Isuzu Trooper Frequently
by jesse stevens
The Isuzu Trooper was introduced in 1984. The '84 had a 1.9l Carbureted
motor. In '85 The Trooper had a 2.0l Carbureted engine. From '86-'87 the
Trooper had the 2.3l Carbureted engine or the 2.2l diesel. The '88 had the
2.6l MPFI engine. The '89-'91 Troopers had either the 2.6l MPFI 4 cylinder
engine or the 2.8l TBI v-6. The '92-'98 Trooper had the 3.2l MPFI v-6 in
either single overhead cam or dual overhead cam configuration. The '98-'00
have a 3.5l MPFI v-6. The '85-'91 Trooper is commonly referred to as the
first generation. After '92 the body style changed significantly and they
are referred to as 2nd Generation.
Troopers until 2000 where only available in 4x4. They where also available
in several trim levels, S, LS, and RS. They where also available in either
Short wheelbase(SWB) 2 door, or long wheelbase(LWB) 4 door up until '95.5.
After '95.5 the SWB model was no longer available.
What size tires can I fit on my truck?
32x11.5R15 tires seem to fit well on a 1st gen Trooper. Any larger than that
and fender trimming is likely.
285/75R16 is about the largest tire that will fit on a non lifted Trooper.
With that size of tire there is a good chance of rubbing since they are
almost 33" tall. A much better fit is 265/75R16 or 32x11.5R15. Anything
larger than that will require fender trimming and lift.
-What lifts are available for my Trooper?
Three companies make lifts for the Trooper, ARB/Old Man Emu (OME),
Darlington Off-Road (DOR), and Calmini. The OME and DOR lifts for 1st gen.
Troopers (85-91) uses new leaf spring packs. The Calmini uses an Add-a-Leaf
to gain the lift. All the lifts for 2nd gen. ('92-00) use new coil springs.
The Calmini 3" kit also includes heavy-duty torsion bars, new upper control
arms for the front, and stainless steel brake lines. The DOR 3" uses the
stock control arms and uses ball joint spacer plates to correct the
alignment after the lift. The OME kit does not lift 3" so; correction of the
alignment is not necessary.
Another lift option is commonly referred to as the CP lift. This lift has a
maximum height of about 1.5" above stock without other modifications. You
just crank the torsion bars in the front and install add-a-leaf or extended
shackles in the rear. On coil sprung Troopers you will have to have new
springs made to the new specifications. Here is a good write up of this
Performance Accessories makes a 3" body lift for 90-94 Troopers. This will
not fit automatic transmission trucks and can be made to fit earlier models.
Old Man Emu
-What axles do I have in my truck?
'85-'87 Isuzu 8 bolt front/ Isuzu 10 bolt rear
'88-'00 (non TOD) Isuzu 10 bolt front/ Isuzu 12 bolt rear
All TOD models Modified Isuzu 10 bolt front/ Modified Isuzu 12 bolt rear
Some Troopers where equipped with a limited slip rear differential. This is
designated by the code G80 on the option ID plate in the engine compartment.
-What are my gear ratios, what is my crawl ratio?
Some '88-'91 Troopers where equipped with the factory "wide tire package"
that included 4.77:1 axle gears. This would bring the crawl ratio to 41.0:1
with a manual transmission. This is designated by the code S2J on the option
ID plate in the engine compartment.
-How can I get more power out of my engine?
There are several engine swap upgrades available to 1st gen. Trooper owners.
The 2.3l engine can be swapped out for the larger 2.6l fuel injected engine.
This will require the fuel injection wiring harness and computer to be
swapped over from the donor vehicle as well.
The 2.8l engine can be swapped for the GM 3.4l TBI engine. The factory
wiring harness can be re-used as well as the factory throttle body. The
starter will have to be relocated to the other side of the block, but on
most 3.4s there is a provision for this. The GM Performance Parts 3.4l crate
motor can be used as well. This conversion is livened up even more with the
addition of the 4.3l Holley throttle body for the non-Vortec engine.
There are also several performance upgrades if you want to keep your
One upgrade that will work on any engine except DIS (No Distributor, coil on
plug) ignitions is a high output Ignition. Jacob's Electronics makes systems
specifically for Isuzus that seem to work well. MSD Ignitions have universal
ignition amplifiers that, with a little wire splicing, can work with the
Weber makes performance carburetors for the 2.3l engine.
Calmini has performance camshafts, rebuild kits, and high compression
Calmini also has exhaust headers and performance exhaust systems. You can
also have a custom exhaust system made at any exhaust shop. The exhaust
diameter has an effect on the RPM range that the power is helped. 2.25"
tubing seems to be the best for all around performance, but some have had
good results with up to 2.5" tubing.
A performance clutch is a good idea once the engine is making more power.
Centerforce sells both the Centerforce 1 and the dual friction clutch for
2.3l equipped Troopers.
First there is the K&N cone filter that clamps onto the MAF sensor. This
replaces the airbox and the air intake tubing up until the MAF. The outside
diameter of the MAF is 3.14" so the filter must have the same inside
The MAF sensor and intake manifold can be replaced with one from a '94
Amigo. The '94 MAF and Throttle Body had a larger diameter than previous
parts and provides greater airflow. This has been said to provide only
negligible power gains though.
Delta and Calmini sell performance camshafts for the 2.6l. The Calmini cam
is an entirely new cam that is said to increase upper RPM power with little
or no effect on low RPM torque. The Delta cam is a regrind of original
factory cams that is said to increase low RPM torque at the expense of some
upper RPM horsepower. None of these claims have been verified with hard
numbers from a dyno, they are all impressions of the people who have
Calmini also markets high compression pistons for the 2.6l.
Calmini and Pacesetter sell exhaust headers for the 2.6l. Calmini also sells
performance exhaust systems for this engine. A custom exhaust can also be
bent up at most any exhaust shop as well. 2.25" tubing seems to be the best
size for all around performance.
Centerforce also has the Centerforce 1 and the Dual Friction clutches for
2.6l equipped Troopers.
The 2.8L is the same 60* engine that was used in GM vehicles. Therefor, many
of the performance modifications that are for the Chevy S-10 and other 2.8l
equipped GM vehicles will fit the 2.8l in the Trooper.
One of the common mods to this engine is the Holley throttle body for the
TBI 4.3l non-Vortec Chevy engine.
Calmini sells performance Cat-Back exhaust systems for 2.8l Troopers. A
custom exhaust can also be made up.
Centerforce has both the Centerforce 1 and Dual Friction clutches for 2.8l
There are few choices for someone looking to get more performance out of the
3.2l engine. There is a high flow intake system made by Calmini. Along the
same lines some people have made their own brackets to support a cone filter
and used a K&N on the end of the stock intake pipe. There is also an ECU
upgrade from Jet. That particular mod has been said to produce little power
gains for the amount of money it costs. Finally, There are headers produced
by Bob Land Racing. These combined with a well-designed exhaust system could
produce some power gains, but the headers alone have not been shown to free
up any power.
The 3.5l is in the same boat as the 3.2. There is a Jet ECU upgrade and the
Bob Land Headers, but neither have been shown to liberate much power.
None of these power modifications will transform your Docile Trooper into a
fire-breathing monster, but they can help create a little more
Many of the modifications listed are not emissions legal. That is not saying
that they make the engine any less clean. Be sure to check local emissions
laws before modifying your engine.
Bob Land Racing
-How do I get the O2 light to go out after I change the sensor?
The O2 light is triggered by the odometer at 90000 mile intervals. The light
is just a friendly reminder that it is time to change the sensor. There is a
switch located on the back of the speedometer cluster that simply must be
switched to the other position. The light will go out and you don't need to
worry about it for awhile.
-What Locker options do I have for my truck?
For '85-'87 Troopers there is one locker made, the Lockright PN 3111 for the
rear axle. There is also the Power Brute LSD available PN TL14-4 for the
For '88-'97 Troopers there are a few options. The ARB Air Locker PN RD-44 is
the only locking differential available for the rear. There is a limited
slip Power Brute PN LOM14-12 that also fits the rear. For the front there is
the Lockright PN 3111 and the Power Brute Limited slip PN TL14-4.
For '98+ Troopers there are a couple options. The ARB Air locker PN RD-85
fits the rear, and Meca manufactures both front and rear cable actuated
lockers. The Power Brute LSD PN LOM14-12 also works in the rear
What low gearing options are there for my Trooper?
For Troopers through '87, there are no low gearing options available.
'88-'98 trucks not equipped with the 4.77:1 axle gears can have 4.77:1s
Troopers that have Non-Slip yoke rear drivelines can also have the Tera-Low
Gears installed in the transfer case. This provides a 3.07:1 low range
ratio. Tera-Low gears for slip yoke trucks are possibly slated for
production later in '01.
'98+ trucks have a few options too. 4x4 Mountain Sport has 5.38 axle gears
for these trucks. The Tera-Low 3.07:1 transfer case gears will fit in these
4x4 Mountain Sport