Re-gear for better MPG?

[ifewel]

Hey guys,

I just bought my 2000 supercharged V6, 5 speed, which I think has 4.10 gears. 90% of the time I will be driving it on the street. Currently, if I'm driving 75, it's pushing 3000 rpms.

I think my 2wd runner had 3.9s, is it possible to swap these into a 4wd, and will it net the result I'm looking for? Or do i need to get rid of the supercharger if I want to see any increase in fuel economy (probably not gonna happen )?

Let me know if there are any other options you can think of.

 

[IanB]

Keep in mind that if you do regear, you need to do both the front & rear diffs on a 4x4, so the gears from a 2wd won't work without a matching gear for the front diff.

 

[zacattack20]

I vote for get rid of the supercharger. And since I'm local, I'll do you a favor and dispose of it for you. Haha

 

[PitbullRescuer]

What kind of mileage are you getting? Most guys with S/C's seem to do better than the rest of us, at least when they keep their foot out of it. I would think with the SC/5 speed combo you should be doing better than 20 MPG highway.

 

[ifewel]

What kind of mileage are you getting? Most guys with S/C's seem to do better than the rest of us, at least when they keep their foot out of it. I would think with the SC/5 speed combo you should be doing better than 20 MPG highway.

I'm getting around 16-17 mpg mixed.

 

[PitbullRescuer]

That's not terrible really. How's the maintenance? Plugs, wires, Fuel Filter, Air Filter, O2 Sensor, PCV Valve? Have you cleaned the MAF and TB lately? You might pick up some MPG's there.

Honestly, regearing just for MPG's isn't a great investment. You'll be measuring it in pennies over a very long period of time.

Also, 75 MPH might be your problem. I never believed it when other told me, but just south of 70 seems to be the sweet spot for highway MPG's on these things.

 

[ifewel]

Thanks Pitbull. I'm new to working on and learning about my car, so I'm trying to apply what I have observed from my automatic 2wd V6 runner to this 5 speed 4wd supercharged runner. I was getting 19-20 mpg mixed in the 2wd, and I was expecting a decrease in mpg, but I thought it would be less than what I'm seeing. I mostly wanted reassurance that this was normal.

 

[PitbullRescuer]

It's pretty normal but going through all the maintenance items above will help if they're not up to date already. More than anything though, enjoy the truck for what it is.

 

[4-Ripcord]

Yup, clean the MAF/TB maybe a new air filter and keep her under 70. You'll see much better numbers.

 

[Sherwood4Runner]

Maybe your 2wd might have had slightly better mpgs from the reduced front end resistance (no front differential and gears to turn even in 2wd). I know some 3rd gen guys end up swapping in selectable locking hubs on there 4x4 to improve gas milage by 1 or 2 mpg. That also is not a very inexpensive swap.

 

[theizzardking]

Also, 75 MPH might be your problem. I never believed it when other told me, but just south of 70 seems to be the sweet spot for highway MPG's on these things.

all of what pitbull said is 100% right on the money especially this last part, no SUV does good with fuel economy at those speeds especially the older ones just due to aerodynamics, these things since the way they are shaped can only move so much air around them before they start pushing a massive wall of air which really starts eating the mpg's .
this is the main reason why the national speed limit was reduced back in the 70's and aerodynamics in vehicles started to become more prevalent. you cannot expect to be doing 75-85 in these things and get great gas mileage.

also i don't know about your build but i see you have a roof rack that takes a few mpg's , and you probably got bigger tires as well since your talking about re-gearing so that's a few more mpg's, so basically you keep doing things to the truck that takes away from what is already less then stellar mpg rating and as mentioned by pitbull before swapping gears is the most expensive way to get those mpg's back, your really better off doing like what others have said here, keeping up on maintenance making sure sensors are clean/clear and are operating within spec and beyond that you're really better off just pulling some of the things you've added to the truck to get the mpg's back where you want them......


75mph's at 3k isn't terrible not bad enough where it would be strongly suggested you re-gear ,basically with that you shouldn't have to re-gear, i would say though that re-gearing is a better option then adding manual locking hubs or a cyclone fuel dispenser, lol.....

realistically though you should just live with it and see what you can do to get a mile or two back from maintenance and keep your foot off the gas....

 

[Baja Runner]

If you're worried about high RPMs on the highway then the best fix for that is larger tires !! C'mon now !!

 

[RIDEALL]

If you're worried about high RPMs on the highway then the best fix for that is larger tires !! C'mon now !!

Lol!!!
Beat me too it!

The battle of Mods vs MPG will drive you bonkers every time. Wish I never paid attention, ignorance is bliss;-)
I try not too worry about it, however still try too get the best I can.