INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

Is it possible to build a 5 seats passenger car weighting max 1000kg?

Is it possible to build a 5 seats passenger car weighting max 1000kg?

(OP)
Hi All,
mine is just curiosity in a field which is not mine (I'm a electronics eng. specialized in microwaves).
The question is:
would that be possible to build a passenger car with following specs:
-5 seats, 4/5 doors
-respectable engine specs (at least 200bhp, 350Nm)
-respectable economy, max 6-7 liters/100km gasoline, or electric 500km autonomy (no hybrids)
-dry weight max 1000kg, still being able to pass all safety tests

When you look at the market, a 5 seats limousine weights at least 1700kg. If you're looking for an estate, then think more of 1800kg. Would that be possible to reduce the dry weight to a minimum, sacrificing perhaps luxury things, but not safety?

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

A Toyota Yaris or Mitsubishi Mirage or Nissan Micra come close to your weight target but are missing one seat and have less power and are on target for your fuel consumption. That is what something of that weight and fuel consumption will look like using today's normal production methods and which fully meets today's safety standards and which a normal person can afford.

Next size up - A Honda Civic has three seat belts in the back, weighs only somewhat more than your target (certainly not 1700 kg), comes somewhere close on power and economy targets, and is built using today's production methods and meets today's standards, and which a normal person can afford.

If you want physically bigger than that but with less weight than that, something has to give. You cannot "give" on the compliance to safety standards, so that means the materials of construction has to give. That means it's gonna be expensive.

If you want wide enough so that three across can fit comfortably, it increases both the frontal area and the weight. It punches a bigger hole through the air as it moves. That increases drag which uses more fuel. Not to mention that parking gets more difficult.

Aluminum helps, but for the type of size and weight that you are talking about, it's not going to get the job done. You are into carbon fiber and other composites.

A battery-electric with 500 km range (with realistic real world driving!) has not been developed - period. (May happen within not too many years, though.)

You may wish to take a close look at the BMW i3, which is an example of what can be done using alternative materials. It still won't meet your power and range targets.

"Possible" - perhaps, at some point in the future. Who would be able to afford it, is quite another matter.

I should add that I just had a rental 2015 Chevrolet Impala for a couple of days. Perhaps this is the size of vehicle you are looking at, if perhaps not the weight. I was impressed at the end of the rental period that this big sedan got 31 mpg US (about 9 L/100 km) in normal driving.

The main problem with that car is that it doesn't look like an enormous square box which people seem to buy much more frequently than a very aerodynamic sedan.

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

I'd add that no current battery or hybrid system would help you achieve your weight target, you'd be better off with a petrol or diesel engine. The way I'd do it is ignore the power requirement, find a 5 seater that meets your weight target, and then stuff as much turbo in as necessary. It would not be a pleasant car to drive, but then this really seems like a rather odd exercise to me. Why not concentrate on what people want? which sure as hell isn't arbitrary weight based metrics.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

1926 Ford Model T 4-door Touring car- 5 passengers, empty weight under 682kg (1500lbs). Complied with all safety requirements in 1926, and can still be driven on US public highways. 20hp 4-cylinder engine was respectable for 1926, but would not be adequate for a modern auto. Could get fuel economy as low as 11L/100km.

While it is probably not practical to produce a 5 passenger automobile with an empty weight under 1000kg that meets your requirements, if you use the metric of 200kg empty vehicle weight per passenger then a modern type D school bus would meet your standard. This school bus model carries 90 passengers, meets all current safety standards, has a very efficient 300hp turbo diesel engine, and an empty weight around 28,000lbs (141kg/passenger).

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

Sure.
An example would be the 1980 VW Passat B2.
It would not meet your engine specs, but who cares? With less than 1000 kg dry weight, who needs 200+ HP?

Benta.

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

It also wouldn't meet today's safety standards.

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

Not to mention the electric everything that today's car buyers seem to require. I'd like to see what the weight difference is between a model with power windows, 5 way power seats, electric locks, auto lights, auto high beams, auto wipers, remote start, heated steering wheel, heated seats, seat massages, power lift gates, power folding back seats, power sliding side doors, etc. and the same vehicle with all manual controls. Of course the manual versions can have some weight penalties too. Replacing the massaging seats with a hooker may have more than just weight penalties.

----------------------------------------

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

Doors that go "thunk" instead of "tinngggg" when you close them, and unibodies that are torsionally stiff enough to not rattle and squeak all the interior parts over every bump, in addition to the crash requirements, add a lot more weight than the power seat motors. Of course all the power gadgets don't help matters. And the sound insulation. And the soft-touch padding everywhere (my '70s Civic had bare metal at the top and bottom of the inside of the doors and on the inside of the A-pillar and on the inside along the top of the door). And the 18" rims with the brakes to go along with them instead of the old 12" - 14" rims.

Just try telling a customer in this day and age that they should do without all that.

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

OP has never logged back in, looks like we'll never find out why he asked such a stupid question. Anyway based on a Toyota Yaris, yes, just about possible, but it wouldn't be much fun.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

I have a 1999 Saturn SL I use as a daily driver. Manual transmission, four door with no power steering, no power windows, no power locks, just A/C, rear window defog, and AM/FM Cassette, and lots of miles. Can seat five. Dry weight 1050 lbs. When new, it would get 42 mpg (17.86 km/l) at 60mph with three passengers and the A/C running.

The 1999 Saturn were the most fuel efficient. In 99 they added roller rockers, and changed the pistons and rods to get a little better fuel mileage. In 2000 the body changed some and the cars were slightly longer and heavier.

Meets most of the specs. Just not the 200 bph

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

I guess that should be 1050 kg not lbs?

je suis charlie

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

A 99 Saturn might scrape through the current legal crash standards (I doubt it) but certainly wouldn't be 4 or 5 stars NCAP. Yet again our silent OP needs to clarify.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

(OP)
Hi all,

sorry for not having been able to write back before.
And also sorry for not having been able to clearly state my question.

Let me try again. With an example from the market, a type of cars which I like, because of design, perhaps space, and maybe engines. I am talking about Mercedes Benz E-Class, BMW 5 Series, Audi A6. I am talking about gasoline models >=200bhp.
Those cars' weight is about 2 tons. Body, engine, perhaps I guess the fuel tank are the heaviest components (correct if I'm wrong).
Now those cars are equipped with a lot of luxury which most of the drivers dont need. So the question is now (reconnecting to the specs I gave you back a few days ago):
Is that possible to reduce the weight of one of those cars, by eliminating unnecessary things, but keeping safety and just a little bit of the sofa-like comfort they offer?

I think, if someone were able to slash the weight by such an important fraction, automatically you would also slash fuel consumption (perhaps not in the same fraction...).
Thanks all of you for your interest, and patience with me not so good in automotive.

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

The short answer is "no".

The long answer is "Not while maintaining the safety, comfort, durability, ride quality, and luxuries that a buyer of a vehicle in that class has come to expect and at a price that people can afford".

All of the answers previously given, still apply.

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

It is a parallel answer to that of the question under engines - why are modern engines so much more powerful/better than muscle car engines?
Because engineers haven't been sitting on their hands over the last 40 years.

Jay Maechtlen
http://www.laserpubs.com/techcomm

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

If cost was no issue and some of the luxury items were omitted it would be possible. Extensive use of composites, downsized turbocharged engine etc.

je suis charlie

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

"If cost was no issue...."

You can't have it all. Production automobile design is an exercise in compromise. The designers must balance the competing requirements of cost, performance, weight, emissions, fuel economy, reliability, crash safety, etc. And they do a very good job at it. Sure, it might be possible to construct a 5-passenger automobile with a 200HP drivetrain and an empty weight of under 1000kg if cost was no concern. But just who would be willing to purchase such a vehicle if it cost $500K?

A Robinson R66 helicopter seats 5, has a 270hp drivetrain, comes with air conditioning and leather seats, has a range of 350 miles at a speed of 144mph, and meets very demanding crash requirements. It's empty weight is 1280lbs. But it's purchase price is over $800K.

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

So we need to identify why some rich person would worry about the unladen mass of their vehicle, rather than paying 1/10 as much and getting a better car, which weighs twice as much. Perhaps they live at the end of a very long and rickety bridge?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

RE: Is it possible to build a 5 seats passenger car weighting max 1000kg?

Weight is an attribute of the product, but not a primary one in the way that cost, acceleration, pax volume & comfort, fuel economy & emissions & safety are. It affects all of them, but as a product design of car, if anything more weight is desirable because of the advantage a heavy car has in a collision- aside from crumple material and safety equipment, the lower velocity change goes to the heavy car. So all other things the same I'd take a heavier car- collisions where intrusion into the passenger compartment is not a concern, you're proportionally better off in the heavy car.

Times when you would spec the weight would be when it directly affected the user, people will pay thousands for a sub 20lb road bicyle, because they power it, and the perceived power of marginal advantage (winning a race).

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close