Aeromodding the Astro Van
 

Hello hello! I'm am about to have a large undertaking.. taking a 94 Chevy Astro van w/ 4.3L i6 engine powering an automatic all wheel drive train and turning it into a 30mpg+ hwy van.

I need to make a 33% increase!!

I'm starting with the basic weight reductions and air dams for the front and rear wheels.. maybe the front if I can do so safely. Also as always, plugs, wires, filters and cheap sensors.

I need ideas or success stories with monsters like these! I'm trying to not break the bank here, anything will be considered. No boat tails though, its already almost 13ft of truck like van, I cant add another 8ft for the tail hahah

http://images.craigslist.org/00y0y_i...L0_600x450.jpg
http://images.craigslist.org/00x0x_d...bO_600x450.jpg
http://images.craigslist.org/00y0y_i...NA_600x450.jpg

Whoa, you have an uphill battle ahead of you.

I think at a minimum you will have to disable the AWD, swap to a manual transmission (if not a different engine) and add at least a partial boattail.

I just read an older forum about a gentleman that took his 89 astro and turned it into a 30mpg+ diesel/ stick conversion van. I might not be able to high five a 30mpg tank, but any increase over 20hwy will be awesome. I was also considering a partial kammaback, but the rear window raises on struts, so securing it might be more difficult that I could do working in a simple 'screwdrive and wrench' garage.

BTW I had the 84 mazda b2000 that I was requesting help for a few months back. After removing the bed and custom building a plywood boat tail, I was able to achieve 33mpg over the stock 26 highway. Wish I would have had pics of it, it looks like an aeroplane :(

You asked for aeromods but I think you already know the answers: bug shield delete, mirror delete, roof rack delete just for starters; grille block, skirts, flat hubcaps, air dam, partial/total belly pan, and most importantly by far a tail of some sort.

On this buggy the wipers MAY be in the air stream; can you set them lower (closer to the hood) and/or delete the passenger side arm. Have you driven it in the rain and noticed if the raindrops get blown off the entire windshield, or do they just sit there on the bottom 4-7" like they do on my 3-box cars? No movement there = stagnant air bubble = don't fret about the wipers then.

Are the springs good? Can't tell if the rear of the van is low; on most designs good aero calls for a slight nose down attitude.

I completely forgot about exterior drag xD

Deletion is a must.

So speaking for practicality: I am a safe driver and confident in my abilities to handle the astro with out bumpers, but would a bumper delete also negate the ability to mount the front air dam without drilling 5 holes in the chassis? I might as well go for it.

What are we currently using for bellypans. All I'm seeing in searching it is what it does.. not how to fit or what its made of :/

33%
 

If you did the 33% mpg increase solely through streamlining you'd need a 66% drag reduction.
If you were starting at say,Cd 0.34,then you'd have to go below Cd 0.12.
I think that your windshield is not of sufficient curvature that you could pull off extreme front modifications to get you near Klemperer's 'minivan' of 1922,with Cd 0.16.And it had about 3-feet of boat tail.
A reverse-Template could get you to around Cd 0.142,but you'd never be able to see out of the windshield at the angle it would require.
You might try some extreme cardboard and duct tape mods long enough to see if they 'showed' at the pump.
The 1987 Renault Vesta II was Cd 0.19.
The Mercedes-Benz Boxfish is Cd 0.19.
Both of these would be worth looking at as starting points.
The Pontiac Trans Sport,Cd 0.30 will get Cd 0.12 with a full boat tail.Lay tested 'it' in 1933.It could be inflatable.
My VW Transporter went from 27 mpg,to up to 35 mpg with a full belly pan,rear wheel skirts,steel radial tires and 18-inches of boat tail.
That enormous wake behind the Astro is killing you at the pump.

What are you doing that you need the van for? Towing, hauling, big family?

What kind of driving do you typically do? Short city commute, lots of highway, poor roads/ off road you need awd for at times?

I'm definitely a granny when it comes to driving. We do a lot of travel on and off throughout the year, so the awd is a must for the mountains and the van is a must for comfy sleeping, the roads are always unpredictable but we could safely say smooth roads 90% of the time :)

I've got a 97 AWD cargo. Empty I average 19-20 mpg, but it's never empty anymore, so I'm at 14.5 mpg.

On the Astrosafari forum some have dropped the front drive line, but only reported a 1 maybe 2 mpg increase, their still turning all that gear in the front diff. The only way to truly dump the AWD is to swap to a 2wd sub frame.
The biggest gains we've seen in mpg is a V8 swap, probably 3-5 mpg increase.

There are other ways to make those front wheels freewheel.