The wife and I have been trying to sell our GV because of the amount of fuel it goes through on her 70 mile round trip daily commute. Unfortunately, we are having difficulty selling it for the price we are asking. I guess the economy is really tight.
So, this brings up my point of this thread. How to improve the economy of this thirsty beast. My full sized Mercedes Benz v-8 powered suv gets only about 3 mpg less and is twice the rig. This is disappointing. But other than fuel usage, we love the little thing. My wife really loves it and really does not want to part with it. So, lets discuss different things to improve mileage and keep the discussion open.
My rig is a 2000 GV V6 with slightly oversize tires. The tires make a 3.8% difference in speedometer error. Taking that into consideration, my wife is averaging around 21.5mpg in an almost 50/50 split of city and highway. I would like that number to break 25mpg.
I currently have synthetics in the engine and semi-synthetic gear oil in the diffs. The engine is in a good state of tune. Here are my suggested planned mods. You guys tell me what you think the end result will be in mileage.
*K&N or other air filter in stock air box
*Remove stock cooling fan and replace with electric. Wired so it comes on when hot and when the AC pump is on.
*Replace fluid in transmission, transfer case and diff's with 100% synthetic.
*Install manual hubs on front axle
*Replace entire exhaust system with a free flowing (but quiet) system. High flow cats, 2.25"-2.5" piping, etc.
*Keep tires at 35psi (I am at 32 right now)
Now it is your turn. On this forum there must be some people who have done some of the above mods or know the link to threads where they have been done. Lets discuss these, what the end result you think they will net, and if you have additional ideas/thoughts.
Get rid of the oversize tires, put something skinnier than stock on and run high pressures. I doubt your wife approaches the limits of your current tires and skinnier tires don't aqua plane as easily. My tracker came with 205/70R15 uniroyal tiger paws(which are downright scary in rain or snow, don't get them) I don't really see why you couldn't go a size thinner.
Switch to all synthetic oil in the driveline, I have the 4 banger and in the cold mornings I can really feel all that thick 75W90 oil dragging before it gets up to temperature.
Manual hubs on the front, I've read its worth 1 or 2 mpg here.
Check your cooling fan but it shouldn't be on all the time. Only when needed.
One other thing is adjusting the timing, I don't know specifically if you can on your engine but advancing it slightly lets the engine make a bit more power at the lower rpm range. Listent for knock though, all engines will pull timing with knock but I doubt the sensor/computer is not really designed to always be adjusting the timing. I'm sure it will not fine tune the timing, just pull it back to something very safe and then after a while go back to normal until it senses knock again.
I doubt the exhaust will have any benefit.
Probably if you do the math, over 5 years it would be better for you to even give away your GV and buy a 3 year old toyota echo for that kind of commute... Real world I think they get 40mpg on the highway, and are dirt cheap and don't break down.
I have a 50 mile round trip commute and average about 26mpg with my tracker in the summer, in the winter with snowtires this drops to 23mpg. This is with the 4 cyl, manual trans, no air conditioning, normal oil in everything, stock tire size, no mods, clean air filter.
That's not bad if its an automatic tranny and 4WD. Those options each cost you 1-2 mpg. My 99 GV, 5-speed, 2WD, 2.5 V6 gets 24 to 26 down the road in overdrive with cruise at 65, with 118K + on the odometer. Best way to boost mpg is tune up stuff, plugs, wires/coil packs, air filter and granny-type driving (55-60 tops). Don't think you can adjust timing. Also helps to clean the fuel/injection system regularly with Sea Foam or similar additive in the tank. Tires help a little, stay stock with recommended psi, but gearing is what makes a real difference. Mine turns 2,500 to 2,900 rpm at highway speed in overdrive, wish it were geared to only turn 2000 rpms to save a little fuel. A note: Wife's 06 Montego with 3.0 V6 actually gets 27-29 mpg down the road in overdrive with cruise at 65-70 mph. Love that ride, big and roomy and gets 18-20 mpg in town.
The V6's are same as the Mazda 626 V6, my Dad had a '96 626 and it probably wasn't getting much better than 28-30 mpg. And that's in a relatively areo dynamic car without; rwd, a transfer case, and an extra drive axle turning all the time. These all cost hp to turn.
I have a bad oxy sensor on my tracker and I have been considering just putting a "fake" voltage on the wires telling the computer the motor is running to rich so it leans it out. I think the optimal solution is to a potentiometer attached to the throttle so that the engine runs lean under light loads but rich(or normal) under heavy loads. You don't really want to be lean at full throttle for too long... How much this would help I don't know, my Dad had a dodge omni that would lean itself out and advance the timing for mileage, this would send the NOx emissions way up, which is why cars don't do this today.
The only other relatively cheap thing to do improve mileage that I've heard of is to put a front air dam on that limits air flow under the car. On low cars the black plastic garden edging has been used, for a GV I don't know what would be readily available. I guess lowering the vehicle would help too, removing the roof rack if there is one, the passenger side rear view mirror, radio antenna. Get your wife to draft big rigs... I do this sometimes and you can definetely feel the difference even 100' back. If you had the will power to do this all the time I'm sure that would get you your 25mpg. They never seem to going fast enough though so eventually I'll pass them...
Ian
Quote:
Originally Posted by tmcalavy
That's not bad if its an automatic tranny and 4WD. Those options each cost you 1-2 mpg. My 99 GV, 5-speed, 2WD, 2.5 V6 gets 24 to 26 down the road in overdrive with cruise at 65, with 118K + on the odometer. Best way to boost mpg is tune up stuff, plugs, wires/coil packs, air filter and granny-type driving (55-60 tops). Don't think you can adjust timing. Also helps to clean the fuel/injection system regularly with Sea Foam or similar additive in the tank. Tires help a little, stay stock with recommended psi, but gearing is what makes a real difference. Mine turns 2,500 to 2,900 rpm at highway speed in overdrive, wish it were geared to only turn 2000 rpms to save a little fuel. A note: Wife's 06 Montego with 3.0 V6 actually gets 27-29 mpg down the road in overdrive with cruise at 65-70 mph. Love that ride, big and roomy and gets 18-20 mpg in town.
I researched the free wheeling hub option a while back - the consensus (from people who had done it) was that there was no discernable difference in fuel economy.
My number one target (and what I will be doing in the near future) is removing the viscous hub cooling fan. That will make a difference to the power available and (if you don't use it!) the economy will improve due to less drag on the engine.
You can change the timing settings on the 2.7l engine so I've guessing the 2.5l is the same? A remap by someone who knows what they're doing would be the best option as I suspect the engines are running a bit richer than they need to. The timing could also be tweaked at certain revs rather than the whole rev range - as happens via moving the electronic pickup on the end of the cam.
The exhaust I'd be careful of- you want to maintain torque at lower revs to improve driveability. Most free flowing systems will move the torque curve and you'll basically need more revs for the same torque. Not what you want to do if you're going for economy. (The peak power and torque levels should improve, but you'll need more revs to access them.) Perhaps just replacing the mufflers with free flowing items would be a good start point?
Air filters, synthetic oils etc will only get you minor gains if anything. Most of the claims are just marketing ploys from the manufacturers with little proof to back them up.
Tyre pressures should make an improvement, but the ride might not be worth the gains? Getting an on road HT tread pattern over an aggressive off road; sticking to the recommended diameter should also help- but who knows as Suzuki might have done the gearing more for acceleration over economy at highway speeds?
I have a 2000 GV Limited w/2.5L V6 Automatic w/78,000+ Miles. I've had it about a month and immediately did a good tune-up on it. No synthetic oil in anything just standard oils changed. I changed the fuel filter, Spark Plugs and stock air filter. Ran a can of Sea-Foam in it. I average 25-26 MPG on Highway (Doing 65-70)and 21 MPG in the city. Every other tank of gas or so, I'll do a fuel cleaner too. So far I have no complaints. I had a Older Honda Accord (1989) for years and while the GV does not get the type of MPG the Honda had, I have no complaints. I know with the Honda I changed to a K&N and got a 2-3 MPG differance afterwards. I may look into doing that with my GV. BUT OVERALL NO COMPLAINTS WITH THE GV, I LOVE IT!!!
I have a 2000 GV Limited w/2.5L V6 Automatic w/78,000+ Miles. I've had it about a month and immediately did a good tune-up on it. No synthetic oil in anything just standard oils changed. I changed the fuel filter, Spark Plugs and stock air filter. Ran a can of Sea-Foam in it. I average 25-26 MPG on Highway (Doing 65-70)and 21 MPG in the city. Every other tank of gas or so, I'll do a fuel cleaner too. So far I have no complaints. I had a Older Honda Accord (1989) for years and while the GV does not get the type of MPG the Honda had, I have no complaints. I know with the Honda I changed to a K&N and got a 2-3 MPG differance afterwards. I may look into doing that with my GV. BUT OVERALL NO COMPLAINTS WITH THE GV, I LOVE IT!!!
I am a serious gear head. While my automotive tastes lie mostly in Germany, the GV is a good runner. My GV is in a great state of tune. I just need to get some synthetics in the diffs and transmission. I change the transmission oil every 20k as well. Still can not budge above 22mpg. One reason I bet you are getting better mileage than I is where we live. What is your elevation IASukiGVL? I also bet it is pretty flat compared to here in the rocky mountains. I probably have more elevation change on the way to work than you do in your state, no offense, just making a statement.
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