All information given below are general guidelines. Each
car or engine is slightly different and may require additional tuning for
-Why can't I use
the stock ecu/mass-air meter for the turbo swap? -Why can't I use the stock 2.3 n/a
engine for the turbo swap? -What turbo computer should I use for optimal performance? -What turbo should I get for
"X" hp? -What mods do I need for
"X" hp? -What do all those turbo specs mean? -How much boost
can my turbo safely put out?
-How much boost
can I safely run? -How much power will
the stock ECU handle? -How much power will the stock 35lb injectors handle? -How much power will the stock
vane air meter (VAM) handle? -How much power will the stock
turbo engine handle? -Can I convert my air meter to blow-thru? -Can I use a n/a head on a turbo motor? -Can I just put forged pistons in my stock 2.3 n/a engine and convert to
turbo? -What spark plugs should I use? -What should I gap the spark plugs to? -What spark plug wires should I use? -Can I use a small air meter/injectors with a computer that came with large
air meter/injectors (or visa-versa)? -What options do I have for tuning/modifying the computer settings? -What is a wideband oxygen sensor and why do I need one? -What
is the purpose of a blow off valve (bov)? -What
is the purpose of a bypass valve (bpv)? -What
is the purpose of a wastegate? -Should
I use an internal or external wastegate? -Will
3" exhaust kill my low end power because it doesn't have enough
is the best size of intercooler tubing? -Will
too large of an intercooler or too much tubing cause excess lag? -What
clutch do I need for "X" hp? -Can
I use the stock Mustang fuel pump with my new turbo engine? -What
fuel pump should I use for my modified 2.3T?
can't I use the stock ecu/mass-air meter for the turbo swap? The main reason you can't
"safely" use the stock Mustang computer and mass-air meter is
because there is nothing available to tune the stock ECU for larger
injectors, a larger air meter, timing retard under boost, etc. The stock
air meter and small stock n/a injectors wouldn't support more than about
130rwhp which isn't even worth messing with.
Why can't I use the
stock 2.3 n/a engine for the turbo swap?
In all honesty, you can. I just
wouldn't suggest it. Between the higher compression, heart shaped
combustion chambers, and cast pistons, it will be a ticking time-bomb. I
know at least a dozen people who have turbocharged the stock naturally
aspirated engine and all of them have eventually blown them up because of
a minor tuning issue or part failure. As cheap as the turbo engines are,
it's silly to do it any other way. If you drop forged and dished pistons
into a n/a engine, it will work though.
What turbo computer
should I use for optimal performance?
I prefer the computers from 87-88
Thunderbird Turbo Coupes. This would include the LA3, LA2, LA, 8UA, and
LB3 code ecu's. All of them are functionally interchangeable with each
other as long as a 5 speed is used. The automatic trans ecu's work just
fine with a 5 speed, they will just throw a few codes but will not trigger
the check engine light. If running an automatic, you'll need
the 8AU or LB3 to control the transmission, unless it's a 3 speed auto
which isn't computer controlled..
The reason I prefer this ECU is because it is the last generation of 2.3T
computers and they have faster processors, more excess space for
modification, and there are multiple piggy-back tuning devices available
to modify the fuel and timing tables, rev limiter, and about anything else
you can think of.
What turbo should I get for "X" hp? -Stock (87-88 Turbo
Coupe) Ishi-Warner IHI: Less than 250rwhp, super quick spooling (full
boost at 1800-2000 rpm with a few airflow mods) but runs out of steam at
higher engine speeds. Great for heavy cars or daily drivers. Good to 18psi
or so. -Stock (83-86 Mustang/Turbo Coupe, 84-89 Merkur) Garrett/AiResearch
T3: Up to about 300rwhp. Full boost at 2500 rpm or so with a few
airflow mods, pulls pretty well up top. Has a very hard "kick"
when boost kicks in. Great for a daily driver/street terror with minor
mods. Good to 23psi or so. -T3/T4 Hybrid T04E 46 trim compressor/Stage III exhaust side with .48 a/r for
street cars, .63 a/r for street/strip. Great for engines in the
250-350rwhp range. Full boost at 3100rpm or so with a header and
supporting mods. Nice linear power throughout rpm range. Great for
street/strip cars in the 12-13 second 1/4 mile range. Good to 25psi or so. -T3/T4
Hybrid T04E 50 trim compressor/Stage III exhaust side with .48 a/r for
street cars, .63 a/r for street/strip: Great for engines in the
300-430rwhp range. Full boost at 3300rpm or so with a header and
supporting mods. Nice linear power throughout rpm range. Great for
street/strip cars in the 11-12 second 1/4 mile range. Good to 35psi or so. -Holset HY35:
Great for engines in the 300-480+rwhp range. Full boost at 3600rpm or so
with a header and supporting mods. Pulls like a freight train in the
higher rpm range. Great for street/strip cars in the 10-12 second 1/4 mile
range. Loves 30+psi of boost. -Holset HE351:
Slightly upgraded version of HY35. Great for engines in the 300-480+rwhp
range. Full boost at 3600rpm or so with a header and supporting mods.
Pulls like a freight train in the higher rpm range. Great for street/strip
cars in the 10-12 second 1/4 mile range. Loves 30+psi of boost. -Holset HX35:
Great for engines in the 380-500rwhp range. Full boost at 3800rpm or so
with a header and supporting mods. Pulls like a freight train in the
higher rpm range. Great for street/strip cars in the 10-11 second 1/4 mile
range. Loves 30+psi of boost. Split scroll exhaust housing causes boost
control problems unless an external wastegate is used or the divider is
cut out. -T61:
Great for engines in the 400-600rwhp range. Full boost at 4000rpm or so
with a header and supporting mods. Great for serious street cars or drag
cars in the 9-10 second 1/4 mile range. Can handle upwards of 40psi. -There
are also many new GT series turbos that will work on 2.3T applications. I
did not include them because they are a much more expensive turbo and
since they have many more options available, they should be spec'd out
specifically for your setup.
What mods do I need for "X" hp? All combos are assumed
to be utilizing the best "stock" setup which includes 35lb
injectors, large vam, 87-88 ECU, stock or ranger roller cam, and
most importantly, a good tune.
engine, stock intercooler, no significant mods, 15-20psi will produce
roughly 170-215rwhp. -Above
setup plus cone filter, 3" exhaust, 15-20psi will produce roughly
setup plus front mount intercooler, more timing/boost, elevated fuel
pressure, 255 lph fuel pump, ~22-23 psi will produce roughly 265-280rwhp. -Above
setup plus ported or gutted intakes, mildly ported head, ~22-23 psi will
produce roughly 275-300rwhp. -Above
setup plus professionally ported head flowing 215+cfm on the intake,
extremely high fuel pressure, ~22-23 psi will produce roughly 275-330rwhp.
Below requires upgraded injectors, piggyback ecu tuner or stand-alone
ecu, and preferably
conversion to mass-air along with race fuel or alky injection.
turbo header, professionally ported head flowing 215+cfm, cone filter,
3" exhaust, 255 lph fuel pump, ported/gutted intake, large
aftermarket cam, ~25-30 psi will produce roughly 350-450rwhp.
Below requires many unmentioned items plus a standalone EFI system or a
very firm grasp of tuning a piggyback system. -Above
mods plus Upgraded Rods/Pistons, 225+cfm iron head or Esslinger Aluminum D
port head, ~25-30 psi will produce roughly 400-525rwhp. -Above
mods plus Esslinger SVO head, Stage III or larger Bo-Port cam, ~25-30 psi will
produce roughly 500-600rwhp. -Above
mods plus Esslinger ARCA head, Stage IV or larger Bo-Port cam, 2.65L+ stroker
engine, ~28-35 psi will produce roughly 650-800rwhp.
What do all those turbo specs mean?
A/R is the Area to Radius
ratio...literally a measurement of the size of the exhaust housing. Picture of
a/r measurement from Garrett Turbos:
III exhaust wheel is a larger/higher flow version of a standard
wheel. The physical dimensions of the wheel are larger. These require a Stage
III exhaust housing that matches the shape and size of the Stage III wheel.
exducer diameter of
1.898" and a major
stage II T3 has
exducer diameter of
2.122" and a
major diameter of
stage III T3 has
exducer diameter of
2.229" and a
major diameter of
Trim is a ratio of the minor (inducer) diameter compared to the major (exducer)
diameter of the compressor wheel as calculated below. Pics from Garrett
360 degree bearing means the thrust bearing is a complete circle, not cut out
in one section like the 270 degree bearing. Obviously a full bearing will
provide more thrust support than a partial bearing which makes a 360 bearing
better for performance applications.
Adiabatic Efficiency of a Compressor: The ratio of the work input required to
raise the pressure of a gas to a specified pressure as related to the actual
work input. Basically it shows how efficient the compressor wheel design is at
pressurizing the air to a certain pressure/ how well it can pump air without
heating the air more than thermodynamic law says it should.
How much boost can my turbo put out before it becomes overly inefficient? -IHI~18psi -T3~23psi -50
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. If detonation is
heard, get out of the throttle 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.
-Assuming no intercooler, stock timing with an early (not LA or PE series) ECU. 14-16psi. -Assuming stock intercooler, stock timing with an LA or PE series ECU. 17-20psi. -Assuming large efficient front mount intercooler, stock timing with an LA or
PE series ECU. 19-24psi. Other
factors to consider: -93 octane should allow additional 1-2psi, 89 octane will lower max boost
2-3psi, 87 octane will lower max 3-5psi. -Small or inefficient intercooler (Volvo, Saab, Probe, etc.) should lower max
boost 3-6psi. -Cold air temps may raise max boost 2-4psi. -Hot air temps may lower max boost 2-4psi. -Water/Alcohol injection can raise max boost 2-8psi. -Larger than stock turbos may raise max boost 2-4psi because of increased
How much power will the stock LA series ECU handle?
In general terms,
about 300rwhp. 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.
How much power will the stock 35lb injectors handle?
In general terms
with stock fuel pressure, about 250rwhp, though you can push them to ~300rwhp
if using elevated base fuel pressure.
How much power will the stock large vane air meter (VAM) handle?
In general terms,
about 300rwhp. It's actually quite a restriction at anything over about
240rwhp and people have pushed them to nearly 400rwhp, though it's like
sucking a cheeseburger through a straw at this point.
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 I use from http://www.innovatemotorsports.com
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.
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.
What spark plugs should I use?
Stock Motorcraft plugs
for 2.3T engine.
What should I gap the spark plugs to? -.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.
Can I use a small air
meter/injectors with a computer that came with large air meter/injectors (or
No. You must use
the same size air meter and injectors as came with the ECU from the
What options do I have
for tuning/modifying the stock computer settings? -F3
(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)
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)?
(View Here) -Pre-Assembled
(View Here) -F.A.S.T -Holley Commander -Accel DFI -Big Stuff 3 -SDS
What is a wideband oxygen
sensor and why do I need one?
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
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.
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.
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.
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
Widebands and Performance
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
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 11.5-12.0:1
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.
Source: Bosch Wideband Oxygen Sensors Precisely Measure AirFuel Ratios
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. Source:
TurboByGarrett.com - Turbo Tech101
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. Source:
TurboByGarrett.com - Turbo Tech101
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.
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.
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?
street/strip vehicles with stock turbos or small hybrids in the middle of
their power range can use internal wastegates without issue. 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
Will 3" exhaust kill my low end power because it doesn't have enough
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
What is the best size of intercooler tubing?
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, though it won't offer a
power increase over 2.5" tubing unless you are making 600+hp.
Will too large of an intercooler or too much tubing cause excess lag?
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.
What clutch do I need for
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, Clutchnet 3 Button "Red" disc with
stock pressure plate.
400-500rwhp: Spec Stage 3+, Clutchnet 3 Button "Red" disc
w/Red pressure plate. (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.
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 intank) must either convert to intank pump or get inline Walbro
If you have any questions or have suggestions for new FAQ's, feel free to