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Turbo I to Turbo II conversion
This article deals with converting pre-1988 Chrysler
turbo 1 cars to turbo 2 status. This article also specifically deals with
converting a 1985 turbo 1 L-body (ie Shelby Charger, GLHT) but will apply
to other bodies and years and known differences will be noted. Also I assume
no resposiblity as to the validity of this information, and assume no responsibility
for any damage or harm that may come to you by using this information.
And as always when working on an automobile certain safety procedures must
be followed. This article is written as my experince with converting my
1985 Shebly Charger with the knowledge mostly gained from those generous
souls on the SDML (Shelby Dodge Mailing List - www.sdml.org).
The most popular reason for doing this conversion is
the addition of an intercooler. An intercooler could be added to a 1988
and later turbo 1 quite easily becuase of the revision of the intake design
lends itself much better to intercooler tubing. If you notice the outlet
of your early turbo 1, the turbo and the inlet of the intake they are pointing
directly at each other with no room to run tubing in between. It is possible
to cut off the inlet to the intake and re-weld it pointing forward in order
to add the intercooler tubing but the later style intake used in the turbo
2 conversion flows much better and more evenly between ports. The reason
people like to add intercoolers to their turbo cars is that it allows higher
levels of boost pressure to be safely run in the engine and thus more power
put out because the more air molecules in the combustion chamber (ie higher
pressure and more dense from cooling) the more expansion occurs. The intercoooler
allows this because the boost pressure safely run is limited by detonation
within the engine or high combustion temperatures, both of which will ultimately
ruin pistons as well as other internal components. The intercooler prevents
this by cooling the compressed air coming out of the turbo before it goes
into the head of the engine.
While it may seem that one could just add the new intake
and run tubing to the intercooler, you will find several small porblems
that add up to warrant doing the complete conversion.
1. The new intake is from a blow-through type system
where the throttle body is after the turbo instead of before like you may
have now (suck-through system).
2. The new intake with its longer runners, hits the early
turbo one exhaust manifold (solved later in article).
3. Since the old intake did not flow evenly amoung cylinders
some injectors are fired richer than others by the computer to compensate.
4. The electronics changed in 1986 to use a new distributor
( this only applies to 1984 or 1985 turbo cars).
5. The wiring is slightly different between the new intake
setup and the older one.
1. Along with new intake you need the new style throttle
2. Get the later style exhaust manifold, or use your
own and grind down the section where the intake and exhaust hit. Note this
is the only difference between the early TI and the later TI/TII manifolds
is the later is notched appropriately).
3. Use a TII computer
4. If you have a 1985 distributor, get the new shorter,
wider, 1986 distibutor and internal elctronics (hall-effect pick up).
5. Get the new end connectors for the TPS (throttle position
sensor) and AIS (automatic idle speed) motor
Intake: 1988 or later turbo intake off any model
This can be a one piece
or two piece intake (off Shelby TII or Daytona TII cars). The two piece
intake is much rarer so I would advise using the one piece, while tuned
for slightly more low end, is much more abundant.
Injectors: stock TII injectors or mopar performance
While you could use your stock injectors keep in mind
that the computer you will be using is calibratred for the TII injectors
that flow more and thus you would have to keep an eye on your air to fuel
ratio (oxygen sensor guage) to make sure that you don't run lean at higher
boost. 804's may run richer than the sotck injectors allowing more boost
but that is up in the air some respected individuals have said that Chrysler
changed the flow of the injector and is now the same as stock TII injectors.
Fuel Rail: You need the fuel rail and pressure regulator
that goes with the intake you got
Distributor: If you have a 1985 car get a 1986
The turbo elctronics changed in 1986 so if you are intercooling
a 1985 turbo I get a 1986 turbo distributor and the internal pick up. L-body
turbo 2 cars, 1986 and 1987, both use 1986 electronics. If you have something
like a Daytona I belive that the electronics may have been changed in the
distributor again in 1987 so I would suggest a 1987 distributor.
Throttle Body: 1988 and on turbo blow through intake
or 3.0 - 3.3 V6 multi-point injection throttle body
You can use any blow through throttle body. They are
of 46mm diameter. You will also need the AIS
and if possible the TPS that goes with the throttle body. The earlier TPS
is the same electronically but if you wish to use the later
wiring connector the new TPS is needed. The new AIS is a four wire
system instead of two and the wiring will be addressed later. You can also
use the throttle body off a multipoint injection Chrysler 3.0 or 3.3 V6
which is of 52mm diamater. The TB can be found more easily on early 3.0's
(1989?) and all 3.3's I think. This is the TB used in the Super 60 system.
It will yeild more power at high rpm and high boost levels but may reduce
your fuel efficiency because of lower port velocity. The intake throat
must be opened up a bit to accomodate the larger TB butterfly. This will
be addressed more later.
Exhaust: 1988 and on Turbo I/II exhuast manifold,
or grind your existing one.
If possible pick up the later style exhaust manifold,
this will make your job easier. If you can't find the later style or don't
want to spend the money on it, it is possible to modify your existing manifold.
The only real difference between the two is that the later has a notch
in it to clear the new style intake. You can simply use a bench grinder
to notch your exisitng one. More discussion will follow on this later.
Computer: Turbo II computer
Dependent on what body car you are converting your computer
options may change. For L-bodies you can use the 86-87 GLHS computer with
the least effort. It only requires that you add
two wires to the red wiring harness connected to the computer. I will
address this specifically later but it is for the new two wires on the
four wires AIS. These computers may be hard to come by so I would suggest
picking up a GLHS Stage II computer from
Mopar, they only run $130 from the place I got it. The other choice is
to run the CSX Stage II or stock type computer ( I believe the Daytona
may use this computer too). This requires the addidtion of the two wires
as above and moving two wires to different cavities on the connector. The
advantage of this computer is that it has more on RAM and I believe that
it makes faster calculations as well. For other body styles, I believe
that the Daytona or CSX Turbo II computer should be used or use the CSX
Stage II computer.
Intercooler: Stock Turbo
II/III/IV intercooler, aftermarket incooler, or Ford, Isuzu, Dodge
If you want to go for that stock look, pick up a stock
turbo II/III/IV intercooler and radiator. These may be installed into a
turbo I with only minor modifactions to mount the radiator. Or just pick
up any stock mopar turbo II/III/IV intercooler, a Spearco or other aftermarket
intercooler, or other make like a Conquest or Volvo intercooler and mount
it up front in the fascia where it will get the most air flow across
it like I am doing. Warning some intercoolers may be better than others.
Mopar intercoolers are a good choice but the Conquest intercooler is better
if you put bigger hose barbs on the end tanks. If you do mount it up front
you will have to make your own tubing. But this is not difficult given
2.25 inch exhaust pipe and radiator hose to make it custom to where ever
you decide to mount it. Remember the more air that goes through it, the
cooler the air inside gets, and the more power you'll produce.
Wiring Connector: 1988 and on Turbo I/II throttle
body connection and O2 wiring connector or get GM wiring connectors at
NAPA, Car Quest, or other parts outlets
By far the easiest way to add the wiring connectors for
the Turbo II blow though throttle and three wire O2 sensor is to pick up
these off a salvage yard car. The Turbo II has a three
wire O2 sensor. The new two wires just go to ground and ignition 12
volts. While it is not essential to have the three wire oxygen sensor,
it would be beneficial to use it since it has an internal heater and will
reach operating temperature quicker giving more consistant readings, better
emissions, and better cold fuel efficiency. If you cannot find a salvage
car to pull these connectors off, you can buy the assembled harnesses from
Turbo: Turbo II turbo or modify existing turbo
The inlet and outlet of early turbo 1 turbo's points
straight up, this does not lend well to intercooling since you will have
to make sharp turns to point the tubing towards the front of the car. However
the compressor housing may be turned forward,
so there is no need to get another turbo. Note on turbochargers:
The Garret turbo are larger and will flow more air at high boost while
the smaller Mitsubishi turbo has less turbo lag and will spoll quicker.
Choose turbo's by your planned top boost pressure.
Airfilter: Turbo II or late Turbo I airbox or Cone
style universal filter
If you are going for a stock look, pick up a Turbo II
or late Turbo I airbox and tubing. If you want maximum performance then
I would go with a open element high flow filter perferably ducted with
cool air. This is what I will be doing.
Blow-Off Valve: You can get away without picking
up a BOV, but if you want the most life out of your turbo then I would
suggest getting one. Stock Chrysler BOV's will hold without leaking until
about 15 psi and only cost $15 from the dealer. Early Eclipse and Talon
BOV's (90-95) will hold until about 20 psi I believe. They
use a metal diaphram so they won't swell and burst under high boost.
Enough already! Let's get to it.
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