Project: Ereshkigal
 

Before you begin digging in to this post, get some popcorn, a drink and do a quick trip to the bathroom. It's gonna be a bit of a read.

One or two of you may recall my intro thread titled "Eco-Unfriendly" (see
http://ecomodder.com/forum/showthrea...dly-17772.html) in which I discussed running 200 MPH in my 2009 Mazdaspeed 3.

Unfortunately, due to limitations of the vehicle, drivetrain and powerplant, I've since deemed it infeasible and have abandoned the platform as the tool to reach my goal of joining the 200 club.

All is not lost, however, and the dream continues with a new vehicle; a 2-door 1965 Ford Falcon Wagon. Originally, I was going to chop and channel a pre 1967 Karmann-Ghia, but I couldn't find one that didn't need over a month worth of body work before the modifications could be done. I drummed up the above on Craigslist (which was listed for an AMAZING price considering the rarity of the vehicle in question), and body work has been ongoing.

I'm getting to within a month of being ready to chop the top on this thing, and that brings me to the point of this thread.

Ya see, the aero on this thing is pretty terrible; the Cd is listed as being 0.58 from the factory, which is terrible compared to my daily driver (2009 Mazdaspeed 3) @ 0.32. I figure if I can get the Cd down to 0.4 I should be in pretty good shape for 200 MPH in a standing mile event; the only issue is I don't know how much I can expect to get out of the modifications I already plan to do to the car (and this is where you folks come in).

Starting out, I've got a short list of comparative aero statistics between my Mazda and various levels of modification done to the Falcon; the ultimate goal here is to get as close to if not better stats than what my Mazda already has:


MAZDA FACTORY:
Curb weight: 3153
Width: 69.1 in
Height: 57.7 in??
Cd: 0.32
Frontal Area: ~22.427 ft
CdA: 7.176

FALCON FACTORY:
Curb weight: 2815 lbs
Width: 71.6 in
Height: 60 in??
Cd: 0.58
Frontal Area: ~24.165 ft
CdA: 14.0157

FALCON CURRENT:
Curb weight: ~1800 lbs
Width: 71.6 in
Height: 50.5 in Front, 52 in Rear
Cd: 0.58
Frontal Area: ~20.943
CdA: 12.146

FALCON CHOPPED & GUTTED:
Curb weight: ~1500 lbs
Width: 71.6 in
Height: 47.5 in Front, 49 in Rear
Cd: 0.58
Frontal Area: ~19.734
CdA: 11.44

FALCON FINISHED (hopefully):
Curb weight: ~3200-3500 lbs (or better)
Width: 71.6 in
Height: 47 (before ride height adjustment)
Cd: 0.40 (or better)
Frontal Area: ~19.734
CdA: 7.893

With those references in mind, I present to you the following is a list of tweaks I plan on doing to the car already (aero wise), with the goal of getting the 0.58 Cd down to .4 or lower:

Planned:
MASSIVE frontal area reduction (via chop top and lowering)
Slight windshield angle change
Side mirror delete
Door handle delete
Radio antenna delete
Badge delete
Rain gutter delete
Custom front bumper (rolled?)
90% front grill block (leaving enough for brake ducting/engine air intake)
Full aluminum undertray
1 piece front body clip (two body seams total; the "hood" will actually be a tilt front end)

These are the things I'm not too sure about doing or could use a little tiny bit more info (and yes I've already been through the master aero list a couple of times); items are numbered with my questions to follow:

Uncertainties:
1. Tire Spats
If I do add these, I'd probably try to channel the deflected air to under the car, which might add a touch of downforce at speed. Considering I intend on having the car extremely low to the ground (within 3 inches) during the high speed pulls, will I even need spats? Might interfere with ride height adjustments or bottom out on bumps. My Mazda has these from the factory, so I can look at them for reference if needed.

2. Rear tire boat tails
I could see how these could help a bit, but I'm not sure how much of an improvement they will really be. Also, might interfere with ride height adjustments or bottoming out on bumps.

3. Radius front wheel arches
The result from doing this would have to be pretty significant for me to consider it. Any anecdotal evidence/science to go along with this mod? I didn't find any (though I didn't look too hard either).

4. Partial kammback or spoiler(s)
This mod I *know* would have real gains on this car, however, I'm questioning if it would provide more than just doing the sharp edge airflow separation/airflow trip. Any input on this?

5. Front air dam vs splitter
If I understand these two correctly, having a really low ride height means I may not really require a full air dam and might be able to get away with just a splitter, correct?

6. Rear airflow trip/separation
As you will see from the images below, there are areas that could use some improvement as far as unsticking the air goes. My question is, should this be done around the entire outside edge of the vehicle, or are there just specific points that would be needed to reach a level of effectiveness approaching diminishing returns? I'm also wondering how much of the factory body lines I should mess with at the rear of the vehicle.

7. Rear diffuser
I know these work, or they wouldn't be on supercars. I also know that some vehicles route the exhaust into them to help with scavenge; what I'm not certain of is how large they should be, sweep angles, and the like. Would an off the shelf one work, or should it be done custom with specific requirements (which I'm not certain about)?

Your thoughts/criticisms are appreciated.

On to pictures of the car!
(Click for big)
Next to the Mazda:
http://i1100.photobucket.com/albums/...h_IMG_0412.jpg http://i1100.photobucket.com/albums/...h_IMG_0411.jpg

Lowered:
http://i1100.photobucket.com/albums/...h_IMG_0384.jpg http://i1100.photobucket.com/albums/...h_IMG_0409.jpg http://i1100.photobucket.com/albums/...h_IMAG0054.jpg

Rear modification reference images:
http://i1100.photobucket.com/albums/...h_IMAG0066.jpg http://i1100.photobucket.com/albums/...h_IMAG0067.jpg http://i1100.photobucket.com/albums/...h_IMAG0068.jpg http://i1100.photobucket.com/albums/...h_IMAG0070.jpg

There's other misc images in the library.

Below are some other modifications I plan on doing to the vehicle which will help improve efficiency (and as a side effect, mileage); they don't really have any bearing on the focus of this thread, but some may find my plans interesting.

Misc Mileage:
Lean burn (maybe)
Variable displacement (maybe)
Fully polished/cryo-treated six speed manual transmission
REALLY low cruising RPM from gear ratio
Mild camshaft (tuned for turbocharging; low lift high duration)
Carbon fiber drive shaft
Lightweight engine internals/flywheel
Under-driven crank pulley (10-15%)
Dual electric water pumps
Multiple electric fans


Well, that's pretty much it until the discussion starts. Thanks for reading this far and for your input as a community.

Which engine are you going to use in the Falcon?

If you're a purist, you're going to hate me for this.

302 LSX running E85, fed with twin TS EFR 9180 turbochargers. On pump gas, I'll have enough airflow at 8k rpm (which is where I'll set peak torque to hit at) for 1500 horse. E85 will be probably close to 2000, if I ever get brave enough to push the boost that high (35 PSI @ 8000 RPM).

My thoughts are as follows. The Kammback or a boat tail will be essential for getting your cd down. The biggest area for cd improvement is always at the rear of the car. Hitting all of the low hanging fruit will be good though. The less concave the front end is, the better. Because that will (iirc) create a high pressure area. As far as the splitter/airdam goes, the splitter will add downforce. The airdam only keeps extra air from getting under the car, but the belly pan + lowering the car should negate this. For #6 I will refer you to the rear end of the Audi R10 TDI. The kammback works on the principle that with sharp edges the air keeps flowing rather than detatching and becoming turbulent. Which brings us back to the kammback. Sorry if I am stating the obvious or if I got anything wrong. But I'm sure I will be corrected if I did. ;)

I would hate you if you were slapping a Ford engine into a Chevy :D

Among gasser V8s, Chevrolets are my favorites, I like them even more than any Hemi. In spite of the OHV valvetrain being labeled as "outdated", they're better than many European, Japanese and even some recent Ford engines with SOHC or DOHC valvetrains.

That would depend on the motor. My Mazda's block is mfg by Ford (the balance shafts and other various engine parts say FoMoCo on them), and I'd have no issue throwing a modern DOHC Coyote block into something if it didn't need mountains of power.

The reason I'm going this route is because of parts availability, and the fact that the block is 2000+ horsepower capable.

Small step back in technology, huge leap forward in potential output.

Sure. The LSx is a well-proven platform, and has an outstanding power-to-weight ratio.


Even labeled as a step-back, the OHV valvetrain allows for a lighter and more compact layout, even with a larger displacement in comparison to its European and Japanese opponents. And even before the introduction of VVT, their torque band was also better.

I only call it a step back as the Mazda has DOHC 4 valves per cylinder, VVT (which I know I can kinda get in the LSX but don't really want/need), direct injection and all kinds of other goodies that this motor won't have.

It also won't have any of the limits the Mazda has as well, which is largely the point.

200 in the mile
 

I just re-visited an article CAR and DRIVER did about their grudge-match at the TEXAS MILE between a Ferrari Italia and modified Corvette.
Wheel spin was a big consideration in getting enough power to the track in order to accelerate to speed within the mile.
The Corvette managed it with Don Sherman finessing the throttle of the twin-turbo engine of over 800-bhp.
With enough horsepower your Falcon can do likewise,but I don't know about the 'Salt.'
Wheel-spin really tears up the salt and is vigorously frowned upon.
You could do a 'gentle' 1-mile for the 130-Club,which would qualify you for the 150 Club,which would qualify you for the long course,where in a good year might give you 12-miles to play with.
Under constant acceleration you'd get to your 200 (and red hat) without destroying the track for everyone else.

Yeah my plan is to do a reverse taper boost curve limited by traction (so boost increases as speed increases on a per-gear basis). I also currently have no plans to run on the salt (far too lazy to clean the car after something like that).