Chassis stiffening foam result - Part 1, qualitative result*long post 56k go away*

[gunluvS14]

For those who are not familar with this topic, it was previously discussed in this thread and many others in the past.
http://forums.freshalloy.com/showthread.php?t=161474

This is my qualitative result, and I will share my quantitative (experimental research) later once I collected those data.

I was first inspired by Mike Kojima project Z32, and really motivated by Epstein(Chris) and the SAE paper 1999-01-1785.

Previously, we had serious and detail discussion over the pro and con of chassis foam; there were plenty of successful cases out there, like Kojima's project Z32, Mines, Apexi, and MCR demo R34; and maybe more. And what really get me going is the test results and strong evident from the SAE paper by DaimlerCrysler Coporation, which performed a test on a SUV. So I want to try this first hand.

Before I start describe the qualitative result, i want to share some result that was perfomed by DaimlerCrysler Corp first, and due to copyright, I can not post the entire article here.

First of all, Vibration 101: Natural Frequency of a body is square root of stiffness of the body over mass of the body.
Fn = (K/m)^(1/2)
K is the stiffness coefficient of the body, m is the mass, Fn is natural frequency. So the stiffer the body, the higher the natural frequency.

Credit goes to DaimlerCrysler


here is a study of which joint is most sensitive to foam filling


Here is the original Abstract of that SAE paper 1999-01-1785

Stability and structural intergrity are extremly important in the design of a vehicle. Sturctural foams, when used to fill body cavities and joints, can greatly improve the stiffness of the vehicle, and provide additional acoustical and strucutural benefits.
This study invovles modal testing and finite element analysis on a Sport utility vehicle to understand the effect of structual foam on modal behavior. The modal analysis studies are performed on this vehicle to inverstigate the dynamic characteristics, joint stiffness and overall body behavior. A design of experiments (DOE) study was performed to understand how the foam's density and palcement in the body influcences vehicle stiffness. Prior to the design of experiments, a design sensitivity analysis (DSA) was done to identify the senstivie joints in the body structure and to minize the number of design variables in the DOE Study.

And the Conclusion:

The most sensitive area of the body were found to be the A-pillar, the D-pillar and their joints. With structural foam injected into this sensitive areas, the vehicle body was significantly stiffened, as shown by the increase in modal frequencies. The 1st torsional mode was most effected with an increase of 29.1% in modal frequency.
The design sensitivity analysis and design of experiments described here, can be used to identify the sensitive ares of the body structure. This results are useful in the determining the best application locations for structural foam.

--------------------------------------
Well, enough talking, let's get down to business. First of all I want to thanks God gave us a safe working environment; my boys Ryan and Jason whose came all the way to my house to help me; and my fiancee Julie who put up with our boys for the entire weekend.

At first we tried to do some physical measurement of the chassis flex, like how much the door gap distort and close up while it was jacked up


But it was no luck, we ended up having 3 wheels off the ground, and the door still shut perfectly, i was impressed and yet upset.


We should have measure the distance between the frame rail holes as described in the FSM. But we were ready to Git-R-done.

First step is remove both seats, interior trims, and carpet. So the A,B,C pillar and rocker panels are fully exposed.

A pillar (noticed the drain hose)


B pillar


C pillar (again, another drain hose)


the longest process is the tape everything carefully, since that junk will harden and sticks on the paint if you are not careful. Here is the rocker taped up.... me love you long time


Duct tape works wonderful to cover up some big holes


Handifoam II-22 kit


Have the interior well cover is very important, get duct tape ready to cover the holes after injection


Foam filled rocker panel


as you can see, it was a good, uniform, completed filled


We found a trick, it is filled the cavities more than enough, and before it expands out of the holes, cover it with duct tape to force the foam to have a tighter fill, result as a slightly higher density.


completed Rocker


completed A pillar


completed floor pan cross rail


completed B pillar


B pillar middle


completed C pillar


everything back together



like nothing happened at all

[gunluvS14]

Impression:

This stuff works!!!

I'm very happy. Not only the turn in is quicker, the poping noise I used to had when I load/unload the rear suspension on a hill/curb is gone.
I think filling up the joint between the A-pillar and the firewall helps the most, since the front end is much stiffer, and I started to experience more initial entrance understeering that I didn't have before.

The over all dynamics of the car is solid, and I can feel my suspension is working, also I might need some tires with stiffer sidewall b/c I finally able to feel the flex in the tires. Also I can feel all those slop from the worn out bushings. I can't sense none of those feedbacks before.

Another dramatical result I experienced is, I never able to lock up my rear brakes, I have Q45 brakes front, and stock rear, that's a very bad front bias setup (About 78.5% front from calculation). But since the rocker panels are filled, I guess the rear does not "droop" anymore under extreme weight transfer, and the rear tires are lift up more since the middle is way siffer, and now I'm able to lock up the rear tires under some very heavy stop. Then again, the gutted trunk doesn't help here.

In some slow-mid speed corner, I can induce throttle oversteer quicker and has more linear feedback. I want to describe it as its easy to do weight transfer and it helps rotate the car around some tight stuff. Kinda similar my first impression when i had VLSD and thicker rear swaybar

Another impression is driving across the railroad tracks and bridges gaps, it feels much smoother and less bumpy, quieter too.

So overall it feels likea new car. The car behave differently since I have more entrance understeering, and I have to re-learn how to modulate my brakes.

just for reference information, here is what I have on the car.

Front & Rear strut tower bars
Project Silvia Tension bar (similar to Nismo powerbrace)
Powertrix spherial solid T/C rod (with upgraded rod ends)
Tein S tech springs
AGX adj. shocks.
Stock front anti roll bar
S13 HICAS 21mm rear anti bar
Polyuretane endlinks bushings.
SPL subframe spacers

I think those are the only items that are relevant to the handling feedback. So I'll leave the rest

That's all I have so far, if I missed something, I will add them later on.

thanks for you time.

ps. I drove my fiancee's S14 and my car back to back, and also compare it to Ryan's S14, My S14 is definately the stiffest I want to say it is as stiff as the S2000, closest feeling is probably the 350z that i drove, Ryan said its stiffer, idk

[gunluvS14]

a few tips:

Dress properly, gloves, old cloths, shoes, pants, and hat are recommended.
Few of these foam got skeet skeet on Ryan, and it took him a very long time to scrub all of them off his hands.

Don't inject these foam if it is under 50F, it was recommend to do it around 75F. otherwise the expansion rate won't be consistence.

Shake well before use, and plan ahead, since the mixed foam will harden within minutes, if you are not careful, you will waste a nozzle (each kit supply an extra nozzle).

Use duct tape, spray a bit more than enough (manufacture recommend 1/3 of the volume), let it expands and cover it with duct tape and force them back into the cavities to ensure 100% uniform fill.

Fill those cavities when the car was on ground level, pay attention to JOINTS, that's where most of the gain come from.

Have fun doing it, and tell your friends how much you appreciated their help, since this is not a one man job.

FYI: a few useful information

MSDS component A
http://www.fomo.com/pdfs/A16178A_Two...vision0405.pdf

MSDS component B
http://www.fomo.com/pdfs/A16178B_Two...vision0405.pdf

TDS
http://www.fomo.com/pdfs/A16129_Hand...I-12_II-22.pdf

foam free rise density 1.75pcf
foam in place density 2.00 pcf

[Blurple240]

Excellent write-up! I can't wait to see the data.

[Illegal Fun]

any idea how much weight you added?

[gunluvS14]

thanks, sorry I didn't ask you to come hang out. I should let you drive my car someday since we live some what close

oh yeah, i have to post these pictures. Good time.















look at Julie at the background "OMG, what have yall done?"


oh yeah, for those who want to see this foam in ACTION.
take a look at these videos





thanks for you time

[gunluvS14]

Originally Posted by Illegal Fun

any idea how much weight you added?

A really conservative estimate is less than 15lbs. Actual figure will probably less than 10lb
I only used 2 II-22 kits with plenty left. those are 2lb/ft^3 foam.

[SoSideways]

What is up with y'all's obssession with holding objects near crotch? lol j/k, I do that all the time with random tubes/pipes.

How much of that foam do you have left? I'll buy it from you hahahaha

Man I wanna try this stuff now.

Me wants stiffy stiff S13 nowwwwwwwww!!

[NismoState]

Nice write up! Think im gonna do this on my s13 hatch as well. how much was the foam?

[turtl631]

Very cool, sounds like a summer project for me. I wouldn't mind having a little bit stiffer/quieter ride. I'm not so sure the stiffness is a problem yet with just 8/6 rate coilovers and Kumho MXs, but this can't hurt.

[gunluvS14]

Originally Posted by NismoState

Nice write up! Think im gonna do this on my s13 hatch as well. how much was the foam?

thanx
you can purchase it from here
http://www.foampower.com/store/two_component/index.html

or at Grainger (this one is the II-12 kit, smaller capacity vs. the II-22 kit, credit goes to Epstein, he found this at Grainger)
http://www.grainger.com/Grainger/wwg...mId=1611574493

[shane_B]

Wow. Great Job. Only on FA.

[Epstein]

Gunluv, Awesome write up and documentation! You know that I've done this twice now and never read that you're supposed to shake the kit up first? There it was in the TDS plain as day. Great shots of people standing on the foam, too. You increased the rigidity of that 20oz by several 100%! haha. The videos should clear up any questions on consistency and how it acts. Good job all around!

Your driving impressions are exactly what I've felt after foaming my rockers. It's also exactly how I'd expect a stiffer chassis to react. I'm going to stop by Grainger so that I can do my pillars and floor bars this weekend. For the little money that this costs, this should be high up on people chassis prep list. Especially with so many old, coilover-shod cars.

[Kim_Jong_Il]

Sold. I'm buying some.

[_Def_]

Nice post. I'm sold, just gotta wait to find the time to do the rest of the stuff I've been backlogged on with the car.

So it looks like that II-22 kit posted above is cheaper per unit than the Grainger stuff given that it's twice as much I'm guessing?

Would 3 II-12 kits do it, or would it take 4 II-12s?

[Blurple240]

Originally Posted by Kim_Jong_Il

Sold. I'm buying some.

I'm going to do this when the car gets back from being painted.

And the picture with the foam coming out of the can made me lol.

[GlacierFreeze]

How long does it take to "cure" or totally harden?

[dangle01]

Does the kit come with hoses to spread the foam evenley in the hard to reach places. I'm looking at the pics and it seems like some parts that you were treating were hard to get too.

Great Job by the way!!

[gunluvS14]

thank you guys I'm glad this post gets everybody motivated.
Def, 2 II-22 kits would do the job, that would cover all pillars, floor pans rail and both rockers with a good bit left. use 3 if you want to do the frame rail at the bottom of the car. (or 4 II-12 kits, and 6 II-12 if you want to do the frame rails too)

Glacier, its tack free about 2 minutes, and fully cure about 1 hour, we gave it 3 hours.

Dangle, the kits comes with a "mixing chamber" nozzle, so you can squirt it up to some really tricky tight spot.

I really like this kit, its so user friendly verus some other 2 parts composite that require pre mix and funnel into places. If Handifoam makes 8pcf density kit, that will be even better.

[Subliminal240]

Does this affect crash safety? Crumple zones and all that crap...

[Broaner]

Wow; great write-up. I'm very interested in doing this when I get my metal chassis work finished. Is the stuff real flamable? The famability issue and body repair issue are the things I worry about most prominently with doing something like this. With a foam implemented chassis doing body work on a rollover or sideswipe would be nearly impossible I'd imagine. How do the OEM's do it? I wonder if there is an agent that will melt the foam when repairs are required.

I'm sure it effects crash safety in some manner. Whether it does it positively or negatively I don't know.

[cdlong]

well, he didn't put it in any crumple zones. the joints he filled are the ones you definitely don't want to colapse in a wreck. the foam should help keep the roof up in a rollover and the pillars out in a side impact. overall i'd say it makes the car safer. now if he filled the front frame rails or if the stuff is flamable when hard then that's a different story.

[codyace]

Now you're gonna make me tear the entire inside BACK apart....damn you guys!

I wonder how (or if) it crushes that poor sunroof drain.....what would happen if they were to get crushed?


EDIT: Do you believe that one of those small kits is sufficient for JUST the rockers????? What about filling up the beams underneath the car as well??

[johnc]

Thanks for the write up.
I am going to do this for sure but only after I am done with all the body
work. Reason being this:

Originally Posted by FROM PRODUCT TECH DATA

High temperatures will raise the pressure in the containers, which may lead to rupturing. Extinguishing media include: dry
chemical, carbon dioxide, halon 1211, chemical foam, or water spray if used in large quantities (water contamination will
produce carbon dioxide). Wear self-contained breathing apparatus to protect against toxic decomposition by-products,
including CO, CO2, NO, and traces of HCN or HCL. Cured foam is organic and, therefore, will burn in the presence of
sufficient heat, oxygen and an ignition source. Main hazards associated with burning foam are similar to burning of other
organic materials (wood, paper, cotton, etc.) and precautions against exposure should be taken accordingly. Avoid welding
or other “hot work” in the vicinity of exposed cured foam.

[Illegal Fun]

Anybody thought of filling the subframe with foam? I'm hoping it'd significantly reduce driveline noise.... what do you guys think? Worth it?

[drew935]

I'd do it for a noise reduction and smoother ride. They did this in that one GM pickup. They even had a comercial about it. It's been out for awhile but it's good that gunluv did it first.

[xcbomber]

Well we actually tried to light some of the extra foam. It was a slow burn, nothing that i would really be afraid of. Mostly it just melted. oh and this is ryan, the kid in the green shirt from the pics.

[Mr_Nice_Guy]

Originally Posted by gunluvS14

ps. I drove my fiancee's S14 and my car back to back, and also compare it to Ryan's S14, My S14 is definately the stiffest I want to say it is as stiff as the S2000, closest feeling is probably the 350z that i drove, Ryan said its stiffer, idk

pfft, you wish. :hsdance: Looks good man, have to get a ride in it some time.

[Epstein]

Originally Posted by Illegal Fun

Anybody thought of filling the subframe with foam? I'm hoping it'd significantly reduce driveline noise.... what do you guys think? Worth it?

This was done on the Opera 350Z, as detailed in a back issue of SCC. It's the first 2 pics here:

http://www.sportcompactcarweb.com/fe...0z/index3.html

[gunluvS14]

man, you beat me to it Opera Performance did a great job on chassis stiffening, so many tricks in their bag.

They are the another clue that inspired me to pay attention to pillar joints and strength.

[SoSideways]

I need to dig that issue back up and read it.

What was on the cover of that issue?

[gsracer]

Originally Posted by SoSideways

I need to dig that issue back up and read it.

What was on the cover of that issue?

the new gtr over a japanese flag

[johnc]

xcbomber,

Thanks for the input.

[codyace]

Originally Posted by codyace

Now you're gonna make me tear the entire inside BACK apart....damn you guys!

I wonder how (or if) it crushes that poor sunroof drain.....what would happen if they were to get crushed?


EDIT: Do you believe that one of those small kits is sufficient for JUST the rockers????? What about filling up the beams underneath the car as well??

Reposting, as it probably just got skipped in the mayhem

[gunluvS14]

my bad buddy. the small kit II-12 probably won't be enough, that wil be really pushing it.

If you don't want to fill the pillars, just the rocker, and the rails underneath the car, my best guess is TWO of the II-22 kit. Just remember doing it under the car will be tricky; you have to move quick, and make sure the car is level and not preloaded to any form/direction.

There are chit loads of holes on the rails, so be it will be a hand full, good luck man

[codyace]

Good to hear. I never took into account the entire 'car needs to be level' aspect when getting underneath of it. I was just hinking about throwing it on the lift and going to town, but with that in mind, it may be easier/smarter to use my buddie's dad's alignment rack (drive on ramps) and then go underneath it that way...




Also:

Did you think/know if it did crush the sunroof drain though? I have no problem adding foam there, but don't want it to clog up and leak or whatnot....a moldy car isn't a planned mod hehe

[Refill]

It's hard to imagine it crushing the sun roof drains. The force needed to crush them would prob be greater than the amount it would take to push through the masking tape which doesn't look to be budging at all.

Boss write up, been thinking about doing this for ages but never knew how the foam expanded so I was always apprehensive about doing it.

[codyace]

Originally Posted by Refill

It's hard to imagine it crushing the sun roof drains. The force needed to crush them would prob be greater than the amount it would take to push through the masking tape which doesn't look to be budging at all.

Excellent point...why I skipped over that fact/was overthinking was and is beyond me hehe....

Looks Like I'll be making an order soon

[jr_ss]

I'm curious, how does the foam affect road noise? Is it quieter in the cockpit now that all the pillars and side panel are filled? Or do you hear more road noise than you use too?

[gunluvS14]

its quieter, much quieter. Rattles from the door panels, sunroof slide are gone.
My SAFC (I have it mount on a bracket) used to vibrate pretty bad when I was driving on interstate. Plus the ride is smoother when I go across railroad tracks and bridges now.