Pre Tune Information

by Michael Decipha Ponthieux
Posted: 2013-08-17
Last Updated: 2023-01-03

Before inquiring about an EFIDynoTuning Custom Tune, be sure you have verified the following for best results.

Note: The following information is specific to high performance daily driven ford vehicles making up to 1500 rwhp utilizing the factory ford computer.

Engine / Transmission Mounts

OEM type transmission mounts should always be used NEVER use a solid mount for a transmission as it can cause damage. The transmissions must be allowed to move otherwise transmission damage will eventually occur.

Engine mounts should be OEM grade as well, solid mounts can be used on road race vehicles and the like but should NEVER be used on drag vehicles. Poly bushings are often used without issues as well. In all high horsepower drag vehicles use ONLY oem type rubber mounts or complete engine plates.
Note: Foxbody mustangs with 302 sbf engines are known to split the engine at the lifter valley after exceeding 500rwhp. This is due to too harsh of motor mounts. For all sbf engines making over 500rwhp rubber mounts MUST BE USED. The primary cause for engine block failure is due to the chassis twisting at launch and with solid motor mounts the engine acts as a chassis brace which rips the engine apart at the valley every time.

Rotating Assembly

A forged crankshaft is not usually needed for stock blocks (excluding modular blocks and 6 cylinder engines). For small block ford applications, a cast crankshaft is typically able to support 900hp and is often stronger than the limitation of the stock block. For modular v8 applications, the stock cast crank should be replaced with a forged crank after exceeding 450rwhp. This does not apply to V6 engines; V6 engines are more susceptible to crankshaft harmonics and thus forged crankshafts are recommended on all performance oriented V6 engines.

*Aftermarket blocks should be used for all engines that exceed these ratings.
Factory rod bolts should be replaced with ARP high strength rod bolts in all boosted applications. Gapless rings should not be used in any application, all boosted engines should have at least .006" per inch (of piston diameter) regardless of the piston manufacturer's recommendations. The second ring should be gapped at no less than the gap of the top ring, again regardless of the manufacturer's specifications. Highly boosted and/or heavy-nitrous injected engines should have at least .008" per inch (of piston diameter). All coyote 5.0L engine's subject to nitrous and/or heavy boosting, SHOULD have the factory ring gap of 0.008" opened to at least 0.016".

Compression Ratio

As a general rule of thumb if your running E85 then go straight to 13:1 as boost doesnt matter.
If your N/A on premium pump gas then 11:1
If your N/A on regular 87 octane -OR- running premium gas with boost under 8lbs then 10:1
If your boosted on premium over 15lbs -OR- boosted under 10lbs on regular 87 then 9.5:1
And if your boosted on regular 87 over 10lbs then no more than 9:1

Cylinder Heads

Factory SBF E7 heads should be the absolute first component replaced in the engine. All engines should have MLS head gaskets and ARP head studs. This is neccessary for all boosted engines.

For all modular engines converted to 4v DOHC (cobra-heads) the block MUST BE DRILLED for the additional water jackets. Failure to do so will result in heat spots and engine damage. It is not recommended to use Felpro 1250 intake gaskets as they are designed for temporary use only. Only use O.E. equivalent gaskets. DOHC engine designs generally suffer from poor low end toque by design, as a result, DOHC engines aren't recommended for heavy towing applications.

The same applies for using sbf 302/351 heads on a sbf 289 block. The block must be drilled for the new water passages using the head gasket as a template.


An OEM stock distributor is required for all high performance engines that use a ford TFI ignition system. Aftermarket distributors CANNOT be used for high performance applications and SHOULD NEVER BE USED regardless. OEM ford distributors are manufactured with a precision cut 0.002" tolerance on the reluctor wheel. Its not uncommon for aftermarket reluctors to be up to 0.100" off causing SIGNIFICANT spark variances per cylinder. Most all aftermarket EFI distributors are also not designed for EFI use. This is evident by the oil drive shaft typically being 1/2" too short and the shaft diameter too small for a roller cam gear to have an interference fit. I highly recommend using ONLY genuine ford hall effect sensor pickups and modules. Aftermarket sensors are never recommended. If using an aftermarket sensor, it is highly recommended to keep a known functional spare replacement in the vehicle at all times for quick replacement when it does fail; which it will. If using an aftermarket harness for TFI ignition modules, the ignition ground MUST be grounded to the distributor case and engine block. Failure to provide adequate grounding will result in ignition signal noise that is very common on aftermarket harnesses.

See the
Ignition Systems Reference Data for more details. Verify all 94+ vehicles have a BLACK ignition module. The GREY module are for older ecu's and WILL CAUSE MISIFIRING IF INTERCHANGED. All 95+ ecu's are pre-programmed for BLACK MODULES and as such must have them present or the CCD_SW disabled in the calibration to prevent misfiring at higher loads.

Spark Plugs

Spark plugs will be dependent upon the CYLINDER HEAD, in all cases, ALWAYS compare the thread reach and washer design from the old plug to the new plug. If your spark plug currently has a washer present, the new spark plug MUST have a washer present as well. All DOHC cobra engines MUST have a washer present. I do not recommend running projected tip plugs on E-85 engines, use only non-projected plugs for E-85.

Plug Gap

Ideally you want to run the most gap you can get away as it will give you the most complete combustion. The larger the gap the more spark energy is released but the more strain it puts on the ignition system. On most stock ignition n/a setups I gap to .060 and go from there. On my ls1 camaro with a hot ignition system I've ran a gap of .070. Boosted engines will need the gap tightened so as to not blow out spark. The list below includes the published recommendations of plug gap for reference.

The following is a list of typical spark plug specifications, for boosted applications up to 15 psi and n2o up to a 75 shot.
Engine TypeYearHeadCIDLitersN/A Plug - Gapw/ Boost - Gapw/ n2o - gapNote
SVO83 - 88SVO4 Cyl2.3APP104 - .054APP103 - 0.032"
Pushrod SBFWorld Windsor Lite Sr/Jr3025.0APP 3925 - .054APP 3923 - 0.035"0.460" 5/8hex
Pushrod SBF89 - 95E73025.0APP 25 - .054APP 24 - 0.040"
Pushrod SBF93 - 95GT40 / GT40 P3025.0APP104 - 0.54APP103 - 0.032"
Pushrod SBFGT40X & SVE3025.0AR3924 - 0.045"APP3923 - 0.030"
Pushrod SBFGT40 Y3025.0AR 94 - 0.028"
Pushrod SBFTFS Twisted Wedge3025.0Autolite AR3924 - 0.050"APP 3923 - 0.032"
Pushrod SBFRHS3025.0APP3924 - .054APP3923 - 0.032"NGK R5671A-8
Pushrod SBFEdelbrock Performer RPM3025.0APP 23 - 0.028"
Pushrod SBFCanfield3025.0APP 3922 - 0.030"
Pushrod SBFAFR3025.0 Motorcraft AGSP32CK (3924) - 0.056"3923 - 0.032"
Pushrod V689 - 95 SCEssex SC2313.8APP 5144 / APP 2544 - 0.054"APP 103 - 0.044"
Modular93 - 04SOHC2814.6APP 764 / APP 104 / NGK TR55 - 0.054"NGK BR7EF - 0.032"(Do not recommend TR6 but is OK)
OEM is 1/2 thread
Modular97-04SOHC3295.4APP 103 - 0.064"
Modular92 / SVO / FRPPSOHC2814.6AGSF-32CAGSF-12EESVO / FRPP & (SOME early 4.6L)
Modular93 - 04DOHC2814.60.0350.030"
Modular93 - 04TFS Track Heat2814.6NGK (copper heat=6) - 0.030"
Modular05+3 Valve2814.6APP 5143 / Bosch 8120
Duratec V62000+SOHC1833.0Motorcraft 8GFF32WX - 0.044"
GM BBEdelbrock RPM 60054287.0Autolite 3924 - .045"
Note: Use copper or irridium plugs for nitrous use, DO NOT use platinum plugs on nitrous engines. Resistor plugs should be used on all digital ignition units to prevent interference.
Note: The above AP numbers are AUTOLITE part numbers, in all cases, read your plugs and adjust the heat range and gap as needed.
For nitrous applications up to a 75 shot the N/A heat range typically works well. For every 50 shot above 75, its typical to reduce 1 heat range.
If your engine currently has CHAMPION plugs they MUST BE REPLACED prior to getting your engine tuned.
NEVER, use a half thread plug in a full thread head!!!
However, using a full thread plug in a half thread head is acceptable.
Again, be sure you always use/reuse washers if they are present on the plugs being removed.

Anatomy of a Spark Plug
Half thread VS Full thread plugs

Spark Plug Cross Reference
Autolite #NGKMotorcraftTipThreadsStyle


Boosted engines generally should not have high overlap and duration as-is typical of a high revving performance oriented naturally aspirated engine. Stock camshafts typically provide satisfactory results on daily driven boosted engines. A slight performance gain can be ascertained by retarding the stock camshaft by -4 degrees (PTV clearance shouldn't be an issue unless pistons are above the deck, but should be checked). Custom camshafts for turbocharged applications often lean on the exhaust for a slight decrease in spool time. Turbo-specific cam grinds should not be used on a supercharged or nitrous engines. Nitrous specific cams typically open the exhaust sooner to remove excess combustion heat. For this reason, nitrous specific cams should not be used in towing applications or where low end torque is needed. Generally, supercharged and nitrous cam shafts are cut on similar profiles as opposed to turbocharged camshafts. For daily driven budget supercharged / nitrous sbf engines the F-cam has proven itself to be worthy. For naturally aspirated engines only the TFS-1 cam has proven itself to be worthy. A custom cam is always recommended and is typically only a few bucks more than an off the shelf cam. As an aside, custom cams are typically cut from a better core providing a much more durable camshaft for performance engines. It is not recommended to replace the camshafts on DOHC or VVT engines unless major modifications are performed such as CNC porting, bore diameter, or large ratio stroke variations. For VVT - variable valve timing engines, any replacement camshaft that has more lift than the factory cam's MUST have phase limiters installed to prevent accidental PTV clearance issues due to faulty tuning / hydraulic lag.

Intake Manifolds

Ported stock GT40 intakes are most ideal for all SBF engines BOOSTED making up to 400rwhp. For higher HP applications, 'bread-box' style manifolds are highly effective. Ideally the throttle body should be located in the center front of the engine (not typically possible).

Inlet Air Temperature Sensors

If your intake manifold is designed to accept an IAT/ACT sensor, it should be plugged and the IAT/ACT sensor relocated to the inlet piping.
ACT/IAT sensors located in the manifold are prone to heat soak and cannot accurately represent the actual air charge temperature. If using a slot style MAF sensor or those with integrated IAT sensors, it is most ideal to utilize these.
Note: When relocating the IAT/ACT to the inlet piping, the ACT fuel, spark, and VE modeling SHOULD be corrected in the calibration.
When doing an eaton M112 4v / cobra swap on an N/A engine and harness, the IAT wires need to be tapped in to the IAT2 sensor wires integral to the MAP sensor on the lower intake manifold.


It is imperative that your ECU and FUEL PUMP relay's are in 100% functional operating condition. If the relay's are more than 10 years old or if their age is unknown they must be replaced. A faulty/failing ecu or fuel pump relay will cause unstable fueling and can lead to engine damage. It is highly recommended to upgrade the alternator charging post to the battery terminal using at a minimum 4ga wire. It is also highly recommended to add a ground cable from the battery negative terminal to the transmission bellhousing (nearest the starter) using at a minium 4ga wire. Note: All electrical loads must be grounded through the chassis for filtering to prevent ground loops. The only grounds that should be ran direct to the battery are chassis and engine grounds. NO OTHER GROUNDS must be allowed to be ran to the battery or ground loops will occur. On vehicles equipped with a IRCM - Ignition Relay Control Module, the fuel pump relay trigger should be tapped prior to the module and ran to an external high amperage relay with a minimum 10 gauge wiring ran to the fuel pump and relay. The relay power feed is recommended to be ran to the alternator charging post for the greatest voltage achievable. This is required on all high performance vehicles.

Oil and Filter

First and foremost, most cam synchros failures, bearing failures, or lubrication related failures are almost always due to running the improper oil viscosity.

Little background:
Back in 1992 when the crown vic went from the 5.0L engines to the 4.6L modular's there was a sudden in-rush of thousands of reports of engine failures from police and fleet vehicles. Many were even blowing the oil filters off during high speed pursuits or when driving at highway speeds. Every single one of those cases were positively identified to be due to running improper oil viscosity. In those days the only oil that was readily available in bulk by distributors to police and large fleets was 20w50 which they used for everything. After ford identified the problem and the fleet and police maintenance shops got wind of the cause the problem miraculously went away over night.

Unless you designed and built the engine yourself. Use ONLY the oil viscosity the engineers that actually designed the engine to use recommends. Chances are they know more than you about their engines they designed and if you do so choose to go against their recommendation you cannot be upset if an engine failure results.

Make sure you have fresh oil in your engine before getting it tuned, if you have a new engine use proper break-in oil such as straight 30w with high zinc content (specified off road use only) think Gibbs Driven. NEVER use Fram or Champion-labs (STP, BOSCH, MOBIL1, K&N) oil filters. Use only Motorcraft oil filters for all Fords. All other filters do not have anti-siphon drain back valves and will cause premature engine damage usually resulting in broken timing chain tensioners and cam phasers. For all high horsepower drag race engines you should have a magnet attached to the oil filter with a large capacity filter (1 quart). Recommend using fully synthetic oil after proper break-in is completed. If your engine has been running at an idle lambda richer than 0.75 for more than 5 minutes, it is REQUIRED to change your oil to prevent engine damage. The excess fuel will 'wash-down' the cylinders and contaminate the oil, fuel does not lubricate and as a result will damage the engine bearings and cylinders. If you are unsure if your oil is contaminated, the dip stick can be checked for any fuel odors, this is not always a good indication and fuel may still be present in your oil. If in doubt, change your oil and filter. For engines that are very contaminated or if the engine oil turns black, the engine should be flushed by running the vehicle with fresh engine oil for approx. 5 minutes (until it gets up to operating temp) then draining and replacing along with the filter and repeating the cycle until the oil shows to be fresh golden clean oil.

See oil drain notes for turbos at bottom of page
Turbo Drains

On 3 valve ford engines the cam phasers are prone to failure, however, the cam phaser isn't the cause its the result. The typical cause of phasers to wear are due to too low of oil pressure at idle, the 3v engines should have 75 psi of oil pressure at cold idle and 40 psi of oil pressure at warm idle with 35 being the ABSOLUTE MINIMUM REQUIRED for proper cam phaser operation. The primary reason you get low oil pressure is from the timing chain tensioner seals blowing out and reducing the oil flow to the top of the engine. I highly recommend on all 3 valve engines to modify the oil bypass with a spacer to get more oil pressure. Also note that the 2007 model year 5.4 3v engines have a tendency to eat up the thrust bearing and destroy the crank journals. Be sure you use a good motorcraft/ford oil filter ONLY on all 3 valve engines and use the manufacturers recommended oil viscosity.

Rear End Gear Oil
It is never recommended to run synthetic oil in rear ends not even when factory specified. Use a good non-synthetic gear oil and change at typical intervals for better reliability and wear.

Coolant System

Since water is the most effective coolant with the greatest heat dissipation properties, for initial break-in the engine can be operated with water only (if you live in a climate where freezing is not a concern). After the engine has been broken in, the coolant should be drained and replaced with GREEN anti-freeze coolant. If you live in an area where freezing is common, it is highly recommended to use GREEN anti-freeze for engine break in. DO NOT use the red DEX-COOL unless factory equipped. Water wetter can be added to your coolant system if desired. Verify all radiator hoses are in like-new condition and do not have any cracks or dry-rotting present. Squeezing the hoses is a typical method to check for wear. When filling the coolant for the first time, the vehicle should be at a slight angle with the front end (radiator) higher than the engine. The lower radiator hose should be pinched repeadily until all air bubbles are purged from the coolant system. All factory THERMOSTAT BYPASS hoses should be blocked off and a 195+ degree thermostat WITH BYPASS HOLES should be installed. All race engines and high performance street engines should have a high pressure water pump with a high pressure radiator cap and an adequately sized overflow reservior. The fan must be properly shrouded to the radiator with the lower air dam in place for best results.

Serpentine Belt

Verify your belt is properly tensioned and that all pulleys are spinning in the correct direction. Some water pumps are reverse directional. Proper tension can be checked by placing a socket on the alternator pulley and turning the serpentine belt which cause the crank pulley to turn if adequate tension is present. The belt should be checked for cracking / dry rotting, and should be in like-new condition.


It is imperative that your brakes are functioning at 100% of optimal performance prior to getting your vehicle tuned. NEVER install cross drilled rotors on any high performance or towing vehicle as they are susceptible to cracking. It is highly recommended to use only slotted and DIMPLED rotors when possible. Use only high quality synthetic brake fluids and be sure to flush and bleed the brake fluid at each and every pad change interval. All brake pads should be replaced at the same time front and rear. If rear pads do not need replacement at time of front pads then inspect proportioning valve for faulty cotrol. Use only metallic or semi-metallic pads as they contain the most stopping power. Never use ceramic (ultra quiet & low dust) pads on any high performance or towing applications.


All wheels must be hubcentric, aftermarket wheels must have hubcentric rings. The lugnuts are not load bearing and should not support the weight of the vehicle. Wheel spacers cannot be used on high performance or towing applications. I highly recommend running tires with no less than 110mm of sidewall clearance on any vehicle. Make sure your tires are not dry-rotted and they are inflated to the appropriate pressure. Street tires should not be operated any less than 35psi unless otherwise specified. Slicks should be operated at the manufacturer's recommended pressure during the initial tuning phase.

All slicks and ultra high peformance tires should only be pressured up with nitrogen only.

Never let your vehicle sit in storage for an excessive amount of time with racing tires bearing the full load of the vehicle as this will induce flat spots and cause damage.

MAF Sensors

I highly recommend slot maf sensors for all applications. A link to best pricing and recommended sensors is
The maf sensor can be cleaned by simply removing the HOUSING from the inlet piping and using electrical parts cleaner to spray the maf sensor element.
DO NOT unbolt the maf sensor from the housing on 90mm ford sensors, this will usually strip the housing and the sensor will not reseal.
Using a q-tip to swab the element is not recommended but can be done if extreme caution is used.
Be sure to let the sensor sit overnight in a warm and dry area for all residual traces of the cleaning solvent to fully evaporate.
Failure to do so may cause sensor damage upon power up.
MAF flow sheets are often available from the manufacturer for an additional fee. Some manufacturers even claim to flow the maf before sending. I do not recommend paying for a maf sensor flow test unless the complete intake trac is used including the intake manifold. Otherwise the flow data will not be accurate and is not needed.

Inlet / MAF

Be sure your intake piping is completely sealed with no sharp bends or transitions. Airflow does not like to bend anymore than 15 degrees at a time, although thats almost impossible to follow in an automobile, you want the minimal amount of bends as possible. DO NOT place your air filter in the fenderwell where it can suck in water. All inlet piping should be of the same diameter as the MAF sensor and throttle body. PMAS HPX-E High flow Slot style MAF sensors are recommended for all applications. If using the stock MAF sensor with a 'calibrated' MAF housing, I only recommend purchasing a MAF "calibrated" for 60lb injectors, REGARDLESS OF YOUR ACTUAL INJECTOR SIZE. When tuning, you DO NOT have to have a maf sensor 'calibrated' for your injector size. Calibrated mafs ONLY apply to untuned vehicles running the stock tune ONLY.
CLICK HERE for more details in the MAF Write Up.

It is highly reccommended to install a screen on all MAF setups, however, If you are using larger than 3" piping or experience turbulence, it is REQUIRED to have a screen installed before and after the MAF sensor.

A screen can be made by using fine screen door mesh available from your local Lowes, Home Depot, or home improvement store. If possible, it is reccommended to have a screen BEFORE and AFTER the sensor element (when applicable). Screens should be done in a minimum of 2 layers, its not uncommon to have 4 or more layers to straighten out highly turbulent airflow most common in supercharged engines.

Note: a 75mm throttle body is adequate to support 500 hp naturally aspirated. This does not apply to configurations where the throttle body is a pre-supercharger restriction such as MN12, Terminator, GT500, and Lightning/Harley setups.

See THIS external link for stock throttle body size reference.
MAF Placement
The MAF should always be configured in a blow-through configuration such that the meter ONLY measures airflow entering the engine. Therefore the BOV or Bypass/Recirc. Valve should always be located BEFORE the maf on the discharge pipe of the supercharger or turbo BEFORE THE INTERCOOLER. The BOV or Bypass/Recriculating valve should vent to atmosphere in this configuration. Turbocharged engines utilizing a turbocharger with integral surge vents are not recommended to use a blow off valve. Ideally the MAF should ALWAYS be in the center of the longest straightest length of pipe available, this is typically the charge pipe that runs from the outlet of the intercooler and up to the throttle body. NEVER mount a maf in the corner of an elbow. Note: On modular engines with a hosed IAC valve, the IAC suction line must be ran to the inlet piping prior to the throttle body and AFTER the MAF. It is most ideal to pipe the IAC suction into the middle of the inlet piping elbow at the throttle body.

"Clocking" the MAF
Slot style sensors are most ideal and measure airflow from the central portion of the piping, thus, they do not typically benefit from "clocking". Older MAF designs that utilize a sampling tube can be 'clocked' to improve MAF accuracy by simply loosening the coupler clamps and twisting the maf housing until the HIGHEST MAF VOLTAGE is ascertained.

Cold Air Intakes / Air Filters

Cold air intakes that REPLACE the stock MAF housing, such as most all 2005+ Mustang CAI kits, must have the MAF transfer recalibrated. Never use a CAI setup that places the filter low in the fenderwell where it can suck up water. This can lead to hydrolocking the engine when driving in wet conditions. Reusable air filters are not recommended. If a reuseable filter is used the minimum amount of oil must be applied. Follow the manufacturer's guidelines to the T as this is the most typical cause of maf sensor contamination. Typically most air filter manufacturers required the air filter to dry for 24 hrs rendering the vehicle inoperative for an entire day.

Supercharger Bypass / Recirculation Valves

It is imperative that on all supercharged engines a supercharger byass or recirculation valve is utilized. The recirc. valve should ALWAYS be mounted on the discharge pipe of the supercharger AS CLOSE TO THE SUPERCHARGER AS POSSIBLE. If the MAF is configured in a blow through orientation as-is recommended, the SC Bypass / Recirc. can and should be vented to atmostphere to minimize supercharger surge. If the MAF is configured in a draw-through application, the SC Bypass / Recirc. must be recirculated to the suction side of the blower to prevent metered air from being vented to atmosphere.
For supercharged engines with larger camshafts resulting in lower manifold vacuum at idle, a low vacuum supercharger bypass is REQUIRED otherwise driveability issues will result.

PCV / Breather

Be sure your PCV system is completely sealed, the crankcase should be under vacuum when the engine is running, this will reduce emissions while improving throttle response and increasing power. A faulty PCV or unsealed PCV setup will result in windage and will cost power. NEVER use a filter type breather vent on the valve cover. The PCV system MUST be completely sealed. For boosted engines, a check valve is required to be installed between the valve cover breather and the inlet/suction side of the turbo/supercharger. The check valve must be mounted in reverse so under non-boosted conditions, the PCV will evacuate the crankcase and suck the check valve shut. Use only PCV valves that have internal checks and will lock to prevent backflow or bleeding of boost pressure into the crankcase. With this configuration, during boosted conditions, the manifold reference PCV valve will lock and the check valve on the breather line will open from the inlet vacuum to evacuate the crankcase. For race engines, it will be necessary to install a catch can to prevent oil from entering the intake. For more details see

Fuel System - Fuel Injectors

if using a ford ecu other than the SVO 4cyl ecu, be sure you have high impedance 12+ohm injectors only. Proper injector size can be calculated using the following formula.

INJSIZE x NUMBER OF INJECTORS x 1.6 = MAXIMUM RWHP then multiply by 0.8 for boosted applications
For quick reference typical injector size horsepower limits are given as follows:
Injector SizeColor4 Cyl N/A4 Cyl Boosted
or N/A w/ E85
6 Cyl N/A6 Cyl Boosted
or N/A w/ E85
8 Cyl N/A8 Cyl Boosted
or N/A w/ E85
8 Cyl Boosted w/ E85
24Dark Blue150120230185305245196
36Light Blue230185345275460370296
80 Black 500 400 760 615 1,000 800 650
To convert from lbs/hr to lbs/min simply divide by 3600 [60 sec * 60 minutes].
Injectors up to 210lb/hr have been proven to work perfectly fine for daily driven applications using the stock ford ECU's.
For injectors larger than 210lb/hr an aftermarket ECU should be considered.

Note: The 17lb injectors used on some ford's trucks have a base fuel pressure of 65psi making them effectively flow approx. ~21.25 lbs/hr.
The values given above can be increased by approximately 25% (x 1.25) by increasing fuel pressure to 65psi.

I highly recommend using no less than Siemens Deka High Impedance 80lb injectors in ALL ENGINES (excluding split port).

Fuel Pressure

Fuel pressure determines injector flow capabilties! Most injectors are rated at approximately 43.5 psi hence why the injector high slope is slightly below the advertised injector size. Fuel pressure has a significant impact on overall fuel control. A higher fuel pressure generally provides better fuel control and better fuel atomization leading to reduced emissions. Hence why all modern vehicles are using higher fuel pressures than in the past. The base fuel pressure determines the actual injector flow data on return style fuel systems. Simply changing the fuel pressure on a return style fuel system will require updating the injector data in the tune for the new injector flow. When raising the fuel pressure the injector flow is increased appoximately 1% per each 1 psi of fuel pressure increase. Decipha recommends 65psi of base fuel pressure for injectors smaller than 80lb.

Fuel Pressure Regulators

Adjustable fuel pressure regulators are not needed and should ONLY be used when you have borderline injector capacity. However, if an adjustable fuel pressure regulator is installed, it MUST have a check valve present to prevent pressure drop when the pump is powered off or excessive cranking will result. Kirban regulators are known to have check valves. Many aftermarket regulators such as aeromotive do not have check valves and are not recommended. Be sure to VERIFY your regulator holds fuel pressure after the pump has primed. Typically fuel pressure should remain constant for 30 minutes or more after the pump has shut off. Fuel Management Units - FMU's are not recommended, however if one is present (due to insufficient injector sizing) it should typically be set to raise fuel pressure by using the 6:1 disc so long as the fuel rail pressure does not exceed 75psi at maximum boost levels.

Fuel Pumps

Fuel pump(s) must be adequate to support the horsepower of the engine. Fuel pump requirements can be calculated by using the following formula:
fuel pump LPH x 2.8 = horspower limit of pumping capacity.
For those in the UK with pump flows listed in Imperial GPH (UK gallons), 1 GPH = 4.55 LPH
Verify your fuel pump has a check valve to prevent pressure drop after priming.
Note: Most aftermarket pumps do not incorporate an internal check valve; If not it is recommended to install a check valve on the pump outlet [typically 5/16"].
Failure to utilize a check valve will result in excessive cranking to fire off.

The ONLY fuel pump recommended for ALL APPLICATIONS is an OEM stock replacement 280 LPH fuel pump for 2011+ 5.0L Coyote Mustangs. This pump is capable of supporting over 700hp N/A and over 600hp boosted. This pump is most ideal for true street vehicles and daily drivers with unsurpased longevity and reliability. If needed multipled pumps can be installed for increased fuel flow capacity on higher horsepower applications. All return style fuel systems with pumps larger than 280lph must have a fuel cooler installed.

Fuel Pump Sizing Reference Chart - MAX LIMITS
rated lph
@40 psi
or E-85 N/A
RWHP Boosted
w/ E-85
Stock Application
28075062050011+ Coyote Mustang
162450360290Vortech T-Rex Inline
15844035028099-04 2V 4.6L Mustangs
14941533026599-04 SVT Lightning/Harley
88245195155Older Foxbody Mustangs

Returnless Pumps

Returnless style fuel systems were only used on select 1999-2010 modular fords. On these applications the stock basket should have holes drilled to help prevent fuel starving. A cobra twin hat is highly recommended for all 1994-2010 engines making over 400rwhp. The cobra hat will support 700 rwhp with a boost a pump voltage amplifier and wiring upgrade. Ford GT Supercar pumps are not recommended and will require FPDM and line modifications. The walbro returnless specific pump requires cutting of the basket and is not recommended. The stock 2005-2010 Mustang GT pump is adequate up to approx 400rwhp with a boost a pump. The stock 2011+ coyote mustang fuel pump is sufficient for up to 625rwhp with a boost a pump on pump gas only.

On return style fuel systems (99-10) and return style fuel systems with variable pump speed control (11+ coyote) it is IMPERATIVE that the fuel pump rubber isolated is in place to prevent electrically grounding and thus shorting out the fuel pump to the hangar body. On these fuel systems the FPDM regulates the ground to the pump to control the pump voltage / duty cycle. If any part of the metal body of the fuel pump touches any metal object in the fuel tank is will short to ground and cause the fuel pump to run at full speed! This is yet another reason why retaining the factory installed PRV (over-pressure relief valve) is critical for a properly functioning and safe fuel system.

Fuel Rails

Fuel rails are dependent upon length and internal diameter. The quick reference chart below will give you a general ball park estimate for fuel lines up to 12 feet in length.
EFI Fuel Rail and Line Sizing (up to 12ft)
I.D.Max RWHP SupportedNote
1/4"500Stock foxbody line and rail size

On all modified fuel systems a fuel rail pulse damper is required to prevent lean spikes and improve overall fuel distribution. Pulse dampers are available from
Radium Auto amongst others. Failure to use a pulse damper can result in un-tunable fueling inconsistencies at varying RPM's or conditions that occur at the fuel pulse resonance.


It is highly recommended to fill up with fresh fuel. It is common for vehicles to sit for extended periods while being worked on. This usually results in fuel degradation and solid deposits at the bottom of the fuel tank. The fuel pump and fuel filter should be replaced if the vehicle has been sitting for more than 3 years or if any fueling issues arise during the tuning process. If the vehicle has been sitting for more than 7 years it is recommended to remove, drain and clean the fuel tank. Use only the highest grade PREMIUM fuel available unless otherwise discussed with your tuner and set-up to do so. Failure to use high octane fuel will result in engine damage. If you forget to fill up with high octane fuel you do not need to drain your tank. Simply drive the vehicle keeping the throttle below 35% until your next fill up. REMEMBER, always FILL UP before going to the track or autocrossing. Fuel slosh is a serious concern and will cause your engine to run dangerously lean causing engine damage. Always keep a full tank of fuel when racing your vehicle. The little bit of weight savings is not worth damaging your engine over. Also note aftermarket fuel pumps have a much shorter operating life when not completely submerged in fuel. It is highly recommended to keep no less than a half tank at all times.

Water & Methanol Injection

What is Methanol? Methanol is the blue windshield washer fluid rated down below 0 degrees due to the methanol's alcohol content that prevents it from freezing. Methanol was first introduced in WW-II planes to give them that extra ooomph to get a burst of power when they needed it, like taking off short run ways for example. Methanol or water injection should be used on EVERY high performance boosted engine. It is REQUIRED on all non-intercooled setups to prevent excessive air charge temps. Methanol is required for all engines making in excess of 15lbs of boost on pump gas. Up to 15lbs its perfectly fine to run water only. All meth injection setups follow the same basic principles, it injects atomized water or methanol into the air stream. The best pricing I have been able to find is at
coolingmist for $280. Be sure to order the correct nozzle for you setup. I recommend for a ballpark guesstimate dividing rwhp/35 to get a gph nozzle size needed. Keep in mind heavily overdriven blowers will required significantly more meth injection to keep cool due to the excess heat build up. Typically, your aircharge temps should be no more than 120-130 degrees at WOT with a properly sized and functioning injection kit.
RWHPNoz GPHCoolingMist Nozzle CM#
420/3512CM10 = 12.8 gph
175/355CM3 = 4.9 gph (310cc/min)
140/354CM3 = 4.3 gph (275cc/min)
105/353CM2 = 3.4 gph (215cc/min)


It is critical that your exhaust is leak free and that your o2 sensors are new and are functioning properly. Only the front two oxygen sensors control fuel mix, the rear two o2 sensors are not absolutely needed but should be kept as they serve a dual purpose in performing fore/aft oxygen sensor correction to make sure the front o2s are working correctly. All vehicles that have stock wideband o2 sensors SHOULD ALWAYS keep the rear o2s even when doing a cat delete. For vehicles equipped with catalytic converters, be sure you specify that you have cats present in the vehicle info sheet or on the tune application. High flow catalytic converters often do not flow more than most OEM catalytic converters. Proper size exhaust length and piping is necessary for proper delta pressure. If your exhaust is inadequate it will typically result in the engine reaching MBT ignition timing much lower than practical, this will cause a loss in engine performance. For all naturally aspirated engines making less than 500 horsepower, 2.5" dual exhaust is adequate. A single 3" pipe flows approximate to dual 2.5" pipes. For turbocharged applications, all piping past the turbo will need to be doubled as compared to a naturally aspirated engine.

Note: X-Pipes will require that your tune be updated to disable the 2nd hego; due to cross scavenging, a full explanation can be found by

WBo2 & o2 Sensors - HEGOs

In all cases, the wideband and HEGO must be mounted AFTER the turbo in the downpipe with the sensor installed at the top most area of the pipe - NO EXCEPTIONS. On single turbo setups only 1 hego is used and must be connected to the passenger side connector Bank 1. More details can be found in the
HEGO Write Up.

If you have a wideband installed in the exhaust it must be POWERED ON when the engine is running. If not the exhaust gases will damage the sensor.
Stock Wideband Details - (Coyotes)
For vehicles with stock wideband o2 sensors such as the 2011+ 5.0L mustang coyotes it is imperative that only ford wideband sensors be used absolutely NO AFTERMARKET WIDEBAND SENSORS for any reason! Being that the stock widebands are controlled by the ecu an o2 extension harness cannot be used on any vehicle with stock widebands. If extensions are needed F-150 wideband sensors are an exact match with longer wiring and should be used for longtube installs etc...

As outlined above ^^, you MUST have new and fully functional o2 sensors in order for your vehicle to be properly tuned. On older 2010- vehicles that do not have factory widebands, a wideband is recommended for higher horsepower engines is highly recommended but not absolutely required. I highly recommend the AEM 30-4110 widebands. Be sure to set the wideband to report LAMBDA on the gauge by setting the adjustment screw on the backside to mode P1. The best pricing on the AEM widebands I have found thus far is from MAPerformance which is less than $160 shipped. If you find better pricing please do let me know.
CLICK HERE for the Logging Input Write Up with the Wideband Transfers.


The MINIMUM recommended turbo sizes are as follows:
Engine CylindersEngine SizeTurbo FlangeTurbo SizeARMax HP
41.5 - 2.5T-370mm.68550
63.0 - 4.0T-470mm.96550
84.6 - 5.8T-476mm.96700

Header "hot-side" piping can be easily calculated by multiplying the pipe diameter by 1000.
1.25" header is good for 1250 hp
1.50" header is good for 1500 hp
2.00" header is good for 2000 hp
2.50" header is good for 2500 hp
3.00" header is good for 3000 hp

For turbocharged applications the cold side exhaust needs (downpipe) are doubled as per naturally aspirated. All race turbo engines should have a cut out present. All turbo's should have a heat blanket and all hot side piping should be wrapped. It is highly recommended to keep a fire extinguisher in all turbocharged vehicles for safety.
For all remote mounted or low lying turbos a scavenge pump and reservior is required. A scavenge pump SHOULD NOT be used without a reservior or oil can back up in to the turbos and cause turbo damage.

It is imperative that an oil restrictor be used on all ball bearing turbo's. Failure to use an oil restrictor on a ball bearing turbo will result in turbo failure and engine damage. Journal bearing turbo's do not require oil restrictors and must not have an oil restrictor present or damage will result.

Blow-Off Valve

For all turbo applications that utilize a BOV, verify the BOV is CLOSED AT IDLE, Part Throtte, and WOT. The BOV must ONLY open when there is more pressure in the inlet piping than the intake manifold. Any BOV that opens during normal driving will result in driveability issues due to functioning incorrectly and must be resolved before the vehicle can be properly tuned. A BOV is not required or recommended for turbochargers that have 'surge vents' in the casing such as airwerks / borg warner. BOV's are not necessary on all out race engines or diesels.


As boosted levels are increased, the wastegate requirements are reduced. The wastegate discharge should be piped into the downpipe and not vented to atmosphere for all street vehicles. The discharge piping should be of equal to or greater size of the wastegate discharge. The placement of the wastegate should be so positioned that it is in direct flow of exhaust gas with no bends directly before or after the wastegate valve. If the placement of the wastegate is such that it is at an angle greater than approx. 70* to direct flow, the hp suppression begans to reduce. In all applications the wastegate must be COMPLETELY closed until manifold pressure (boost) exceeds the wastegate spring threshold. The table below gives an approximate hp suppression for typical sized wastegates. The HP suppression is the amount of horsepower (calculated from airflow) that the wastegate is capable of bypassing. For example, if your turbocharger is capable of moving enough airflow to support 1200hp, and your desired hp limit is 800 due to your engine components, you must have a wastegate that is capable of 'suppressing' at least (1200-800) = 400 hp.

SizeHP Suppression
60 mm~1600hp
50 mm~780hp
48 mm~600hp
46 mm~520hp
44 mm~450hp
39 mm~320hp
38 mm~290hp
36 mm~220hp

Note: The above values are approximate, there are just too many variables to
have a definitive answer, as a general rule of thumb, when in doubt go larger.


For all superchargers with sealed oiling systems it is imperative that the oiling system is not over-pressured or leaks will result. After filling the oil or changing the oil on the blower. It is highly recommended to open the oil fill plug after the vehicle has been ran hard the first time with the supercharger at full operating temp to relieve excess pressure. This will cause the blower case to be under a slight vacuum when the blower has cooled to ambient temps and will prolong the life of the seals.

The following applies to vortech superchargers only. Vortech makes the following pulley sizes.
3.87 3.80 3.70 3.60 3.47 3.33 3.25 3.12 2.87 2.62
Generally you can assume 1 psi per .1" pulley change; of course this is not exact science but a general rough estimate.
Vortech Blowers Flow Ratings
S-Trim628 hp
SCi-Trim659 hp
Si-Trim722 hp
T-Trim753 hp
YS-Trim942 hp
YSi-Trim1005 hp
Note: The V1,V2,V3,V7 all fit the same mounting brackets.

...continue on to
Learning to Tune

Return Home
Jump to Forum - EFIDynoTuning LC - New Orleans, LA