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TutorN1

Another gas mileage question

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Ok, here's what I'm running into. I just bought a 99 R50 SE 4x4 with the manual transfer case, 3.3L with the auto tranny. It has 163,xxx on it.

I had before this one a 95 WD21 SE 4x4 with the manual transfer case, 3.0L with the manual tranny.

 

The 95 was knocking, and using oil, but I could count on it to get 18mpg, every time! That's on paper, not guessing.

My 99 tho the best I have ever got out of it so far is 14.8 - 15.

 

To say I was shocked would be a stretch, but was only thinking I might loose half to one mile per with the change from manual to auto.

 

I've read to put manual hubs on, but I was wanting to know if there really was that big of a drop in mileage between the WD21 to the R50?

 

Or did I have a fluke WD21?

The tires on the 95 were 31 BFGs T/A

The 99 is running nexems hwy tread size might be 30.

 

If I do the hubs,I've read that I could pick up the mileage to what I'm looking for.

I didn't have manuals on the 95, that's what's getting me here.

 

Any input?

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Sounds like the combination of the 3.3L and the automatic transmission is causing this issue. Manual hubs might improve it, but not noticeably maybe 1 mpg

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Would the manual tranny in the R50 help?

 

Reason this is starting to be an issue is because I'm driving 50-60 miles everyday. This combined with some other unfortunate events with the truck is taking out my funds to do any extra mods.

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I noticed a difference in my 95 wd21 when I did the auto to manual swap, don't remember the exact number but it was noticeable, depending on how you drive it.

 

Also things like air filter, check your fuel lines, any exhaust issues things like that would decrease mpg

 

Manual hubs, if you have another reason besides fuel savings and have some money to spend then I would get them. But the cost for them would take you more than a year to make it worth it. Personal opinion

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Ok, those are all things I need to check then. Air filter is good I know, just change it.

 

The hubs I would like to do any way, but it's hard to make the math add up for just the little mpg it would get me.

 

I hate to say this but I do drive like grandpa on Sunday afternoons. Ever more so now with trying to get the best mpgs I can.

 

Beside we all know these are not Zs, but it can get me in and out where a Z could never go.

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Thats pretty much what I get on a consistent basis in city traffic. If you are highway and keep the cruise set for 90% of the trip. Then you should be doing a lil better, 16+.

Check plugs, clean MAF, make sure O2s are good and reading good. (Check actual readings vs just waiting for a SES light.), change fluids; gear oil etc. Normal stuff really.

 

Honestly, once you are in any kind of stop n go traffic. MPG tanks with my R50. But on trips where I can keep the cruise set for 55-65 for 200+ miles. I easily get 17+ with full load. Empty I creep up on 20+mpg.

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Check the exhaust manifolds for cracks, air can get in between them and mess with the O2 sensors. at least that is what i am hoping to case is with my pathfinder and why my mileage is around 13-14.

 

-Kyle

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Thats pretty much what I get on a consistent basis in city traffic. If you are highway and keep the cruise set for 90% of the trip. Then you should be doing a lil better, 16+.

Check plugs, clean MAF, make sure O2s are good and reading good. (Check actual readings vs just waiting for a SES light.), change fluids; gear oil etc. Normal stuff really.

 

Honestly, once you are in any kind of stop n go traffic. MPG tanks with my R50. But on trips where I can keep the cruise set for 55-65 for 200+ miles. I easily get 17+ with full load. Empty I creep up on 20+mpg.

Most of my driving is on hwy, usually around 60-65mph. I'm running it with No extra weight, that's where I hit the 15mpg this last time.

 

Goin to start goin through the fluids. Goin to start with rearend first & move up the line.

 

While fluid is in the topic, does anybody run the Royal Purple motor oil? I've got a few folks here that swear by it. One run it In his 80's model 626, I think. The model that can out in the states with all wheel drive & al wheel steer. Other guy runs it in his drag car.

 

Both say it's a highly detergent, & cleans the inside of the block. The down side is that you have to start replacing seals, bc it make the old one leak. Put new ones on your good.

 

Both of these guys had rebuild there motors fresh when they put it in, so they didn't run into that.

 

NT

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Check the exhaust manifolds for cracks, air can get in between them and mess with the O2 sensors. at least that is what i am hoping to case is with my pathfinder and why my mileage is around 13-14.

 

-Kyle

On the O2 sensors, where are they located? Better yet, when I put new manifolds on, & pipes can I by pass some of the O2 sensors?

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I will agree with what REBELORD said.

do a full tune up type job...fluids, spark plugs, keen the MAF. don't for get the diffs.

check air pressure regularly.

as far as the Royal Purple goes, I have no first hand experience. I do run Mobil 1 High Milage, It tends to keep the engine running nice and quiet and after switching to it the first couple of changes were quite dark at change time. It is noticeably cleaner now.

hwy speed is important as well. I've notice a huge difference in milage between driving at 100km/h and 120km/h (60-75mph)

temperature is important as well. My fuel milage in winter is half of what I get in summer. :angry:

As far as the O2 sensors, you have 4. Two in the intake manifold and 1 in each exhaust manifold. they measure oxygen levels that allow the ECU to adjust air/ fuel mixtures. they are part of the emissions system. I'm not sure if you can delete them.

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No reason to use Royal Purple oil over anything else. Pennzoil has big advertising about their oils keeping engines cleaner, so try any of their oils for a while. Mobil 1 HM and just about any other high mileage oil will have a lot of detergency additives as said above.

 

OBDII will complain if you remove the rear oxygen sensors and the cats. You shouldn't touch the cats unless they're clogged, the ECM is designed to operate with them present and I doubt you will gain any fuel economy by their removal.

 

Use synthetic 75W-90 gear oil in the rear differential and front (if applicable). Use synthetic ATF (Valvoline MaxLife is great and is relatively inexpensive) in the transmission transfer case, and power steering. Ensure tire pressure is correct. Run a 20oz bottle of Chevron Techron fuel system cleaner through a tank of gas, then change the fuel filter. Change engine air filter if not done recently. Don't use anything higher than 89 octane. Drive less aggressively.

Edited by Towncivilian
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I was getting about 12 mpg when I first got my R50 & it ran like a old dog. I Seafoamed it, changed the plugs, air filter, cleaned the throttle body, etc & I started getting about 14-15 mpg. I installed electric fans & manual hubs & I was getting close to 20 on the freeway at 70mph. Unfortunately, I started putting crap all over the outside, (just ask Precise1. :lmao: off road light, sand ladders, roof rack with spare tire, etc), added a heavy bumper & some other weight so now I'm back down to around 14-15 mpg average, including off road. I get about 16 on the freeway according to my Ultragauge. Manual hubs WILL get you some extra mpg, if you're not driving the front axles & front drive train then that's extra power & mpg you free up (same thing with an electric fan). I can really feel a difference when I have the hubs engaged, a lot less "oooomph" :laugh::laugh:

 

Manual hubs are also good to save wear & tear on the front drive train, with IFS the weakest parts of the drive train are the CV joints & drive shafts.

 

 

Edited by theexbrit
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I run some fuel treatment through in the first couple of weeks of having it. I was getting worse, like theexbrit.

 

Trying to get everybit of MPGs out of mine before adding extra weight on add-ons. The hubs would be a good start in mods, bc they would pay for themselves, eventually. 😁

 

I know I need to do a full tune up, had it in mind once taxes came in. That will cover rearend to the wheel bearings in the front.

 

So I know there will be more questions to come. Thanks for all the info on where to start.

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Yep, the hubs should make a difference on the freeway, we saw +2mpg to hit 20mpg. This is with 170k miles, but tuned up.

Unfortunately, so many little things can affect the mileage that it becomes a percentage game. Tune up, tire size/tread/presure, fluids, brake drag, drive train bind, driving habits, etc.

 

TheExBrit in 5 more years...

 

160355.jpg

 

:D

 

B

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I run some fuel treatment through in the first couple of weeks of having it. I was getting worse, like theexbrit.

Not all fuel treatments are effective. Those containing PEA (polyether amine) are the most effective and is also what is found in top-tier fuels (Chevron, Shell, Mobil, etc). Fuel system cleaners containing adequate amounts of PEA are Chevron Techron (not the "ProGard fuel injector cleaner"), Gumout Regane, Redline SI-1, CRC Guaranteed To Pass (not worth the higher price over the others), probably one or two more I'm missing. I'd go for Gumout Regane from Walmart since it's the cheapest and is equally effective as Techron.

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Remember also, Depending on where you get your gas. You may be getting up to 15% or more ethanol blend. Which ethanol is horrible for gas mileage. Check that out where you get your gas.

As for finding non ethanol blended gasoline. Unless its the same price and close (dont have to drive 10miles to get it), you can try some. See if it makes a difference. But most non ethanol gas you will find is called "90 Rec". Usually sold by marina's for boats. I have 90 Rec available to me for free or cheap. I tried it out for 3 tanks worth. Didnt make a difference at all honestly.

 

Oil wise. Mobil 1 5-30 HM fully synthetic is cheapest at Wal-Mart. ~$24 for a gallon/5qt jug. Plus they should have the Bosch filters there also which are good to run. Which the Bosch is slightly bigger than stock too. Dont run a Fram filter. Anything but Fram. I used to run Royal Purple in my LS1. But that was a street/strip car.

 

Your 02 sensors. 4 of them, two before the main cats, two after. There are a second set of cats aft of the rear O2s. But having a shop remove them will probably NOT happen. As it's illegal. But it is possible usually with a cash only place *cough*cough*.

/hijack: this thread has reminded me. I am due for a oil change,spark plug check and fuel filter change. Did the plugs about 50k ago. But did the standard NGK, not the OEM platinum. /end

 

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Would Theexbit and Precise1 agree with at least 10% better mileage with manual hubs? I put mine on 50,000kms ago. With my math that means 5,000kms free. Not to mention wear and tear on the front end, noise etc.

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Your 02 sensors. 4 of them, two before the main cats, two after. There are a second set of cats aft of the rear O2s. But having a shop remove them will probably NOT happen. As it's illegal. But it is possible usually with a cash only place *cough*cough*.

 

There are actually two "pre-cats" close to the exhaust headers, then the typical main cats you would expect afterwards which are monitored by the rear O2 sensors. At least, this is the case on VQ35DE R50s.

Edited by Towncivilian

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At least on my 3.3L it goes: O2 -> Main Cat -> O2 -> Aft Burner Cat

The front O2 are the main ones that determine your A/F ratio. Then the exhaust gasses are to be burned up by the main cats, the rear O2s are there to make sure the mains are working and burning correctly. The aft burner cats are a extra set to burn any extra that may not have been completed.

Pretty much the same setup on my old LS1 car. Hence when we would put in long tube headers, we would use O2 sims for the rear O2s to trick the ECU into thinking the readings where correct. But then ECU editing programs where able to just delete them period. Which was fun!

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Would Theexbit and Precise1 agree with at least 10% better mileage with manual hubs? I put mine on 50,000kms ago. With my math that means 5,000kms free. Not to mention wear and tear on the front end, noise etc.

I won't guarentee 10% increase, but I will say they seem to make a difference on the highway and we experienced a 10% mileage increase when I installed them. Around town still sucks though... :D

 

You might have gotten the mileage 'for free' but the wear items other than the front CVs don't care about that.

 

What did you pay for the hubs and what does your gas cost on average?

 

B

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I don't do any city driving. The other parts don't care about what the front axles, diff. etc are doing as far as wear. The hubs were about $200 and right now gas is going for about $1.28 per litre around here. I think that's about $5.88 Imp. gallon. Not sure off hand in U.S. gallons. Any way it's over $110 to fill my tank and I' sure I've saved at least a few tanks over the last 3 1/2 years.

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Yep, the hubs should make a difference on the freeway, we saw +2mpg to hit 20mpg. This is with 170k miles, but tuned up.

Unfortunately, so many little things can affect the mileage that it becomes a percentage game. Tune up, tire size/tread/presure, fluids, brake drag, drive train bind, driving habits, etc.

 

TheExBrit in 5 more years...

 

160355.jpg

 

:D

 

B

 

:laugh: :laugh: :laugh::rofl: :rofl:

 

"I'll tell you a story 'bout a man named Jed, worked real just to keep his family fed................"

 

You're just jealous that my caR50 can have all that @!*%e strapped on, get 1/2 decent gas mileage & still go off roading :jig:

 

 

 

@kdj, $200 seems a lot for hubs, my Mile Marker hubs were under $100 (us). Are your hubs Warn or some such?

 

 

Edited by theexbrit

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Remember also, Depending on where you get your gas. You may be getting up to 15% or more ethanol blend. Which ethanol is horrible for gas mileage. Check that out where you get your gas.

As for finding non ethanol blended gasoline. Unless its the same price and close (dont have to drive 10miles to get it), you can try some. See if it makes a difference. But most non ethanol gas you will find is called "90 Rec". Usually sold by marina's for boats. I have 90 Rec available to me for free or cheap. I tried it out for 3 tanks worth. Didnt make a difference at all honestly.

 

Oil wise. Mobil 1 5-30 HM fully synthetic is cheapest at Wal-Mart. ~$24 for a gallon/5qt jug. Plus they should have the Bosch filters there also which are good to run. Which the Bosch is slightly bigger than stock too. Dont run a Fram filter. Anything but Fram. I used to run Royal Purple in my LS1. But that was a street/strip car.

 

Your 02 sensors. 4 of them, two before the main cats, two after. There are a second set of cats aft of the rear O2s. But having a shop remove them will probably NOT happen. As it's illegal. But it is possible usually with a cash only place *cough*cough*.

/hijack: this thread has reminded me. I am due for a oil change,spark plug check and fuel filter change. Did the plugs about 50k ago. But did the standard NGK, not the OEM platinum. /end

 

 

What's so bad about Fram filters?

 

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Warn on Summit, $180 shipped, not bad, i have no clue what i paid for mine 2 years ago, i think i paid like $168? if i had to guess, but mile markers are CHEAP.

 

I would get the MM's if you are just after mileage, both the Warn's and MM's do the same thing, i went with WARN's after reading about the good customer service and several people saying they broke MM's out the trails, but that's when i was making my pathy into a trail rig, with plans of lifting her...

 

http://www.summitracing.com/parts/wrn-29091?seid=srese1&gclid=COmDlpH0sbwCFQPZQgodun8ACA

 

-Kyle

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