KuHL 951

If you get a chance that would be great. The most important ones would be the actual unibody areas that are double wall. Even if structural foam would not yield tangible results, I'm sure substantial sound and heat reduction could be had using a much lower density foam. The key is to realize what you are trying to gain. We are lucky that the 944 is already incredibly rigid by design. I have no idea what benefits can be attained on the 944. Maybe this is a solution looking for a problem that's not even there. That's why I posed the question assuming someone's done it here before.

PuttingThePoorBackInPorsche

I'm not sure we all want pictures and/or explainations of your body cavities. . .

Interesting idea nonetheless. I would tend to think the foam would tend to keep moisture, dirt and other crud out of the body cavities and in so doing, reduce the likelihood of corrosion, but it is possible there could be unforeseen issues. I suppose one could foam the cavities as has been suggested and then apply a seam sealer over the holes/access points to seal it in. No way for moisture to get in at that point. . .

Campeck

i remember cutting out the strut towers for geo and noticing it waqs double walled. you should inject some in the slotted holes you can see in the strut towers.

Chupa

If we're getting serious, we could estimate the modes (or even model and FEA them) and figure out which areas a most useful to work on.

DanG

There's a company that walks around with pucks of structural foam at FSAE every year. They're dying for teams to use it. The company is Henkel.com They have a building that does it here in Detroit but can probably also do it a few places around the country.

http://automotive.henkel.com/News/20...+SAE%C2%AE.htm

Henkel is also the company that makes Loctite. They rock.

Here's another company with more info.

http://www.baltek.com/products/airex/sfoamc.html

KuHL 951

I know that Henkel and Baltek both joint venture with Detroit on foam injection. The 90-94 Q45 was well ahead of it's time with extensive structural and dampening foams throughout the body. It is the quietest car I've ever riden in and it's 15 years old and still rattle free. This thread could be be very helpful. The way I see it there are at three approaches that can be taken to identify benefits and ways to accomplish them:

1. Structural enhancement and sound reduction for track service;

2. Sound reduction and corrosion resistance for street use;

3. Combinations of both 1 and 2.

Each of you might haver a special goal or talent to add. Chupas seems to know his modeling, Geo knows what areas might improve the handling of the 951, Yieldsign has a stripped 944 to inspect, and I make a killer Martini and can bore you with corrosion theory.

Geo

My car is also down to the shell right now. My biggest problem is time, but if need be I can get photos of the various holes in the shell.

A little more about structural foam and and SE-R. A very good friend of mine raced an SE-R in Firehawk way back when. A friend borrowed his car and half balled it up. He spliced two cars together an injected the chassis wtih structural foam. The spliced car was far more rigid and way better than the original unspliced car. He also used the foam in his whacko crazy killer twin turbo Z32 300ZX. He reported great improvement in the Z32 as well.

GOSANE

Steve, a lot of cars have foam in certian places. It's used for different things. Sound control, to seal against moisture, and stiffining. Usually all three factors come into play. It will alter the crush dynamics in a crash. Several of the jobbers (auto) have foams and the proper delivery devices made just for autos.

marksportcts

I was considering doing this a few years ago after reading the "Sport Compact Car Project 300ZX"




This is the article, scroll down to the part on "Foam filling the chassis"

http://www.sportcompactcarweb.com/pr..._300zx_part_5/


From that article

" In a final bit of reengineering to stiffen the body, we injected the chassis with catalyzed rigid structural polyurethane foam. Structural foam, in the 2 lb per cubic foot density that we used, can stiffen chassis members up to 40 percent.

Higher densities of foam can increase stiffness by up to 300 percent. Since we cannot retool custom parts to redo the Z's body, we figured that this would be an excellent, low-cost way of greatly increasing chassis stiffness. Injecting foam is not a new technique for chassis stiffening. The Infiniti Q45 uses this sort of foam in some of its chassis members to increase stiffness, as do a few other premium cars. In fact, the foam we chose is the foam recommended to repair damaged Q45s."

"Do not--I repeat--do not attempt to use cheap, hardware-store canned foam. This is not the same thing, and if injected into your chassis, will form a gummy mass that won't dry. Foamseal foam is a professional grade foam, which although it is a little unforgiving to cleanup mistakes, has superior mechanical properties and catalytic curing so it will dry even in an enclosed space." ....I am quite certain that Great Stuff is not to be used as a performance upgrade for your car, keep it for your home or RV.

Geo

That's the 300ZX I was talking about. Mike Kojima is a close personal friend.

Scott at Team Harco

I figured as much when you started talking about the SE-R and the 300ZX. I just talked to Mike a couple of days ago. He's trying to get my fiberglass hood article published.

Interesting info on the structural foam. That is the answer I was looking for. My application is not my 944. I believe that car is already very well designed with respect to structural rigidity. My application is an Eclipse that will see duty as an ice racer, road rally and rallycross car. Additionally, it will be my winter beater - so any corrosion resistance will be a bonus.

Geo

Mike's a really cool guy. He's the one who was instrumental in my engine swap (G20 with SR20DET) article being published in SCC. He's helped a LOT of people. He's getting ready to launch a high quality on-line magazine with seriously good technical info.

SCC wanted to include my G20 in a feature article on sleepers, but sadly it was totalled (not even remotely my fault) when someone crashed into me before they called. I've tried to get a couple of other articles published. I was a little miffed when they did an article on track driving similar to a proposal I sent in even stealing my working title (Lap Dancing).

Mike1982

I am interested in this as well. What good products are out there then for this? How much would something like this cost me? Also, where are good places to do it on the car to gain more stiffness? The cubbie holes in the back, I don't see how filling them or putting braces in there would rigidity, but places like in the door, A/B pillars etc would help some, at least I think.

adrian_jaye

I would be carefull about pumping foam into places for the following

1> Most are flammable and in case of an accident you might be adding more of a risk.
2> You probably need to advise your insurance company because of 1
3> If you put it in the wrong place and you need to do any work it may be messy and cause problems, especially if your gonna weld (see 1)

However,,, I have used body foam in my old capori for 2 reasons

1> fitting a body kit (rear wings which were rivited on
2> put some expanding foam in the bonnet mainly for sound reduction

Oh a lot of expanding foam does not go solid when in an enclosed space as it cant dry, I've opened up spaces when I've bolloxd up ontil to find inside was still liquid, thoiugh the stuff to the air was solid, and this was like 6 months later !

marksportcts

This stuff dries with or without air, otherwise if it is still in liquid form, it wouldn't add any rigidity but rather just more weight. If it is the same foam that is used in the Q45, what is the insurance company's policy on these cars?

Geo, I recall that you posted something about your car being in SCC, good stuff.

So anyone know where to put this stuff in the 944's?