Mike, John and I were at teh mall the other day and I saw in Turbo Mag a classic that had this foam injected into its frame and it said it stiffened the chassis as much as 40%. Anyone ever heard of this? It said it was used alot over in Japan but not many people over here know about it.

Id like to get some more info on this. I know mike kojima knows about it as he wrote the artical. if you guys ahve a way of contacting him, ask him about this and give him the link to this thread.

Don't do it. It's not worth it. I did that to my car, and it did make a little bit of change, but after a while (like a year) it goes back to normal.
What you do is spray urethane foam into the frame. It expands inside the frame and get stiffer and it prevents from body flex. It was a neat idea and everybody in Japan did it becase this thing was in all over the car magazines. But this is only good for a little while. You have to do it right too. If you don't plug every single hopes, urethane foam will come out and mess up the interior, and even exterior. There are hidden holes all over (you have to rip the carpet to do it) and I had that problem when I did mine. I read it will quiet down the inside the car and improve the stereo sound quality, but it didn't do nothing.

While i havent done it, mike kojima also did this on project 300zx. I cant imagine its a bad idea.

It's a 2 part hardening foam used by body shops. Save your money and buy an Autopower bar. You will notice its effects. Not to say the foam is bad, but bars are proven to work. Keep it simple.

I read the same article to. What kind of Foam did you use Carbon Black200?

They stated in that article to stay away from around the home type foam. aKa GOOD STUFF.

I would be inclined that at the very least, it would quiet your car down.

Originally posted by Its311Pete
I read the same article to. What kind of Foam did you use Carbon Black200?

They stated in that article to stay away from around the home type foam. aKa GOOD STUFF.

I would be inclined that at the very least, it would quiet your car down.

I forgot what kind I used, but I used the home type foam. lol There are two different kind of GOOD STUFF foam though. One is intend to expand a lot, another one won't expand much. You need the one expands. I read the article about testing urethane foam for home use and auto use, and they both worked exactly the same.

I said "Don't do it" on my first post, but i should say "I don't recommend it" instead. They do make difference, (That's why people were talking so much about it) but one thing i can really say is this is NOT the long term thing at all. It will slowly lose its effect. Adding bars is the sure way to stiffen the body (IMO). Urethane foam was big in Japan like 3 years ago, but now nobody even does it.

oh i plan to get bars but i was thinking of another way to stiffen the chassis in addition to doing this...it might be good for autocross seasons or something

THe foam Mike recommends is a two part kit. The other stuff really does not stiffen the chassis. The two part stuff works. OEM people use it for sound deading but Dodge uses it on their new truck frames. Made a big change in stiffness. OEM stuff is not used often if it doesnt work.

so what is this stuff then? im assuming that you are saying it works then steve? if it works how much is it and where to get it?

Originally posted by blairellis
so what is this stuff then? im assuming that you are saying it works then steve? if it works how much is it and where to get it?

I am saying that Infinity, Lexus and others use the stuff. It works for them. I don't have the energy to go pooring thru a bunch of old magazines to find the article. The place that sells the stuff has the article on their web site. Do a internet search for Chassis Foaming, Structural Chassis Foam, Frame stiffner, Etc,

the stuff they use in Japan that I have seen comes in a tube like Caulking for a window. They apply this all over the welding marks and joints. Basicly everywhere. This stuff is not really like that yellow expansion foam stuff just this caulking/rubbery looking stuff.

I've been thinking about doing this a couple months ago, so I did some research.

The distributor of suitable product.
http://www.itwfoamseal.com/automotive.htm

The SCC article.
http://www.sportcompactcarweb.com/projectcars/0006scc_proj300zx/

Honda-Tech discussion between some engineer types about the benefits and negatives.

http://www.honda-tech.com/zerothread?id=294835

Originally posted by CarbonBlack200
I forgot what kind I used, but I used the home type foam. lol There are two different kind of GOOD STUFF foam though. One is intend to expand a lot, another one won't expand much. You need the one expands. I read the article about testing urethane foam for home use and auto use, and they both worked exactly the same.

I said "Don't do it" on my first post, but i should say "I don't recommend it" instead. They do make difference, (That's why people were talking so much about it) but one thing i can really say is this is NOT the long term thing at all. It will slowly lose its effect. Adding bars is the sure way to stiffen the body (IMO). Urethane foam was big in Japan like 3 years ago, but now nobody even does it.

The reason it doesnt work for you is because you used the wrong type of foam, if you read my articles carefuly, it specifcaly warns not to use home hardware store types of foam, they do not harden stiffly, they do not bond well and some will not even harden without exposure to air. The only types of foam to use are the ITW foam seal and 3M automotive repair foams.

Thse foams are 2 part catalized foams that are ridged when hard and bond like crazy. Theses foams are used by OEM's like Infiniti and Lexus in the plant to stiffen the chassis and the ITW and 3M foams are sold to repair these cars after a wreck.

I got the 40% figure from an SAE (socitety of Automotive Engineers) paper on the subject for the density of the foam I used. You can go to the SAE web page and order the paper if you want an engineering level explnation of how this works.

Foam filling works well!

Mike