We have been
receiving a lot of e-mail asking questions on many issues, which are
important. We thought this would be a good place to post what we have
learned from different sources and experiences.
- We heard of an ECU recall: VIN numbers
2G500050 to 2G504423. Check yours and get it
into the Subaru dealer immediately!
- We're finding the install time for the
Stage 4 is about 10+ hours of labor. This is because the uppipe takes
about 5 hours by itself to install. The uppipe is the single most
difficult upgrade to install.
- If you are building up your engine, remember the stock WRX engine connecting rods can not
handle torque over 400 ft/lbs. and 420 hp to the flywheel.
We are told they are going to snap or blow a piston....
- If you are
running about 400hp and above, you must be prepared for parts to wear
out quickly. The car is under a massive amount of torque and
it takes it's toll. You could expect early replacement of your clutch,
synchros, gears, u-joints, rings and more. This
is the price of PERFORMANCE! Many say it's worth it!!!!
- Don't waist your money on performance
heads and cams in search of better air flow. Just
turn up the boost.
- We are told for a WRX to break into
the 10s in the 1/4 mile will take more than 400 hp at the wheels,
- To be save, you should not run NOS. it takes a built engine to do
this with some degree safety!
- New uppipes
are available with super hi-flow cats in them. This keeps
your car protected from stock uppipe cats failing and keeps you
visually correct for State Inspections. Many States now are charging
$2500 fines for not having the proper number of cats. Our cats can be seen here.
- If you are going to remove a Stage kit
from your car remember to replace all the stock hoses back. I learned
one of them (where the manual boost control goes in the engine
compartment) has a restricter in the hose. If it is replaced with a non
OEM hose it will not have the restricter the car needs to run, so it
will run like shit, possibly over leaning the engine....
- When adding gauges with O2 sensors, be
careful, many have thrown the CE light....possibly
tapped into the wrong place in the system or ??
- CE lights are
possible with any aftermarket exhaust system: uppipe or hi-flow system.
The CEL code is usually for inefficient operating temperature of the
cat or uppipe. There are aftermarket fixes
for both, so don't worry.
- During hot
temperatures keep your car cool. One suggestion is to force
a larger volume of air onto the intercooler, the temperature will be
lowered, and the volume will be greater. The engine will work more
efficient giving you more horsepower with more air. The scoops are 1
inch taller, a big difference! Secondly, upgrade the stock radiator to
a aluminized one that will be a higher flowing, thicker radiator.
Unknown to most users, a new radiator will keep your car running cooler
up to 6 degrees C. This is a huge advantage when trying to beat the
heat that is slowing you down. Of course this advise will only work if
your car is driving in really hot weather....da!
- During cold
weather, remember to watch the boost. The Chips are
programmed to increase boost based upon temperature, so if it's cold
enough your boost could be higher than recommend. This
is one of the reasons for a boost gauge!
- Here's some
words on turbo timers found from June 2001 Tech TIPS published by
Subaru for Subaru Technicians: "2002MY WRX TURBO COOL DOWN
PROCEDURE:FHI's position regarding this is that it is not necessary to perform a "cool
down/idling" procedure, as was recommended with past turbo models. Our
current 2.0L turbo engine has a far greater cooling capacity and,
coupled with technology advances, makes this practice no longer
necessary. This explains why information about cool down is not
included in the 2002MY Impreza Owner's Manual. The heat contained in
the turbo charger will begin to vaporize the coolant at the turbo
charger after the engine is stopped. This hot vapor will then enter the
coolant reservoir tank which is the highest point of the coolant
system. At the same time the vapor exits the turbo charger, coolant
supplied from the right bank cylinder head flows into the turbo. This
action cools the turbo charger down. This
process will continue until the vaporizing action in the turbo charger
has stopped or cooled down." So I
guess there's no real reason for spending money on a turbo timer.
- On a stock
WRX or when installing any engine management system, be careful of who
is the manufacturer of the intake you are using. The word is
many of the intakes lean the system out further than the chip
programming recommends and then the CE light comes on. Also, when
leaned too much you are running the risk of frying things (see above
street stories). We have found our short ram
intake falls within the programming parameters and our customers are
having a great time without the CE light to watch! Avoid a nightmare on your street!! See stories
- Only the
Automatic WRX has been limited to 130 mph from the factory. If you add
mods, you should be able to go above the factory set limit. But, as you know, speeds over the legal limit are
for 'Off Road' only!!
- If your car has no power over 5,000 rpm (no boost),
the possible problem could be a bad EGT sensor. To test,
disconnect the EGT sensor, which will force the car to default (CE
light should come on). Then try the car. If it runs fine without the
sensor, then its bad and will have to be replaced.
- If you plan to add headers, it could
increase your turbo lag, while increasing top end HP. So, there are
compromises when using some headers. Others will act differently. Check
which header design you are buying and what it will do, so you won't be
- If you change
your plugs and have disconnected the battery to accomplish the task,
remember to reset the ECU!
- Some have upgraded their turbo without
upgrading the associated parts: their fuel pump, injectors and engine
management. This is living live on the edge. If you are running 16+
psi, then you run the risk of stressing your car's system: leaning out
the car, frying a turbo, blowing injectors and more. Everything is max.
out, so don't do it. It may feel good, but only for a short period of
time before it breaks. Upgrade the fuel
pump, injectors and your map or pay the consequences.
- There has been
much talk of the CE light coming on when you replace the Uppipe (has no
cat) and have only one cat in the car. We are
told by the Subi/rally guys that most likely the CE light will not show
up, it hasn't for them. So, with this in mind, the odds are
you probably won't see a CE light with the replacement of the Uppipe.
But, as you know, there are no guarantees. If
a CE Light does show up, the code usually refers to an improper CAT
operation temperature. Since this is after the engine, it shouldn't
create any problems. There is an electronic fix to stop the light, but
you should have additional gauges to monitor your system. Also,
remember to reset your ECU! Like candy left
on the table (tempting), can you resist leaving the power of the
Uppipe, about 7-8hp, on the table....Hmmm that's the question? The
uppipe fix is as follows: All you do is get a 2.2 Ohm resister from
Radio Shack. It should be rated at a 1/2 watt some have burnt theirs
when using 1/4w. Next you want to find your EGT probe which is in the
uppipe. Follow it up until you come to the sensor, that is the sensor
that you are going to unplug. It should be the very last sensor on the
rack. On the other side of the clip is where the resister gets
installed .Wire it parallel between the two wires on the ECU side. It
should look like an H. Wrap it up and you are ready to rock. Make sure
you reset the ECU and that you leave the sensor unplugged.
- When doing State inspections, be aware if you don't
have the proper number of cats, you are not going to pass an emissions
test, or a visual test of the exhaust system. If the visual
test is a concern in your state, either reinstall the OEM exhaust
system before any inspection or purchase Xcceleration's super
hi-flow downpipe, uppipe and midpipe with cats. These pipes are designed to provide maximum
performance and still have 3 cats on your car.
- Watch your OEM uppipes after upgrading/increasing
boost with Stage upgrades. The new
weak link in your exhaust system after spending all your
money on a turbo back exhaust is now the OEM
cat in the uppipe. It will take a pounding from the higher
boost levels and could blow, sending pieces
up into the turbo, UKKKK! Upgrading the uppipe should be
your next consideration before an intercooler. Get
that OEM cat out NOW!!
- If you are
running a hi-hp application and a lightened flywheel, we have found you
run a risk of a CEL for random misfiring or detonation. It
seems the power pulleys are allowing the crank to turn faster, fast
enough to cause issues with the crank sensor, which throws the CEL. If
the CEL is for random misfire, then it's only a light, not actually
happening, but if it's for detonation, you are probably having timing
pulled which means less power. The solution is simple, either don't put
it on or live with it. The code should stay away. It has for others.
Power has it's price!
- If you have
upgraded your engine, and are making more power, a missed shift will
earn you a blown gear or synchro. A major increase in torque
going through the tranny is sufficient to destroy it, if you don't know
how to shift. Be careful! FYI,
built automatic trannys rule. They can't miss a shift and are winning
at the track.
- The three most important aftermarket gauges
to have in your WRX are a boost gauge, air/fuel gauge, knock sensor and
your CE Light! Don't be deceived
into thinking this Light is just an idiot light, it is not. It
represents over a dozen critical codes. The
only problem with the CE light is it could miss important information
you need to protect your engine. As you increase HP, the ECU becomes
less accurate and it is critical to monitor your car's systems. When
you add a boost gauge, air/fuel gauge and a knock sensor, you are
adding additional margins of safety. It is a
small price to pay to safeguard your car, buy them! If not, we may be
writing your street story.
- We have heard
about the new STi as follows: Unlike the standard WRX, the STi in stock trim can,
and does, detonate on 93 octane gas. (We’d hate to see what happens on
reformulated California 91 Octane.) Like the WRX, the STi ECU runs
highly variable ignition timing. Can you say ‘Dastek’
boys and girls? I think you can! The STi likes a nice, free-flowing
turbo back with 2 cats installed to the tune of up to a ~48hp (28whp) gain (assuming similar ignition
timing, of course!).
- Heard that
the new 2004 STi has pistons which are cast and coated, not forged,
along with good rods. This means it most
likely will not product the lofty HP everyone thinks they are going to
get from mods. The word is the STi
engine should be good for about 450-500hp, if the boost isn't over
18psi, while the WRX is good for
about 420HP, if the boost is not over 18psi, before things start to
break. So forget about that 500HP plus monsters at 19psi and
higher, unless you build up the bottom end.
- Blow Off
Valves: the plus and minus - There are many
people who will say that if your car has a MAF (Mass Air Flow) sensor
(which is most modern turbo cars), you can't vent a BOV to atmosphere.
This is not entirely true. In most cases you can, but it pays to be aware of the possible side effects.
Quite often you may find the side effects are so minimal that they are
not really a concern. Most factory turbo cars run some form of MAF
sensor These sensors are used to determine the amount of air the engine
is using so it can deliver the appropriate amount of fuel. In a car
with a MAF sensor, when a BOV vents, air is escaping from a closed
system. This air has already passed through the MAF sensor and has been
measured, and the computer doesn't know that this air never made it to
the engine. This will cause a brief rich
mixture as the computer will still deliver the correct
amount fuel dosage based on the amount of vented air. There are two
stages to a BOV venting, as initially it is evacuating the pressure
from the inlet pipes and intercooler, which usually takes less than a
second (depending on your inlet system). Then once the pressure is
released, the valve stays open to allow the turbo to freewheel, thus
reducing compressor surge and the associated thrust and torsional
loads. It is mainly during this freewheeling
stage that causes the over-fueling, since the turbo is basically
pumping air through the MAF sensor and out to the atmosphere through
the BOV, which accounts for the majority of air that escapes the system.
The resulting rich mixture is
what can sometimes cause backfiring and a puff of smoke in some cars.
The severity of these effects
usually depend on the state of tune of the engine. In cars that are
modified (say with full exhaust, pod filter, a little extra boost etc.)
but still using the factory tuning, it is not uncommon for the ECU to
compensate for the extra airflow it sees by running rich for engine
protection. On a WRX for example,
mildly modded engines can be running as rich as 10:1 with the factory
ECU. It is this poor state of tune that can cause backfiring when an
atmosphere-venting BOV is added. Stalling
is another common problem, many people have had bad
experiences with atmosphere-venting valves causing stalling problems.
However, with the correct spring adjustment this problem is reduced. As
long as the valve closes properly before the engine reaches idle, the
ECU will have no problem maintaining a smooth idle. Most complaints of
stalling actually come from people using certain Japanese brand valves,
which often do not have the range of spring adjustment to compensate. Key is: some cars are affected by backfiring when
venting to atmosphere, and some are not. Even two identical cars with
slightly different mods can react differently. The bottom line is if
you vent to atmosphere with a MAF sensor you MAY use fractionally more
fuel (depending on the kind of driving you do) and there is a chance
you may hear some popping in the exhaust. For those Subies wanting maximum noise from the
valve this is usually not a worry! Also,
if you can not stop the fluttering sound above 3000 rpm, then remove
the spacer inside the BOV, this should allow for better adjustment.
Also, you must make sure a BOV is installed and
working correctly. If not, it could create a vacuum leak, which would
be seen by the ECU as needing more fuel for the system, when it is not
really needed. This fuel rich situation will destroy exhaust cats and
more. So, put that BOV on correctly or
- Boost Creep
(Boost Spikes) The waste gate on the
turbo is controlled by the ECU and is looking for a certain amount of
pressure on both sides of the waste gate. When
you change the pressure by using an exhaust system that is too free
flowing, then the waste gate doesn't have the proper pressure and
doesn't open at the correct time. This
causes the boost to 'spike' too high, which can cause damage. Many have suggested polishing the waste gate on the
turbo, but as usual this is a maybe solution for a complex problem. Polishing
may work occasionally, but the risks from polishing are very high. One
negative side effect is you can't built boost at all. The correct
solution is to install the correct exhaust system in the first place
and avoid the whole situation. A properly designed bell mouth
design and catted exhaust system provides proper back pressure and
maximum performance. Why look for trouble, do it
right to begin with!
- UTECs - We have found that using the UTEC
in low HP applications has worked well for Subies in the past, but
discovered that as HP increases many of our UTEC guys have had many
gremlins, which they were unable to tune out. By
upgrading to the Dastek Piggyback Chip, these issues have all
disappeared. They have found the Dastek operates better
with the OEM ECU, uses all of the OEM sensors, plus includes 2 preset
maps making it a no-brainer for installation and use: true plug n play. In addition the
Dastek is designed for use with all turbo Subarus (WRX, STi, XT, Baja
Turbo and Legacy GT), making it one of the most versatile chips
available. So why fool around?
many engine management systems do not properly compensate for the
changes in temperature, which means boost will increase in cold
weather. You may want to verify your
boost, using a boost gauge and make sure you're on target with the
boost you need when the temperature drops. Also check your A/Fs. When
cars were tuned in the cold, and the weather warms up, making the cars
run richer. The opposite is true and the car could now run lean in the
winter. In short... if you suspect problems, or have noticed
more knock lately, check your boost and A/F, and make adjustments.
- STi guys, if
your car is not idling smoothly, we have found it's the crank sensor
screwing up. When changed the car idles great again. We can not guaranty it will be
this simple all the time, but so far we are batting a 1000 on each car
we checked, vs the dealer. Reset your ECU after the install.
- STi guys, if
your car is not cruising smoothly, feeling like there is resistance, we
have found that cleaning the MAF sensor has helped, and many times it
has also been the front O2 sensor beginning to go. What makes this hard is that there isn't a check
engine light to support the bad O2. We have just found through trial
and error that changing the O2 sensor has helped 9 out of 10 times.
ECU after the install.
- Many do
engine tuning on their own or use theoretical expert tuners. Tuning is
a very complicated process if done right and easy if done wrong. To put your car on a dyno and flog it for hours,
seeking the highest HP number you can find, not remembering the first Commandment
of Tuning: NO DETONATION,
things happen. Many times their results show up immediately, sometimes
later. But bad tuning will always show up. Have a look at what happens
to pistons when this commandment is not kept - broken
- We have had a
lot of calls from guys running Utecs, Reflashes or Ecuteks (reflashes)
for engine management saying they have lost power and/or check engine
lights for inefficient cat code. What
we have found when looking further into the issue is the fellow's car
is running too rich from the maps they are using. The maps have been
set to run 'rich' as a safety precaution against detonation, but are
too rich for converters. If you are going to run 'rich' maps for
safety, then you should not have converters in the car, but this causes
a problem because you need converters on a 'street' car to meet Federal
Regulations. When our guys use the Dastek piggy back chip we have, this
situation does not occur because the maps are designed to work with
either OEM converters or our hi-flow cats. We have not had a single
hi-flow cat failure, either because of the cat or the Dastek chip. Have
a look at what not to do and what happens when the maps are set to "Fuelish". click here
- Many guys are
reflashing their Factory ECUs using several different programs on the
market. Some of these reflashes are even done by Subaru Dealers. If
your car is going to be a "Street Legal Car", not a race car, these ECU
reflashes are not CARB Approved. This means you leave yourself open to Federal and/or
State EPA/CARB fines. The ECU reflashes
were originally designed for 'Race Only' applications ("Non-Street" Use),
so don't be surprised if one day you receive a healthy fine ($2500) in
the mail for not meeting CARB Standards. This would apply to Stand-a-Lone ECUs too. Remember, even if your state does not have emissions,
the Federal CARB rules still apply. The only way for an
ECU "Reflash" to be street legal or a "Stand-a-Lone ECU, is if it is
approved by CARB and has a sicker and documentation to prove it. It doesn't matter who did the ECU reflash, even if
it's a Subaru dealer. It's illegal!
- More power is not
as easy as turning up the boost. In turbo cars, increasing the
boost produces more power as long as the fuel system can flow enough
volume to maintain an optimal air/fuel ratio, using upgraded engine
management. When it can't, the air/fuel goes lean, then the engine
becomes a live grenade! So, don't turn up the
boost unless you have proper engine management and upgraded fuel system
- Not all bolt-on
mods make power. Most Bolt-on mods are not designed to make
power by themselves, but help the engine and related systems reach full
potential. They are just tools to aid in the tuning of your engine more
more power and require proper tuning/adjustment. Many
bolt-ons even though they say the mod will fit the car, may not
actually increase power for the car. Do
your research, many bolt-ons have actually harmed the car!
- Not all
performance cams are better. Many performance cams make power
in the hi-rpm powerband, producing power above 5,000 rpms to over 8,000
rpms. But do not add any power to low or midrange. For street
performance cars, these cams are simply unusable and should be left to
full race cars running hi-rpms for drag racing or circuit racing only. Street cars are looking for more power in the low and
mid range and should select performance cams which add power in these
rpms for maximum performance and drivability. Unless you plan to drive your car at 5,000-8,000 rpms
all the time!
intercoolers make more power. Intercoolers are heat exchangers.
The cooler the air provided by the intercooler means more power can be
realized with additional boost and tuning. However, be careful how you
upgrade your intercooler. A larger front mount intercooler may be great
for cooling, but reduce engine response if the routing of the
intercooler pipes is too long and complicated. For
street and under 500hp application, a larger top mount has it's
advantages because of it's relatively short and direct path.
- Dyno Tuning, it's an asset to
the serious professional seeking to evaluate the performance benefits
of their enhancements, without hitting the race track. But beware, it's
a double edge sword! Remember, dyno testing is about repeatability and
performance gains, not just PEAK OUTPUT!. There
are differences between dyno equipment and technical ability of
operators to be considered. A dyno is a 'tool' and in the hands of an
expert, who has complete technical knowledge about your car and its
mods, is a valuable asset for the serious power enthusiast. But it must
be remembered, it is one tool available to the tuner, not the only
tool. Many 'Professional' tuners actually tune the car on the road,
rather than a Dyno, so they are tuning to actual road and track
conditions. This method yields 'Real World' results. FYI: Proper Dyno tuning
procedure should include a full diagnosis to the engine prior to final
setup. The diagnosis should cover Electrical, Engine Management and
Fuel System, and is a primary fundamental procedure which should be
followed. You should insist on knowing what, if anything, is wrong with
your car before the final setup and the runs begin. A Dyno tuner should
able to make adjustments necessary for the mods you have, showing the
before and after gains of each component, where possible. But in the
hands of the uninformed, inexperienced and technically untrained, it
could become a weapon of destruction. Running a car on a dyno, which is
not in peak shape, could certainly accelerate a hidden problem and
damage the car. Running the car on a dyno without the proper cool down
between runs may damage important components in the car. Not knowing
when your car is reaching its limits, could damage the car. Just to
mention a few variables. It should be remembered, a Dyno checks power
under ideal conditions, not actual road conditions with a 'real world'
load on the engine. Most Dyno runs are in
fourth gear, at full throttle, to redline. Basically this means only
fourth gear is being tuned at full throttle, what about the other 4
gears, or partial throttle??? So, this type of single gear tuning
leaves a lot to be considered, including real world conditions, load,
hills, partial throttle, overall safety margins already in a
manufacturer's map and more. If a car is leaned out too much, or timing
retard excessively things happen. We have seen cats blow, uppipes fail,
exhaust systems leak, turbos and pistons fry and a variety of other
damage from trying to Dyno tune in search of 'ideal' maximum
performance on a Dyno. For additional
consideration, if the Dyno shop is tuning your chip and is not
completely trained with the operation of the chip and the technical
operation of your car, then this is a disaster waiting to happen. Any
aggressive adjustment of boost, air/fuel or timing map could spell 'DISASTER'
in capital letters. IMPORTANT: if the Engine
Management System you are using to tune your car does not have "Live
Tuning", and only has "DataLogging", you are basically tuning 'Blind'. This means you are making changes to
your maps, loading them into the ECU, driving the car and datalogging,
reading the Datalogging, making adjustments to the maps again, loading
them back into the ECU and datalogging again, then reading the
Datalogging to see if all is well. With luck everything is now fine. If
not, start over again! At it's best, it's very
tedious a procedure and requires baby steps or you could harm your
motor. Become too aggressive and you blow your motor! "Live Tuning" is where you are able to see your
maps on a lap top and make adjustments to the maps in "Real Time", in the ECU while driving. This way
you are dealing with immediate data, not historical data and can avoid
any problems immediately, such as running too lean while flat footing
it down the road and popping your engine, while Datalogging. Tuning for real-world conditions is pretty much
impossible on a Dyno. Remember dynos are 'tools', typically inside and
the air flowing inside is never going to be as exact as when you're
driving down the road. So if you must Dyno Tune, there has to be
margins of safety built into the changes you are making. In many respects, using a
G-TECH Pro would provide you with a more real world view of the
benefits of your car and any mods, without racing the xxxx out of your
car. On a positive note: Dyno FYI, issues to consider
about Dynos. For those situations where tuning is required, we offer 'Real World
Road Tuning', where we tune the car on the road!
As we hear more, it
will be posted. Keep coming back!
Please remember they
are only ramblings we hear. Take them for whatever value you get from