MPG, how to improve?

[watchknut]

I am getting close to having gone through my first tank of gas and am a bit surprised that I am getting under 10 mpg. I have read up on the forums, but wanted to get opinions and current MPG from others' rigs.

I am running 285/75/16 Cooper Discover STT and have an ARB roof rack. I am probably going to remove the roof rack because I will not need it but a couple of times a year.

I am thinking of switching to an AT, probably BFG or Terra Grappler, and am wondering if it will make that big a difference in MPG. I would like to get 12 around town and 15 on the road.

Any guidance would be greatly appreciated. Also, is there any market for a set of 5 Cooper Discover STT (1 is brand new and 4 are about 50% treadlife remaining).

 

[Musky]

There isn't really much you can do unless you go with stock size all season tires, lose all the heavy aftermarket bumpers, take off the roof rack, lose the skid plates, take out the 3rd row seats, get new 02 sensors and make sure your 100 series is running like a top.

I know, I know, blasphemy!

I get 17 in the summer all the time though.

 

[petrotk40]

The roof rack is a good place to start. Mud terrain to AT shouldn't make a big difference. O2 sensors might be worth replacing if they haven't been done in a while. You can always try something like seafoam thru a vacuum line and some injector cleaner. I get about 12-13 in town and 14-16 on the highway.

 

[LandCruiserPhil]

I am getting close to having gone through my first tank of gas and am a bit surprised that I am getting under 10 mpg. I have read up on the forums, but wanted to get opinions and current MPG from others' rigs.

I am running 285/75/16 Cooper Discover STT and have an ARB roof rack. I am probably going to remove the roof rack because I will not need it but a couple of times a year.

I am thinking of switching to an AT, probably BFG or Terra Grappler, and am wondering if it will make that big a difference in MPG. I would like to get 12 around town and 15 on the road.

Any guidance would be greatly appreciated. Also, is there any market for a set of 5 Cooper Discover STT (1 is brand new and 4 are about 50% treadlife remaining).

If you are really getting 10mpg GPS I say there is something wrong with you 100. I see 10mpg pulling 5000# hard on the throttle with 285's

 

[watchknut]

I will start with the roof rack and see how that works out. Thanks for all of the advice and I will take a hard look at the mpg once I am completely done with this tank.

Good to know about the slight difference from MT to AT, so I will probably hold off for now since the tires are still good. I am sure about the 02 sensors, but will look into it.

I know there are a million possibilities, but what would be some culprits (other than bumpers, tires, roof rack, 02) that would make it get sub 10 mpg?

 

[yuji]

I am getting close to having gone through my first tank of gas and am a bit surprised that I am getting under 10 mpg. I have read up on the forums, but wanted to get opinions and current MPG from others' rigs.

I am running 285/75/16 Cooper Discover STT and have an ARB roof rack. I am probably going to remove the roof rack because I will not need it but a couple of times a year.

I am thinking of switching to an AT, probably BFG or Terra Grappler, and am wondering if it will make that big a difference in MPG. I would like to get 12 around town and 15 on the road.

Any guidance would be greatly appreciated. Also, is there any market for a set of 5 Cooper Discover STT (1 is brand new and 4 are about 50% treadlife remaining).

I get 12-14 city driving being "normal" on the throttle stock without a roof rack. 16-17 highway.

I've read that a roof rack drops MPG by about 2, so I'd guess I would get 10-12 with a rack.

If I drive aggressively (or just hit that ect pwr button) I've gotten 10.5 on all stock... add roof rack and it would be a little worse.

 

[APKhaos]

I get 17 in the summer all the time though.

Really? That's impressive! What's your secret?

My stock '99 gets somewhere between 14 & 15 in general city driving.

For the OP, 10 sounds like there may be some improvement to be had. Even with the extra weight of your mods you should do better that that assuming this is normal driving unloaded [aside from your bolt-on bits].

 

[Musky]

Really? That's impressive! What's your secret?

My stock '99 gets somewhere between 14 & 15 in general city driving.

QUOTE]

I don't know. I have the stock tires 275 and I don't have a roof rack or any aftermarket attachments.

Most of my driving is highway and I usually try to keep a light foot on it.

I get around 13 in the winter but I warm my 100 up alot and the winter fuel mixtures drive down my mileage.

I also have a huge hole in my muffler.

 

[KlausVanWinkle]

Highway driving I still get 16-18mpg. City is around 12-15 depending on traffic and lights.

The biggest culprit might be math. Are you factoring in the size of your tires? 285/75/16s change the revs per mile by about 5-8%. Factoring that in, you might be getting more like 12mpg which would make sense given your weight and roof rack. Also what tire pressure are you running? 38F/41R PSI, no roof rack and factor in the tire size to your odo reading and you should be averaging 14ish mpg.

Get a scangauge II to monitor your throttle position and instantenous mpg.

 

[Kigiin]

Add steel bumpers and a winch.

 

[petrotk40]

Wow, pegasis you are on a roll. Is it your goal to be a sarcastic a****** on every thread you open?

 

[Kigiin]

No, just a select few.

Just kidding - jeez, relax and lighten up a bit.

How old are your front o2 sensors - some, not me, have reported MPG gains after replacing?

 

[r2m]

Several suggestions:
1. If you are going to go through the trouble of bolting your rack on once or twice a year, then do the same with tires. get a second set of cheap wheels, and get some hard, low rolling resistance, stock diameter tires and swap out wheels when you want to go wheeling/off roading. If you do that, keep the air pressure at the maximum recommended PSI.

2. Then take out/off everything of weight, third row seat, second row if don't need to haul kids or associates. Anything that will reduce the weight.

3. Amsoil everything! Engine, Tranny, Diffs. Anything Amsoil has a product for.

4. Repack all bearings.

5. Make sure your brakes are perfectly flat and not warped. Get new rotors and pads if necessary.

6. Wash and wax your rig to a fine luster. And keep that way.

7. Add a low restriction air intake and exhaust, whether it's a cat-back system or headers on back. The freer your truck can breathe, the better your MPG.

8. Add a high energy ignition system. Coil, plugs and wires. The more thoroughly your truck can burn fuel the better MPG.

9. Adding a snorkel helps too. Ram air, plus cooler air coming in from above rather than warmer air from the engine area.

10. Make sure your throttle body is clean, perhaps an upgrade?

11. Reduce any excess electrical drain if you have any. Pulling a lot of amps off your alternator requires HP stolen from the engine.

There might be more, but this is guaranteed to increase your mileage by a significant amount.

Hope this helps!

 

[jeetS]

In my humble opinion, an air intake only decreases fuel consumption... that's been my experience anyway. I've done it to several of my past daily drivers and always seem the numbers go up.

I think its because more air coming in = more fuel being added to keep the mixture right...

 

[r2m]

In my humble opinion, an air intake only decreases fuel consumption... that's been my experience anyway. I've done it to several of my past daily drivers and always seem the numbers go up.

I think its because more air coming in = more fuel being added to keep the mixture right...

Refer to item 7. If you're allowing more air in, you need to be able to exhaust more gas (exhaust) that's why when you do an air intake or low restriction intake, you should do your exhaust also!
Sooo many people will do one or the other, but not both and wonder why they aren't getting the performance/MPG they thought they should, or read about. If you pushing more air in, make sure you're letting as much out.

 

[TheFuzz]

I've been consistently getting 11.5mpg. I think that elevation combined with the crappy ethanol blended fuels up here really kills mpg on these things. I replaced my 02's last year with no net benefit. I'm due for an oil change so I think I'll do that, clean the MAF and throttle body again, and pull a spark plug to see how they look (and if necessary, replace them). Other than that, I'm about ready to plunk down the $250 on a K&N intake. It certainly couldn't hurt at this point, and maybe it'll make this pig a little more fun to drive.

Honestly, I was getting ready to throw my rig up in the classifieds and get another Tahoe, but I don't think that another car loan is in the cards right now even if I sell the cruiser. Might as well throw a little money at it in the mean time.

I know that lower mileage is to be expected with these things when you add the heavy stuff, but I've pulled the third row seats, taken out the roof rack crossbars, gone from 305s to 285s, and the mileage hasn't changed. When I was stock, I was getting 12.5-13mpg. Bleh.

 

[Manhattan]

No, just a select few.

Just kidding - jeez, relax and lighten up a bit.

How old are your front o2 sensors - some, not me, have reported MPG gains after replacing?

Dude, go back and read your posts - ALL of your posts. Sarcasm works when you pretend to be a dick every once in a while... when it's out of the ordinary. When it's ordinary... you're just a dick.

I went from 17-19 mpg on the highway when the 100 was all stock. That was street tires, no aftermarket rack, etc., and driving 65-70mph. With the Yak rack, 275/70/18s (BFG ATs) and a .55" bump in the torsion bar... I'm consistently at 15 mph.

But - given the option to drive the 100 or my wife's 2008 MDX - which gets MUCH better mpg, we drive the 100. My rationale is this: The Land Cruisers don't depreciate with miles at the same rate as other cars/trucks/SUVs - buyers simply aren't afraid of miles on a Land Cruiser. So, while it cost more in fuel to drive the 100, in the long run, it's not as bad as it may appear.

 

[watchknut]

I am not looking to get 15+ on the hwy understanding all of the mods on the truck, I just want it to be in the 12 to 15 range as the truck will have a mix of city and hwy driving. Luckily it is not my daily driver with my 50 mile round trip commute.

In August I will have my future father in law (he is a mechanic) take a look at everything that was mentioned on here.

I do appreciate all of the tips and time that people spent with responses. Hopefully I will be getting more mpg on the very near future.

 

[DuckLN]

You can believe this or not but my buddy has a 1998 tacoma 4x4 with 33's. He drives about 50 miles back and forth to work everyday and bot fuel at the same station to ensure testing was as close to accurate as possible. He changed all his fluids out with Amsoil and ran the same trip and got the exact same MPG's with full amsoil. Since this guy is a known nerd when it comes to fluids and such, I trust his test 100%. He was really hoping for a noticible difference but as far as im concerned, the amsoil myth of better MPG's is busted.

 

[yuji]

You can believe this or not but my buddy has a 1998 tacoma 4x4 with 33's. He drives about 50 miles back and forth to work everyday and bot fuel at the same station to ensure testing was as close to accurate as possible. He changed all his fluids out with Amsoil and ran the same trip and got the exact same MPG's with full amsoil. Since this guy is a known nerd when it comes to fluids and such, I trust his test 100%. He was really hoping for a noticible difference but as far as im concerned, the amsoil myth of better MPG's is busted.

I haven't done my research on this topic, but I'm just VERY wary of anything easy (like an additive once every XXXX miles) that increases MPG by a noticeable factor. It seems like the world (manufacturers, consumers) have too much to gain by a simple "fix" to increase MPG to not write about it everywhere / recommend / require it in their manuals, etc.

Thanks for the heads up.