Car Cliffs Notes

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I always read the owner’s manuals that come with the new cars I test-drive and review. They’ve morphed from pamphlets to Moby Dick-esque semi-novels over the past 20 years or so. And like Moby Dick, getting through them can be a challenge. So I thought I’d give you the Cliffs Notes version. Plus some stuff you probably  won’t find within the pages…

* All-wheel-drive (and 4WD) may not keep you out of the ditch –Woman Stranded in Snow Using Cell Phone

All-wheel-drive and 4WD (both of which send power to all four wheels, with the difference being that – usually – AWD systems haven’t got a transfer case and Low range gearing while 4WD systems usually do) are great for getting you going and keeping you moving when the roads are slick … but stopping is another matter. Neither system offers any advantage over an otherwise similar rear-drive (or front-drive) car when it comes to scrubbing speed.

If you’re going too fast for conditions – or haven’t left enough gap between you and the car ahead – having AWD or 4WD won’t pull your fat out of the fire.

Also with regard to AWD and 4WD: Tires matter. A lot. If you shoe your AWD car with “summer” (performance) tires meant for dry, paved roads, your AWD won’t be much use when it snows. Stopping distances, in particular, may actually increase due to the decreased traction in conditions the tires weren’t designed for.

The best runner won’t win any races without the right footwear.

This applies to us as much as to our cars.

* Crash test ratings are not created equal –

A given car is rated relative to others of its type and class. So, for, example, a compact sedan with a “5 Star” crash rating does a better job of protecting occupants in the event there’s a crash than a “4 Star” car of the same type (i.e., another compact sedan). But a “4 Star” vehicle of a different type – for example, a full-sized car – may be safer than the “5 Star” compact.crash test pic

As a general rule, size does matter. Bigger, heavier vehicles are almost always more crashworthy than smaller, lighter ones – regardless of their “stars.”

Ride height is another factor to consider. A car that sits lower to the ground is more vulnerable to bumper over-ride, if it’s struck by a vehicle that sits higher up. This is the main reason why the front and rear ends of cars have been getting blockier and taller. Designers are trying to make it more of a fair fight when a car gets hit by an SUV.

* Look for the “twin” (and the cousin) of the car you’re interested in… if you’re interested in saving money –

I recently wrote about the Subaru BRZ sports car (see here). The same car – virtually – is sold under the Toyota (Scion) nameplate as the FR-S, but for less.

There are also similar cars sold under different labels. For example, the Chevy Tahoe and the GMC Yukon. The Chevy version looks a bit different and may not have or offer some of the options and equipment available in the Yukon but the two share what Car People call their architecture, or basic underlying frame and chassis. They’re more fraternal than identical twins. But the point here is that it’s not necessary to pay GMC money to get most of things you like about the Yukon.

You can pay Chevy money instead.BRZ:FR-S

Finally, there are more distantly related kin. For example, the VW Passat and the Audi A6. If you look at the two side-by-side, you’ll recognize they sprang from the same gene pool. But the differences (including the physical size of the vehicles, wheelbases, etc.) are more substantial. Sometimes, in ways that may surprise you. The Passat, for instance, is actually roomier than the A6. Notwithstanding that its base price ($48,400) is some $11k higher than the price of a top-of-the-line Passat ($36,835).

How to find out who’s related to whom? Usually, Googling will do it. Just type in the name of the model you’re interested in and “twin”… or, just ask around. None of this stuff is secret. It’s just not publicized.

For the obvious reasons…

* There’s sometimes not much difference, MPG-wise, between V8 SUVs and V6 minivans and crossovers –

What’s a “gas hog”? It’s often not what you think. As an example, a Toyota Sienna minivan’s EPA mileage numbers (18 city, 25 highway) are hardly better than a Chevy Tahoe’s  (16 city, 23 highway) even though the Tahoe is an SUV with a big V8 while the Sienna is a minivan with a relatively small V6.Sienna sticker

Why the disparity – or rather, why the closeness? In part, it’s because the Toyota’s smaller engine has to work harder to pull the not-so-mini-van (a Sienna weighs 4,375 pounds). The Chevy is heavy, too (5,308 pounds) but it has about 40 percent more engine (5.3 liters) and about 30 percent more horsepower (355) than the Toyota (3.5 liters and just 266 hp).

The Tahoe is like a weightlifter who can max 400 pounds on the bench press doing a light set with 220 pounds… he’s hardly breaking a sweat. While the Sienna is a like a guy whose max is 220 doing reps with 175.bench press

So, the thing to keep in mind is that a bigger engine is not necessarily the thirstier engine.

This is particularly true of standard vs. optional engines available in the same vehicle. Sometimes, the standard (smaller/less powerful) engine’s real-world mileage will be about the same, not much better – or even slightly worse – than what you’d get with the optional engine… because the standard engine just isn’t enough engine for the vehicle. The Sienna, for example, used to offer a four-cylinder engine. Its gas mileage advantage in real-world driving vs. the V6 was negligible … but its performance was noticeably worse.

Toyota dropped the four.

* Premium fuel required vs. recommendedgas lid sticker

This is confusing because of the implication that you’ll hurt something if you feed a car that “requires” premium a tankful of regular.

You won’t cause mechanical damage – but you will probably hurt your mileage (and performance).

What will happen if you dose your premium-fuel-only car with regular is that the computer will sense the lower octane – which is a measure of burn rate, if you want to want to get technical (lower octane fuel lights more quickly than high-octane gas; the octane rating is not a measure of the quality of the fuel) and will adjust ignition timing to compensate. You may notice a slight decrease in fuel economy and – if you did a timed 0-60 or quarter-mile run – that the car’s acceleration is slightly less than it was when you fed it premium.

The Catch-22 is this: To get the advertised best-case mileage, you’ll need to pay extra for the premium fuel. Which will probably wash away whatever the fuel savings would be vs. an otherwise similar vehicle that’s set up to run on regular.

Premium fuel recommended is the more editorially honest term, because it does not imply you’re going to hurt the engine (and possibly, void your warranty) if you decide to use regular – or have no choice, because that’s all the station you’ve stopped at happens to have available. depends on you to keep the wheels turning! The control freaks (Clovers) hate us. Goo-guhl blackballed us.

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  1. 4WD can help with stopping, sort of. I was driving an ’86 Jeep (slowly) in light snow down a hill with a cul-de-sac at the bottom and cars parked all around. I touched the brakes lightly to test traction and immediately began sliding. At that point it became obvious I wasn’t going to be able to stop in time. I slammed the brakes hard and turned the steering wheel, spinning the Jeep until it was pointing up-hill, then gave it some gas and powered my way back up.
    I did this out of sheer instinct without a moment’s thought (to the surprised applause of my passenger), and I’m pretty sure it wouldn’t have worked without 4WD.

  2. It would be worth comparing and discussing the changes in the owners manual. When I bought my first new car, the owners manual providing you step by step instructions to change the oil, to include what size wrenches would be required. Modern owners manual explicitly tell the owner to take the vehicle to an authorized service center because the job requires specific skills, tools, and lubricants that exceed the consumers capacity to support. I currently own a BMW 330i that I bought used (very). It’s proving to be the worst car I’ve ever bought, but the point is that BMW claims that all of their lubricants, short of the engine oil, are lifetime products, not consumable. What does that even mean? I’m not a chemist, but you’d be hard pressed to convince me that brake/power steering/transmission/differential fluids will last forever. To conclude, I still wrench on my vehicles, and generally I’ve found they’re no harder to work on than my ’65 Chevy P/U, but the manufactures have discovered the income potential when tied to their service departments and owners manuals have evolved accordingly.

  3. The comment about premium vs. regular fuel is interesting. My question is, is is an urban legend or is is true that using premium fuel when it is not recommended will improve your mileage? We have a 2014 Nissan Murano Plantinum V6 AWD (a beautiful car!). Premium fuel is not recommended, but because we bought the vehicle new, we have always put only premium fuel in it. Are we wasting money, not breaking even (because mileage does improve but the extra price offsets savings) are are we saving money? This is the first new car I have ever bought in my life and I basically bought it because my wife is not such a confident drive. It is AWD drive and we put Nokian studded winter tires on it. We are more interested in keeping the engine healthy than saving money. If premium fuel will do this, we will buy it even if it is more expensive. Please advise!

    • Hi Jay,

      If a given engine was designed to burn regular, using premium will not improve its mileage and will probably reduce it.

      Here’s why:

      “Premium” and “regular” refer to the fuel’s octane number. Octane is not a measure of the fuel’s goodness. It is more like the difference between half and half and heavy cream. Both can be high quality; but you need heavy cream to make whipped cream. On the other hand, if you just want something to put in your coffee, half and half is the ticket.

      Premium has a higher octane number than regular.

      The higher the octane number, the more resistant the fuel is to premature combustion (from heat and pressure rather than spark) in the engine’s cylinders.

      Basically, you want to avoid the the explosion happening when the piston is still traveling upward on its compression stroke (before “top dead center”) because if it does, the force of the explosion is trying to force the piston (and connecting rod) in the opposite direction of normal travel; i.e., down when they’re trying to come up. This is not good! That “engine knock” sound you’re hearing? It’s the sound of uncontrolled combustion, which is wreaking havoc on the internals.

      Now, modern car engines have knock sensors and can compensate for that so as to avoid physical damage to the engine arising from the use of fuel with an octane rating below what the engine was designed to burn. But the result of that is a less efficient engine – and (typically) a noticeable reduction in mileage as well as performance.

      On the flip side:

      An engine designed to run optimally on lower octane regular fuel will similarly operate less efficiently if it is fed high-octane premium. The fuel won’t ignite at the right time, or burn as efficiently.

      The goal is to use fuel with an octane that results in the air/fuel charge burning at the exact right moment, as completely as possible.

      The engineers recommend a given octane for a given engine for exactly this reason. Sticking with the recommendation is the best policy if you want the best possible mileage and performance out of your engine.

  4. At a previous job, the boss counted the number of vehicles in the ditch on his way to work one snowy morning. 9 out of 11 were SUVs.

    A few years later I saw a person driving their SUV up & on the curb to get the additional traction from the grass. Turns out they didn’t know how to engage their 4WD.

    Just because you bought the SUV doesn’t mean you’re invincible. Especially if you got the 2WD version. If you bought the 4WD version, if you don’t know how to use it you’ve wasted your money. And even if you somehow managed to read the manual and know how to use the 4WD, you still aren’t going to stop any better than any other car on the road.

    Science and engineering can only do so much. The owners still need to drive with a certain amount of caution & restraint.

    • Amen, Chip!

      I remember driving in to work in the snow in DC back in the ’90s, in my ’74 Beetle (RWD). Passed countless SUVs in the ditch.

      Skill and judgment matters at least as much as what you’re driving.

    • Before all the electronic braking, skid control and whatnot I used to be able to stop a bit quicker in 4WD simply because I could heel and toe and could modulate braking to a high degree. I doubt finding one person in half a million these days who could heel and toe anything and make it work better is possible.

      Just mention heel and toe and get blank looks all around. I wish they made big rig pedals more conducive to left foot braking I use when there is a bad air leak. Throw in a jake brake and fast, even stopping is even better.

      • I will bow to technology with regards to braking. ABS & the traction system’s ability to apply brakes (or not) at the individual wheel beats my one-pedal input every time.

        In the same snow event with the person driving on the grass, I was driving a 4WD CR-V with a manual transmission (Honda no longer sells one, even in the smaller HR-V). The ability to feather the clutch was the key to getting home un-dented. Looking over at a BMW 5-series in the next lane, as soon as he lifted his foot off the brake pedal he was spinning a rear tire. He had a Bad Time that afternoon.

        • chiph, I won’t bow to technology. The pulsating brake can’t do as good a job as my non-pulsating brake. In fact, I’ve found that ABS increases stopping distances on really slick stuff. There are times too when you need to lock a brake. I’ve had ABS on pickups get me into trouble since I COULD have stopped long before it ALLOWED.

          I just wish somebody would make a knob you could spin nearly instantly to change the pre-load in electric brake controllers. The reason being it’s hard to quickly move the lever and drive too since you generally can’t see the lever because of your hand and you need to place your hand in a spot you can reference to move the lever only slightly. Ancap knows what I’m talking about.

      • “Throw in a jake brake and fast, even stopping is even better.”

        8, there are 2 signs near the city line at Blackstone, Va. One warns against loud stereos, the other warns that jake brake usage is prohibited, both in accordance with a city noise ordinance.

        I would rather endure the engine noise from a truck doing an emergency stop and using the jake as well as the air brakes than be hit by a logging truck, but then I ain’t on the city council there.

  5. ” The Sienna, foe example,”


    About the enormous size of the manuals; guaranteed the majority won’t bother to read them. Kind of like Congress and the bills the y vote on.

  6. A=F/M.

    Engine efficiency is a factor in fuel consumption so larger engines with more moving parts (and friction) will necessarily be a little less efficient. But no matter what, if you want to move an object of M mass, you’ll need to apply F amount of force.

    The biggest factor in V8 vs 6 efficiency is your right foot. If you have the extra F, you’re more likely to use it.

  7. Nice set of cliffnotes. Hopefully car manuals will not get to “The Count of Monte Cristo” size.

    Since G♦♦glė is blackballing you, you may wish to return the favor..

    Usually, G♦♦glïng will do it. Just type in the name of the model you’re interested in and “twin”… or, just ask around. None of this stuff is secret. It’s just not publicized.

    Instead of mentioning them, you may want to be more generic — Any search engine wil do it — or mention another search engine such as or

    Have a great New Year. May next year be better than this past year.

    • Mith, I never mention the G word unless I’m specifically dissing them. I’ve been trying to get a couple of old buddies to do their own searches for years. I think “search engine” just didn’t compute for them. I finally got some to use DDG years after I had used it exclusively. I used ixquick before that since neither keeps a record of your search. I like that DDG uses virtually countless search engines to find what you’re looking for.

      One guy was always complaining about ads and what he didn’t see alike. I’d continually suggest to him to use Firefox as a browser. I don’t think he’s ever understood and still uses IE to this day. It’s hard to get it across to some the add-ons available in open source browsers. I noticed Chrome was gaining on IE but FF was gaining on all them. I have many add-ons that not only make it more secure but allow me to take a lot of shortcuts. I love the Thumbnail Zoom+ and recently had FF block CoolPreviews due to no security. Adopted the EFF’s HTTPS long before it became part of FF. As far as NoScript is concerned, don’t leave home without it.


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