Certain 4cyl cars that get bad mileage..

[cRiPpLe_rOoStEr]

Originally Posted by 19bonestock88

I don’t know why they don’t make “glider” chassis for regular size cars/light trucks... would allow a consumer to update to a newer body style but keep whatever powertrain they want...

I'm sure it may involve some lobbying. Regardless of being a fully-built unit or a glider kit, a big rig has some value added, plus it became quite "cultural" when most truckmakers still outsourced much of their drivetrain components instead of making their own engines. So, there were savings for truckmakers too.

[ProDigit]

MPG is a combination of engine size, engine and vehicle efficiency, and gearing.

You can gain good results by getting a more modern engine, with tighter tolerances, and aimed more for fuel efficiency. Modern cars usually are built for higher MPG, because of the pollution control.

You can also improve efficiency, by making sure the model is aerodynamic, and light.
Aerodynamic for freeway riders, and light for start-stop traffic.

Last is for city riding of up to 45 MPH, a 3 cylinder 1 liter engine is good enough.
The less cylinders, the better for MPG, and the smaller CC, the better MPG.
But it also depends on gearing.
If your car does 6k RPM to maintain 60 MPH (600 cc Kei cars in Japan, do this), your MPG will suffer, and be worse of a larger car with a larger engine doing the same speed at 2,5 k RPM.

So in order to get best MPG, you'd have to determine in which areas are you going to ride the car most, and how much fun (opposite of granny driving) you want it to be?

Like for instance,

While a 1 liter engine with 75-100 HP is okay for the city, of up to 45 MPH, these kind of cars won't be any fun to drive on the highways!
They're sluggish, and accelerating or surpassing someone doesn't happen over a cup of coffee, even with a gearshift.

Bump it up to a 150 HP motor, 1.4 liter turbo or 1.8 liter NA with on a 3300 LBS chassis, and it'll be kind of fun for speeds under 60-75 MPH, but get over it, and it'll be the same problem as the 1 liter engine.
You can surpass other cars on the highway, but, boy, it takes time..

So if you're going 75MPH, you have the choice to go with an eco car, or bump it up in the 200-275 HP range.
That'll be a 1,8-2.0 liter turbo, or a 2.4+ liter NA.

Once you increase the 1,8-2.0 liter turbo on a standard eco sedan style body, the fun factor on the highway increases, but the MPG will start to suffer.
3-4 liter cars make better MPG than 2.0 liter turbos at speeds well over the legal speed limit.
For that reason they're not an option if you care about fuel efficiency.

A Camaro, A Kia Stinger, they have 2 liter turbo engines that are on the threshold of great MPG and fun. Any larger, and your MPG will come down into the high 20s.

It all depends on how the manufacturer has geared the car, but generally speaking, that kind of engine gets avg MPGs in the low thirties, and highway MPGs in the high thirties.

Especially with Turbo engines, you should look at the speed you're driving the car most (eg: 75MPH), and the RPM range of the car in final gear at that speed (eg: 2250RPM in 6th); and where the engine starts making power. Like, if the engine starts making power at 2k RPM, but below is kind of sluggish, you'd want a car that's geared tall enough to get you to the speed you like, in final gear, above the RPM range where the car starts making power..


The smart for instance, has a 1 liter engine that's hopelessly undergeared.
It revs at like 3k RPM at 45MPH. This is the main reason for it to have low MPG.
But the manufacturer had the choice, to either make it sluggish in final gear, or have MPG suffer.

This all to say that there are many factors that come into play of MPG

[Prophecy99]

i drive a 2003 nissan maxima (v6 3.5L) , and get 25-26 mpg around town and highway

your 22 mpg for the v4 does sound pretty bad !

[cRiPpLe_rOoStEr]

Originally Posted by ProDigit

MPG is a combination of engine size, engine and vehicle efficiency, and gearing.

Gearing might be one of the most underestimate factors contributing to mileage. Earlier this week I had a talk about it with a guy who attends the same technical school I'm currently attending.

[JRMichler]

My wife used to own a Chrysler PT Cruiser. That car had the worst combination of engine, transmission, and transmission shift points that I have ever seen. As a result, it got terrible gas mileage. I was only able to get 24 MPG on the highway at 55-60 MPH while driving for mileage.

I especially hated the feature where, slowing for an uphill turn, it would stay in third gear with not enough torque to accelerate, then downshift to first with a jerk. The correct gear would have been second gear.

[JSH]

Originally Posted by triangles

Engine swaps in the US are legal. What is not legal is to put an older engine with looser emission standards in a newer car with more strict standards. Regardless even this is rarely enforced.

Also the trucking industry somehow found a loophole in the EPA regulations because they can put an old rebuilt engine into a newly manufactured truck that never had an engine in it. This "new" truck is only subject to the emission requirements of it's 30 year old engine.

Certification of heavy duty trucks follow the engine instead of the chassis for some reason. The kits you speak of are called gliders and originally where used to fix low mileage crash damaged trucks. Say a guy rolls his new truck with only 50,000 miles. The frame is bent and cab smashed but the drivetrain is basically new. He could order a new glider chassis and swap his drivetrain into that new chassis. When emission regulations tightened in the 2000's some dealers started ordering new chassis and installing a remanufactured drivetrains in them. These per purchased by small fleets and owner operators that didn't want to invest in the equipment and training required to maintain modern computer controlled drivetrains. That business grew and now about 5% of the new truck fleet are "glider kits". Obama closed that loop but Trump has rolled back the regulation to allow gliders to continue to be built.

Gliders also aren't required to comply with computerized log books so small time owner-operators can continue to drive more miles than allowed by law.

[order99]

Originally Posted by JSH

Not in the USA. Exceptions to emission laws for test vehicles are handled at the Federal level by the EPA. You need a special vehicle ID number and the vehicle can never be sold for road use.

If you plan to do it legally at least.

Not to drift too far off topic JSH, but do these same laws apply Federally to motorcycles and/or scooter? I have a project in the drafting stage and the NC DOT website is such a mess...

More germane to the topic though-I drove my late Granddad's 1989 Camry for about 3 months when my late '93 Festiva had her first trans rebuild (in 24 years ) and averaged between 25 and 28 MPG with roughly 50/50 combination of city and interstate driving at the speed limit-I can only assume that the '89 models were still in the 'midsize' category rather than the luxury? Or maybe I just lucked out...

[ProDigit]

Originally Posted by JRMichler

My wife used to own a Chrysler PT Cruiser. That car had the worst combination of engine, transmission, and transmission shift points that I have ever seen. As a result, it got terrible gas mileage. I was only able to get 24 MPG on the highway at 55-60 MPH while driving for mileage.

I especially hated the feature where, slowing for an uphill turn, it would stay in third gear with not enough torque to accelerate, then downshift to first with a jerk. The correct gear would have been second gear.

I used to own a PT Cruiser, and coincidentally I was remembering how much I did like the car.
Yes, it was poor on gas, but for me (the manual version), the 2.4 liter engine was pretty peppy, even in fifth gear on the highway!
I remember pressing on the pedal, and in the lower gears, it felt like a mini-HotRod, while it had plenty of juice to overtake on the highway!

[JSH]

Originally Posted by order99

Not to drift too far off topic JSH, but do these same laws apply Federally to motorcycles and/or scooter? I have a project in the drafting stage and the NC DOT website is such a mess...

Yes. Car, motorcycle, scooter, boat, train, plane, etc. The EPA has emission standards for pretty much everything with an engine from your lawn mower to a Boeing 787. Emissions standards and compliance are set by Federal law and only California has the authority to set their own emission standards. NC does not have the authority to allow you to violate Federal law. They can only chose not to enforce Federal law.

The Clean Air Act makes it illegal modify your engine unless it is with parts that have been certified to meet the emission standards for the year the vehicle was sold. It is also illegal to remove or disable any part of the emission system. The pertinent section of the law is below:

US Code 7522

(3)(A) for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this subchapter prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser; or

(B) for any person to manufacture or sell, or offer to sell, or install, any part or component intended for use with, or as part of, any motor vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this subchapter, and where the person knows or should know that such part or component is being offered for sale or installed for such use or put to such use

§7524. Civil penalties

(a) Violations

Any person who violates sections 1 7522(a)(1), 7522(a)(4), or 7522(a)(5) of this title or any manufacturer or dealer who violates section 7522(a)(3)(A) of this title shall be subject to a civil penalty of not more than $25,000. Any person other than a manufacturer or dealer who violates section 7522(a)(3)(A) of this title or any person who violates section 7522(a)(3)(B) of this title shall be subject to a civil penalty of not more than $2,500. Any such violation with respect to paragraph (1), (3)(A), or (4) of section 7522(a) of this title shall constitute a separate offense with respect to each motor vehicle or motor vehicle engine. Any such violation with respect to section 7522(a)(3)(B) of this title shall constitute a separate offense with respect to each part or component.

[Ecky]

Originally Posted by ProDigit

Last is for city riding of up to 45 MPH, a 3 cylinder 1 liter engine is good enough.

My 67HP Honda Insight 3 cylinder is perfectly fine on the freeway. It accelerates to 60 in ~10 seconds with the hybrid system active, and even with it turned off, has no trouble merging into traffic or maintaining 75mph in the incredibly tall top gear.