A quick and dirty guide to all the turbo system components needed
to make ~220whp on a Saturn 1.9 L engine
Relatively speaking turbo charging a Saturn is not that difficult.
Time and time again people have proved that with a limited budget
one can build and install a reliable turbo system on their daily
driven Saturn. These turbo systems have differed in many ways mostly
depending on the amount of power desired and the working budget.
In this article I will be covering several different turbo system
components to help tailor the system to suit your needs.
The very first step in your quest for power is deciding how much
you want. Starting with a goal you can add the components to achieve
your desired horse power desires. Be realistic with your goals,
remember the more power you desire the more your project will cost.
Also, the more power you make the more parts you will break; guaranteed.
This beginner's guide will cover horsepower levels to about 220whp
which is by far the most economical and easiest to achieve. Every
major component will be addressed with additional information allowing
you to mix and match parts or just follow our sure fire recipes
at the end of the article. So let's get started!
To save money a stock Saturn engine can be used as a turbo engine.
The stock internals and high compression ratio will limit the amount
of maximum boost but 7psi should be attainable on a t3 and a bit
more with proper tuning. At 8psi you should se somewhere in the
range of 200-215whp depending on the tuning. None-the-less this
is a fun ride for cheap.
Saturns made from 1991 to 1997 possess a return fuel system which
means that the fuel pump runs continuously at full capacity and
any additional unused fuel is returned back to the gas tank via
the return fuel line. These fuel pumps and systems have been proven
up to 300whp but I do not recommend that you try for more than that
on the stock pump. The take home message here is that if your power
goal is less than 300whp you do not need to change the stock fuel
Starting in 1998 Saturn switched to the returnless fuel systems.
The returnless fuel system is controlled by the PCM. As fuel demand
is increased voltage to the fuel pump is also increased. At this
time there is limited information on the potential of these fuel
systems. There are a few work around options though like inline
fuel pumps (can be noisy) or converting the returnless system to
a return system. Check the forums for the latest information on
turboing with a returnless fuel system.
The stock fuel line diameter and the fuel rail are sufficient to
support over 300whp but if you're shooting for anything above 300whp
it's a good idea to install a larger fuel rail.
There are quite a few injector sizing equations out there but it's
safe to say that you will be looking to purchase injectors in the
35-45 lbs/hr range depending on your goals. Make sure that you choose
the correct style and impedance. Saturn's can use any injectors
that will fit GM or Ford cars.
Injector size is just as important as what you are using to control
A raising rate fuel pressure regulator, although the easiest to
install, is the least desirable. It's difficult to adjust and tune
properly and more times than not you run into excessive fuel pressures.
If you do use this method make sure that you do not exceed 80psi
at maximum boost as this could lock the injectors closed. Also,
this method of fuel delivery should only be used with smaller t3
or t25 turbos to ensure that adequate fuel is being delivered. This
method has been used on a lot of other cars including Saturns. The
problem is two fold. First there is the excessive fuel pressures
i.e. the more you turn up the boost the higher the fuel pressure
and two fuel is delivered on a liner curve while a boost curve follows
a steep increase once under full boost. This method works just be
Another method is the SDS or extra injector controller. This is
a bit more difficult to install but relatively easy to tune. This
setup has been proven to reach 300whp but at the same time blown
a few engines in the process. Using stock injectors with this system
will insure stock idle quality and plenty of fuel once boost kicks
in. There is limited amout of tuning needed; just two knobs. How
much simpler can it get? Words of caution, the extra injectors are
your only defense against a lean combustion condition. If an injector
locks or your vacuum line comes off you will be replacing your engine.
When it works; it works well, just be sure to have everything secured
The mega squirt is still the most flexable option. This requires
the most wiring and setup of any of the previous fuel controller
but it is far more tunable. You will be able to extract more horsepower
from this fuel system than any others short of a full stand alone.
Also, the cost tends to be cheaper than the SDS controller. Please
do not underestimate the tuning that is required with this system.
This is basically a stand alone fuel system so you control all aspects
of fuel delivery. You will want a wide band O2 sensor to get the
best results. Make sure you have another car to drive so that you
can take your time and tune your system right. Check the forums
for the latest information on this system.
There are other extra injector controllers on the market that are
laptop programable. These offer the ease of setup like the SDS system
along with greater tunability similar to the mega squirt. I have
been looking into these controllers which can be adjusted on rpm
and map pressure. This type of tuning holds a lot of promise but
it will take more research and actual use before it's given a thumbs
There are many choices when it comes to turbos. You can stare at
the compressor maps all you want but when it comes down to it there
are only two basic choices for a Saturn; a T3 or a T3/T4. The T3
should be a super 60 trim with a .48 or .63 hot side. This is a
good choice that should get you in the 220whp range. Look for the
power to die out before you hit your rev limiter but the spool up
around town should make up for the lack of top end. This turbo will
be good for 200-220whp. If you're looking for more than that a T3/T4
with a 50 cold side and a .48 hot side should net you 300whp with
very good tuning. Be sure to beef up the rest of the system to keep
up with the additional horsepower demands.
I personally like the idea of a .63 hot side on smaller turbos.
This will help soften the torque curve a bit allowing for better
traction. You will loose torque down low switching the a larger
Save your money and use an internal wastegate. If you're shooting
for 220whp there is no need for an external wastegate. A t3/t4 system
can benefit from an external wastegate and if you can take the noise
you can dump to atmosphere for some extra horsepower. A 2 1/4"
downpipe is plenty for a t3 turbo you could even use a 2" if
you wanted. Sure bigger is better but you can save some cash using
a smaller downpipe and it's easier to fit under the car. Also, with
a smaller turbo and stock internals you won't be pushing the kind
of volume of air which facilitates a bigger downpipe. Keep it simple.
The easiest and cheapest way to have a reliable system would be
to use a log style manifold. These manifolds tend to be heavy duty
and will last for a very long time. The log style will not be a
big factor in reducing horsepower unless you are shooting for really
high numbers. I have seen log style manifolds make over 350whp on
Most Saturn turbo cars have used manual transmissions. Clutches
that can handle the extra power are readily available through several
manufactures. The stock clutch should hold to about 200whp anything
above that and expect slipping and faster wear. Automatic transmissions
should be able to hold about 200whp but they will slip more than
the manual. If you are looking to make big power and you have an
automatic than a manual swap is in your future. There is just no
one making automatics that will hold a lot of power.
One of the weakest points of the Saturn transmission is the differential
pin. It is a press fit from the factory and under high stress this
pin dislodges and destroys the transmission. Disassembling the transmission
and welding the pin in will keep it from flying out of the differential.
Consider this a must have. I highly recommend that you do this mod,
you don't want to be on the side of the road with a busted tranny
As a side note, the hot ticket when turbo charging your DOCH engine
is using a SOHC transmission. The gear spacing is far better for
turbo charging and you will get the economy from the high ratio
The stock radiator, although small, will work especially if your
horsepower goals are less than 250whp. If your target is 300whp
than an upgrade in cooling capacity should be considered. There
are a few companies that make direct bolt-in aluminum radiators
but they are expensive. If you have some fabrication skills I suggest
purchasing a universal fit radiator from Jegs or Summit and make
the mounts. You will save some cash and get a greater cooling capacity.