden Sie noch mehr Informationen - Engine FAQ
BASIC ENGINE ADJUSTMENTS
Throttle Position Sensor Adjustment (Green and Black Wires)
To maintain optimum performance of your 5.0 L 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 4-6° 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°-21° of timing.
Camshaft Installation
When installing a flat tappet cam (non-roller) it is important to install new tappets or lifters, valve springs and retainers. 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.
- Always use the right type of lifters or tappets with your cam.
- Always match your parts. One of the biggest mistakes is the installation of a cam that is too big (too much lift and duration).
- Flat tappets cams must use prelube before installation. Roller cams are made from steel billet and only require a generous coating of fresh engine oil.
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.
Cylinder Head Torque
When tightening head bolts, torque the upper bolts (near the intake manifold) to 80 ft-lbs and the lower bolts near the exhaust manifolds to 72 ft-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.
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 it. 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° which is fine for most. Installing a 180° thermostat will cause the engine to run slightly richer thus
producing more power. Don't install a thermostat cooler than 180° 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 supercharger or nitrous, a 155 lph pump minimum will be required. 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 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.
