Is that low expansion foam that "great stuff"? only stuff I've used seems to keep swelling for a week.
That's one reason to take the undertray panel off the car to use the foam. You could make a simple mold out of bent plastic sheet, squirt the foam, and let it rise and cure at its own pace, then sculpt/sand/paint.
Hey ALS, I was the guy with the carpet pad turned undertray on a 94 965. I remember reading your original post on TB and I was very impressed by the workmanship. I'm glad to see the car is still on the road. I don't drive the 960 anymore, moved on to a BMW 318i 5 speed but my GF drives an 850 5 speed. Driving volvo carefully we managed 32.7 mpg on our last 500 mile road trip. I also found that I can get away with taping up 50% of the grill, removed the wipers and folded in passenger side mirror. Theres a lot of room for improvement under the 850 as well. I was also thinking about doing rear wheel covers but I'm not sure what kind of material and fasteners to use.
Theres not a lot of Volvo aero information in this forum so I'll add my modifications here in the name of being concise. I'm preparing our volvo 850 for a 1700 mile trip to Seattle. I picked up a 8'x4' sheet of Coroplast at Tap plastics. So far I have the rear of the car finished. Next I will move on to the front.
I cut out a fitted sheet of coroplast.
Epoxied on some strategically located aluminum right angle strips for stiffness.
This is how the car left the factory. There are huge air gaps underneath the rear end between the fuel tank, spare tire well and rear bumper.
After. The panel is secured in place with a special mixture of zipties and bolts through the bottom of the spare tire well. I left a lot of room on the driver's side for the exhaust. Probably too much room but better safe than sorry when it comes to melted plastic.
I'm cooking up something special for the front To be continued
The rear area of my 960 wasn't as as bad as your 850. My spare tunnel hump looks like a big donut. Justin it is looking good what you have done with the rear area. I'm going to have to link this thread to a post over on the Brickboard. There is a guy that is trying to improve his gas mileage with a 960wagon.
I put about 1 hour of work into the front end this afternoon. So far, so good.
Left front before
Right front before
Looking across from passenger side to driver's side.
Thats all the work I'm willing to do. We'll see how it pans out on the highway. The car does an honest 32mpg at 65mph in stock form. I don't have time to grow old and die in the car so I drive a bit faster. If I can pull off the same 32mpg at 70 or 75mph I'll be happy.
You should see how many IPD parts my 745T has.
Sways, lowering springs, chassis Braces U&L, and HD Bilsteins.
I want a factory lowering kit for my 960. The problems is, it is over $2,000 through the grey market to get it. That is way more than what the fuel economy gains could ever be recovered by making the change.