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GzrGlide

10-18-2003 12:50 AM

4cyl vs 6cyl: my opinions & experiences

Well since this seems to come up a number of times a year, I figured I'd
post this so if anyone does a Google search, at least they'll get it
fairly quickly.

4 Banger vs 6 Cylinder Jeeps

If you’re reading this you’re probably wondering whether you should buy
a 4 cyl (2.5) or 6 cyl (4.0) Jeep. I hope this helps. As you’re reading
this keep in mind it’s written based on my experiences with my wifes ’98
TJ SE. This Jeep is used as her daily driver to go to and from work, go
shopping, cart kids around and we also use it as our primary 4-wheeled
transportation. We take it on holidays, to the lake etc etc. To date it
has over 111,000 miles on the odometer, and we’ve had it since September
1997. The only real change we’ve made is that we replaced the stock 27
inch Goodyears with 30x9.5 BFG ATs.

Why did we buy a 4 banger TJ? Because I’m a cheap bastard! Here in
Canada, when I bought her the Jeep in ’98, the Sport package was an
extra 5 grand. Besides I figured the Jeep with a 4 banger would get
better gas mileage. She only had a passing interest in off-roading at
the time so the 4 banger was good enough. Or so I thought.

Enough background info. On to the facts.

The first thing I noticed was that the 4 banger is severely underpowered
for hwy driving. If you want to pass anyone, take a lunch or be prepared
to drop it into a lower gear and rev the hell out of the motor (4th
gear, 4000 rpm usually does it). The problem is even worse if you’re
pulling a trailer. We have a utility trailer with a 4x8 foot box on it
and when the trailer is hooked up, we don’t even try to pass anyone.
There usually isn’t enough room.

So what was the first thing any guy thinks when there’s a power problem?
“Well we’ll just soup up the motor!” I have done a huge amount of
research and even tried a few things to get more power from the 4 angry
squirrels. In the end it comes back to: “There’s no replacement for
displacement!” Don’t even think about boosting the horsepower with
things like K&N filters, computer chips, throttle body spacers, headers,
exhaust, electric fans, ancient tribal dances, chinese incantations etc.
Some of these mods are either snake-oil, or they’re designed to work at
the higher end of the RPM scale, which very few Jeeps ever see in any
situation. By the time you pay for all that, you might as well drop in a
bigger motor, or buy a Jeep with the 6 cyl in the first place.

The 4cyl has some other issues as well (this is all from 6 yrs
experience). Some of these may or may not be an issue with you, but they
warrant mentioning.
The only tranny to get is the 5spd (don't bother with the auto). No
problem right! Except if you want to pull any kind of trailer, it's too
weak to handle 5th gear when the trailer is loaded up. You end up in 4th
turning 3000 rpm at 60 mph. Really bad gas mileage!

Lack of aftermarket parts for the motor. The aftermarket mfgs cater more
to the 4.0L guys. However some of the technology used in the ricer world
may be applicable to the 2.5 Jeep motor, but again that may only apply
to the higher end of the RPM scale.

You would think that the 4cyl would get better gas mileage (such that it
is with a Jeep), but after talking to 6cyl owners, the difference isn't
worth mentioning.

The SE package only comes with the Dana D35c axle ( the other Jeep
packages either give you a D44 option or come std with the D44) which
when combined with larger tires and a locker have a reputation for
breaking at the most awkward times. Getting a Sport or higher package
gives you the option to have the better D44 axle.

If you plan on putting bigger tires on the jeep, the 4cyl lack of power
will be exaggerated! We went from the stock 27 inch Goodyears to 30 inch
BFG ATs in 2001 and there was a definite drop in hwy performance when
you hit ANY kind of incline, or trying to pass someone. Although this
would be true with any motor, the 4 bangers already poor performance is
made worse. The remedy? When you’ve settled on a tire size (30s, 31’s,
33’s or whatever) you’re going to have to re-gear your diffs to get the
performance back again.

Having said all that, the 4 banger is a good motor. The gearing is
around 4.10:1 and believe me that is plenty good enough for around town
and on the trails. I’ve test driven a brand new Sport and although they
do have a lot more horsepower, because they’re geared at around 3.73:1
(or higher, depending on package) you don’t really feel a difference.
You will however notice that they pass faster at highway speeds, they
will maintain their speed better on inclines and will pull a trailer
easier than a 4 banger.

As far as maintenance is concerned; don't worry about it. Our TJ has
185,000 km (111,000 miles) on it and it's been really good to us. I've
replaced the rad, replaced the pinion seal in the front diff twice, and
had to get the starter repaired and then replaced. Total cost to date
Cdn $1100. That’s 0.006 cents per km (0.007 cents/mile) for maint $
(doesn't include fluid changes and regular preventative mtce). Take care
of it and it'll take care of you!

I know this write-up makes it sound like the 4banger is biggest piece of
junk out there. It’s not! For a lot of people it will do what they want
it do very well. For those of us that want to push the Jeep as far as we
can, the 4 banger leaves a little to be desired at times.

My recommendation to people on what they should look for in a Jeep is to
get the 6 cyl in whatever model they can afford (Wrangler X, SPORT,
SAHARA or the RUBICON), preferably with the D44.

Get the 6cyl, D44, your transmission of choice and drive the wheels off
the Jeep.

Mike
98 TJ SE (wifes)
02 FLHTCi (mine)

L.W.(=?iso-8859-1?Q?=DFill?=) Hughes III

10-18-2003 01:39 AM