Topic: gas milage

[jagular7]

97 TJ, stock 4cyl/auto, 4.88s, lockers, 4"+ lift, 34x10.5 LTBs. No speedo adj., maybe 11 at 70-75mph.

[chardrc]

ya its got over 150k miles on it.... so it does need a rebuild or swap... espicialy since its leaking oil again and i thinkl its coming from the rear main seal.. which is a total pain since i jjust had the motor out to replace the clutch slave cylender during christmass..


and speaking of dirty air filter.. it has a new one since when i got it tyhe air filter was so full of dirt and crap that it looked like there was a rats nest in it(cant remember if there was forsure but proalby wasnt since no wires were chud throw and it was a dalydriver.)

as bad as it sounds and is i might endup runing this motor tell it blows and or totaly gives up on life.... but hopefully i do something engine wise gefor that.

ow ya and does anyone (cough cof jeffy(or anyone else)) know were i can find a map / guide for te vacum lines for a 1990 yj(my jeep) because i have a bid ball dryroted vacumelines behind the plastic iner fender of my rear pasenger fender. i asume it has something to do with the gas tank since when i have a fun tank of gas i can smell gas and it takes a longer than ususla to start..

[supryj4]

I only have a few tanks of gas sense cam, head, and rockers  and I didnt wright the numbers down but I think at @12 mpg but I drive it prety hard. :nothing:

[chardrc]

hey supryj4 is that right that you have a 1990 yj with mpi??? did you convert it or get a new ingine.. cuz i have a 1990 and it only comes with tbi..

[supryj4]

yes I converted the whole wirring harnes,intake,etc from a 94

[chardrc]

how much of a performance gain did you get.. how much it cost... how much time did it take....

so it was just (understatment) replace computer wireing harness intake manifuld.??/   but for that much work i could just put in new motor but it is still an interesting idea..

[supryj4]

I had the whole thing torn down to a bear tub and I had a 94 parts jeep so it wasnt much more work than what I had to do any way to get running again.I had a brand new 2.5 on the stand already or I might have done an engine swap.But I really like my little 4 and I origanly was planning for a supercharger wich is the reason for the supr yj 4. And for the how much did I gain part it was about 5 years and a whole lot of work between the two so I cant realy say but part of the swap was that the are alot more aftermaket parts available for the MPI than there is for the TBI

[chardrc]

ya thats what ive run into is that there isnt much aftermarklet for tbi 2.5 so your stuck unless you do what you did to get mpi.

[superman1456]

i got  4.0 whit a blower and upgraded injectors it gets around 15 to 16 and my other 4.0 gets aroud 8 to 10 so if you got the money get yourself a 4.0 with a blower it makes a huge amount of power compaird to the extreamly little 2.5l and gets pretty good mpg too in my opinun go with the 4.0 youll engoy the power and the mpg wont be much diffrent from yours now but then agan you wont have to have it to the floor anymore to clime the hills :D

[chardrc]

well i dont think i said it in this thread but i do have a rebiult 4.3l chevy v6 siting in my gatrage waiting for a home(soposed to go in a cj2a we have siting around but i want that to change). but to swithc motors i need to get a stronger trany than the ax5.. we do have a trany that i can get a kit so it will work in my jeep but its ony a 4speed with a grany first so i would lose my highway speeds in a decent rpm range..

[jagular7]

I just took a 12 hour drive up to and back same roads to Camp Jeep in Wisconsin. Driving up, I kept a 65-70 mph. On the way up, I'd shift into 2nd gear (auto) to keep and accel from 3000rpm to 5000rpm. Then shift back to 3rd and get 3200rpm to maintain the speed. That's my normal driving. Worst 8mpg, highest 12mpg. Then on the way home, I drove like an elder person. No accel but constant rpm speed. The auto did downshift or unlock the TC and gain 400rpm. I got much better mpgs!!!, 16 high and 14 low.

So sort of proof of driving habits due impact the mpg.

[GrimJeeper]

Looking at everyone's mileage has got me a bit upset. :?  I'm jealous of you guys seeing the 20 mpg mark!  I get about 14 mpg combined highway/city.  

BUT I drive with the top down and doors off! How about you guys?  Nobody is saying how they generally configure their Jeep when driving.  

For example when I used to drive the Jeep with the top up (back when it was my daily driver) I was getting a few miles more per gallon. I have 31inch BFG A/T's, along with a spacer and 4.0 TB, and have not corrected the speedo calibration so I know I'm losing a little there.

[Jesse-James]

I've had a Safari top and no doors since May and mileage was checked during that time. However, I just replaced plugs, wires, cap and rotor in preperation for the Jamboree. It's embarassing that I haven't checked it since I bought it last year, but it seemed to run fine. :oops:  Plugs looked ok, but the inside of the cap was severely corroded and the wires fell apart while taking them off. I'm sure mileage will be better now. I'll check on the way to Crandon and see what I get.

[Jeffy]

This was talking about on the list.  What comes into play are speed, aerodynamics and weight.  For city, it's probably best to use the soft top.  It's weight is minimal compared to no top but it's still aore aerodynamic then no top.  With no top, wind is very turbulant and all of this wind does slow you down to some extent.  Now a hardtop is more aerodynamic then the soft top but adds a lot of weight to the Jeep.

As speeds increase aerodynamics becomes more important and weight becomes less.  At higher speeds the soft top will baloon up.  Keep in mind the soft top is 4" taller then the hardtop.  Also to some extent the texture of the cloth will grab the air a bit.  At higher speeds the pressure increased inside which causes the doors to flap a bit too.  So at higher speeds the hardtop is better while the worst being no top.  Now if you stripped the interior and removed the spare, seats, carpet, and just about everything else you can think of, you might edge towards the soft top more.

You'll also get some differences from those running a stock jeep compared to those that are lifted.  More air under the body will cause drag.  Flat fenders will also trap more air at speed.  Smaller tire cut through the ir easier then larger ones.   Wider flares up front catch the wind more then no flares.  Wider rear flares probably help move the air up and over the tire though.  What's the difference between the front and rear?  Well the front flares are open at the front unlike the rear.  This catches the wind.  In Europe, the openings at the front are closed off on the TJ.  This is done for safety, I believe but also increases the jeeps aerodynamics...

[Guardian7]

I work with a guy who only gets 10 mpg with his 4.0L Cherokee! I feel something is wrong here.