BOLT-ONS
FOR YOUR 2.5L
For most of us an engine swap can't be justitied. Oh sure, we'd
love to have 350 hp in every Jeep we own but the truth is that
the engine swap is usually only the beginning. The relationship
between V-8 horsepower and torque and factory Jeep drivetrains
usually ends up in a violent breakup and even divorce when the
parts really fly. Other things to consider are smog legality
in some states, gas mileage, and -dang it-engine swaps are just
plain expensive
The first thing to remember is that you are working with a four-cylinder
here. Generally, advertisements that claim a 25hp increase without
the addition of a supercharger or nitrous do not apply to you.
If you get 5 hp out of one modification you should be peeing
your pants. We gathered info and ordered some bolt-on power
parts for the 2.5L Then we headed down to K&N Engineering
for some time on the in-house Dynojet 248-H dyno to see what
these parts really do for you. We slapped them on in succession
staring with the Turbo City air tube and K&N filter, then
a Dynomax exhaust, a Venom 400 computer from 4Wheel Drive Hardware,
and finally a Turbo City throttle body and spacer. Here's what
we found.
AIR
TIME
 What
: Turbo City Rock-It Parts Air Tube and K&N filter
Max output : 95hp, 110 lb-ft
Cost : $114.90
INSTALL
The Air Tube and K&N filter are super easy to install. It
took more time to remove the old air box than it took to install
the new tube. However, we did have to bend the mounting bracket
on the air tube so it would fit our Jeep. Apparently there are
several different variations of intake manifolds on the 2.5Ls
and ours was an odd ond. A quick twist in the bench vice and
a couple hose clamps later and we were done in less than 10
minutes.
WHY BOTHER?
The single most beneficial mod you can do to just about and
engine is a factory air box replacement kit. The original parts
are very restrictive. If you only do one engine modification
this is the one to do.
MORE PURR
 What
: Dynomax tail pipe and Ultra Flo welded muffler
Max output : 93hp, 107 lb-ft
Cost:$139.90
INSTALL
The factory exhaust on most newer Jeeps is held together with
clamps. We removed the clamps and had to slice the tube with
a die grinder so we could remove the original muffler and tail
pipe. Expect this to be a pain if you live in a wet climate,
unless your exhaust is so rusty that it has practically fallen
off. The new Dynomax parts looked like they would fit well in
a stock application. Our Jeep has a raised transfer case and
engine, which made the install a little more difficult, but
it still fit. We had the pipe and muffler hung in about an hour.
WHY BOTHER?
We actually lost horsepower and torque by installing the tail
pipe and muffler. However, the new welded muffler is much thicker
than the cracked and broden tin jobbie that we took off, The
bummer is that you can't order the welded muyffler in a kit,
but you can piece the parts you want together, whick is what
we did. We think the Ultra Flo muffler gave our four-popper
a better sound , but a few buddies and some car alarms don't
agree
CRANKIN' COMPUTER
 What
: Venom400
Max output : 95hp, 107 lb-ft
Cost : $349.95
INSTALL
We ordered our Venom 400 from 4Wheel Drive Hardware and had
it in a couple days. Once weopened the box we found that any
idiot (including us) can install it. There are only four wires
to connect and color-code instructions are included to wire
it into your specific year and model. It took less than 30 minute
to put in and it even comes with an LED light that lets you
know it's working properly.
WHY BOTHER?
Even though torque remained the same we did have an almost3hp
increase with the venom400. However, the computer on our 2.5L
had a slight stumble between 2,000 and 2,500 rpm, but only under
minor load. We called the maker of the Venom400 computer, python
Injection, and were told the Venom 400 is designed for mostly
stock Jeeps and that our high-flow air filter is most likely
the reason for the problem. The bonus is that you can send your
Venom400 to them to have it reprogrammed for any number of additional
modifications.
BORE IT
 What
: Turbo City Rock-It spacer and modified throttle body
Max output : 97 hp, 111lb-ft
Cost : $208.95 plus core
INSTALL
You could do this swap in a parking lot with tools that fit
in your pocket. It took us about 15 minutes to get the old throttle
body out and replaced with the boredout unit. All of the connectors
and cables fit exactly like stock. The spacer fits right under
the throttle body and comes with new gaskets and longer bolts.
WHY BOTHER?
We gained almost 2 hp with the throttle body and spacer and
over 3 lb-ft of torque. With a four-poper every little bit helps.
You V-8 guys can stop laughing now.
SOURCES
Dynomax
800/594-9815 for tech, 800/767-3966 for your nearest dealer,
www. dynomax.com
4Wheel Drive Hardware
800/333-5535, www.4wd.com
K&N Engineering
800/858-3333 for tech, 800/213-4182 for you nearest dealer,
www.knfilters.com
Python Injection
714/828-1406 for the nearest dealer, www.venom-performance.com
Turbo City
714/639-4933, www.rock-it.com
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