V6 v V8 v Diesel
- Thread starter Jesse1983
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Walk away? I don't think many people would be interested in racing a 4Runner against a GX. And there was no such conflict when the 4Runner had the same V8 as the Lexus during the 4th gen run.
Besides, not many people cross shop a 4Runner and a GX. Two very different demographics.
Extra weight doesn't help fuel economy, period. A heavier vehicle will tend to carry it's momentum more than a lighter vehicle? Okay, but every time you're going XX miles per hour in that heavier vehicle, you still have to consider that it takes more energy to accelerate the heavier vehicle to that (or any) given speed in the first place. It also takes more energy to maintain speed on a heavier vehicle, all else equal. If you theory were correct, auto manufacturers wouldn't be so big on weight reduction in the name of fuel economy.
That's probably 99% due to the transmission, not the vehicle weight.
I'm saying the extra weight doesn't punish the fuel economy on the highway as much as you'd expect. You get a far bigger bang for buck in the city mpg by reducing weight than you do on the highway. The reason weight plays a bigger role in the city numbers is exactly because it takes more energy to get the higher weight up to the same speed.
If you would actually read my post, instead of coming out swinging, chomping at the bit for an argument, you'd see that we are saying the same thing regarding city driving. I'm simply saying the impact of weight on highway mileage is generally pretty small amd I feel that it is due to momentum.
We are not saying the same thing at all. You can compare weight all day long whether you're talking about city driving or highway driving. A heavier car on the highway still needs more energy (read: fuel consumption) to maintain a steady speed, all else equal. This should be logical to anyone. BTW, I'm not coming out swinging. If I were, my words would be quite different.
You are not listening. I'm saying the differences in energy required to keep the 5100lb GX running at the same speed as the 4600lb T4R is marginally larger. You are stuck on the word "more". I'm saying it is more, but just ever so slightly. Carrying that extra momentum probably helps on some driving cycles.
I'm listening.... you also said this:
The heavier GX is carrying more energy than the T4R when traveling the same speed because of the extra weight (E = 1/2*m*v^2). Basically, once you get it up to speed, the it wants to stay at that speed thanks to conservation of momentum.
Lets just agree to disagree. I'm not in the mood to get into a long-winded debate about this.
I disagree. In any driving test, where you begin from a stop, the heavier vehicle will use more fuel, all other things being equal.
Take a look at this to understand where DocMT is coming from
Rolling resistance - Wikipedia, the free encyclopedia
Rolling resistance (the main force a vehicle needs to constantly overcome beyond wind resistance at highway speed on a flat road) is a function of vehicle mass as well as the radius of the wheel and a coefficient relating to how much the tires deform etc (hence why high pressure tires yield a better gas mileage).
Rolling resistance - Wikipedia, the free encyclopedia
Rolling resistance (the main force a vehicle needs to constantly overcome beyond wind resistance at highway speed on a flat road) is a function of vehicle mass as well as the radius of the wheel and a coefficient relating to how much the tires deform etc (hence why high pressure tires yield a better gas mileage).
Yeah, that's pretty much all I was trying to say. When you have two identical vehicles with the same tires, drag coefficient, frontal area, etc... but one weighs more than the other, the heavier of the two will always be at a disadvantage when it comes to fuel efficiency.
Thai
Elite Member
With fuel prices going up again (and economy is still shaky) and Obamanation cranking down on EPA ratings per manufacturer, there is no way in hell is the 5th gen getting a V8. Not gonna happen. Not next year, not midcycle. With the way the Middle East is shaping up, there is just too much unsteadiness for manufacturers to put in a V8 and expect good sales. The good old days are just that...the good old days...good old days are not coming back.
Although some folks will get good mileage with a V8, the bottom line is that EPA ratings on a V8 are NEVER the same nor better than a V6, given everything else being equal. The current EPA method is quite accurate for the average driver. Unless you tow, the general public will always favor a V6 over a V8 when gas prices are high or economy is bad. I think that Ford is real smart in introducing their Econoboost V6...with clever marketing. Whether Econoboost V6 is any more fuel efficient than a V8, the fact that it is "just" a V6 is attractive to the general public.
Although some folks will get good mileage with a V8, the bottom line is that EPA ratings on a V8 are NEVER the same nor better than a V6, given everything else being equal. The current EPA method is quite accurate for the average driver. Unless you tow, the general public will always favor a V6 over a V8 when gas prices are high or economy is bad. I think that Ford is real smart in introducing their Econoboost V6...with clever marketing. Whether Econoboost V6 is any more fuel efficient than a V8, the fact that it is "just" a V6 is attractive to the general public.
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Yeah, I agree. A V6 engine has a psychological effect on people when gas prices rise, even if the V6 gets the same fuel economy ratings as the V8. Most people just automatically rule out V8 engines when gas prices really start to climb. And all the so-called experts are predicted gas prices to approach the $5/gal mark soon.
Yup, I agree. The V8 is a non-starter, unfortunately.
Toyota really needs to make the 4Runner a lot more fuel efficient.
I agree, the general public just reads that it is a V6 which in their eyes is more fuel efficient. It remains to be seen whether or not the Ecoboost really gets better fuel economy under load (ie. spirited driving, while hauling/towing etc.) This thing is a V6 but it moves as much air as a V8, which means more fuel.
If you want to tow and get decent fuel economy in an SUV I say diesel is the way to go. Audi Q5, VW Touareg, BMW X5, MB M350 all offer medium duty diesel engines, its a shame none of the other automakers have gotten serious about this yet...
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Thai
Elite Member
Well, whether Ecoboost (sorry about bad spelling earlier) is economical under load is irrelevant...because all that matters is the EPA rating and how that reflects the company's overall EPA rating. Spirited driving or towing is usually not done on a regular basis for your average midsize SUV consumer. Towers will look elsewhere...and their numbers are quite small because most of them buy diesel trucks. Spirited drivers will also look elsewhere, towards BMW X's, Infinity FX's, etc..
Diesel is nice and all, but tight emission standards will limit their sales along with high diesel prices (same or higher than premium gasoline at this time) and overall public perception of diesels. In addition, to meet these tight emission standards, most diesel engines nowadays require UREA additive every oil change, which only adds to the overall maintenance cost.
Actually, Honda has a wonderful 4-cyl diesel in Europe that gets excellent mileage and does not need this urea stuff. It was destined to come to the US via Acura TSX in 2010...but the plan was deleted because of rising diesel prices over here. There was some rumor that the Honda diesel got canned over here because it would not meet EPA stricter diesel standards.
For me, i just want the damn center diff back in the Trail...screw the V8!
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That is true...It's all about what the sticker says. However, in reference to this thread which is as hypothetical as you make towing or spirited driving in an SUV out to be, I think it's boiled down to a power/torque vs. fuel economy debate. I'm simply saying if someone wants both in an SUV diesel is a viable, if not better option.Well, whether Ecoboost (sorry about bad spelling earlier) is economical under load is irrelevant...because all that matters is the EPA rating and how that reflects the company's overall EPA rating. Spirited driving or towing is usually not done on a regular basis for your average midsize SUV consumer. Towers will look elsewhere...and their numbers are quite small because most of them buy diesel trucks. Spirited drivers will also look elsewhere, towards BMW X's, Infinity FX's, etc..
Diesel is nice and all, but tight emission standards will limit their sales along with high diesel prices (same or higher than premium gasoline at this time) and overall public perception of diesels. In addition, to meet these tight emission standards, most diesel engines nowadays require UREA additive every oil change, which only adds to the overall maintenance cost.
Actually, Honda has a wonderful 4-cyl diesel in Europe that gets excellent mileage and does not need this urea stuff. It was destined to come to the US via Acura TSX in 2010...but the plan was deleted because of rising diesel prices over here. There was some rumor that the Honda diesel got canned over here because it would not meet EPA stricter diesel standards.
For me, i just want the damn center diff back in the Trail...screw the V8!
Case in point: My V10 TDI Touareg has 313HP/550 ft-lbs stock and I routinely get 18-20mpg with mixed (city/highway) spirited driving. I recently averaged 25 mpg on a road trip from Gunnison to Denver on two-lane highways with a lot of full throttle passing. It's also rated to tow 7000 lbs. Where I live, right now, diesel is 10 cents cheaper than premium. When I bought it a year and a half ago, diesel was on par with regular.
However, everything you mentioned (tighter emissions, urea fluid, higher maintanence costs, public perception) could be a potential road block vs. gasoline powered SUV's...
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Remove the starting from the equation. You keep getting hung up on starting from a stop when that isn't a major player in the highway mpg game. If you are starting and stopping frequently, it isn't highway driving.
And I've said over and over, it definitely does take more energy to get something heavier up to the same speed. I'm not debating that. I'm talking about momentum and when the thing is moving. It is the same reason you'd rather be hit by a 3000lb civic traveling 50mph than a 5500lb F250. There is a lot more energy in that F250 even though it is moving at the same velocity. Aero drag is the biggest force that a car has to overcome to keep moving. Packing that extra energy pushes the air out of the way with more authority* the same way that the Civic bounces off your 4Runner instead of barreling straight through you like the F250. That is all that I'm saying.
* This is, of course, assuming same drag coefficient and frontal area as those are the major players in the drag equation.
Thai
Elite Member
Remove the starting from the equation. You keep getting hung up on starting from a stop when that isn't a major player in the highway mpg game. If you are starting and stopping frequently, it isn't highway driving.
I'm talking about momentum and when the thing is moving. It is the same reason you'd rather be hit by a 3000lb civic traveling 50mph than a 5500lb F250. There is a lot more energy in that F250 even though it is moving at the same velocity. Aero drag is the biggest force that a car has to overcome to keep moving. Packing that extra energy pushes the air out of the way with more authority* the same way that the Civic bounces off your 4Runner instead of barreling straight through you like the F250. That is all that I'm saying.
* This is, of course, assuming same drag coefficient and frontal area as those are the major players in the drag equation.
I am no physics expert...so, i won't contest your formula and reasoning. I wonder how EPA calculates EPA for highway. And in all cases, highway mileage of a V8 vehicle vs. a V6 of the same vehicle, the V6 always win.
I think this is the source of your confusion. First of all, you're not packing "extra energy", you are carrying extra weight. Two completely different things. Secondly, as you said, if the vehicle identical, then it has the same frontal area & aerodynamics, so that extra weight is a penalty for fuel efficiency, even if you're talking about 100% highway cruising.
If you took any vehicle over a controlled test loop (and you can design whatever test loop you want) and then repeated the same test in the same vehicle, only with 500 extra pounds of ballast in it, I can 100% guarantee you that your fuel economy will decline when you have that extra 500 pounds on board. It doesn't take a degree in engineering to understand the fundamentals here...
