[stretch]

Product link:
http://www.foamseal.org/auto_aftermarket.htm



I mentioned this stuff in another thread and realized it's never been discussed here (that I could find).

Has anyone ever tried this stuff? I've considered doing it before, but never went through with it. I've only read great things, and it's catching on with OEM's as a lightweight and effective way to stiffen a chassis.

You inject the foam into the car's frame wherever it is hollow, and the foam expands, sticks, and hardens. Viola, your existing frame is suddenly much firmer. Besides being potentially messy, the only installation hassle seems to be relocating any wires or lines that run through the frame so they aren't permanently encapsulated.

More reading:
http://forums.freshalloy.com/showthread.php?t=162693
http://www.sportcompactcarweb.com/pr..._300zx_part_5/
http://forums.freshalloy.com/showthread.php?t=161474

[syrarch04]

subscribed...

[psuLemon]

I had a friend use it on his truck of his car for when he got a system. The trunk became as hards as a rock but damnit, it didn't rattle.


But it is possible to provide the strength of some of the braces out there?

[twiSTies]

where on the STi is the frame hollow that we can access?

My buddy used this on his track Neon SRT. It worked very well!

[Slowwrx]

I did it, its a huge pain in the ass and the results aren't worth it.

Don't bother.

Matt

[stretch]

Originally Posted by Slowwrx

I did it, its a huge pain in the ass and the results aren't worth it.

Don't bother.

Matt

Ha, that pretty much kills this thread! You're the first person I've heard not impressed with it, but I trust you.

Do you mind sharing what parts of the chassis you did?

[Slowwrx]

Originally Posted by stretch

Ha, that pretty much kills this thread! You're the first person I've heard not impressed with it, but I trust you.

Do you mind sharing what parts of the chassis you did?

Sure....

I did every structural member I could get too. Even up the pillars.

There might be a slight increase in overall stiffness, but nothing you can feel. The problem with this stuff is that its expensive, (about 450 bucks for the whole car) and when people spend that much money they want to feel a diffrence so they usally do. Same deal with strut tower bars. Me I don't care how much it cost if it sucks...it sucks.

If you want to add stiffness I highly recommend the Car-Lab X Brace and the M1 front subframe. Both are very nice parts and the money is well spent.

[MGizzle]

I have seen something similar being used in uprights on smaller race cars but I think it is a waste for our cars or similar. You are just adding weight (stuff looks light, but believe me it adds up) and our chassis is made in such ways that this foam will not really be stressed. You also have to make sure it expands considerably so that it creates pressure on the frame because without the pressure it will not absorb a lot.

Great stuff to use when considered in inital design but using on high tensile strenght steel frames will not make a significant difference I think.

[Turninconcepts.com]

Oddly enough I was discussing this stuff with Rick from Raamaudio just last week. they did it to their Tc and said it helped, but it seems from above that it's not going to help the scoobies much.

[stretch]

Originally Posted by twiSTies

where on the STi is the frame hollow that we can access?

The rocker panels, the frame rails, the rocker panels, all the pillars, and the area connecting the two rear strut towers:

Originally Posted by Slowwrx

I did every structural member I could get too. Even up the pillars.

There might be a slight increase in overall stiffness, but nothing you can feel. The problem with this stuff is that its expensive, (about 450 bucks for the whole car) and when people spend that much money they want to feel a diffrence so they usally do. Same deal with strut tower bars. Me I don't care how much it cost if it sucks...it sucks.

Agreed about people wanting to feel a difference. $450 though? Holy crap- you MUST have done the whole damn car! The Nissan 240 owner managed to do his car with two packages and still had much left over. He didn't do the frame rails- just all the pillars and rocker panels (which is still a lot of stuff).

Anyway, I finished reading through the threads I linked in the first post, and whether the stuff works on the Subaru or not, here are my notes:

There's some similar but much cheaper foam in several densities:
http://www.shopmaninc.com/foam.html

Another article:
http://www.abrn.com/abrn/article/art....jsp?id=132468

And here's the SAE paper (authored by Chrysler) showing how effective the foam is (it costs money, unfortunately):
http://www.sae.org/technical/papers/1999-01-1785

However, through the miracle of the internet, someone has posted a synopsis of it:

Originally Posted by from the freshalloy forum linked above

In SAE paper 1999-01-1785 said "8pcf density gave the best strength to weight ratio." That would be best for rocker panels and frame rails.

But for pillars and joints, SAE paper #960435 said "the greatest benefit came from a lighter weight foam, as heavier foams didn't work that much better vs the cost and weight." also it mentioned, "there was no real benefit to be gained by filling the entire pillar" so PAY ATTENTION TO THE JOINTS.

so i would say 8lb density for rockers, and 2lb density of pillars and joints.
You have to pay attention to the flow rate, and expansion rate when you work with the pillars b/c spaces are limited. 2lb kit is ideal since you really don't want to add more weight with high center of gravity.

Results: up to 30% rigidity increase by just filling joints.

Other nuggets found in the above threads:

The paper I had was about road cars, not SUVs, but the results were similar. The one on road cars was better, because it went into detail about the different foam types. One important detail was the definition of "structural foam." Chemical technology is advancing all the time, but at the time of the test, foam that required heated application was by far and away the best. Even the 2 pound structural foam was shown to be amazingly rigid, however the test went up to 16 pound foam or heavier.

Well, I tried searching for the SAE paper but couldn't find it, however I did run across a paper that might interest wiisass. The paper is SAE paper J2621, "Qualifying Aftermarket Two-Component Structural Foams". The paper is recent, and has been used as the basis for a recent article in Auto Body Repair News. Again, the placement of foam specifically in joints, pillars (yes, and rails) pops up. My old paper made an issue of other uses for the rigid foams used for NVH reduction. The newer paper focuses on structural foams that are heavier but also gets as hard as concrete. These are already being used by automotive manufacturers to stiffen up the frames of newer cars - a treatment our older cars never received. It makes you wonder where all these rapid advancement in new vehicle stiffness comes from. I bet it's from foam.

[MGizzle]

I believe the 30% increase is just in the section that is filled, but when you consider torsional stiffness with respect to the hubs (the test that carlab did for their X brace) I would be surprised if it helped significantly.

Also, keep in mind that stiffer parts transmit/distribute stress better so that means all the parts you stiffen up will weaken the parts you didn't because it would transmit more stress into them.

Imagine fillin' the whole trunk with this stuff?? Heheheheh

[thrlskr]

Worked awesome in my old Miata, but it was a noodle compared to the STi.

[hoffit]

I'm looking at doing this now based off the articles.

[ELD4AU6]

I thought impreza's had a very stiff chassis?

[CGMDan]

Originally Posted by ELD4AU6

I thought impreza's had a very stiff chassis?

Depend on who you listen to. If you listen to all the people who whine about their windshield creak, you'd think its one of the most flexible cars in existance. BUT, thats not the case. It is a pretty stiff chassis.


In regards to the foam, Back when I was involved on Miata.net people over there starte using it on the bottom frame rails with success. But that was back in the mid to late 90's.
So who knows.