Featured Chevrolet Equinox Diesel

It's 32 city for the Equinox diesel FWD. 31 city, 37 highway for the AWD model.

Also, knock about 13% off of all diesel MPG numbers for MPG gasoline greenhouse gas equivalent...

 

I thought about diesel, but the additional cost per gal. for fuel, it would would need to get 10%-15% mpg better to break-even on fuel costs alone.

Then there is always the "stink and maintance factor"

 

I can't find if the diesel version is even rated to tow. All I see is the 2.0T gas motor is rated for 3500 lbs. What good is a diesel SUV if you can't tow anything?

 

That's true, but if you recall our discussions on TDIClub several years ago, EPA uses a "correction factor" which includes "ethanol in fuel" ("Final Technical Support Document - Fuel Economy Labeling of Motor Vehicle Revisions to Improve Calculation of Fuel Economy Estimates." December 2006, page 3). To the best of my knowledge, EPA still uses this correction factor for all vehicles (non-EV) including diesels. Of course, diesel fuel doesn't contain ethanol, so that artificially suppresses the fuel mileage ratings of diesels and why (I think) diesel tend to exceed their official fuel mileage ratings.

 

Interesting, although the implication from that document is that only about 1.2% of downward adjustment is coming from fuel composition - the rest of the 9.5% downward adjustment is coming from the load side, rather than the fuel side, and would affect diesels as well.

That's definitely something to be considered by the EPA in their adjustment factors, and an argument for removing the fuel composition adjustment from diesels. (Although, you'll have a smaller fuel composition adjustment necessary for states with B20 mandates...)

 

True. Maybe it would be more accurate to say "one of the reasons" diesels tend to exceed their official fuel mileage ratings.

According to an article in "Green Car Reports" (EPA gas-mileage labels accurate, helpful, unlike 2005: Consumer Reports), a Consumer Reports analysis showed that LD diesel vehicles exceed their official fuel mileage ratings by an average of 0.7 mpg. Not sure what percentage that is, but it looks like it's more than 1.2%.

 

By the EPA's own research from 2008, diesels can get up to 10% better than their label.

Will also add that the diesel Equinox has start/stop standard, and those systems have little impact on the EPA tests.

 

I wonder if that research still holds true for compliant diesels today.

Note that all of the diesels they had available to them in 2008, with any significant data, were old diesels that had high NOx output (legally, mind you). I wonder if there's something in the measuring approach that biased high-NOx engines' fuel economy figures down?

 

I stand corrected, and looks like that article was wrong on the city mileage in the place I was looking in it.

 

Well, if they are honest diesels, any negative effects to fuel efficiency from the emission system should be equal on the test and on the road. Then DPFs started showing up before 2008, so the effects of their regen cycles could be in that data.

 

Actually, another factor I just thought of... how many of the pre-cheating diesels were actually compliant?

A lot of TDI enthusiasts (the kind of people that will submit their data to fueleconomy.gov) install modifications that increase the emissions profile significantly, but also improve efficiency (advancing injection timing and removing the EGR being the two big ones for improving efficiency). So, those mods won't show up in the data, but their effects will.

However, there's another possible explanation for diesels doing better in the real world - extremely light load isn't very well covered in the test (see idle stop systems also not helping much on the test), and extremely high load isn't seen at all. Diesels are better than straight gasoline engines in both regimes - wide open throttle at all times reduces pumping losses for light loads, and no need (or ability) to enrich the mixture to cool the intake charge and avoid detonation helps significantly at very high loads. That could account for some real-world improvement (and calls for the test to be modified to include those operating regimes, I'd say).

 

A fair consideration, but also one for the gasoline cars that get reported. While most gas cars that are purposely non-compliant are likely for performance reasons, and not self reported for fuel economy, there are still the ecomodders out there. What does the Aerocivic - Honda Civic modifications for maximum gas mileage - aerocivic.com do to the spread?

Selection bias is the downside to user reported data like this.

Another factor is in the 55:45 city:highway split used for combined mpg. That average reported by those users was around 43:57. This is also close to the default ratio the EPA uses in their MOVES model.

 

Diesel . . . NOX . . . EquiNOX. it makes sense.

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If only Toyota could fix the HSD towing issue. The Rav4 hybrid's rating is half that of the Equinox diesel.

For fun, I personalized the numbers at Fueleconomy.gov with these hopefully temporary prices, and the Rav4h might cost me 10 cents more to go 25 miles than the Equinox. Before the the storm, the Rav4h could be 20 to 30 cents cheaper. Back to default city/highway mix, and random Costco prices in California has the Nox 8 cents cheaper.

 

It's cooling that affects that, and the P610 appears to be improved (to the point that, in some markets, even the Prius gets a tow rating), we'll see if the P710 gets a better tow-rating in the next-gen RAV4.

And, there's always going to a multi-stage approach, like the L310 as used in the LC 500h and LS 600h. It'd be tougher to package, but maybe you could get a 2-speed reduction box in there reasonably, and through that, get better towing performance.

 

Or use an actual gear oil in the transaxle instead of the automatic transmission fluid that was sitting on the shelf.

Even with cooling, the gen4 Prius tow rating is lower than cars a size class smaller than it in those markets. Toyota could just be overly cautious though. Either way, I don't expect the next Rav4h to double its tow rating. In truth, that really isn't needed for the segment.

But, but, what about the mechanical simplicity that is the end all be all?

I think Toyota wouldn't try this because of costs, but I say that not knowing customer towing needs in other markets.

 

In the US, towing doesn't matter much, because people think they need an F-150 to tow.

In Europe, people will tow with anything - they'll tow big campers (granted, they're lightweight, but they're big) with a subcompact that can't do 30 mph up a hill with the trailer.