2012 Toyota Tacoma Double Cab 4X4 MPGs....

[aardvarcus]

To the best of my knowledge, there are the available configurations for 2005+ Tacomas:

4x2 Non Prerunner Double Cab:
2.7l 4 Speed Auto

4x2 Prerunner Double Cab:
2.7l 4 Speed Auto
4.0l 5 Speed Auto

4x4 Double Cab:
4.0l 6 Speed Manual
4.0l 5 Speed Auto

4x2 Non Prerunner Access Cab:
2.7l 5 Speed Manual
2.7l 4 Speed Auto

4x2 Prerunner Access Cab:
2.7l 4 Speed Auto
4.0l 5 Speed Auto

4x4 Access Cab:
2.7l 5 Speed Manual
2.7l 4 Speed Auto
4.0l 6 Speed Manual
4.0l 5 Speed Auto

4x2 X-Runner Access Cab: (discontinued 2014)
4.0l 6 Speed Manual

4x2 Non Prerunner Regular Cab: (discontinued 2015)
2.7l 5 Speed Manual
2.7l 4 Speed Auto

4x4 Regular Cab: (discontinued 2015)
2.7l 5 Speed Manual
2.7l 4 Speed Auto

[aardvarcus]

If I was buying a Tacoma with and auto and expected to drive it “reasonably nicely” like a normal person (think cruise and not flooring it), I would expect the automatic transmission models to just about equal their EPA estimate within a MPG or maybe two. If you want to do better than that you would probably need to modify the vehicle.

If I was buying a Tacoma with and manual and expected to drive it “reasonably nicely” like a slightly eco-conscious person (think cruise, not flooring it, coasting on steep hills, etcetera), I would expect the manual transmission models to beat their EPA estimate by several MPGs. If you want to do better than that you would probably need to drive differently (P&G, DWL) or modify the vehicle.

These are just my expectations from my experiences with several Toyotas in auto and manual form. All this goes out the window with excessive idling, stop and go, bolt on accessories, aggressive tread pattern tires, heavy wheels, lifts, high speeds, etcetera.

[Asanelli]

are there any possible economy gains to be made from the removal of the front drive shaft when 4x4 is not needed?

[Asanelli]

Originally Posted by aardvarcus

If I was buying a Tacoma with and manual and expected to drive it “reasonably nicely” like a slightly eco-conscious person (think cruise, not flooring it, coasting on steep hills, etcetera), I would expect the manual transmission models to beat their EPA estimate by several MPGs. If you want to do better than that you would probably need to drive differently (P&G, DWL) or modify the vehicle.

What about with respect to the V6?? I see your experience is with the 4 cylinder, any thoughts on the V6??

[aardvarcus]

There are no gains due to disconnecting the front driveshaft. The transfer case and the front differential both have electronic disconnects, thus the front drive shaft is not spinning when the truck is in 2WD. Note everything outboard of the front differential on the front end is spinning, such as your CV joints, and due to the function of the front axle disconnect some components within the differential are also spinning. Slight gains could exist for swapping over to lockable/un-lockable hubs like the older Tacomas had.

I have no direct experience with the V6, but I have some opinions. I will type them out here when I have time.

[aardvarcus]

Fundamentally, from the perspective of I4 versus V6, the I4 has less displacement (captain obvious I know) so typically it will be operating at a higher % of load, which should be at a higher BSFC. This is muddied somewhat by the fact that Toyota put vastly different gear sets in the different configurations, so for a given cruising speed the RPMs of the engine and also the partially loaded BSFC will be different. One counterpoint to that is that the V6 is a completely different, more technologically advanced engine. This should improve its BSFC figures.

One way to try to wrap our minds around the differences is to look at the Toyota provided estimates for mileage. For consistency, all the models will be the Access Cab version, for an apples to apples comparison (The double cab and regular cab figures won’t be vastly different, but are only available in more limited configurations versus the access cab which is available almost however you want.

4x4 V6 5 Speed Auto (3.73 Rear End, 0.72 Overdrive)= 16/21 City/Hwy MPG

4x2 PreRunner V6 5 Speed Auto (3.73 Rear End, 0.72 Overdrive)= 17/21 City/Hwy MPG

4x4 V6 6 Speed Manual (3.73 Rear End, 0.85 Overdrive)= 16/19 City/Hwy MPG

4x2 PreRunner I4 4 Speed Auto (3.58 Rear End, 0.71 Overdrive)= 19/24 City/Hwy MPG

4x2 I4 4 Speed Auto (3.58 Rear End, 0.71 Overdrive, Smaller Size Tires)= 19/24 City/Hwy MPG

4x2 I4 5 Speed Manual (3.31 Rear End, 0.81 Overdrive, Smaller Size Tires)= 21/25 City/Hwy MPG

4x4 I4 4 Speed Auto (4.10 Rear End, 0.71 Overdrive)= 18/21 City/Hwy MPG

4x4 I4 5 Speed Manual (4.10 Rear End, 0.81 Overdrive)= 18/21 City/Hwy MPG

I will draw a few conclusions from these numbers, realizing these are imperfect estimates from EPA.

You will notice that typically in the 4x4 versions, the V6 gets taller rear end gearing, but in the 4x2 versions the I4 gets taller rear end gearing.

You will also notice for the V6, the prerunner automatic and the 4x4 automatic which are almost identical trucks with identical gears get exactly the same highway MPG. Interpreted differently, the CV shafts, differential, driveshaft, and transfer case are not significantly hurting the highway MPG as long as identical gear sets are used. The differences in weight and friction are quite minor for highway MPGs, but you can see the city MPGs are lower probably due to weight. You can see for other configurations, different gearing is used which punishes the MPG of the 4x4 models.

You will notice for the V6, the really short overdrive gear in the manual transmission is the reason for the manual to have such poor highway MPG numbers compared to the automatic.

Comparing the I4 prerunner and the V6 prerunner, which have only a 6% difference in gearing in favor of the I4, the I4 posts over 14% better highway MPG. Most of the other configurations have such different gearing it is impossible to compare V6 to I4.

Comparing the I4 prerunner auto to the I4 non prerunner auto, notice the hwy MPG numbers are the same. Notice this is despite the non-prerunner being smaller, no wheel fender extensions, less ground clearance, 165 lbs lighter, having a lower CD of 0.368 versus 0.394, and identical* gearing. The reason is the non-prerunner has less “rubber gearing”, as the tires are roughly 12% smaller in diameter than the prerunner.

Comparing the 4x4 I4 auto to the V6 auto, you can see the highway MPGs are the same. I attribute this mainly to the 9% difference in gearing.

I hope that these comparisons have illustrated that the gearing in these trucks has a huge impact on the MPGs you can expect out of them in addition to the selection of a I4 or V6 engine.

One point of note is that there are kits for the V6 trucks to swap in a T56 manual transmission, which could give you an appropriate overdrive to make up for the less than ideal gearing. I feel that with a very tall overdrive (like the available 0.5) the V6 Manual could put out impressive highway mileage figures.

I would still maintain my opinion that the automatic transmission trucks will probably get close to their EPA estimates when driven reasonably nicely in stock trim, V6 or I4. My opinion is that the manual transmission trucks will beat the EPA estimates when driven reasonably nicely in stock trim. This is probably more true for the I4 (which I have experienced personally) and less true for the the V6 due to the stock gearing.

Remember all the above figures are all for the stock trim, aka stock amounts of drag, friction, etcetera. My opinion is that the more you mod the truck and the more you drive like a hypermiler the more of a gap will widen between the I4 and the V6 as well as the manual versus automatic.

[Asanelli]

So changing final drives and overdrives would likely give dramatic economy gain, with respect to the V6 4x4 6 spd manual??

[aardvarcus]

Yes, my opinion is that gearing changes could dramatically improve the V6 4x4 manual fuel economy. Note there are no taller differential gears that will fit the 4x4s because of the front differential. The 3.73 already in the V6 4x4 is the tallest offered for the front. The only taller gear sets are only for the rear differential. Barring having custom gears ground or modifying your differential somehow, the only real “bolt on” option for taller gearing would be swapping a transmission.

For a V6 4x4, you would probably need to use the URD T56 Swap Kit with a Rockland Standard Gear Tremec T56 6 speed transmission for 4 wheel drive pickup trucks. This transmission will have 5 or 6 bolt flanges with 27 or 32 spline output shafts to accept Chevy, Ford or Dodge transfer cases.

Obviously none of this would be cheap! Possible doesn’t mean practical.

[Asanelli]

Is there any use in looking into different tires in order to accommodate a lower engine rpm??

[BamZipPow]

Originally Posted by Asanelli

Is there any use in looking into different tires in order to accommodate a lower engine rpm??

When most 4WD owners lift their trucks so they can put on bigger tires, they usually have to regear to a higher ring gear in order regain the lost torque from going to bigger diameter tires. If you don't regear, you will find that you will have a loss of power when accelerating or climbing steep grades. You may even find yerself not making it up a steep grade at all. So while going with bigger tires to drop yer RPMs may sound fine, you will end up making a compromise with yer power band.