New Fuel Economy Information site

[Ecky]

Originally Posted by mpgmike

I just spun my wheels for the past hour trying to look up fuel economy ratings for similar vehicles offered in the US, NZ, AU, and EU. Sadly, for some vehicles, I can easily find fuel economy ratings for the US, but not other areas, or the other way around.

I had a similar question arise in a US Federal court case (where I became officially recognized as a Fuel Economy Expert) back in 2008. Back then, I was more easily able to look at the VW Jetta Diesel, Subaru Outback, and other global models to compare regional fuel economy ratings. What I found was the US versions ALWAYS got the worst fuel economy. European models faired 10-20% better than the US. AU/NZ models were rated at 20% to a whopping 70% better fuel economy. (Specifically, Volkswagen had their Blue Diamond Diesel engine that was getting the equivalent of 72 US MPG Down Under versus 42 MPG in the US in the Jetta!)

This begs the question; do NZ/AU versions get worse emissions, or do US versions leave a lot on the table??

Though I cannot verify this, a friend of mine spoke with a Toyota engineer that claimed they can get well over 200 MPG US in their Camry (in the lab), AND MEET EPA EMISSIONS STANDARDS OF MAXIMUM EMITTED EMISSIONS TOXINS! However, the EPA tells them what fuel delivery system they must use, that they have to use specified catalytic converters, what software limitations they must stay within.... All evidence suggests the EPA has mandated a maximum fuel economy capability that must be enforced by the ECU -- at least in the US.

From the minor amount of research I've done, most overseas markets have looser emissions standards, so that accounts for part of it. One example, the US 2001-2006 Honda Insight automatic runs at stoichiometric air fuel ratios, whereas in Japan it leaned out to nearly a 25:1 AFR. Folks who have installed JDM ECUs in their USDM cars have seen as much as a 20mpg improvement (65 -> 85mpg) under certain conditions. The manual transmission Insight can do this in the US, but it meets a looser emission standard (Ultra Low Emissions) rather than the Super Ultra Low Emissions the automatic meets, because in order to get that kind of economy, the engine ran dirtier. Emissions are considerably worse when running in lean burn, even with the addition of a second catalyst to neutralize some of them. That adds cost to the car, and I'm sure there's some penalty for selling a more polluting vehicle.

Part of it is that the engines themselves are different. Two examples: The Mazda Miata in Japan, NZ and AU have a 1.5L engine, whereas in the US we got a 2.0L. The smaller displacement NZ model is rated for 49mpg highway. The 2.0L from the US car was later introduced to their market, and is rated for the same 35mpg highway there as it is here. Additionally, most of Europe and Asia get a Honda Fit (Jazz) with a 1.3 or 1.4L engine, whereas it comes with a 1.5L in the US, as well as shorter gearing. The explanation from Honda is that US customers have different expectations. One being, that 35mpg is enough, and another that a 1.3L four with a tall transmission would be dog slow and not worth buying, no matter how good it is on gas.

I do engine tuning myself. There is no magic 200mpg tune. All of the variables are exposed in my car's ECU, and you can change them and see what happens. You choose how much fuel to inject, you choose when spark happens. On some engines you can phase the camshaft or vary valve lift and duration. Changing these variables DOES affect fuel economy - AND emissions. You can sometimes squeeze another few mpg out by tuning the engine differently, but emissions are increased.

[Ecky]

The third factor is that the actual tests are different. The US EPA highway cycle includes things like running the A/C, accelerating and decelerating, and runs at a higher speed. Many European tests simulate driving at a steady, low speed with nothing running. I think the Prius in Japan is rated for something silly like 120mpg, but you bring a Japanese Prius over to the US and it gets the same average fuel economy as ours.

[Ecky]

Here's a quick article I found on the unrealisticness of the Japanese test cycle:

https://www.autoblog.com/2009/04/03/....4%20mpg%20(US)!

In the US, the 2010 Prius is rated for 48mpg highway. In Japan, it was rated for 90mpg. Japanese Prius drivers tend to get around 50mpg equivalent in real world conditions. It isn't that their version of the car is any more efficient, their test is just bogus.

[mpgmike]

I've done quite a bit of tuning in the past myself. I adamantly agree with you that on a stock engine, playing with tuning can get you maybe 20-30% more fuel economy, but possibly at the expense of increased emissions. I've been fortunate to have access -- and the means to test various technologies over the past few decades. Usually we would start with a stock engine and maximize it. This became OUR baseline. Then we would add some technology and retest without retuning. Then we would play with the tuning to see what it liked. Emissions testing has been an integral part of this process all along. (Twenty+ years ago I was using a 4-gas analyzer. For the past several years I've used a 5-gas.)

Based on that experience, I'm not much of an advocate of these "tuner modules" that report to improve your stock engine efficiency by some notable amount. I AM an advocate of improving on what the factory did mechanically (think Combustion Efficiency), then go to tuning to get the mechanical gains working with the software. There have been so many different technologies I've tested that I could prove improved what goes on inside the combustion chamber, but the factory ECU would only tolerate a slight amount of improvement then default to "gas guzzling mode" (for lack of better term).

I suppose if you firmly believe that the OEM's are delivering the best fuel economy and performance they know how to provide, then there's nothing I can say, link to, or post pictures of that will change your mind. HOWEVER, if you realize the OEM's hands are tied -- by not only the US EPA and CARB , but also other governmental agencies, all of which must be funded somehow, and willingly receive contributions from entities that stand to benefit from legislation -- you may realize that science has the ability to virtually eliminate harmful pollutants while simultaneously raising the engine's efficiency from a paltry 20% to a more reasonable 60% (or much more!). That fair and reasonable step triples fuel economy at the engine level! After all, 60% efficiency is NEVER considered out of the realm of probable -- even factoring in Faraday's Laws!

[mpgmike]

Originally Posted by Ecky

Here's a quick article I found on the unrealisticness of the Japanese test cycle:

https://www.autoblog.com/2009/04/03/....4%20mpg%20(US)!

In the US, the 2010 Prius is rated for 48mpg highway. In Japan, it was rated for 90mpg. Japanese Prius drivers tend to get around 50mpg equivalent in real world conditions. It isn't that their version of the car is any more efficient, their test is just bogus.

Someone I did work for in the past (Diamond Larry) bought a new Prius back in 2006. He found Japanese controllers he adapted to his US Prius that gave him far better fuel economy. One of them extended the "low charge" range so he could run off batteries when the stock US controller kicked in the engine (for example). I challenge your research (not you personally) based on my correspondence with Diamond Larry. Larry was getting around 107 MPG average on his Prius the last I spoke with him.

[RealityRacer]

Hey MPG mike, I totally agree with you regarding the imposed MPG limits incurred by EPA specified components. This has been my personal experience and from all the evidence I have seen. We can do a lot better just as you mentioned regarding the blue diamond engine that gets 30MPG better overseas.
Does the overseas version of the blue diamond have the same emissions or is there a teade-off?

[mpgmike]

As I recall, the Blue Diamond diesel engine was manufactured in Pennsylvania, but not available in the US. All production was for export use. Because the engine was so incredibly efficient, the EPA had to fabricate some new ruling to prohibit its sale. Traditionally emissions are measured in grams per mile. Using this gauge, the BD was the cleanest diesel engine on the planet. However, the new ruling looked at grams of emissions per gallon of fuel consumed!

The US Jetta Diesel would travel 42 miles on a gallon of fuel. To calculate total emissions, multiply grams per mile by 42. Even though the BD was much cleaner, by the time you multiplied the grams per mile by 72 it looked much worse.

[RealityRacer]

Excellent information MPG mike,
So what did your Roush testing results prove?

[mpgmike]

Originally Posted by RealityRacer

Excellent information MPG mike,
So what did your Roush testing results prove?

In short, we can improve combustion efficiency. At the time, the Sonata was a late model car. We also proved that improving combustion efficiency could at best improve emissions, but at worst, didn't hurt them. Though not part of the Roush testing, we proved that improving combustion efficiency improved performance. The 4-cylinder Sonata would keep up with my mother-in-law's V-6 Sonata right up to near red-line. The V-6 could actually walk away at the top end.

Over the years I talked with a couple inventors that spent the money to verify their gizmos with Roush-like testing. They would be getting anywhere from 50% to 300% increase in mileage over stock in the real world. However, when they took it in for testing, they all found the results for fuel economy were pretty close to stock. (One poor guy said the results came back worse than stock!)

I can tell you we got extremely consistent 60+ MPG from that Sonata, but you'd have to take my word for it (that is in fact what we got driving it regularly). However, I can tell you Roush gave us 42 and our proof will hold up in US Federal Court.

[RealityRacer]

MPG mike, WOW! That is fascinating. Is any of the engine efficiency aftermarket technology that you put on that sonata available? If not, will it be available in the near future?
I am an environmental talent engineer with 22 years experience and I would love to test it. I know that I put very effective hardware on my vehicles but had minimal results. I heard and read that gas prices are moving beyond $10 per gallon soon!