terry, i've heard about the foam stuff too, also from z-car guys. i did some checking and i still have some information about it around the office somewhere. they are using it to stiffen the frame but the manufacturer is billing it more for a vibration (rattle) dampener. the manufacturers name is 'ITW foamseal' or something like that. many of the import manufacturers have been using it for the last few years to eliminate squeaks and rattles. they inject it into the subframe areas and it has something like an 8:1 expansion rate so you have to be somewhat careful as to the amount you use. the rep i spoke to guestimated that i could need about 8-10 cans to inject my frame at a cost of about $30 per can.
i don't really know how much benifit we would get from this type of product although it's good to throw into the mix. if it was a noticeable improvement, it would be the heck out of anything else we've talked about here from a 'bang for the buck' perspective.

 

Interesting. Maybe I'll have to break new ground here. Would it be prudent to weld up the frame first though??

Should also prevent water from sitting in the frame and rusting through too! ;)
-terry

 

That was my apprehension, WATER~ Would it keep it out, or hold it in? Would it promote rust, or prevent it?

Would this work on the same order as the Balsa Injected Floor on the C-5?

Hmmm...... very interesting..............JIM

 

Here's info on the foam. Sounds REALLY good. I think I may be the guinea pig for this one of these days. :) This is a writeup from Sport Compact Car magazine where they added it to their project Nissan Z.
-terry

Foam-Filling the Chassis
In any high-performance car, it is impossible to make the chassis too stiff. The stiffer the chassis, the higher its natural frequency, making the energy imparted to it by bumps less likely to excite the body's structure. A stiffer chassis enables the use of stiffer springs and shocks without hurting the ride. This is because a stiff, non-flexing chassis transfers more force into the suspension where it can be dissipated by the springs and shocks instead of transferring the force to the occupants. A stiff chassis is also more responsive to roll rate tuning for balancing understeer and oversteer. This is one of the reasons why automotive engineers are continually investigating ways to stiffen chassis without adding weight.

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.

To get the correct foam for our project, we contacted Art Goldman, Foamseal's automotive product manager and author of an SAE (Society of Automotive Engineers) paper on the use of structural foam for the stiffening of automotive unibody structures. We used Foamseal's two-component foam kit, p/n 11-22 to fill the main members of the chassis. Like we mentioned earlier, Foamseal is the supplier that I-CAR, a national certification group for quality auto repair, recommends for the repair of damaged, foam-filled chassis. The Foamseal kit uses a two-part catalyzed polyurethane foam, which quickly cures into rigid, waterproof, closed-cell foam. To prep the car, we carefully masked off all painted areas anywhere where the foam could drip. As this sort of foam is a thermosetting catalyzed plastic, we realized it could be icky if it spilled on paint or any part of the car's interior. This foam is nasty stuff. It is impervious to all known solvents and cleaners.

Rubber gloves must be worn. Get some of it on your hands and it will stay there for more than 3 weeks--don't ask how we know. Do not get this stuff on your paint. Wear old clothes; we ruined ours while learning how to handle the product. We injected the foam into the rocker panels and frame rails of Project Z through existing bolt and drain holes. When injected, the foam reacts like shaving cream and quickly expands to fill the empty space. You can judge how much foam to add by watching its expansion progress through some of the holes. Once injected, the foam expands and begins to cure in about a minute so you need to work fast and plan how you inject the foam before you start.

The life of the foam kit is limited to a few hours once the seal is broken. We filled all of the Z's unibody frame members using five foam kits. When foaming a chassis, you must remember the wires and other lines that pass through the chassis must be relocated or they will be entombed forever.

We were amazed at how this simple procedure improved the performance of the car. The chassis now almost feels like it has a roll cage. A sloped driveway can be driven up sideways with nary a creak. Even though the Z already has a pretty tight chassis, it feels more solid. The ride has improved and road noise has been reduced noticeably. We bet that the car will be even more responsive to chassis tuning measures in the future. If you are a slalom racer, a road racer, have a lowered car or even just want a smoother ride; foaming is a worthy, easy-to-do modification. Foamseal has foams in densities as high as 10 lbs per square foot if you desire to make things even stiffer.

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.

 

They were talking about adding foam to a unibody construction right? I would think it would be less effective in the frame area in the middle of our cars. Don't get me wrong, I'm sure it will do something to stiffen, but i think you would need to increase the cross sectional area of the frame rail, as well as tie both sides together to get better bending/torsional stiffness. Just MHO

How about injecting that stuff in certain areas around the bird cage to stiffen the body up???

 

http://www.foamseal.com/auto_aftermarket.htm

ITW Foamseal's AUTOSEAL Automotive Sealant Foam
ITW Foamseal's AUTOSEAL is a two component foam kit that has been specially formulated for automotive aftermarket applications such as chassis stiffness improvement, sound damping, and reduction of vibration and infiltration of air, water and dust.

Featured in the June 2000 issue of Sport Compact Car Magazine in the article entitled Nissan 300ZXTT, Part V, More Suspension Tweaks and Tales of the Magic Foam (pages 236-242), AUTOSEAL (HandiFoam II-12) significantly improved the chassis stiffness of the Nissan 300ZXTT. Five (5) kits were used to stiffen the chassis. Each kit yields approximately one (1) cubic foot.

The below has been edited and was posted in Dec.2000
---------------------------------------------------------------------------------------
Hi,
Some of you may be aware of a relatively cheap and effective means to
improve your car's handling by stiffening the chassis by drilling access holes in the floorboards and injecting an aerosol-propelled
expanding-hardening foam into the car's hollow chassis members.

I'm sure this has been around for awhile, but I first became aware of the process through an article in the June issue of Sport Compact Car in which a Nissan 300ZX project car received the treatment. The 300ZX required five "kits" so I figure a smaller Miata likely requires only three.

I contacted Art Goldman at ITW FoamSeal, the company that makes the hardening foam material used in the SCC article to see if I could
arrange a quanity discount for those of us in the Miata community. He
kindly agreed to extend a discount to us if we can put together a bulk
order, shipped to one address.

Here are the prices below. For reference, the regular price if you were to buy enough for one car would be $30.00 + $ 6.00 shipping=$36 for 1 kit or $30x5=$150+$13 shipping=$163 for 5 kits.

(1 case = 12 kits = estimated 4 Miatas)

1-49 cases @$26.50/kit or $318.00/case + shipping of $6/case
Thanks,

Bill Wilner
SOCALM VP http://www.socalm.org

---------------------------------------------------------------------------------------
This is all I could find on the internet, I wonder what it would do in a C-3 Frame? JIM

 

Wrote a reply already, and got kicked out !!

Anyway, made an important discovery today !
While making some mnor adjustments to my t-tops, and checking for water leaks (what else is new) I decided to re-check the #2 body mounts whilst the kick panels were already removed. While the bolts were torrqued, I realized the mounts would move with the persuation of a wrench. I backed one of the bolts out, and upon close examination, discovered that the shoulder was worn where the threads had been bottomed-out, and the shank showed wear from side contact. Two additional washers served as a quick fix, allowing proper torque and compression of the mount with room to spare. Lesson learned - my poly mount kit came without hardware and 3 1/2" bolts differ slightly from each manufacturer. Had I did it all over again, would have stuck with the complete stock kit with mounts, shims, and hardware. I tried to insert pictures, but that's when I lost the reply. Tomorrow, I'll check the #3 mounts, as these are the only other caged-nut mounts, the others are fine. Then will see if there's an improvement. :yesnod:

 

The foam injection does sound VERY interesting but removing it would be next to impossible if there was a problem with holding moisture thus causing rust.
The manufacturer would have to assure me that their foam is NOT hygroscopic.

Check out this semi-related link about foam injection causing a rust problem on a Pantera. From what I've read, it seems like Pantera's already have inheriant rust problems to begin with.
Subject: Re: Pantera Soundproofing http://realbig.com/detomaso/1999-01/297.html

I wonder if an aluminum beam fabricated to to mount somewhere behind the dash would provide any support? >> http://www.carbuytip.com/reviews/200...nte_carlo.html
The interior features a cast magnesium beam, called a MagBeam, that fits behind the instrument panel to further increase chassis rigidity and provide a stiff mounting for the dashboard systems. As a result, the latest Monte Carlo is much quieter than any previous generation. Increased chassis stiffness also makes the car less prone to squeaks and rattles over time.

 

This does sound pretty good, from the MFG's web site.

ITW Foamseal's AUTOSEAL is a two component foam kit that has been specially formulated for automotive aftermarket applications such as chassis stiffness improvement, sound damping, and reduction of vibration and infiltration of air, water and dust.

:cool:

 

My feeling is that the foam will help a little but not a significant amount. Primarily because of the difference between a unibody and a full frame. A thin wall tubing or thin sheet metal design can see huge increases in stiffness by adding foam or via continuous bonding because the seams aren't seam welded, they are spot welded. When the chassis is loaded the thin metal can flex between the spot welds. The foam adds strength because it is has stiffness as well and because it's stiffness is similar to the material (thin sheet metal). The foam isn't nearly as stiff as the .09 or .125" thick material used for the frame on our cars. Therefore it can't contribute, proportionally, as much stiffness as it would in a unibody application. If the issues for rust/water accumulation are addressed I don't see the foam hurting anything. It's just that I don't like it will stiffen the frame a significant amount.

To revisit the spine idea, I was under the car the other day and noticed that you can easily fit a 4 or 5" diameter pipe in the drive shaft tunnel. This would be the back half of the spine. You could actually cut the pipe in half (lengthwise) and flange the edge so you can bolt on the lower half. The pipe can be tied into the transmission cross member and the rear end cross member.