fuel efficient 2.5L YJ???

TwistedCopper · #1 (**permalink**) 09-07-2005, 06:53 AM

With gas prices being what they are, and the fact that I will be driving 130 miles a day round trip to work I've been thinking...

The XJ doesn't get good gas mileage. It'll cost me 400-500 a month for gas: 130 per day / 16 mpg x 4 days a week x$3.25 a gallon = $105.63 a week and that's if the prices don't go up

Not good.

I'm wondering if I modded a stock 4 banger YJ to be fuel efficient just how good I could do.

It would have to be a '91-95 YJ 4 banger without power steering or A/C (like my '92 was).

Electric fan conversion
Roller rockers
Front hub conversion (to manual hubs)
Synthetics in the tranny, transfer case, and axles
K&N filter & restrictor removed
Free flowing catalytic converter
Cat back exhaust
4.0 throttle body and spacer
Upgraded ignition & coil

Any ideas? I had my old YJ at around 20 mpg with 32" tires. I'm thinking on this one I'd leave the suspension stock and put some 235 all-terrains on it. Think I can squeeze 25 mpg out of a YJ? Maybe more? Or am I dreaming :?

I know, kind of backwards wanting a YJ for a DD and an XJ for a trail rig, but it kinda makes sense (or doesn't it)?

It's that or I sell the XJ and buy a Subaru (and that AINT gonna happen).

currupt4130 · #2 (**permalink**) 09-07-2005, 07:14 AM

why would you need to do the front hubs? just make sure the VD works and theres your drivetrain drag gone, or better yet pull the axle shafts and carrier and run like that (although youd have to keep the outer axle shaft bolted to the hub because thats what holds it together)

88Wrangles · #3 (**permalink**) 09-07-2005, 11:32 AM

I think if you found one with an engine that was in really good shape it would be doable. I'd say it's at least worth a try...since you know for a fact that 20mpg is possible out of one!

What all did you have done to your last YJ as far as things that would increase the fuel milage?

TwistedCopper · #4 (**permalink**) 09-07-2005, 03:41 PM

Fan, K&N, removed restrictor, dual tipped plugs, cat-back exhaust (well sort-of), and not having power steering are all I can recall. Seems like I'm missing something... I dunno if I think of it I'll post up.

TwistedCopper · #5 (**permalink**) 09-07-2005, 08:26 PM

oops wrong thread

Sparky-Watts · #6 (**permalink**) 09-07-2005, 10:11 PM

About a month ago, I ran a test on my YJ with driving habits and got one tankful just over 24 mpg. That's with 31" tires and the only real mod being the air restrictor removal. I'm currently getting anywhere from 21-23, depending on how I drive it.

mud4feet · #7 (**permalink**) 09-07-2005, 10:16 PM

And, of course, you may consider a little acetone!! (No, I'm not a salesman!!!

)

geopig · #8 (**permalink**) 09-08-2005, 10:30 PM

Hey TC, I posted on your other thread regarding your thoughts on commuters. I'm sure you've done the calculations but even if you get 24 mpg from the YJ (plus the cost of the mods) you're looking at ~ $71 per week where as a little s-box that gets say 34 mpg costs you ~ $49 per week. That's about $1K savings per year if you only work 44 weeks of the year. I say go for the s-box and a pool or vacation or mods to the XJ!

P.S. I'm happy to get 21 mpg out of my 91 YJ with 31's, a K&N, air restrictor removed and a tail wind coming from the beach. Haven't resorted to acetone yet though!

Junkpile · #9 (**permalink**) 09-11-2005, 12:59 PM

I think with that setup you'll find better mileage with a slightly taller tire, maybe. Run a lightweight "P" metric size and not a "LT"......car tires

You've pretty much got everything covered. I'd also suggest doing any weight reduction you can get away with. It will really help out mileage in city driving, and increase performance in all aspects at the same time. Remove anything you don't need to drive the vehicle. Strip it down.

My 93 2.5L was doing good if I could wring 12mpg out of it after all of the mods. It was using $50-$60 a week in gas back in 98 when I got rid of it

Sparky-Watts · #10 (**permalink**) 09-11-2005, 09:56 PM

I had a 6mpg drop when I went from the 29" AT to 31" MT tire....then when I pulled the air restrictor, I got a 7mpg jump!

Snitty · #11 (**permalink**) 09-16-2005, 09:20 PM

Quote:

better yet pull the axle shafts and carrier and run like that (although youd have to keep the outer axle shaft bolted to the hub because thats what holds it together

I'm a little late on this.. but that's not really true... the axle nut does nothing to hold the hub together. I never liked the way the hubs are held together.. Just pressed, that's it. There is nothing holding the axle inside the tube, so if that hub broke off, that axle shaft would just slide right out with it.

MuddinYJ88 · #12 (**permalink**) 09-21-2005, 05:51 PM

u can get around 22mpg out of a yj if u drive it nice and keep it tuned religiously. im running an 88 2.5l with 127k and i get 21 around town on an average. its been extremely reliable as well. been through desert trails, mountain runs and the beach many times. a little more effiicent than the xj's. i know from experience im an auto broker and have worked with many jeeps over the years.