The on and off-road four wheel drive vehicle

I bought an 87 Wagoneer Limited, Here’s the specifics:

1987 Jeep Wagoneer Limited
(Same as a Cherokee but less of an off-roader)
4.0l I-6
Sequential Fuel Injection
4 speed auto trans (with Comfort and Power modes)
Selec-Trac 4wd
Limited-slip rear axle (I think)
3200 (?) pounds (A guess, the base model is about 3000, this one
                 has all the toys.)

The engine has 65k on it, the rest of the truck 117k.   I use
it to tow a motorcycle trailer and as a grocery-getter.  The
handling is adequate,  I would like to get a little better
performance out of the Jeep without going too nuts.  
First off, I have to determine if the truck is performing as
it should be from the factory.  I’d like to get some rough
1/4 mile and 0-60 times for it, and compare them to the published
figures from 1987 (which I don’t have) and try and altitude
correct them.  Can anyone help me with performance figures and/or
altitude conversions?  

Supposedly, the truck has something like 175 hp.  It’s also a bit
lighter than my Mustang was.  If I can get it to produce about
200hp, I think I’d be quite happy, and I don’t think that will
overly stress the rest of the driveline.  These are the mods I’m
thinking about:

Higher-ratio rocker arms  (ratio? 1.6?  1.65?)
High-flow exhaust and converter (Tube size?  2 1/2"?)
More timing advance   (as much as I can manage with mid-grade fuel)
Some sort of performance air filter

Well, that doesn’t sound like 25hp to me, more like 15-20.
Anyway, any thoughts?  Does this 4.0l I-6 correspond to
any old CJ or Javelin motor, or anything like that?  Anyone know
anything about the Fuel Injection system, i.e. Mass Air or
Speed Density, or what?  What about performance cats?  I
have never fooled with a catalyst car, performance-wise.
Who makes a good one?  This is an inline six with a single
exhaust, with a 5k redline, it might need a decent 2 1/2"
system to make a difference.

I don’t know if decent performance parts can be had, but this
motor was upgraded to something like 195 HP in later model years,
so I may be able to make similar mods and get the same gains.
FWIW, My brother had a 1988 Cherokee, and claimed he hit a top
speed of 130+ at Bonneville (after he unhooked the boat).

Thanks!
-Joel (fr…@colorado.edu)

This entry was posted on Wednesday, January 13th, 2010 at 6:29 am and is filed under Uncategorized. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.