How do I get the most performance from my Jeep Cherokee?
First, we have to define performance. Since the Jeep Cherokee is such a
versatile vehicle, people use them for many different purposes and therefore
have different performance expectations.
I have different performance expectations from each of my Jeep Cherokees.
So each of them is prepared differently.
My off road farm truck has big tires, a welded differential and no sway
bars. It has an old 2.8L V6 as I don’t need much power where I go. Traction
and articulation are more important to me off road than speed.
My Rally Racing Jeep Cherokee has a 4.7L stroker motor with a high lift cam
built by Titan Engines especially for high speed gravel road racing. The stock
intake is used but the exhaust is open with no muffler only the required
catalytic converter as a restriction. The suspension is stock with small sway
bars and rubber bushings. The tires are small with stiff sidewalls and an
aggressive rally racing tread. The emphasis on this vehicle is on speed,
stability and durability.
My daily driver Jeep Cherokee is more of a compromise. Since it spends most
of its life on pavement, I have used the middle sized sway front sway bar and
poly bushings. The front control arms are also fitted with poly bushings. The
stock rear sway bar is used in the stock rubber mounts. The tires are 30"
BFG All Terrains. The engine is stock for now but has a K&N air filter and
a Dynomax exhaust. The rear differential is fitted with a lock rite automatic
locker. For off road adventures the rear sway bar is removed and the front
sway bar is fitted with quick disconnects.
So, you are still asking’ "How do I get the most performance from my
Jeep Cherokee?"
Begin with simple things in the engine. Whether you are running a hot
stroker or a stock 4.0 I recommend regapping the spark plugs. The stock coil
will fire up to about a .055 gap. A hotter coil, like a Jacobs or MSD, will
fire a .065 gap. In either case, you must use high quality plug wires. The
larger spark gap seems to give more complete combustion as I have seen
increases in both torque and fuel economy by increasing the spark gap. I use
the RC9YC Champion Plugs or the Autolite equivalent.
Opening up the intake and exhaust will also help in the upper RPM range. I
have mixed feelings about the K&N filter on my 1991 Jeep Cherokee. It
makes a cool sound and reduces the chances of taking in water on creek
crossings, but its location allows it to suck in hot air. I think this reduces
torque and fuel economy. I have reinstalled the stock air box in the Rally
Jeep as it seems to work better at rally speeds. I have opened up the exhaust
on both the 1991 Jeep and the Rally Jeep. I have not tried a header on either
one but I plan to in the future. The Rally Jeep uses as straight a pipe as
possible from the cat back. No muffler is used and the sound level is still
below the required 96 db. On my daily driver I use the Dynomax 2.5 inch
muffler and tail pipe. It makes a nice mellow tone.
I just made a huge improvement in the handling of my 1991 Jeep Cherokee Laredo
that I use as my daily driver. I replaced the front Gabriel Shocks with
Bilstein shocks. The bushing were worn on the Gabriel's letting them
rattle. I could have just replaced the bushings as the shocks are fine
but I wanted to see what improvement better shocks would make. I chose
the Bilsteins because they had the largest piston diameter (46mm) I could find
in a shock with the stock cross bar and stem mounting system. They we
also a lot less expensive than true off road racing shocks. I have to say I am
absolutely amazed by the difference in handling! The truck now tends to
oversteer in corners rather than understeer like it always has. I may
have to get a matching set for the rear axle to even things back out.
For more information on my RallyJeep see www.rallyjeep.com
For more information on installing Poly control arm bushings, see this
page.
For more low cost suspension tricks see my Cheap
Jeep page.
