New fuel economy ratings

[Even Steven]

Now these numbers could be lying a bit unless we know how the test were taken:

Compare the figures for each engine in both 2wd and 4wd:

2008

V6 2wd: 16/21
V6 4wd: 16/20

V8 2wd: 15/19
V8 4wd: 14/17

With the 4WD V6 model, was the study taken while the vehicle was in 4WD? Or was it a 4WD vehicle drive in 2WD? Also from my real world experience, I've driven my 4WD V6 in 4HI and the mileage difference was negligeble compared to running it in 2HI. I think the reason is that even if I'm only running in 2HI, I'm still carrying around the weight of the 4WD components. Also I as I understand it, the V8 model is heavier than the V6. During stop and go driving, the extra weight would explain the MPG penalty.

Feel free to check my mileage numbers in my signature. Most of my driving is in DC Metro traffic so that explains the lower mileage but it still is inline with the EPA estimates for the most part.

A couple of thoughts here--

1- It wouldn't make sense to test the fuel economy of the V6 4wd while in 4wd, considering that it allows the use of 2wd. If the option is there, then I'm 99% sure that the EPA tests with the most economical option available, which in that case would be 2wd operation

2- Knowing that the 4wd V8 doesn't allow the option of 2wd operation, it is obvious that the 4wd penalty includes both the extra weight associated with 4wd components in addition to the extra drag placed on the driveline from the full-time 4wd components. In comparison, the V6 has the same weight penalty of the 4wd components, but does not have the burden of driving the extra drag associated with a full-time 4wd system. Therefore, I believe the reason that the V8 has a bigger fuel economy loss because of the full-time operation of its 4wd system. In my mind, this pretty much proves that there is a real fuel economy benefit to driving in 2wd when you have the option.

 

[Thai]

Don't forget that the V8 4runner also weighs more due to it's heavier V8 engine which has an iron block versus aluminum block in the smaller V6.

 

[Even Steven]

Don't forget that the V8 4runner also weighs more due to it's heavier V8 engine which has an iron block versus aluminum block in the smaller V6.

That may be true when looking at the overall fuel economy numbers, but it is pointless when you look at the 2wd and 4wd models of both the V6 and V8. In other words, when comparing the V6 2wd and the V6 4wd, the weight is the same, other than the additional hardware associated with the 4wd system. The same thing is true of the V8 models.

Therefore, the only "real" difference is the additional drag associated with the full-time 4wd system, when it comes to comparing each engine's 2wd versus 4wd fuel economy ratings. That's why I keep thinking Toyota should offer the V8 with the V6 4wd system! They would raise the fuel economy rating for the V8!!

 

[Even Steven]

Don't forget that the V8 4runner also weighs more due to it's heavier V8 engine which has an iron block versus aluminum block in the smaller V6.

I see what you're saying, but I'm not comparing the V8 versus the V6, I'm simply saying that the V8 suffers a bigger loss of fuel economy between the 2wd and 4wd versions. Why do you think the V6 2wd and V6 4wd models get almost the same fuel economy rating, while the same cannot be said of the V8 2wd and 4wd models? Do you agree that the difference must lie with the fact that one engine comes with full-time 4wd and the other has the ability to run its 4wd system part time?

That's the only reason that makes any sense to me, all else considered.

 

[Thai]

I see what you're saying, but I'm not comparing the V8 versus the V6, I'm simply saying that the V8 suffers a bigger loss of fuel economy between the 2wd and 4wd versions. Why do you think the V6 2wd and V6 4wd models get almost the same fuel economy rating, while the same cannot be said of the V8 2wd and 4wd models? Do you agree that the difference must lie with the fact that one engine comes with full-time 4wd and the other has the ability to run its 4wd system part time?

That's the only reason that makes any sense to me, all else considered.

Yeah, it makes sense. I am sure that when you're in 4wd, it uses more fuel.