Frequently
Asked Questions:
With the turbo so far back,
don't you get a lot of turbo lag?
No, our turbochargers are sized to operate at
this remote location. Just like any turbocharger,
once the turbo is up to temperature and in the
rpm range for which it was designed to operate.
The boost comes on hard and fast. All of our systems
will produce full boost below 3000 rpm.
If you were to take a conventional turbo and place
it at the rear, you would have lots of lag and
consequently, our turbo wouldn't work properly
if mounted up front.
Doesn't
water get into your engine with the filter mounted
down low?
No, even under very wet conditions the filter
sheds most all water. Under wet conditions the
throttle position is usually very light because
of traction issues so the engine is taking in
very little air anyway. However, we do rigorous
testing with our truck systems because many off-road
wet conditions may require full throttle. Even
under extremely wet conditions, where the water
is flying clear over the top of the vehicle plowing
through deep puddles, we have never had a water
related drivability problem with any of our kits.
However, if you were to completely submerge the
filter, you would draw water through the filter
and into the intake tubing.
Without a muffler, how does the vehicle sound?
The turbo does an amazing job of muffling sound.
Most people think it sounds like a Flowmaster.
You can add a high flow muffler to the system,
but most of our customers like the performance
sound with just the turbo.
How long does it really
take to install your system?
Average install times are 4-6 hours for first
timers. Our install techs usually spend 3-4 hours
for a typical install.
With so long of intake and exhaust tubes, doesn't
it take a while for the boost to build up?
No, our intake tubing volume is about the same
as most conventional turbo setups that are running
a front mounted intercooler, and less than many
of them that run large intercoolers. We aren't
talking about a small compressor filling up a
large air tank, we are talking about a huge compressor
filling up a very small volume which only takes
a fraction of a second. Our systems compress the
intake tubing in about .05 seconds. So much for
turbo lag...
How is the turbo lubricated?
Our system uses the engine's pressurized oiling
system to supply the turbocharger. This pressurized
oil travels approximately 12 feet through tubing
which dissipates heat out of the oil just like
an oil cooler to provide cool oil to the turbocharger.
The oil is then scavenged from the turbocharger
via an electric oil pump which returns the oil
to the engines valve cover through another long
length of tubing which again cools down the turbo-heated
oil before entering the engine.
Is a turbo timer or pre-lube device necessary
with your system?
No, the turbocharger temperatures on our systems
are approximately 500F cooler than turbo temps
on conventional systems so the oil doesn't get
hot enough to carbonize in the turbocharger bearings.
With the turbocharger located where it is exposed
to ambient air rather than trapped under the hood,
the turbocharger quickly cools down as well so
cool down times after runs don't need to be 5
to 10 minutes. As far as pre-lubrication, our
system incorporates our "Wet Start"
system which keeps oil at the turbo inlet at all
times so that the turbocharger has an instant
oil supply at start up.
How much boost can I run with this turbocharger?
The basic kits run 5-6 psi boost. The turbocharger
on our basic kits is capable of producing higher
boost of 15+ psi. However, in most cases a larger
turbocharger would be more efficient at higher
boost levels. There is more to running higher
boost than just turning the boost up. You must
also be able to meet the fuel demands of higher
boost as well as set up the engine to handle the
extra power so that you don't cause mechanical
failures with the engine.
Higher boost will also raise the "boosted"
compression ratio of the engine that will require
higher octane fuel to prevent detonation. Bottom
line - Don't crank up the boost unless you have
done your homework and made the necessary modifications
to handle the boost.
We handle high
boost applications on an individual basis to ensure
that you are getting the right turbocharger setup
for your specific needs.
What happens
if something goes wrong with the oil pump?
In the event of an oil pump failure, the system
is equipped with an alarm which will sound inside
the vehicle to warn you that you are experiencing
an oil system problem so that you can prevent
any damage to the turbo or engine. This alarm
is designed to warn you of any problems with the
oil pump well before a complete shutdown of the
pump.
With the turbo located under the fuel tank
on the Camaro, doesn't it heat up the fuel?
We have done temperature testing on this issue
and found that the factory heat shield does a
great job of preventing the transfer of heat into
the fuel tank. The temperature of the air on top
of the heat shield only rose about 15F higher
than ambient temperature with a full boost run.
The only time you might see an increase in actual
fuel temperature would be during extensive stationary
dyno testing when there isn't any substantial
airflow around the turbocharger and rear of the
car. We recommend running a full tank of gas for
any dyno testing.
What type of tuning is needed with this setup?
Our low boost turbo systems are designed to run
without the need for additional tuning. However,
there are substantial gains available from tuning
and tuning is essential if you want to run higher
boost. We sell the Diablo Predator for GM vehicles
and Unichip for Toyotas.
Is their any way I could
upgrade once I build a shortblock to handle more
boost or will I have to buy an entire kit again?
That is the beauty of the turbocharger. If the
engine is built to handle it, power can be gained
by simply turning up the boost. The turbo kit
does not need to be upgraded. However, there are
several turbocharger upgrade options which will
be more efficient at higher boost levels. The
stock turbo is capable of 15 psi boost with some
loss in efficiency. We recommend putting on the
turbo that best suits your end result goals from
the start of your project. This will remove the
need for a turbo upgrade later. Then when you
are ready for higher boost, just flip the switch
on our dual stage boost controller to "HI"
and your upgrade is that easy.
Wouldn't twin turbos work better?
In theory, twin turbos spool up faster because
they have less "MASS" to their rotating
parts (the compressor and turbine wheels). However,
this difference isn't huge and most likely won't
be felt in the seat of your pants. Twin turbos
do, however, cost a lot more in parts, labor,
and plumbing. This money would be better spent
in upgrading the turbocharger to a higher efficiency
turbocharger with Ball Bearings. This will produce
better HP and quicker spool to go along with it
without the extra costs and work associated with
twins.
Do I need to put headers on to optimize the
turbo system?
No, the extra expense and work to install aftermarket
headers isn't necessary. Headers are designed
to eliminate backpressure in the exhaust system
and facilitate exhaust scavenging and flow on
normally aspirated engines. Turbocharged engines
work on slightly different principles. Namely,
there is exhaust "Pressure" between
the cylinder heads and the turbocharger because
the turbocharger is the smallest diameter orifice
in the exhaust system. The turbine housing gets
smaller in diameter to increase the velocity of
the exhaust gasses before they hit the turbine
wheel. This is how you get 100,000 rpm wheel speeds.
Turbocharged exhaust gas pressures can see as
high as 30+ psi on high boost applications. So
spending money on higher flowing exhaust components
designed to lower exhaust backpressure is usually
a waste of money. This money would be better spent
on an upgraded turbocharger which would produce
more efficient boost with less backpressure or
just spending the money on upgrading the engine
and fuel system to handle more boost.
Will a bigger
cam make more power with a turbo?
Cam choice in turbo applications is critical.
In many cases, a stock cam will work better than
a typical "race cam" that would work
well with an aspirated engine. What you want to
avoid is the "intake and exhaust valve overlap".
This is the time that the exhaust and intake valves
are open at the same time. In aspirated engines,
this theory facilitates the scavenging of all
burnt exhaust gasses from the cylinder after the
power stroke so that an "uncontaminated"
and 100% burnable charge fills the cylinder on
the next cycle which produces maximum power. Some
of this condition can be tolerated with supercharged
applications as it merely blows some of the boost
out with the exhaust. However, on turbocharged
applications (many people believe that the boost
also is just blown out with the exhaust) however,
the opposite is truer to the case. With exhaust
pressures sometimes exceeding boost pressures,
the exhaust can flow into the cylinder and into
the intake manifold during this overlap time which
contaminates the intake charge, decreases HP,
and can cause pre-ignition as well. Also, most
cam applications begin flow at .050" of valve
lift. On forced induction systems, there can be
substantial flow below this amount of lift because
of the higher pressures behind the valves.
So, if in doubt go smaller on your cam rather
than larger. Go wider on lobe separation angles
(114 degrees is usually safe) Smaller on durations
(stick around 220) and check with the cam manufacturer
to make sure that it is a good "turbo"
cam and not just a generic supercharger/turbo
cam. A good option is to install a set of higher
ratio roller rockers on your stock cam. Better
pushrods and stiffer valve springs will help as
well because boost and cylinder pressures will
be way higher than stock. Stiffer springs will
help close the valves against the pressure of
incoming air and stronger pushrods will help open
the exhaust valve against the increased cylinder
pressures.
How much octane
do I need to run a turbocharger?
We recommend running Premium gasoline on vehicles
that are running 5 to 12 psi.
What is the difference between a Supercharger
and a Turbocharger?
First of all, there are a couple different types
of superchargers (positive displacement and centrifugal).
The most popular these days seems to be the centrifugal
supercharger which is basically the same design
compressor as a turbocharger compressor. These
compressors both increase in airflow and efficiency
with impeller RPM's. (Which basically means that
doubling the impeller RPM doesn't double the airflow,
it increases the air flow exponentially.) So in
the case of the supercharger, where it is directly
run from a belt and pulley attached to the crankshaft
which ties impeller RPM in a direct ratio to crankshaft
RPM, the boost increases linearly with engine
RPM.
Example: If you want to run maximum boost of 8
psi, you would gear the drive pulleys to produce
8 psi at maximum engine RPM. Lower RPM's would
produce less boost linearly. I.E. 8 psi @ 6000rpm,
5 psi @ 4500rpm, 3 psi @ 3000rpm, and 2 psi @
2500rpm.) Thus, maximum boost is only attained
at maximum engine RPM which only lasts for a fraction
of a second then when the engine shifts to the
next gear and the RPM's drop back down, so does
the boost which then builds up again with increasing
engine RPM's.
Supercharged engines
produce good "maximum rpm" dyno numbers.
Don't be fooled by maximum dyno numbers. Unless
you have a "Snowmobile Clutch" in your
vehicle which allows your engine to stay at peak
RPM all the way down the track, what you need
is "Usable Power" which comes from sustained
boost levels across the entire RPM range. This
is where the Turbocharger outperforms the Supercharger.
By using exhaust
gasses to drive the turbocharger you gain two
benefits: First is that you don't pull Horsepower
off of your crankshaft to drive the compressor
(Just like you wouldn't replace your electric
fan with a large "belt driven" fan or
run your A/C down the track because these devices
take Horsepower to run as does a Supercharger
compressor capable of pumping 50 pounds of air
per minute @ 8 psi). Secondly, since the turbocharger
is driven by exhaust gasses, the more air the
turbocharger puts into the engine, the more exhaust
gasses the engine produces, which in turn produces
more turbocharger RPM's and air discharge or "Boost".
So, to sum it all up, the turbocharger can go
from literally "No Boost" to "Full
Boost" in a fraction of a second because
of the compounding effects of the Compressor Efficiency
increasing with impeller RPM's and the compounding
effects of the Exhaust Gas increasing exponentially
with increasing Boost.
So if you are
only concerned with Peak Dyno Numbers the supercharger
does produce good "Peak" numbers, but
if you want "Full Boost" across a broader
RPM range along with those high "Peak"
Dyno numbers. The Turbocharger is a better solution.
If I want to
run higher boost will I need a bigger wastegate?
Running higher boost doesn't require a larger
wastegate, in fact in most situations running
lower boost requires a larger wastegate than high
boost applications. The wastegate flows exhaust
out to lower the boost level. The lower the boost
requirements, the more exhaust has to flow through
the wastegate valve. Running higher boost will
require a stiffer wastegate spring or the use
of a boost controller. Our Electronic Dual Stage
Boost Controller works very well and gives you
the option of Hi or Low boost at the flip of a
switch.
What about ground clearance with the turbo
down low on LT1?
Ground clearance hasn't been a problem as all
of the kit sits higher than the stock equipment.
The lowest areas are near the wheels which give
it added clearance going over bumps.
How does your dual stage
boost controller work?
The electronic dual stage boost controller lets
your wastegate operate normally on the "low"
setting on the switch. When you flip the switch
to "high" the system adds pressure to
the other side of the wastegate diaphragm. You
can choose how much pressure is added, 0-5 psi
or 0-15 psi. The "high" setting is adjustable
and once set at your predetermined amount, will
give you that much more boost above the "low"
setting. If your wastegate is 5 psi, you'll run
5 psi on the low setting. If you set your controller
to 3 psi, when you flip the switch to "high"
you will have 8 psi boost.
This system can also be used to "arm"
the methanol injection or water injection system
so that it only runs on "high" when
you need it and doesn't run out of fluid driving
around town. System can also be set up so that
when the methanol system isn't working (if it
runs out of fluid) the boost can be defaulted
back to "low" boost as to not damage
the engine.
Don't
turbos have to be really hot to work properly?
Putting a torch to your turbo and getting it hot
doesn't produce boost. What produces boost is
airflow across the turbine which causes the turbine
to spin. If turbochargers required very high temperatures
to produce boost, Diesel trucks and Methanol Race
cars wouldn't be able to run turbos. However,
each of these "Low Exhaust Temperature"
vehicles work very well with turbochargers when,
like any turbo application, the turbocharger is
sized correctly.
In a conventional, exhaust manifold mounted turbocharger
system, the extra heat causes the air molecules
to separate and the gas becomes "thinner"
because of the extra space between the molecules.
This extra space increases the volume of air but
doesn't increase the mass of the air. Because
the volume is higher, the velocity of the gas
has to be higher to get it out in the same amount
of time.
By mounting the
turbo further downstream, the gasses do lose heat
energy and velocity, however, there is just as
much mass (the amount of air) coming out of the
tailpipe as there is coming out of the heads.
So you are driving the turbine with a "denser"
gas charge. The same number of molecules per second
are striking the turbine and flowing across the
turbine at 1200F as there is at 1700F.
Front mounted
turbos typically run an A/R ratio turbine housing
about 2 sizes larger because the velocity is already
in the gasses and the volume is so big that the
turbine housing must be larger to not cause a
major restriction in the exhaust system which
would cause more backpressure. With the remote
mounted turbo, the gasses have condensed and the
volume is less, so a smaller A/R ratio turbine
housing can be used which increases the velocity
of the gasses while not causing any extra backpressure
because the gas volume is smaller and denser.
Sizing is everything
with turbos. There is more to sizing a turbo for
an application than cubic inches, Volumetric Efficiency,
and RPM ranges. A turbo must also be sized for
the exhaust temperatures. A turbine housing sized
for 1700F gasses would have lag if the gasses
were 1200F. This is why turbo cars have lag when
they are cold and not warmed up yet. Both systems
work well if sized correctly.
Isn't there
a huge pressure drop with such long intake tubes?
No, if the pipes were 100' long there would be
but we are only talking a few extra feet and we
size the charge air tubing so that it will flow
without a large pressure drop. We typically will
get about 1/4 to 3/4 lb difference between the
turbo compressor and the intake manifold, which
is nothing compared to the pressure drop across
an intercooler. With high boost applications,
these numbers will increase slightly.
What type of coating
is on the pipes?
All of the intake pipes are HPC non-thermal coated.
HPC coating is one of the few coatings that doesn't
lessen the heat transferring characteristics of
the metal. For more information visit - http://www.hpcoatings.com/
If water hits the hot
turbo, will it crack?
Seems like it might when you first think about
it, however, when I asked the Garrett engineers
this questions they just laughed. There is a big
difference in water splashing on a hot turbo and
submerging it in enough water and fast enough
to really cool it down fast. Both the new turbocharged
Vette systems and the new Porsche systems sit
the turbo down low and exposed to water and anything
else that goes under a car.
Plus, our turbos just don't get that hot and when
weather conditions are such that there is a lot
of water around, you can't push enough boost to
get the turbo hot anyway because you'd just spin
the tires.
Aren't the
stock manifolds and exhaust system restrictive?
For certain normally aspirated or supercharged
systems, stock exhaust is somewhat restrictive
and can cause backpressure in the system and rob
HP. However, with turbocharged applications, the
turbocharger is the biggest restriction in the
exhaust system. All of the exhaust gasses (except
the ones that are vented out the wastegate) pass
through the turbine housing. The inlet hole in
the turbine housing is about 2"x3",
however, as it scrolls around the housing it gets
smaller and smaller causing the exhaust gasses
to increase in velocity. At the smallest point
where the gasses exit and hit the turbine wheel,
the hole is no bigger than about 1" in diameter.
This tiny hole will create backpressure in the
entire exhaust system prior to the turbo and clear
back to the exhaust valves.
So sticking larger diameter pipes and high flowing
headers doesn't make lots of sense when you have
a 1" tailpipe hole. These additions probably
won't hurt, but the money would be far better
spent elsewhere. Our Turbo Camaro put down 522
RWHP and 620 RWTQ through the same restrictive
exhaust manifolds and I-pipe that came stock on
the car. Turbocharging is very different than
Supercharging or Normally aspirated. That is good
news because you don't have to spend the extra
money on the exhaust system!
Will
your methanol injection setup work with any turbocharged
car?
Yes, our Methanol System is designed to work with
any turbocharged, supercharged, or even Normally
Aspirated engines. We typically will see 100F
intake temperature drops with this system. The
Octane requirements are lowered, the cylinder
temperatures are lowered, and the exhaust temperatures
are lowered. It's all good! We installed our Methanol
System on a Supercharged Viper. We lowered his
intake temperatures from 220F down to 100F. The
extra fuel allowed him to lean out his injector
map and the water cooled the cylinder temps down
enough to add 4 degrees of ignition timing. He
lowered his ET from a 10.8 down to a 10.6. He
raised his MPH from 134 to 140 MPH!
How does your methanol
system work?
Unlike many methanol or water injection systems
on the market. Ours doesn't just turn on at a
predetermined boost level and dump fluid in, causing
flooding at lower rpms and part throttle positions
and leaning out at high rpms and WOT.
With our Sequential Methanol System, you inject
your extra fuel and/or water mixture at the same
rate as your stock fuel injectors do. The more
throttle you give it, the more fluid goes in.
The higher the rpms go, the more fluid goes in.
The system is adjustable as to when it kicks on,
and also adjustable as to the gallons/minute flow
rate, as well as tunable with the Methanol/Water
ratio. It is simple to install and easy to adjust
and tune for optimum performance. Combine this
with our Electronic Dual Stage Boost Controller
and set it up to only run on High Boost. You can
also set it up so that if the Injection shuts
off for any reason, such as it runs out of fluid,
the boost controller will default back to low
boost. It is a definite "Must Have"
for any turbocharged or supercharged vehicle.
How
efficient is the intercooling from your longer
piping?
We typically get at least 50% Intercooler Efficiency
numbers from our systems and some of the truck
systems which have better exposure to cold air
are even better. Combine this with a pressure
drop of only about 1/4 to 3/4 psi and it makes
for very good numbers.
Testing on our LS1 prototype produced the following
results:
Turbo outlet temps
at 5 psi boost were 175F and intake temps were
115F which is about 52% efficient.
Turbo outlet temps
at 8 psi boost were 225F. This is a 50F increase
with only 3 psi added to turbocharger boost. Even
most large, expensive intercoolers have a pressure
drop of at least 2+ psi. This causes the turbocharger
to have to work harder to create 2-3 or even more
psi to force the air through the restriction of
the intercooler to get that much less boost into
the manifold.
So in comparison,
with our intercooler efficiency of 50%, combined
with virtually no pressure drop, yields in all
actuality, a better intercooler efficiency number
than the 50% because with a standard pressure
drop the temperature difference would be 225F
at the turbo and 115F at the intake manifold which
would require nearly 70% intercooler efficiency
to produce.
How much cooling
is provided by the Methanol system?
The amount of intercooling provided by the Methanol
Injection System is somewhat varied by how much
methanol you are injecting. Here are results of
testing we did on the LS1 Camaro:
At 5 psi without methanol, the turbo outlet temps
were 175F and intake temps were 115F which is
about 50% efficient.
At 8 psi with
the Methanol Injection System running, turbo outlet
temps were 225F and intake temps were 70F. This
is 94% intercooling efficiency. All this without
the cost and installation problems that go along
with trying to put a large intercooler into the
front of your vehicle.
Where do you
mount the Methanol Injection tank?
The tank can mount just about anywhere. We usually
stick it in the rear and mount the pump there
also just for better weight transfer. FWD's would
probably want it up front though. You don't want
it to be exposed to a lot of heat though as the
Methanol boils at about 150F. We also have several
tank sizes to better accommodate individual needs.
What intake air temps
do you get?
Intake Air Temps are a function of several variables.
Ambient temps and Boost levels drastically affect
IAT's. Most of our turbo systems get at least
50% Intercooler efficiency with 1/4 to 3/4 of
a pound pressure drop. The actual numbers vary
with our different kit applications as different
vehicles have different air flow characteristics
and lengths and diameters of tubing. In most cases,
our 50% efficiency is comparable to about 70%
efficiency with a 2-3 psi pressure drop across
an intercooler.
Will this system work with my modified stroker
and high stall converter?
Yes, the system will work with different engine
sizes and converter options. However, we handle
these modified cars on an individual basis so
that the proper size of turbocharger can be installed
with the kit. We have several turbocharger options
that we can tailor to suit individual needs without
adding extra costs to the kit. We also offer upgraded
turbochargers for those who want to get maximum
efficiency and HP.
Doesn't heat create the
velocity in the exhaust gasses to spool the turbo?
No, heat doesn't create velocity. Heat creates
volume. If you look at any of the physics laws
for gasses, you will find that pressure and volume
and heat are related. PV=NRT is a popular one,
The V isn't for velocity, it is for Volume.
The turbine housing is what creates the velocity.
The scrolling design that reduces the volume of
the exhaust chamber as it scrolls around causes
the gasses to have to increase in velocity and
pressure to maintain the same flow rate.
Hotter gasses
have more volume, thus requiring a higher A/R
which in effect means that it starts at say 3"
and scrolls down to approximately 1". Lower
temperature gasses are denser and have less volume,
so they require a lower A/R housing which would
start at the same 3" volume, as the turbine
housings use standard flanges, and scroll down
to say 3/4".
Now if you were
to reverse the housings in application, the conventional
turbo would spool up extremely quick, at say around
1500 rpm but would cause too much backpressure
at higher rpms because the higher volume of gas
couldn't squeeze through the 3/4" hole without
requiring a lot of pressure to force it through.
On the reverse side, the remote mounted turbo
with its cooler denser gasses, wouldn't spool
up till say around 4000 rpms but once spooled
up would make efficient power because it doesn't
require hardly any backpressure to push the lower
volume of gas through the larger 1" hole.
