Hey Guys, How is everyone? I have an 89 Trooper with a 2.8. My goal is to get the best possible gas mileage and I am wondering if anyone has any suggestions. In my mind the options are to rebuild the 2.8 in a way that would optimize gas mileage or upgrade to the 3.4 and build it to optimize gas mileage. Diesel is also a remote possibility in my mind. Does anyone have any insight on how I can accomplish the best gas mileage with the options listed above or any options I have not thought about. I would like to try and get 25 mpg or better and also improve power... (I know I am asking for a lot). Is this possible? All suggestions are welcome. Steve @ humanesocietysteve@yahoo.com or 865-742-3070

I would lease a prius

Do you always give such good advice? Steve

Welcome, Steve.

The bottom line is you are not going to get 25mpg or more out of either of those engines. It is a cross between the aerodynamics (or lack thereof) of the vehicle and the design of the engine. We are talking about TBI fuel injection that is at least 17 years old in it's design. It just is not going to happen on a *consistant* basis. Downhill, with a tail wind and the engine off, might net you the low 20's.

If that is your ultimate goal, then buying a small commuter type car is going to be the best route for it.

Good Luck,
Michael

Michael, Thanks for the input. In that case I would still like to get the most efficiency possible from the Trooper. I use the Trooper for everything including my Humane Society duties transporting Critters and supplies back and forth from our events and it is the perfect vehicle for me. I have had it for 7 years and plan to keep it forever.However I have been planning an engine rebuild or upgrade for a while since I have 249,000 miles on this engine. It still runs fairly well and I have been getting an average of 17 to 19 MPG on this high mileage engine. I am just trying to get the techinical advice I need before I start the rebuild or upgrade to get the best mileage since I do not believe gas prices are going down and I want to achieve the best numbers possible. Steve

This is one of those things, if you are getting 17-19 now, I would suggest not touching it. A rebuild is going to cost you at least $1000, but probably closer to $1500 and even higher if you have someone else do the work.

17-19 is about as good as you can expect. Dropping $1000 to get the same mileage or maybe 1-2 more (which I doubt) is never going to pay off. At best, you are paying ~$0.16/mile. An additional 2mpg will net you a savings of about a penny a mile. That means you would have to drive between 100K and 200K to just recoup the cost of the rebuild. That is probably a 7-10 year payoff time and that is assuming that the rest of the rig does not fall apart too. And, that is if you actually saw any benefit post-rebuild.

The best I can suggest is to drive it until it blows up and then deal with it. That is the most cost effective thing to do, as you get every last cent out of the old motor.

Other than that, a good tune up with plugs, wires, cap/rotor and clean filters will maintain the mileage you are getting. Tires inflated to their proper (or max) pressures will help. A free flowing exhaust may also help, but we are back to where you will never justify the cost of the exhaust(unless it is being replaced anyway) because it won't deliver that much of a gain.

If you are still bent on doing something drastic, get yourself a 3.4 block and rebuild it. Do it now, while the trooper is still functional so you are not under the gun. That way, you will have a fresh and ready motor to drop in when the 2.8 dies.

Good Luck,
Michael

PS. Keep up with the HS work.

upgrade to a high flow cat and get rid of the pellet converter

switch to propane it is a cheaper cleaner fuel. similar milage but at less cost for now

I get 18 MPG highway fully loaded with gear and with the AC on. I consider that damned good for a big old brick. A few things here and there may help a tiny bit (synth oil, high flow filter, new exhaust), but I'd be surprised if you even got 1-2 MPG out of that.

My last car was a 1.0L 3-cyl Geo Metro. Totally lacking in cool points..but it cost $500 and got 50 MPG+ easily. It was scary as hell at 80 MPH though. So I definitely feel your pain, since I'm paying 3X as much for gas now.

I also drive a 1st gen 2.8. Has a 3" lift and 33s. Changed the gears to 5:38s. I get 13 mpg after the odo adjustment. I would be jumping for joy if I ever got 18 mpg.