2.3 Turbo Frequently Asked Questions

All information given below are general guidelines. Each car or engine is slightly different and may require additional tuning for safe/optimal performance.

Additional FAQ topics can be viewed on our support forum here: Support Forum FAQ

How much boost can I safely run on 91 octane?
These are general guidelines only. Always test with windows up, muffled exhaust, radio off, etc. so you can listen for audible detonation. Detonation sounds like gravel rattling in a tin can down near the back of the engine/transmission bellhousing. If detonation is heard, get out of the throttle immediately and lower boost or timing until it goes away. Since there are so many factors that effect this, I'll try to cover as many as I can but keep in mind that every vehicle is different and many other factors besides those mentioned below will effect maximum allowable boost. Please do not just crank the boost to the top of the range listed below and assume it will be OK as this almost always results in a blown headgasket or melted pistons. The lower side of the range would be for 91 octane, the higher side would be 93 octane.

-Assuming no intercooler, stock timing with an early (not LA or PE series) ECU, premium fuel.
12-16psi.
-Assuming stock intercooler, stock timing with an LA or PE series ECU, premium fuel.
16-20psi.
-Assuming large efficient front mount intercooler, stock or slightly turned down timing with an LA or PE series ECU, premium fuel.
19-23psi.

Other factors to consider:
-93 octane should allow additional 2-3psi over 91 octane, 89 octane will lower max boost 3-6psi, 87 octane will lower max 7-10psi.
-Small or inefficient intercooler (Volvo, Saab, Probe, etc.) should lower max boost 3-5psi.
-Cold air temps may raise max boost 2-3psi.
-Hot air temps may lower max boost 2-4psi.
-Water/Alcohol injection can raise max boost 2-10psi.
-Larger than stock turbos may raise max boost 1-3psi because of increased compressor efficiency.

How much power will the stock LA series ECU handle?
In general terms, about 250-275 rwhp. This will require elevated base fuel pressure, elevated boost, and other airflow mods before this power can be achieved though.
Early ECU's running 30lb injectors or small air meters will support significantly less power, somewhere closer to 235 rwhp.

How much power will the stock 35lb injectors handle?
In general terms with stock fuel pressure, about 230-250 rwhp, though you can push them to ~275 rwhp if using elevated base fuel pressure.

How much power will the stock large vane air meter (VAM) handle?
In general terms, about 275 rwhp. It's actually quite a restriction at anything over about 215 rwhp and people have pushed them to over 300rwhp, though they are no longer reading additional airflow over about 215 rwhp and it's like sucking a cheeseburger through a straw at this point. The easiest way to remove this restriction and allow the use of larger injectors and full tuneability is our PiMP ECU's.

How much power will the stock turbo engine handle?
With stock crank, rods, pistons, etc., many people have safely ran them in the 400-415rwhp range for quite a long time. A few people have made 515-550rwhp for a few wide open pulls before throwing a rod. 

Can I convert my air meter to blow-thru?
Yes, it is possible, though I wouldn't suggest it without a means of monitoring the Air/Fuel ratio with a Wideband Oxygen Sensor such as one's we sell: Widebands

Can I use a n/a head on a turbo motor?
Yes, you can, though I'd suggest you port the chambers to remove most of the "heart" shape so it more closely resembles the stock turbo head's "D" shaped chamber. You will also need to upgrade the exhaust valves and install hardened exhaust seats.

Can I just put forged pistons in my stock 2.3 n/a engine and convert to turbo?
Yes, though I'd suggest you still do the swap as if you were dropping in a complete 2.3 Turbo engine as far as wiring, air meter, injectors, etc. go, or skip the wiring modifications and air meter stuff involved with the stock ECU and go straight to one of our PiMP ECU's.

What spark plugs should I use?
Stock replacement Motorcraft, Autolite, or NGK plugs for 2.3T engine. Copper only, absolutely no platinum plugs or plugs with multiple electrodes.

What the max spark plug gap I should run?
In general, too tight of a gap won't really hurt anything but too large of a gap will allow the spark to blow out so it's fine to run .024" for 15psi for example. New spark plugs will need to be gapped as they come out of the box gapped WAY too large. Max gaps for different boost pressures are listed below:
-.032"-(10-15psi).
-.030"-(16-20psi).
-.028"-(21-25psi).
-.024"-(25+ psi).

What spark plug wires should I use?
Motorcraft. Parts store brand wires and many more expensive wire sets cause issues under boost. They also include a lifetime warranty which can come in handy.

Can I use a small air meter/injectors with a computer that came with large air meter/injectors (or visa-versa)?
No. You must use the same size air meter and injectors as came with the ECU from the factory.

What options do I have for tuning/modifying the stock computer settings?
-F3 Chip (View Here) with Jaybird (View Here) (Cheapest tuning option)
-Binary Editor and EEC Analyzer Software (View Here) (Tuning Software to be used with F3 or Quarterhorse)
-Quarterhorse (View Here) (Tune and Datalog in real time)

The F3 chip plugs into the stock ECU's service port and basically "interrupt" the signal to the ecu.
They are tuned with a computer (laptop or pc). They are not tuned "on the fly" meaning the engine is off during tuning. You can adjust "anything" that the ecu controls, rev limiter, injectors, timing, etc...anything you can dream of really.
The main difference between the J3 and the Quarterhorse is that the F3 uses and external chip burner and can't tune with the engine running while the Quarterhorse is self burned, meaning the "burner" is part of the chip board and can datalog and tune in real time (engine running) which is a huge benefit when tuning. The F3 uses removable chips that can have different tunes burned onto them for easy swapping of tunes without a computer (at the track or something).

What other EFI tuning options do I have (Stand-Alone EFI)?
-Stinger Performance PiMP (View Here)
-Megasquirt (View Here)

What is a wideband oxygen sensor and why do I need one?
Air/Fuel Ratio Primer: When air and gasoline are mixed together and ignited, the chemical reaction requires a certain amount of air to completely burn all of the fuel. The exact amount is 14.7 lbs of air for every pound of fuel. This is called the "stoichiometric" air/fuel ratio or 14.7:1 a/f. It's also referred to the Greek letter "lambda."

Lean mixtures improve fuel economy but also cause a sharp rise in oxides of nitrogen (NOX). If the mixture goes too lean, it may not ignite at all causing "lean misfire" and a huge increase in unburned hydrocarbon (HC) emissions. This can cause rough idle, hard starting and stalling, and may even damage the catalytic converter.  Lean mixtures also increase the risk of spark knock (detonation) when the engine is under load.

Rich mixtures: When the air/fuel ratio is less than 14.7:1, lambda also is less than one and the engine has a rich fuel mixture. A rich fuel mixture is necessary when a cold engine is first started, and additional fuel is needed when the engine is under load. But rich mixtures cause a sharp increase in carbon monoxide (CO) emissions.

By monitoring the level of unburned oxygen in the exhaust, the sensor(s) tell the engine computer when the fuel mixture is lean (too much oxygen) or rich (too much fuel). To compensate, the computer adjusts the fuel mixture by adding more fuel when the mixture is lean, or using less fuel when it is rich. That's the basic feedback fuel control loop in a nutshell.

Narrow Band Sensors (Stock): The stock oxygen sensor used on most vehicles is referred to as narrow band. This is because it is designed to only be accurate over a very narrow band of air/fuel ratios. They are not useful for performance tuning. The reason is, conventional oxygen sensors give only a rich-lean indication. They can't tell the computer the exact air/fuel ratio. When the air/fuel ratio is perfectly balanced, a convention O2 sensor produces a signal of about 0.45 volts (450 millivolts). When the fuel mixture goes rich, even just a little bit, the O2 sensor's voltage output shoots up quickly to its maximum output of close to 0.9 volts.  Conversely, when the fuel mixture goes lean, the sensor's output voltage drops to 0.1 volts. Every time the oxygen sensor's output jumps or drops, the engine computer responds by decreasing or increasing the amount of fuel that is delivered. This rapid flip-flopping back and forth allows the feedback fuel control system to maintain a more-or-less balanced mixture, on average. 

Wideband Sensors: The newest generation of oxygen sensors are being called "wideband" lambda sensors or "air/fuel ratio sensors" because that's exactly what they do. They provide a precise indication of the exact air/fuel ratio, and over a much broader range of mixtures - all the way from 0.7 lambda (11:1 air/fuel ratio) to straight air.

When the air/fuel mixture is perfectly balanced at 14.7:1 (the stoichiometric ratio and lambda equals 2), the sensor produces no output current. When the air/fuel mixture is rich, the sensor produces a "negative" current that goes from zero to about 2.0 milliamps when lambda is 0.7 and the air/fuel ratio is near 11:1. When the air/fuel mixture is lean, the sensor produces a "positive" current that goes from zero up to 1.5 milliamps as the mixture becomes almost air.

Widebands and Performance Tuning: Many performance engine builders and tuners have discovered the benefits of using the wideband oxygen sensor technology to monitor air/fuel ratios. Being able to see the actual air/fuel ratio at any given instant in time allows the fuel mixture to be fine-tuned and adjusted on the fly - something which previously could only be done on a dynamometer using expensive equipment.  

The air/fuel ratio is critical with high performance, turbocharged and supercharged engines to make power and to keep the engine from leaning out at high rpm and boost pressures. If the mixture leans out, it can send the engine into self-destructing detonation. If it is too rich, it will lose substantial power and create excess heat.

Target Air/Fuel Ratios: Typically, naturally aspirated engines make best power in the 12-13.5:1 range under load. Turbo engines are typically safer in the 11.3-11.8:1 range under load. Each engine is different however and the best ratio for your particular combo may not fall within these ranges. These engines should still idle and cruise at near 14.7:1 a/f ratio for best fuel efficiency and minimal emissions. Large cams will idle at richer ratios typically in the 13's AFR range.
Our Widebands are listed here: Widebands

What is the purpose of a blow off valve (BOV)?
The Blow-Off valve (BOV) is a pressure relief device on the intake tract to prevent the turbo's compressor from  surging from the backed up pressure waves caused by a suddenly closed throttle. BOV's do not control boost levels. The BOV should be installed between the compressor discharge and the throttle body. When the throttle is closed rapidly, the airflow is quickly reduced, causing flow instability and pressure fluctuations. Airflow bounces off the throttle plate and the pressure waves can reverse direction. These rapidly cycling pressure fluctuations are the audible evidence of surge. Surge can eventually lead to thrust bearing failure due to the high loads associated with it. The BOV releases these pressure waves into the atmosphere when the throttle is closed during shifts or deceleration, creating an audible "woosh".
Blow-Off valves use a combination of manifold pressure signal and spring force to detect when the throttle is closed. When the throttle is closed rapidly, the BOV vents boost in the intake tract to atmosphere to relieve the pressure; helping to eliminate the phenomenon of surge. Engines with air meters (VAM, MAF) require dual pistons BOV's.
Our BOV's are listed here: Stinger BOV's

What is the purpose of a bypass valve (BPV)?
The Bypass valve (BPV) performs the same function as the BOV above. The only difference is the air is recirculated back into the intake tract in front of the turbo, not released to the atmosphere. The BPV recirculates excess air when the throttle is closed during shifts or deceleration, creating a muffled "woosh" sound.
Our BOV's are listed here: Stinger BPV's
 
What is the purpose of a wastegate?
On the exhaust side, a Wastegate provides us a means to control the boost pressure of the engine. The vast majority of gasoline performance applications require a wastegate. There are two configurations of wastegates, internal or external. Both internal and external wastegates provide a means to bypass exhaust flow from the turbine wheel. Bypassing this energy (e.g. exhaust flow) reduces the power driving the turbine wheel to match the power required for a given boost level (speeds up or slows down the turbo). Similar to the BOV, the wastegate uses boost pressure and spring force to regulate the flow bypassing the turbine.

Internal Wastegates are built into the turbine housing and consist of a “flapper” valve, crank arm, rod end, and pneumatic actuator. It is important to connect this actuator only to boost pressure; i.e. it is not designed to handle vacuum and as such should not be referenced to an intake manifold.

External Wastegates are added to the exhaust plumbing on the exhaust manifold or header. The advantage of external Wastegates is that the bypassed flow can be reintroduced into the exhaust stream further downstream of the turbine. This tends to improve the turbine’s performance. On racing applications, this wastegated exhaust flow can be vented directly to atmosphere.


Should I use an internal or external wastegate?
In general, street/strip vehicles with stock turbos or small hybrids in the middle of their power range can use internal wastegates without issue. If trying to run low boost (under 15psi) it's harder to control with an internal gate. As the power limit of the turbo is reached (bordering on being too small), and internal wastegate will become less reliable at controlling boost. If the exhaust side of a turbo is being pushed near the limit, an external wastegate should be used. Also in setups where an external wastegate will simplify installation, or those getting over 350rwhp, and external gate should be used.

Will 3" exhaust kill my low end power because it doesn't have enough backpressure?
No. The turbo creates more than enough backpressure for the engine. The best turbo exhaust is the least restrictive possible. This includes large tubing, mandrel bends (not crushed in the bends), and a straight through muffler design.

What is the best size of intercooler tubing?
In general, the best size is that which minimizes size changes throughout the system. Considering stock 2.3T's have a 2" outlet at the turbo and a 2.5" inlet at the throttle body, using 2.5" tubing only requires one size change; from 2" to 2.5" at the turbo outlet or intercooler inlet. If a 65-70mm throttle body is used, 3" tubing from the intercooler to throttle body can be used but realize that 2.5" tubing will support around 600 hp so 3" shouldn't offer a power increase over 2.5" tubing unless you are making 600+hp but the larger air volume in the 3" tubing will slow down throttle response a bit.

Will too large of an intercooler or too much tubing cause excess lag?
Simply put, no. The amount of air contained in the tubing/intercooler compared to the amount of air the engine ingests every second is very minimal. The difference in lag between no IC tubing to a large FMIC will be hundredths of a second. In other words, it's not noticeable. With that said, it can slow down throttle response a bit, more so with stock ECU/VAM but the gains greatly outweigh the slower response.

What clutch do I need for "X" hp?
Clutch needs will vary greatly depending on driving style, vehicle weight and usage, torque curve, and many other factors. These are just general guidelines. Of course you can always run more clutch than you need...it's better to have more than you need than not enough.
Up to ~250rwhp: Stock Turbo Clutch or Spec Stage 2.
250-300rwhp: Spec Stage 2.
300-350rwhp: Spec Stage 2 or Spec Stage 2+
350-450rwhp: Spec Stage 3 or 3+
400-475rwhp: Spec Stage 3+ or 4 or 5, (Consider upgrading to a 5.0 clutch package with our adapter plate at this point as it becomes difficult to hold the power with a 9" clutch at this hp level)
500+rwhp: Dual Disc (Expensive) or Upgrade to a 5.0 clutch package with our adapter plate at this point as it becomes impossible to hold the power with a 9" clutch at this hp level.
Our clutch offerings can be viewed here: Stinger Clutches

Can I use the stock Mustang fuel pump with my new turbo engine?
If you leave the engine stock with only a few basic mods...cone filter, slightly elevated boost, etc. you can most likely get away with it because the stock Mustang pump is the same size as the stock turbo pump. If you plan to make 250+rwhp, see below.

What fuel pump should I use for my modified 2.3T?
Walbro 255 liter/hour High Pressure for 87-93 5.0 Mustangs. Early SVO's and such with inline pump (not in-tank) must either convert to in-tank pump or get inline Walbro 255 lph HP pump. Our fuel pump offerings are listed here: Stinger Fuel Pumps

Factory 2.3T Vehicle Information:
The following information came from the seemingly abandoned FordTurbo.com, recovered from: www.angelfire.com/wa3/fastest4d/faq.html to make sure the information wasn't lost if the site was pulled down.

Numbers ?
What years were the Cougar XR-7 made?
84-86
What years were the Turbo Coupes made?
83-88
What years were the SVO made?
84-86
What years were the Merkur XR4TI made?
85-89
What years were the Mustang GT (2.3turbo) made?
83-84 Gt in convertible and hatchback only
79-81 The GT's were a carb turbo
What years were the Capri RS Turbo made?
83-84
79-82 Capri's were a carb turbo

Engine ?
What/where is the VAM meter?
The VAM is the Vane Air Meter, it is a pre mass air unit.
It is located on the pass. side under the air filter box.

Which cars have the big VAM and small VAM?
Small VAM's are found in:
85-89 Merkur
83-86 Turbo Coupe
84-86 XR-7 Cougar
83-84 Gt Turbo
83-84 Capri RS Turbo

Big VAM/s are found in:
-All SVO's
-87-88 Turbo Coupes

What/where is the TPS?
The TPS is the Throttle Position Sensor, it is located on the throttle body and allows the computer to read the position of the throttle and adjust accordingly.

What/where is the IAC?
The IAC Idle Air Control solenoid it is located on the throttle body just above the TPS and helps control the idle.

What/where is the ACT?
The ACT is the Air Charge Temperature sensor and is located on 87-88 Turbo Coupes (and 87+ non turbo 2.3's). It measures the air temp coming into the intake after the turbo so the computer can correctly alter the timing. It is located in the lower intake manifold facing the firewall. It is the lower of 2 sensors found in that area.

What/where is the Knock Sensor?
The Knock Sensor allows your computer to hear detonation in the engine and retard the timing. (4 square)It is located in the lower intake manifold facing the firewall. It is the lower of top sensors found in that area. (4 in-line) is located in the lower intake manifold and points at the fender. This sensor is commonly unplugged as it to prevent unnecessary retarding of the timing due to false detection of detonation.

What/where is the O2 sensor?
The Oxygen sensor is used to sense the amount of oxygen in the exhaust gas and signals the computer, which can reference the voltage signal to an air/fuel ratio. It is located on the elbow of the exhaust system which connect the turbo to the down pipe.

What/where is the FPR?
The FPR is the Fuel pressure regulator. It helps keep a constant pressure of fuel to the engine. It is located between the upper and lower intake manifold at the end of the fuel rail.

What/where is the BCS?
The BCS is just an electronically controlled solenoid. If you look at the way it is set up with the "T" fitting, it works the same as a bleeder valve. But instead of using an adjustable valve it has a specific sized hole in the "T" fitting that allows a specific amount of air to escape away from the wastegate's pressure line. The BCS either turns on to allow the air to escape away from the wastegate's pressure. Since this air is escaping then the more air is needed to reach the actuator's "preset" 10 PSI spring rate to allow it to push open the wastegate. With the BCS off then all of the air pressure goes to the diaphragm and as soon as 10 PSI is reached the wastegate flapper is pushed open. It is located on the passenger inner fender next to the BAP.

What/where is the Wastegate?
The wastegate is just a valve that allows air to bypass the turbo's exhaust turbine. No air blowing on the turbine means no boost is made. It is controlled by the diaphragm that I described above. It is just a flapper door that is controlled by a spring set for 10 PSI. All the turbo cars have diaphragms set for 10 PSI.

What/where is the BAP?
BAP is a derivative of MAP. It's actually the same sensor on the MAP is referenced to manifold pressure and a BAP is referenced to atmosphere (not connected to the engine). BAP is a barometric pressure sensor. In is a minor computer input that allows the computer to make corrections of the fuel and timing tables for different altitudes. Air density is different at different elevations. Just like how you had to tune a carbureted car differently if you drove it into the mountains. It is located on the passenger inner fender next to the BCS.

Where is the PCV?
The Pcv Valve in these cars is hidden behind the alternator in a 5/8" ID hose that runs under the lower intake and then up to the Upper intake right near the throttle body.

What/where is the EGR?
The EGR is the Exhaust gas re-circulation. It allows gases from the exhaust to go back though the intake and get re-burned. It is pretty much an emissions thing. Although it does help with gas mileage. It is attached to the throttle body near the TPS. There is a tube that runs from the back of the exhaust manifold around the back of the
engine and to the EGR.

What stock fuel injector is 35 lbs/hr?
The 35lb fuel injector is a low impedance fuel injector. The top of the injector is brown.
It can be found in:
85.5-86 XR-7 Cougar
85.5-88 Turbo Coupe
85-89 Merkur
85.5-86 SVO

What stock fuel injector is 30 lbs/hr?
The 30lb fuel injector is a low impedance fuel injector. The top of the injector is green.
It can be found in:
83-85 Turbo Coupe
early 85 Merkur
84-85 SVO
84-85 XR-7
83-84 Mustang GT Turbo
83-84 Capri RS Turbo

Intake manifolds, 4 in-line vs. 4 square?
The 4 in-line intake manifolds were found in pre 85.5 2.3. The runners are in a line.
The 4 square intake manifolds are found after mid year 1985. This version has more aftermarket support as far as porting, fuel rails, etc.

What car(s) have a Garrett T3 turbo?
**All Merkur XR4Ti's
**All SVO's
**All 83-86 Turbo Coupes
**All 84-86 XR7,2.3 Cougars
**All 83-84 GT Turbo
**All 83-84 Capri RS Turbo

What car(s) have an IHI turbo?
**All 87-88 Turbo Coupes

What cars have what size turbo housings?
83-84 GT Turbo .60 & .63 A/R
83-84 Capri RS Turbo .60 & .63 A/R
84-86 XR7 Coug .60 & .63 A/R
84-85 SVO .60 & .63 A/R
85.5-86 Svo .60 & .48 A/R
83-86 TC .60 & .63 A/R
87-88 TC IHI Turbo
Early 85 XR4TI .60 & .63 A/R
85.5-89 XR4TI .60 & .48 A/R

What is the diff between a Garrett and an AiResearch Turbo?
There is no difference. They are the same company.

Which 2.3T engines were factory intercooled?
84-86 SVO
87-88 Turbo Coupe

Which cars have an E3 or an E6 exhaust manifold?
E3 and E6 exhaust manifolds are defined by their production number E3 means
that is was produced in 83. E6 means it was produced in 86 so all turbo
manifolds post 86 are E6.

Trans ?
How do I know what trans I have?
83-84 GT Turbo ----T5
83-84 Capri RS Turbo----T5
84-86 Cougar XR-7 ----T5 or C3
84-86 SVO ----T5
83-86 TC ----T5 or C3
87-88 TC ----T5 or A4LD
85-89 XR4TI ----T9 or C3

How do I know if my T5 is a world class version?
All T5 transmissions after 86 are World Class.

Diff ?
What diff and gears does the Svo have?
The 84 SVO had a 3.45:1 final drive
The 85-86 SVO had a 3.73:1 final drive
All SVO Mustangs came with a 7.5 rear diff.
They all were 5-lug and were rear disc brake equipped.

What diff. and gears does the TC have?
83-86
3.45:1 final drive
83-86 TC were 4 lug with rear drum brakes.

87-88
The auto had a 3.73:1 final drive
The 5sp had a 3.55:1 final drive
All 87-88 TC came with the more stout 8.8 rear diff.
They all were 4 Lug and were rear disc brake equipped

What diff. and gears does the Merkur have?
5sp final drive is 3.64:1
Auto final drive is 3.36:1
They have an 7.5 diff. from the American produced 7.5. they have a 26 spline instead of a 28 spline.

What diff. and gears does the Mustang GT Turbo have?
3.45:1 final drive, all had the 7.5 rear with 4 lug rear drum brakes.

What diff. and gears does the Cougar xr7 have?
3.45:1 final drive, all had the 7.5 rear with 4 lug rear drum brakes.

What diff. and gears does the Capri RS Turbo have?
3.45:1 final drive, all had the 7.5 rear with 4 lug rear drum brakes.

Electrical ?
What is an EEC-IV?
The EEC-IV is the Electronic Engine Control processor the 83-95 Ford vehicles are equipped with. This is the pre OBD-2 standard.

Where is the EEC-IV computer located?
It is inside the vehicle and is located just behind the passenger kick panel.

What are the different EEC-IV and what cars did they come in?
84 Svo 5sp --- ZBA and TE
85 Svo 5sp --- TJ and PJ
85.5-86 Svo 5sp --- PE
83 TC 5sp --- PC1 and ZGA
84 TC 5sp --- PC1 and TF and TC
85-86 TC Auto --- PK1
85-86 TC 5sp --- PC1
87 TC 5sp --- LA and LA2
88 TC 5sp --- LA3
87-88 TC Auto --- LB2 and LB3
88 TC Auto --- 8UA
85 XR4TI Auto --- PK
85.5-89 XR4TI Auto --- PK
85-89 XR4TI 5sp --- PF2 and PF3
83-84 GT Turbo 5sp --- TA
83-84 Capri RS --- TA
84-86 XR7 5sp --- PC1 and TA
84-86 XR7 Auto --- PK1