OTR NOx testing may eliminate small turbocharged engines.

Discussion in 'In the News' started by Carcus, Nov 1, 2016.

  1. Carcus

    Carcus Well-Known Member

    xcel likes this.
  2. ALS

    ALS Super Moderator Staff Member

    I've never been thrilled with the idea of engines below 1.5L-1.6L. Take Toyota and the Prius they actually increased the fuel mileage by going from 1.5L to the present 1.8L. I'm old school with the thinking size matters, it's easier to make more horsepower with more cubic inches. There is point of diminishing returns as you get below a certain level cubic inches. Me, I figure the best fuel mileage can be had with engines between 1.6L and 2.0L motors. The more cubic inches mean higher torque numbers meaning you can lower the rpms at normal operating speeds.

    Give me a 1.8-2.0L normally aspirated engine in a 3,000 lb car with a decent Cd below .30 that runs <1900 rpms at 60 mph and I could easily pull 40 plus mpgs on the highway running 65 mph or less.

    The problem is the people that own a car with a turbo motor, in most cases have no idea how to get the best fuel mileage out of it.

    BTW- I owned a 2.1L-2.3L Turbo motored cars from Feb 1981- July 2009.
    BillLin and xcel like this.
  3. Carcus

    Carcus Well-Known Member

    I struggled with my decision to purchase 1.5t Civic vs the 2.0 NA. I do plan to pull a small trailer with it eventually and I suspect the 2.0 would be a better choice for that purpose, but because the towing would be infrequent, I decided to go with the 1.5t. I have the advantage of access to E0, and am hoping that E0 (or even higher octane (91) E0) may prevent the turbocharger from "stepping in" as much in during a tow. Dropping to 5th gear might be an option as well.

    It will be interesting to see what temperature (x gauge) readings I can monitor with the scan gauge.
    BillLin likes this.
  4. ALS

    ALS Super Moderator Staff Member

    The problem with the Turbo motors is when they go into boost it's based on throttle position and power demand. The trick with a turbo motor is to stay in vacuum or in as low as you can boost psi's that you can handle. The minute the computer senses positive atmospheric pressure it automatically starts adding fuel to (A) make more power and (B) as a cooling charge to prevent detonation under boost. When you're under boost fuel mileage drops like a proverbial rock and there is nothing you can do about it until you drop out of boost. If you live a relatively flat area you will find your gas mileage will be pretty good. You have hills around you getting EPA is going to be tough with out some use of advanced hypermiling techniques.
    Last edited: Nov 1, 2016
    BillLin likes this.
  5. Carcus

    Carcus Well-Known Member

    Relatively flat, .. but wind can be a problem. I test drove a 1.5t hatchback (cvt) and staying out of the turbo (at least according to the Honda graphic display) didn't seem to be a problem (city or highway). The manual transmission will be spinning faster on the highway, so I would suspect turbocharging might be less likely for the 6mt for a given highway speed (and I'm presuming a little mpg was given up for rpm)... but that's just a guess --- we don't really know how much efficiency loss there is with the cvt but might have a better idea when we can compare steady states. And a 6mt 1.5 driver from China reported that the eco button was basically a "turbocharger off" button below 3,000 rpm.

    add/ There are several refinements/innovations mentioned in the "drive train deep dive" and in the cutaway video that are intended to reduce heat/detonation... so I'm hopeful these improvements will result in "less cooling fuel needed" and improved fuel economy.
    Last edited: Nov 1, 2016
    BillLin likes this.
  6. Jay

    Jay Well-Known Member

    I like turbos because they really are more efficient by making the heat lost via the exhaust do some extra work. The turbo also acts as a silencer so the muffler need not be so restrictive. Finally, with the right waste gate management, a turbo can maintain sea level hp at altitude. A turbo makes intake and exhaust tuning less complex as well.
  7. seftonm

    seftonm Veteran Staff Member

    From the article, it sounds like the issue is particulates, not NOx. A lot of turbo DI engines seem to have pretty sooty exhaust pipes, so this sounds about right.

  8. Trollbait

    Trollbait Well-Known Member

    This might be more of an issue for Europe where there lab tests are a less stressful than the EPA's, and available engines are even smaller than what we get in the US.

    Gasoline DI engines produce more particulates than port injection ones, whether it has turbo or not. Then even a few port injected models would have required an exhaust filter if we applied the particulate limits to them as we do to diesels.

    I have no complaints about fuel economy in my Sonic with 1.4 turbo, and I have some steep hills on my commute.
  9. joshdurston

    joshdurston Rogue Canadian

    I had no complaint with the fuel economy in the 2.0T in my VW Tiguan (mt). I put my foot into it quite often and it did alright.
    Turbo's let you make more torque at lower RPM which usually means high brake specific fuel economy. Engine friction losses go up quick with RPM.
    I have noticed soot or visible particulate in the exhaust when a direct injected car suddenly accelerates beside me on a multi lane highway. It's pretty short lived though, I think once the turbo starts moving air the exhaust cleans up pretty quick.

Share This Page