Foam Filling the chassis......

[Shawn B]

Here is the link to the Suspension Thread with Steves and Mikes wisdom on chassis-grade foam:

B13, B14, B15 Suspension Information...

And a direct link to the SCC article by Mike K:

Project Nissan 300ZX: Part 5 - Project Cars - Sport Compact Car Magazine

Anybody done this recently to a B13?

My car is at the body shop as we speak, body repair, sunroof delete, and IKEA brace. Interior currently completely gutted, nothing but the dash, steering wheel, pedals, and stick-shift shaft.

Next week it goes to the mechanics shop for the engine bay fixes, afterwhich I can test drive it.

Then the Classic goes back to the body shop for a damned $eriou$ paint job. All trim, windows, lights, everything off the vehicle. All new window/door seals, shiney new bad-ass Nissan OEM black paint job. Spending stupid money, I might add.

I am seriously considering foaming the chassis during this re-birth process. I'm already soooo deep into this financially, what the hell is another hundred bucks worth of structural foam? According to Mike K, you can never get the chassis "too stiff." And because the car is going to be freshly repainted after I did the foaming, I don't have to freak out so bad about an accidental drip or spill. Apparently, if you get this stuff on pretty much anything, it is a bitch and a half to get off.

1) Already armed with an IKEA brace, AT RSTB, and Cusco FSTB, should I still see (feel/hear) pretty noticable improvements in lessening NVH with the chassis foam?

2) Being that I am mechanically inept, what is the best place(s) to foam-fill in a B13 chassis? Ie...what places make sense to fill in? Rocker panels are fairly obvious and mentioned by Steve and Toolapcfan. Should I just do the rocker panels only? Mike did both the rocker panels and the frame rails on his 300zx.

3) Steve mentions that if I use too strong of a foam, I can actually bend the metal (outside the cavities) of the places I am trying to fill in. The foam expanding with enough force to "push out" the sheet metal. Yikes! I do NOT want to fuxor this up.

4) Are there any places in a B13 that should definitely NOT be foamed due to wire-runs or any other reason?

Thanks for any input or advice.

[BenFenner]

Have you considered seam welding? Too costly/time consuming?

[Shawn B]

Originally Posted by BenFenner

Have you considered seam welding? Too costly/time consuming?

Yessir, I believe that it would be both too costly and time consuming. I wouldn't know what the hell to do with a welder, and I cannot imagine the cost involved at the body-shop.

However, I want the car to feel as tight as a drum. Like new, or actually better. I am also adding some weight (Egads!) and installing Elemental Designs fancy-ass sound deadening to the cabin, doors, and trunk. I don't really care if I lose a 1/10 in the quarter mile that I am never going to run. A small weight concession for a less "tin can" feel/sound to the vehicle.

[sqd]

shawn! glad to see you're still around and kickin!

here's the quote from mike's article on my car back in the day:

"With the interior stripped, I took advantage of its condition to inject Foamseal Catalyzed Urethane Foam into the car's unibody. Foamseal foam is pretty amazing stuff. It can increase the stiffness of the cross section chassis members by up to 40 percent. We have used it in several project street and race cars to stiffen unibodies with good results. The Foamseal foam was injected into every major frame section through the factory access holes. Foam injection is a popular mod in Japan to stiffen the chassis, but few are aware of it here in the States. Do not try to duplicate this with cheap hardware store spray foam, which won't harden inside the framerails of a car and has no structural properties. "

it's not THAT detailed but when i've gone through the car, all cavities are filled. also, i've stripped several b13's and iirc there arent any wires running INSIDE the actual cavities.




the chassis foam should SIGNIFICANTLY increases the chassis rigidity. you should be happier with the ride as well since the shocks will be forced to do their job.

[HP10T]

I have been thinking of doing this myself Shawn, thanks for posting up. Sorry I don't have any input though.

[Shawn B]

Originally Posted by sqd

shawn! glad to see you're still around and kickin!

Interesting times my friend. Overwhelmed best describes it.

Originally Posted by sqd

here's the quote from mike's article on my car back in the day:

it's not THAT detailed but when i've gone through the car, all cavities are filled. also, i've stripped several b13's and iirc there arent any wires running INSIDE the actual cavities.

the chassis foam should SIGNIFICANTLY increases the chassis rigidity. you should be happier with the ride as well since the shocks will be forced to do their job.

So, talk to my mechanic (or body guy) and use common sense? I figure either guy (pro's) should be able to give me a hand and advice.

This seems like a no-brainer given my goals for the vehicle, and its current state of disassembly.

Originally Posted by HP10T

I have been thinking of doing this myself Shawn, thanks for posting up. Sorry I don't have any input though.

Actually, that thought was input. You've been considering the idea.

I was wondering why (apparently) more folks don't do this. The weight penalty seems minor for the additional chassis stiffness provided. Mike K's 300 and Steve's S13 (S14?) both done, and both gentlemen very impressed with the results? That is a consensus enough for me, any day of the week. I think I'd be stupid not to do this at such an opportune time-frame.

It seems like it would greatly benefit daily drivers, auto-x, and road racers. The only folks that would possibly not benefit would be 1/4 mile afficianados where the weight is absolutely critical.

Maybe I've missed the threads, but I never see anyone else follow what Mike and Steve unanimously agree upon. We spend money on FSTB's, RSTB's, and dream up new 3-point versions of the same. Further, we weld in IKEA braces. Yet seemingly very few folks do this recommended $100 major overall chassis stiffener.

Quite frankly, as mechanically inept as I am, the thought was a bit daunting to me. However, now I have seen how (pain in the ass and time consuming) easy it is to really strip an interior. Not that hard, I only needed a little help in some spots from my mechanic. Which means that anybody else on this forum could do it in half the time with zero help required.

Here's the link, the website still works. Looks like I will call them on Monday during normal business hours and find a local distributor in Houston:

Originally Posted by 98sr20ve

I am posting this so that others do not need to spend 1/2 day just trying to figure things out. Most of you are familiar with the "Chassis Foaming" procedure that SCC did on the 300zxTT. Link for those that do not The people that used to sell the foam no longer sell it. The product is called "Handi Foam". You can read more about it at Fomo Products, Inc., manufacturers of polyurethane (PU) foam insulation, sealants, adhesives, and spray foam systems in pressurized packaging. (no jokes please ). They state in the article that the used Part# II-22. What they show in the picture is Part#II-12. Only difference is the size of the can. Fomo's part number is P10600 and P10650. Fomo will not sell direct but they will get you to the distributor. My local dealer did not have a good amount. I bought two of the II-22 and one II-12. Cost was $100. If they actually used the product they took a picture of then that should be about the same quanity as 5 cans of the II-12.

I'm officially "going for it." The guys at both shops will think I am nuts. Er...more nuts.

[Fosters]

I think your situation is a good place/time to give the foam another shot. I think most people get overwhelmed with the idea that the foam could damage their paint - if repainting, you have nothing to worry about.

I would think rocker panels, "A" pillar, "B" pillar, and "C" pillar would be the best spots to do it (if all of those places are accessible).

Off-topic: Shawn, if you want a non-sunroof roof you can have mine if you come get it - it is already cut off.

Josh

[JakeB]

I am excited to see how this goes. I'm hoping there is going to be a full fledged thread with pics galore about this overhaul of your car!

[Shawn B]

Originally Posted by Fosters

I think your situation is a good place/time to give the foam another shot. I think most people get overwhelmed with the idea that the foam could damage their paint - if repainting, you have nothing to worry about.

The car is going from the body shop to the mechanics tomorrow (I hope). While the car is getting wrenched on, I am going to do some foaming. The car then goes back to the body shop for final painting. Anything I screw up, the body shop guys can clean up before they paint.

Originally Posted by Fosters

I would think rocker panels, "A" pillar, "B" pillar, and "C" pillar would be the best spots to do it (if all of those places are accessible).

That is easy enough, thanks for the input. We shall see what I find out.

Originally Posted by Fosters

Off-topic: Shawn, if you want a non-sunroof roof you can have mine if you come get it - it is already cut off.

Thanks, but my sunroof is already gone. Seam welded panel, then some "metal containing super goop", then bondo to smooth everything perfect. I did not want a sunroof from the get-go in '93, I couldn't find an SE-R without one.

Originally Posted by JakeB

I am excited to see how this goes. I'm hoping there is going to be a full fledged thread with pics galore about this overhaul of your car!

I am going to go buy a digital camera tomorrow at Target for just that purpose. I'll start snapping pics. Gotta run by the body shop, then (hopefully) sending the vehicle to the mechanics.

One thing that is tough to locate is a damned non-sunroof headliner.

Once located, I am going to have it recovered and match it to the back window shelf-thing, and the panels in the doors. All in some charcoal/black material.

[Autech]

From my motorpsort and engineering experience you have this main issue to attack.


Pillars twist - they twist in the sense of rotating and not flexing.

Everytime you take a corner or bump, energy its stransferred through yoru shocks and struts to your chassis. Resistance is given on all points of contact with the ground, so the energy will travel the furthest it can until something gives (noramlly the body twisting).

If you can stregnthen all parts where energy can be trasnferred from one direction to another (eg floor to pillar - pillar to roof) you give the enerygy no where to go but back to where it came from.


So for the sentra chassis, i think getting some fender bracing, foam filling the front rails. Foam filling the front a pillar section and boxing in the strut towers is your first step. There is not much room to foam at the base of the sentra B pillar, so maybe foaming in conjunction with a B pillar brace would be very handy. Linking that B pillar brace directly to the rear strut brace would tighten the rear up immensly. But again your not left with much area to foam fill in the rear section. If you already run lower control rear and strut top rear the rear end will be very tight already.

The main achivement is to somehow work out how to link the a-b-c pillars. Our chassis are pretty good for a factory car.


The NISMO n15 vzr's use a special rear beam, with special rear link arms. I can only imagine they were stronger and the rear link arms may have been boxed in to reduce twist and improve rear end response.

sorry for the waffle and slight OT parts. Maybe it can help you?

[squirlz]

As far as the foam itself it is the triple expanding stuff that can bulge out the metal. If you put too much in the foam has no where else to go so it expands too much (for what you want) and bends the metal. If you can use the small gap stuff and start off in a place where you can see the foam expand. This will give you and idea on how much to put in so you do not over fill. Go a little at a time as to not over expand.
I have also thought of doing this but i am not to that point yet. I do not fully understand on where to fill and where not to fill. As Autech was saying the energy has to be transferred somewhere, if the chassis is stiff then some panel might start to kink or bend. But depending on the foam the filled part will still have some flex. Great Stuff gets pretty rigged, just dont use the latex stuff, it is soft and will do nothing for you.

I hope we get some more people to chime in that have done it themselves. I would be interested in learning more.

[HP10T]

Right on Shawn, I am anxious to see how it goes for you. Very interesting we haven't seen more people try this like you were saying, it seems so easy and cheap for how much benefit one is supposed to get out of it. I'll keep watching for updates

[Shawn B]

Originally Posted by Autech

From my motorpsort and engineering experience you have this main issue to attack.

Pillars twist - they twist in the sense of rotating and not flexing.

Everytime you take a corner or bump, energy its stransferred through yoru shocks and struts to your chassis. Resistance is given on all points of contact with the ground, so the energy will travel the furthest it can until something gives (noramlly the body twisting).

If you can stregnthen all parts where energy can be trasnferred from one direction to another (eg floor to pillar - pillar to roof) you give the enerygy no where to go but back to where it came from.

Thank you for your insight.

So the point is, the stiffer the chassis, the more it forces energy (twisting) back into the suspension itself (?). Which is where it is supposed to be.

Originally Posted by Autech

So for the sentra chassis, i think getting some fender bracing,

Hehehehe.....

fender braces - SR20 Forum

Yes, they are still available, and Stephen is shipping me a set on Wednesday.

Originally Posted by Autech

foam filling the front rails. Foam filling the front a pillar section and boxing in the strut towers is your first step.

What exactly are the "front rails"? Yes, I am that ignorant. Please explain further or perhaps a simple diagram (?).

Would the Cusco FSTB and the Stephen Fender Braces (link above) effectively "box in the strut towers"? Or are you discussing something different with that point?

The "a" pillar runs from the roof, down the edges of the front of the windsheild....and....uh....into the car.

Understand that my ignorance level on car frames is wide and deep.

Originally Posted by Autech

There is not much room to foam at the base of the sentra B pillar, so maybe foaming in conjunction with a B pillar brace would be very handy.

I'm gonna have to do the best I can, based on my common sense and the guidance of my mechanic/body-shop dudes. Either of whom will help me out, no problems. Both shops love me, my insanity, and my money.

B-Pillar brace? I do not think one commercially exists (?).

Further, my goal is the stiffest, tightest, chassis possible retaining all the stock functionality (like the backseat) and appearances. No roll cages, nor visible bracing from outside the vehicle.

Originally Posted by Autech

Linking that B pillar brace directly to the rear strut brace would tighten the rear up immensly. But again your not left with much area to foam fill in the rear section.

The rear will have the Active Tuning RSTB and the IKEA brace tack welded into place. Then I will see what I can do to that "c" pillar.

Again, no "b" pillar brace is available that I am aware of, and it sounds like linking a "b" pillar brace to the RSTB would negate the back seat (?).

I really, really like the Bolt-In-Bars new 3-point Triangulated RSTB. However, I already own the 2-point Active Tuning unit, and my costs have already skyrocketed.

Originally Posted by Autech

If you already run lower control rear and strut top rear the rear end will be very tight already.

No comprende. "Lower control rear"....what is that?

Again, I already have an AT RSTB (very stout 2-point RSTB), and an IKEA brace being welded into place.

Originally Posted by Autech

The main achivement is to somehow work out how to link the a-b-c pillars.

Thanks. That makes sense.

Originally Posted by Autech

Our chassis are pretty good for a factory car.

I am not mechanically knowledgable enough to debate this point with you nor anyone else. However, Mike K (and seemingly most everyone else) thinks we have a linguini-chassis.

Perhaps it is all in perspective?

Originally Posted by Autech

sorry for the waffle and slight OT parts. Maybe it can help you?

Partially confused, mostly helped.

Originally Posted by squirlz

As far as the foam itself it is the triple expanding stuff that can bulge out the metal. If you put too much in the foam has no where else to go so it expands too much (for what you want) and bends the metal.

Understood. I am using whatever Steve used, he purposely bought a lower number density to avoid bowing out the metal.

Originally Posted by squirlz

If you can use the small gap stuff and start off in a place where you can see the foam expand. This will give you and idea on how much to put in so you do not over fill. Go a little at a time as to not over expand.

Good ideas. I'm gonne be overtly careful.

Originally Posted by squirlz

I have also thought of doing this but i am not to that point yet. I do not fully understand on where to fill and where not to fill.

Good to know that my ignorant-ass is gonna be blazing a photo-filled trail here.... This is gonna be the blind, namely me, leading those with sight.

Originally Posted by squirlz

As Autech was saying the energy has to be transferred somewhere, if the chassis is stiff then some panel might start to kink or bend. But depending on the foam the filled part will still have some flex.

Well, here's my plan:

a) Cusco FSTB

b) Stephens Fender Braces

c) Active Tuning RSTB

d) IKEA Brace

e) Foam Filling - Every place that makes sense to me, my mechanic, and my body-shop dude.

Originally Posted by squirlz

Great Stuff gets pretty rigged, just dont use the latex stuff, it is soft and will do nothing for you.

No Great Stuff or Home Depot foam whatsover. No way, no how.

Only the foam recommended by Steve and Mike. They warn extensively on exactly what foam to use and why.

Originally Posted by squirlz

I hope we get some more people to chime in that have done it themselves. I would be interested in learning more.

I'm welcoming any feedback. And then jumping off the cliff, feet first.

Originally Posted by HP10T

Right on Shawn, I am anxious to see how it goes for you. Very interesting we haven't seen more people try this like you were saying, it seems so easy and cheap for how much benefit one is supposed to get out of it. I'll keep watching for updates

As soon as I am done here, I am running errands. One of which will be to Target for a (relatively) inexpensive digital camera and the appropriate cables and such to dump the photos into my computer.

I just figure most of you guys, perhaps all of you guys, could do this much easier than myself. Time-consuming, but not that difficult, and relatively cheap compared to all the bracing that we buy/install.

[nogo]

I remember reading an article in SCC a few years ago that dealt with bracing. One of the Japanese tuners welded strips of metal in an x pattern into the inside of his roof from a to opposite b, both sides, and then put his headliner back in. Couldn't see it from the inside but he tested it and said that it increased rigidity a great deal.

Just my 2 cents.

Peas us Riced,
Mark

[Dudeman258]

Shawn, I cannot wait to see your finished product. I am overjoyed you are fixing her back up, and then some .

Really great read here, this is now added to my list of mods. PLEASE take to many pictures, I know it takes allot of time to upload them and all, as many as you can buddy.

I assume you area planning to fill the front fenders right? if you look where that fender brace bolts on, if the B13 is anything like a Honda, there is allot of open space behind there, you could probably squeeze some foam in. Just a thought, give it a look while everything is stripped.

Oh and you are right, I have read numerous times that Mike K. thinks the B13 is floppy as a half cooked noodle. By today's standards anyways..

Best of luck, don't break anything .

Dudeman