Changing over to a part time 4WD and fuel economy. (1 Viewer)

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I've been tossing around the idea of maybe changing over to a part time 4WD, and I was wondering what I could expect to gain in fuel economy. This is a bone stock '92 (4.0L i6), running 32"x10.5" tires, and I'm currently averaging just under 13mpg for all around driving (city and hwy).
 

Dave 2000

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You are not going to gain a lot I am afraid, and you will find the road manners are different as well, I say that but it depends on your typical driving style. Concentrate on keeping your 80 well serviced, tyres correct pressure.....blah blah...you will fair better in the long run.


Regards

Dave
 
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The only situation where I've seen an increase in mpg is in long freeway drives, sticking to the speed limit.

It's absolutely not worth doing for fuel efficiency. It's great if you are trying to avoid front driveshaft vibes or reduce wear on front end components.

Handling in poor weather is significantly worse than stock. It's annoying having to activate the transfer case lock to get moving when you're facing uphill, half on a patch of wet snow, then immediately having to unlock again because you're turning in an intersection where all the snow has cleared.
 
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13 is not bad at all for a 3FE 80.
I did worse than that with part time 4WD FJ62 (11 MPG). My driving was almost exclusively within a small town though, with few runs longer than 9 miles.
 

White Sheep

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I thought about a part-time kit once upon a time. I think the only thing it'll allow me to do it burnouts and put more stress on the front end.

Some people love the part-time kit, but this guy from Africa that argues against the part-time kit.

 
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13 is pretty good for your 3fe, I got anywhere from 12 - 16 depending on the drive with my 91.

Keeping everything in the fuel and evap system up to par is your best bet for fuel efficiency. That and stock tires along with driving habits.

My current 97 is part time and the best I have got so far is 15mpg's and average about 13. So it doesn't do any better than my old 91.
 
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I thought about a part-time kit once upon a time. I think the only thing it'll allow me to do it burnouts and put more stress on the front end.

Some people love the part-time kit, but this guy from Africa that argues against the part-time kit.


Its has its uses. Its great if you blow up a birf and want to limp your 80 off the trail. It also helps me keep street miles off of my rcvs. For most people, it’s not very useful
 
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Its great if you blow up a birf and want to limp your 80 off the trail.
I also thought that was an advantage, until I realized that you can accomplish the same thing by locking the transfer case, removing the front drive flanges, and removing the front drive shaft.
 
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I also thought that was an advantage, until I realized that you can accomplish the same thing by locking the transfer case, removing the front drive flanges, and removing the front drive shaft.

That sounds a lot harder than locking some hubs lol.

Another advantage is a way longer service life on the front axle components and an ability to run more lift with less tinkering on the front to try and get rid of driveline vibes
 
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That sounds a lot harder than locking some hubs lol.
But much, much easier than pulling the rear drive shaft, rear transfer case extension housing, and back cover of the transfer case to install the part time kit in the first place. I'm just saying that the arguable convenience in solving a theoretical trail breakdown is not worth giving up the nice handling and operation of Toyota's "full-time 4wd" system.

But yes, if you want to 1) preserve the front end components, or 2) avoid unsolvable front end vibes, then part time is the way to go.
 

Dave 2000

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IIRC I was answering this question 8 years back or so, and there was all sorts of arguments about the various advantages/disadvantages, one argued about do tail outs around bends now the front was not being driven, I told him to go and sell his 80 and buy something more appropriate, the 80 was not designed for 'drifting', not sure it got through, but then the same advice to forget three linking the front suspension also got ignored (unsure if it was the same guy), that ended in tears with the 80 crashed and rolled.

Good to see the OP asked for advice, you can't be experience.

Regards

Dave
 

Dave 2000

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Another advantage is a way longer service life on the front axle components and an ability to run more lift with less tinkering on the front to try and get rid of driveline vibes
I agree with the comment about drive train vibes but rarely an issue unless you are going over 2", most lifts over that are for the 'look at me' point of view, damn I can barely reach over my engine (5'10") right now and my 80 presently has a loaded roof rack on it! 3" and higher for bigger (read heavier) tyres and wheels are not going to do much for economy, IMO these are trail vehicles only (where they can work well) and have no advantage on the typical highway.

Stay safe

Regards

Dave
 
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I've been tossing around the idea of maybe changing over to a part time 4WD, and I was wondering what I could expect to gain in fuel economy. This is a bone stock '92 (4.0L i6), running 32"x10.5" tires, and I'm currently averaging just under 13mpg for all around driving (city and hwy).
To satisfy your curiosity, simply pull your front propshaft, lock the CDL, and drive around for a few tankfulls.

I've been doing exactly that recently due to a noisy front diff.

Can't say I've recorded lower fuel consumption and, IMO, while it certainly drives 'nicer' with reduced driveline backlash, it doesn't feel as sure-footed in 2WD. I think it would be chalk & cheese on Alaskan roads 95% of the time!
 

Dave 2000

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Agreed, the later models have a 'Viscous coupler' to avoid some of the drive train backlash and was fitted in the later than around 93, and of course works well with the ABS.

Regards

Dave
 

mudgudgeon

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I agree, not worth the effort for an almost unrecordable change in fuel consumption.

And handling is negatively compromised.

I ran more than one cruiser in rear wheel drive long term with front shaft out and hub flanges removed due to no funds to fix busted birf, or diff. Daily driving and tracking fuel costs.
No difference.
 

Dave 2000

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I thought about a part-time kit once upon a time. I think the only thing it'll allow me to do it burnouts and put more stress on the front end.

Some people love the part-time kit, but this guy from Africa that argues against the part-time kit.




Well it is good to see that something I and many others pointed out over the years (me being a time served mechanic to boot) has been vindicated by someone who has been a 'professional' off tarmac user, now all I need to do is prove that having an electric cooling fan something that makes your AC more effective and along with being more efficient and of course does give a lot more room around the engine bay.

Regards

Dave
 
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John Young

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I thought about a part-time kit once upon a time. I think the only thing it'll allow me to do it burnouts and put more stress on the front end.

Some people love the part-time kit, but this guy from Africa that argues against the part-time kit.


Psst! Australia, not Africa, but he spends a lot of time in Africa and traveling.

My Middle East 80s are all part time 4WD. I am nevertheless looking at installing locking hubs to reduce front end wear and tear. Likely I will put in the hubs on each next time they have a serious front end service.
 

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