luder_5555

My suggestion for you would be to start simple. Decide what you want to build. Once you know go ahead and design the chassis and wheelbase to best suit your vehicle's goals. (I.E. If you want a modestly powered light weight canyon carver go for a physically small vehicle.)

Once you have a good solid chassis developed go ahead and design the actual body lines that you hopefully had a rough idea of when designing the chassis. Pick a realistic and well suited powertrain for the car. (If it revs past 9k or breaks any sort of records you might as well forget about it.) If the car is anything but a canyon carver you are going to want more displacement. If your ultimate goal is light weight and handling go with a smaller engine and turbo/supercharge it for more power. Again, if it is naturally aspirated and 2.0l it shouldn't make more power than an s2k. (unless you want to spend the time to specifically design and stress test some new and amazing engine.) Also it might not be as sexy, but I would suggest a front engined car as for your stated "non-exotic halo" goal it is much more realistic.

IMO aero is not terribly important since it sounds like you are trying to make a $30-50k car. Have it look good, and follow the generally accepted rules that will make the car flow through the air fairly well and either create none to a little downforce at speed.

Personally I would either go with a 2500lbs supercharged 4-banger, (miata/lotus fighter) or go 3000lbs with either a 5.0 ford engine or some form of chevy LS, with a rear mounted trans and a bit wider stance to fit good sized rubber.


All of my suggestions are assuming that this is more than a college project and that this is something that you would like to have built at some point. If this is your first attempt at designing a car there is no reason that it has to be the next record holder at the ring. Just make a realistic car that you would want to drive, and that would be one of the most fun and appealing cars to an enthusiast in the $30-50k range.

luder_5555

As for the dick measuring and explaining the 458 diagram, maybe someone car explain to me how the hell their description of the front winglets makes any sense at all? "the aerolastic winglets in the front inlets deflect down by nearly an inch at top speed, directing less air to the radiators and more beneath the car. The result: less drag and slightly more downforce."

Unless I missed something, LESS air under the car normally means MORE downforce, and MORE air under the car nornally means LESS downforce.

Though it is Ferrari, and it is late at night so maybe they are working magic, or I am not thinking clearly.

tallguylehigh

I dont really understand the project.

Are you going to design the exterior of the car or do you have to design every single aspect of the car? The latter sounds quite daunting considering you only have 30 weeks for the project and (no offense) you are an industrial designer with not much in the ways of advanced engineering (aero especially).

I think your decision to go with an affordable car is smart for a couple of reasons. First off, you don't have to go into the extensive aero, suspension work that a supercar would require. Also, making an affordable car is more difficult to make than an expensive car from a business perspective- there is far less profit margin the cheaper the car.

Since you are thinking an affordable s2000, s600, Beat, I would really focus on the style of the car. Perform a detailed analysis on the heritage of the car and marque you are designing. Then for components, try to leverage that company's parts bin as much as possible. It will make the assignment less daunting and you can easily explain it from a business perspective that the probability of this project getting the green light is much greater since you don't need to develop everything from scratch for a $30k car.

If I were in your shoes here is what I would design:

FR, RWD chassis
s2000, Prelude cues
Miata fighter
Si motor
Retractable hard top

Show chassis is modular and submit an Acura 2+2 design off the same chassis using the 3.7 V-6

Now if you want to go crazy, you could design a MR chassis that could fit the Si motor as a Honda offering (new Beat) and the V-6 for the Acura offering (HSC-esque)

Good luck!

Mr.E.G.

Less air under the car is ideal unless you have a well designed underbody system to handle the airflow. Still you want a controlled amount of air flow, but nevertheless the task of limiting airflow altogether (as much as is practically possible) that people apply to most production cars turned road racers is based on the fact that the underbody of most production cars is a lumpy, cavernous, cluster fvkk that creates considerable lift.

On the contrary, if you have a properly designed underbody system (read: you don't ask people on a forum to tell you how to make it ) then your underbody will create negative pressure through the venturi effect.

Check out this pic: http://www.tamiya.com/english/produc...enzo/enzo6.jpg which shows the underbody of the Enzo. Then check out this pic of the front: http://www.mdxers.org/forums/attachm...-get-enzo1.jpg

You can see how the front of the car is by and large designed to limit the airflow under the car save for the center section which clearly is designed to encourage airflow under the car, but to a controlled extent.

An even better example is to check out this pic: http://www.slotracinglemans.com/imag...dyson16_03.jpg
or this one: http://www.grandtouringprototype.com...962white17.jpg and you can see how the same effect at work.

Why the big difference between the two cars with regard to how much of the frontal area is devoted to encouraging airflow beneath the car? The Enzo, as extreme as it is, still has limitations of a street car which includes an appreciable suspension travel. Underbody airflow and suspension walk hand in hand. In the Porsche, the suspension travel will be very limited and the car likely features spring frequencies in the high hundreds. This allows you to deal with the incredibly high downforce that is created by the Porsche's underbody system which features massive venturi tunnels. The opening in the front feeds these venturi tunnels.

Back to the winglets on the 458, I can't say one way or another whether the analysis provided in the picture is true or not; I've seen countless "here's how aero works" explanations from seemingly credible sources that was complete nonsense. However, air flowing through radiators creates drag and air flowing through radiators is a more a product of pressure differentials than an unobstructed path, so as the car reaches ever higher speeds, there is sufficient pressure to move enough cooling air (less air but it's moving faster so more actual volume relative to time) through the radiators, while still being able to "feed" your underbody.

rockville

I generally like what you are saying here but I will disagree that it's easier to design suspension on less expensive cars. The challenges are different. In a Ferrari you can spend money on top dollar dampers. The design can be compromised in terms of say trunk space in favor of better suspension packaging. When you start having to use existing parts (say a common upright) or you can't put the suspension pickups where you would ideally like things get harder. If you look at the total package it wouldn't surprise me if the Camry has more hours engineering it's suspension vs a Ferrari 458. It's just the objectives were different.

To the OP, since you are going for a non-halo car I would think about what has made the Miata, Mustang and Corvette successful. All three have appealed to both serious drivers (Mustang being iffy over the years) as well as Sunday cruising drivers. The Miata is around while the S2000 isn't in part because Mazda realized little old ladies just wanted a cute nice to drive car. They want an automatic (some do), they like the idea of a power hardtop. They don't care if the engine doesn't rev to 9000 RPM, they just want it to feel good. Basically, really think about what the target market is. If you say hard core drivers (generally the S2000 class) you will have a very small interest group. The Miata is still around because it appealed to many types of people, not just a few.

Mr.E.G.

I'm not doubting your intelligence. I'm doubting your understanding. Sorry if that makes me unpopular but you are just so clearly biting off more than you can chew. If I came on here and asked if anyone can tell me how to perform my own hernia operation, you'd all think that my reach has exceeded my grasp, and rightfully so.

I don't think you have to be an engineer to accomplish this task. But I think you do have to have a pretty strong understanding of the concepts at play, and with such an understanding also comes the recognition of how little value a bunch of random suggestions from people on a forum are going to be. And based on some of the suggestions you've been getting, you might as well be asking for advice on how to build a time machine.

To further elaborate on my statement that I don't think you need to be an engineer to accomplish this task, I do however think that there is a huge difference between technically pulling it off and creating something that doesn't suck donkey balls, and that difference is in the engineering.

Here's an example: http://www.ddrmotorsport.com/
These guys built a really shitty kit car that looks kind of decent from 20 feet away. Their website has been updated such that it now looks like they're a professional company, but holy shit, a few years ago when they were designing this turd you could see that they built the thing in a storage facility and that it was easily one of the most ghetto fab pieces of shit ever. The chassis of this thing is a joke and any of the difficult bits such as the suspension and steering were lifted from the MR2. On their site now you can see some spin off vehicle that has a simpler chassis that I would say is a huge misrepresentation because that's not even close to the car that they are trying to plug on the site. These guys have ghetto ingenuity but they are not engineers by any stretch of the imagination. I have a bunch of pics from their old site if anyone would like a good laugh/ be slightly impressed at their techniques at the same time.

On the subject of ingenuity, I would suggest that you'd be hard pressed to find any non-engineer that knows more about suspension and aerodynamic theory than I do. I'm a suspension and aero nerd for sure, and I'm a pretty smart and resourceful guy to boot. If I were bragging, I would say that what I know about aerodynamics relative to your average forum member is like the distance from the earth to the moon. However, I'd put my ego back in check and I would immediately add that the disparity between what I know and what an aerospace engineer knows is like the distance from the moon to the sun.

Again, I'm not saying that a non-engineer can't design a car, but there is a huge difference making some vehicle roll down the road and making some vehicle do it well.

aklucsarits

Is this more of a car design project or a car engineering project?

If it's including engineering too, start with a chassis where a bunch of really smart engineers have already done all the grunt work for you.

e.g. Lotus 7 clone:
Blueprints and plans:
http://www.sevenesque.com/plans/

CAD chassis models:
http://www.sevenesque.com/3d-models/

And then off of that already well engineered chassis, you can design your own body to go over it to make a small, lightweight sports car.

Andrew

luder_5555

^ If I were building my own toy it would probably have a tube frame chassis, but for a realistic road car there are very few who would be willing to deal with one.

Gymkata

One of my aerodynamics professors said, "if a group of aerodynamists took over a car company, it will be a financial disaster." And there is a good reason for that

tiger1964

This.

OK, the Seven has been done to death. But it's a place to start. Forget the atomic suspension and the carbon fiber cigarrette lighter.