Copying the amazing 2011 hyundai elantra manual shift

[mans]

quoted from a magazine review of the 2011 hyundai elantra:

(quote
"Official fuel-economy figures of 29 mpg city and 40 mpg highway
A six-speed transmission, built in-house by Hyundai, is responsible for 4.1 percent of the fuel-economy improvement, and a smart alternator shaves an additional 2.5 percent. Weight loss adds a 1.8 percent improvement, while low rolling resistance reduces inefficiency by another 1.4 percent, aiding the car's claims of best-in-class fuel economy.

Cruising in sixth gear at around 80 mph with light throttle yields an impressive indicated average fuel economy of around 50 mpg—helped, in part, by a tall top-gear ratio of 0.633. More erratic driving at lower speeds lowered our average to just below 30 mpg—spot on with the EPA city estimate of 29 mpg.

A manual-transmission Elantra GLS Standard starts at $15,550,
Read more: 2011 Hyundai Elantra Review - Hyundai Elantra Test Drive - Popular Mechanics"
(end quote)


now....
this 2011 hyundai has a
1. cd of .28 (allowing for the 50mpg highway figure even at 80mph
2. curb weight of just over 2600 lbs
3. a very low highway gear ratio of .633
4. lrr tires
5. smart alternator

it's only problem is the price tag, $15,000 and the cheapest used ones are still currently at $13,000-$15,000 with like 20k-30k on their odometers

so I'm wondering ...
is it possible to purchase a more affordable saturn sc several years old ($1,500-$3,000) and bring it to get the mpg figures of the 2011 hyndai?

I'd have a stock:

1. cd of .32 +/- a drop depending on submodel and year (how do I bring it to .28???)
2. curb weight of 2,400 lbs (200 lbs lighter then the elantra)
3. .73-.605 gear ratio, depending on submodel and year.(the famous 5th gear swap would get me the coveted .605-just as good as the elantra)
4. standard tires (LRR tires could be obtained for it.)
5. standard alternator (I'd perform alternator delete- even better then the "smart alternator")

Now... the only thing I'm missing here in the modded saturn is the .28 cd of the hyndai.

So my question is:

Is it possible to bring a .32 cd down to .28?
if yes, how?

i see many things that people do, like belly pans, moon discs and air dams.
but would these bring a .32 car to become a .28 car?

since most people who perform aero mods dont post their before-and-after cd values, I have some lack of knowlege towards the actual figures, and would appreciate knowing if anyone can forecast by how much any given aero mods would bring down the cd and whether or not I could hit the sought-after .28

[cfg83]

mans -

I don't see why not. Here are the CDs for a 2nd gen :



A 1999 SC1 was already rated at 25/36 MPG (29/40 old EPA MPG) :

1999 Saturn SC Manual 5-spd 4 Cylinders 1.9 Liters Regular Gasoline

Soooooooooooo, you are already in spitting distance. Here is your streamline template for reference :



CarloSW2

[drmiller100]

Cd is coefficient. Also need to look at frontal area.

Also need to look at how efficient the engine is. A modern Hyndai is a pretty cool engine. Don't know if you are going to do quite as well or not.

Other option is go find an older CX or VX honda civic. Should be able to beat the modern stuff pretty easily.

[Sven7]

People don't post their Cd numbers because it's a pain to calculate them. An extreme example of aeromodding is Basjoos' Aero Civic which went from .31 to .17 Cd. But yes, you'll have to look at frontal areas too if you're doing a numbers game.

Why not just swap in a higher 5th gear and call it a day? Or buy a tiny car like a Metro or Festiva and aero mod that? A Saturn seems like an odd place to start from scratch.

.28 should not be very hard, by the way. I imagine with a boattail you'd be pretty much there. Although admittedly I'm as clueless as you are about what mods will improve X amount. Usually people are more interested in hitting a certain fuel economy number than a drag number.

[Olympiadis]

Originally Posted by cfg83

Do you have a source for information like that?
I'm trying to find that info for a 1985 Mustang GT.
Thank you.

[mans]

Originally Posted by Olympiadis

Do you have a source for information like that?
I'm trying to find that info for a 1985 Mustang GT.
Thank you.

unfortunately the old mustangs are horrible. they are unfortunately among the worst vehicles for cd, short of hummers and large suv's. the cd is somewhere around .45 (i'm not kidding, and certainly not trying to bash the mustang gt but I do remember that on a vehicle cd list I was looking at and I was very surprised at the .45 since the mustang is overall a small vehicle
I think it has to do with it's steep back window angle, windshield angle and grille openings and angle ...the thumbnail tells it all)

(now back to the 2500 lb ecocars please....)

[mans]

I see people usually build their boattails out of chicken wire and spray foam. that is certainly the best bang for the buck, and shortest amount of work time, but does it allow for a decent looking vehicle?

have anyone built one from sheet metal and bondo allowing for a proper paint job and better looks?

[cfg83]

Olympiadis -

Originally Posted by Olympiadis

Do you have a source for information like that?
I'm trying to find that info for a 1985 Mustang GT.
Thank you.

That picture is from a 1997 Saturn brochure. There is a website that has Cd data for some but not all cars, but I don't know it offhand. It's been posted on this forum. I am sure someone remembers.

CarloSW2

[cfg83]

mans -

Originally Posted by mans

I see people usually build their boattails out of chicken wire and spray foam. that is certainly the best bang for the buck, and shortest amount of work time, but does it allow for a decent looking vehicle?

have anyone built one from sheet metal and bondo allowing for a proper paint job and better looks?

I think this looks cool :



In terms of the template, a compromise subject to debate is "meeting the template" :




We have speculated that this is what the Ford Fusion 999 is doing :




CarloSW2

[ProDarwin]

1) What is the final drive on the Hyundai? The overdrive gear is only half of the equation. The Saturn has a 4.06 final.

2) The Saturn's BSFC sweet spot is pretty good and certainly not far off more modern motors, but the low load stuff just can't compete with newer VVT Direct Injection stuff. As far as I can tell the DOHC engine has better BSFC numbers than the SOHC engine, however is mated to a more performance transmission. A MP2 trans with DOHC motor is probably the best bet for mileage.

3) As said above, Cd is only part of the CdA. Lowering the area is quite easy. Pass mirror delete (from SL, combine with a Wink mirror), and lower the car. 2" is pretty easy to do and will drop the A by a reasonable amount (~4%). This can potentially reduce the Cd value as well due to a much tighter wheel-body fitment reducing air turbulence in there. What is the Hyundai's CdA?

4) Depending on the model you choose, a curb weight of way less than 2400lbs should be achievable. A manual 2G sedan without a sunroof should easily be in the 2200s. 100lbs is quite easy to lose off the car as well between the battery, spare tire, and wheel/tire combos.