Check my math critique my upgrades (long)

Stock 2WD '93 XJ, 4.0L HO, AW4: 193,533 miles indicated

Against the interstate mile markers I am travelling about 5% more actual miles than my odometer records. I assume this is the difference between the stock speedo gearing and the LT 235/75R15 A/T's that I'm running. When I bought this Jeep three years ago at 130,000 miles indicated it was on standard 205 or 215 passenger radials. I immediately swapped on the 235's from my '83 Ram Charger so I have no idea how accurate the odometer was before the swap. The only reason this is important is that I want to celebrate the soon to arrive 200,000th mile (yes, I have put on approximately 70,000 miles in 3 years - Texas is a B!%@# on miles/year). The question is: when will 200,000 get here - if it hasn't already? If the odometer was essentially accurate with the 205/215's (I don't remember which it was) and the 5% error has only been since the 130,000 mark, then I am currently at 196,710 actual miles. If there was no significant difference from before to after then I am at 203,210 and I've already missed it. I intend to celebrate with a year of upgrades. I let my Ram Charger maintenance slide in favor of the wife's Grand Caravan payments, house payments, daycare payments, food and crap like that until it finally died at 350,000. I intend to treat my Jeep better.

It's a DD and only 2WD so I'm thinking of taking it slowly from stock toward stoplight getti-up and (mostly paved) road performance with whatever light pre-runner capability it has stock. I won't be doing much fabrication on this one - I'll save that for it's replacement (in about 3 years I'll be looking for a '97 Select-Trac XJ to lift and convert to pre-running). For now, I'm thinking (probably in this order):

new motor mounts (OEM - I don't want a stiffer mount until I reinforce the mount-to-block breaking bolts issue - the OEM's have lasted 200,000 and will be good for now)

new shock absorbers (stock length but I;d like a little more control on the compression stroke - I need to research this);

new rear leaf packs (I figure on stealing low mileage late model packs from pick-ur-part - I don't want to lift without addressing all the lift issues at once [e.g., control arm length/angle, SYE, adj. trackbar, etc.]. I'll save lifting for the replacement);

open intake (probably K&N cone with air tube);

bored out TB (60mm, buy it or do it myself);

new header (whatever aftermarket I can get cheap or keep stock for now);

2 1/4" header-back exhaust including new Cat and highlow muffler (not too loud);

better wet road traction than the 235's give (I'm open to suggestions here. If there is something for around $125 a tire mounted with road hazard that will give better wet road grip without looking too gay, please let me know);

LSD or No-Slip for the rear (currently d35 open);

new seats or repair current seats (absolute minimum cost here - I'll probably borrow a welder or get later model pick-ur-part seats);

new sound (non of that jay neon ricer crap and I'm not interested in rattling anybody's windows - it's just that the OEM tape deck crapped out and I really need a CD changer);

check for and repair any floorboard rust through.

That's all I can think of right now. Let me know if I'm missing anything big. The rig runs great!! It looses about 1 quart per 3,000 - mostly on top of the valve cover. I'm getting 17.7 mpg average daily diving (about 50/50 interstate/street) with a very heavy foot. The only noises (besides the broken drivers seat) is exhaust rattle against the frame a high torque (hence the new motor mounts). I love the Jeep even better than the Ram Charger and it was a police special with High Output 360, Rochester Quadra-Jet, and LSD 12-bolt rear-end. I'm stayin' with XJ's from now on, but for now I'm limited to a 2WD DD.

Thanks for your time,

XJ Dreamin'
stock 2WD '93 XJ, 4.0L HO, AW4, d35 open, LT 235/75R15 A/T's

I guess if I was in your situation I would just celebrate the odometer turning to 200000.

I thought that I would try and figure out how many "actual" miles my Jeep had on it also. I am running 31's on stock 3.73's and I record about 9/10 on my odo for every 1 mile I run.

When I put my new gauge cluster in I swapped out my old speedo and odo so the miles are still "accurate."

That said...I know of no one that takes a picture of their odometer at 197,876 or whatever miles because that is when the truck has run a full 200. I always see the 200,000 mile picture.

To that end....when I did my math, I sent my figures to 2 buddy's that are accountants, and 3 that are teachers and I got a few different answers....either they couldn't get the equation right or they just didn't care!!!

Anyway...that is how I would solve the problem if it were my problem!

Good luck on your formulas.

Stock speedos are almost never accurate. My 1988 XJ came with 205/75R15 tires. The speedo is almost perfect running 225/75s and I haven't regeared or changed the speedo gear.

On my wife's stock 2000 XJ Classic, according to the police radar trailers an indicated 45 MPH is an actual 42 to 43 MPH, which is a built-in error of about 5%.

Just celebrate when your speedo hits the 200,000 mile mark and call it good.

Yeah, in the end I'll have to go with the actual reading because that's when I'm going to hit up the wife for authorization to begin replacing junk on the rig. The story of the demise of the Ram Charger is a long one, but suffice it to say that the lesson on what happens when you neglect maintenance was well learned. That was not a pretty death. With a little pick-ur-part action and doing the labor myself, I can sneak in as much upgrade as a 2WD DD deserves. I grew up working on Mopar (CPDD's of the '60's and '70's overhauling everything from slant-6's to 400ci V8's and many, many torque-flites. I've done alot of frame and body work as well, although we were never concerned about appearences (we once grafted the front end of a '67 Dodge Monaco onto a '68 Plymouth Fury after my Mom ripped the fender off on a utility pole). I've been reading religiously for a nearly a year and I think I'm good to get started.

XJ Dreamin'

Eagle said:

Stock speedos are almost never accurate. My 1988 XJ came with 205/75R15 tires. The speedo is almost perfect running 225/75s and I haven't regeared or changed the speedo gear.

On my wife's stock 2000 XJ Classic, according to the police radar trailers an indicated 45 MPH is an actual 42 to 43 MPH, which is a built-in error of about 5%.

Just celebrate when your speedo hits the 200,000 mile mark and call it good.

Click to expand...

Now you've reminded me... I drove past a radar trailer set up in the 20 mph school zone. With my speedo indicating 20, the radar display said I was doing 18. I thought that was cool at the time - I'd always be safe. But, if the interstate mile marker test is accurate and I'm traveling 5% more actual miles than indicated, shouldn't my actual speed be greater than indicated, not less!? Oh well, I give up! That may only indicate that that radar was not calibrated. Anyway, I started the mile marker checks because my math was giving me a MPG a bit over 16. The adjusted milage gives 17.7. I like that better so I'm stickin' with it.

Hey, how are your 225's on wet pavement? Have I got a better chance of finding a wet road grip if I come down from 235? These 235 A/T's are forcing me to use a lighter foot than I'd like. Of course, with an open rear end there's little hope of much traction anyway.

Thanks,
XJ Dreamin'