Sloppy Mechanics

Part 3 - Suspension Obsession

Call me naive, but I can say I was officially bitten by the FFF bug. I typically look at everything on forums as an example; that is, not as a 'how to' but more of an informal source of information that I can use towards fixing/improving my car. I don't mean to sound any more arrogant that I usually am, but I'm pretty adept around cars -- I can essentially do anything (this side of rebuilding transmissions, screw them) and everything I want with my car.

So while looking for a way to improve the structural rigidity of my cheap japanese car's tinker toy subframe, I came across a thread about foam filling it. Now, I've seen such things before, typically in regard to rockers, or inner unibody voids, but never a subframe. Much like any car of this configuration, the subframe is a nicely formed/stamped piece of metal that is hollow. Regardless of it being firmly mounted to the chassis, it is something that can certainly bend under stress, and at the same time transmit noise from the differential into the cabin. Because of these two issues, the Foam especially appealed to me as it would fill the subframe void, while at the same time increasing surface area, which would help absorb sound/vibration. Double win: Stiff Subframe and I can crank Celine Dion without hearing the driveline of the car.

So I read a few threads, and find out that the US Composites Structural Foam kit, in 8:1 variety was the best bet. The Coast Guard requires 2:1 for their boats, so this 8:1 would be more that sufficient for my subframe (but then again, I don't' plan on taking it swimming). By the 'members' comments it would become very hard, but remain plyable to a degree. This seemed great as it would add a great deal of rigitdy (8 to 1) while not becoming like burnt noodles on the bottom a lasagna pan. I order their 16 lb kit, of 8:1 stiffness and went to town.

Now, back to the FFF aspect of things. They all wrote that it was 'easy' and 'no issues'...which was 9/10 true. What they forgot to mention was the 'mess' that this stuff created. Certainly i knew there would be a mess - something that never/does not bother me. BUT in the same regard, i was not expecting anything like the mess that expanding foam creates. After completing the foam project, I will say the following

1. Make sure you ahve some sort of sheeting down to keep the garage clean. I used big pallett sheets. this stuff makes a mess

2. Ensure you have a heat source on the foam. It says it 'works best' at 80 degrees - they don't like. I had the garage at 70 degrees, and until I directed the kero bullet heater onto it, it didnt' expand as it should

3. Don't make more than you need, as it will foam out and all over. If you only need a little bit, make less. Any 'extra' is just wasted.

All in all, it was a great learning experience, and a worthwhile mod. I suggest anyone to do this, if they have sub frame out of the car. It's a no brainer. Rigidity, sound deadening, and cheap - perfect combo.

 

The Kit I used

 

It finds itself eveywhere!

 

Slight Mess

 

Looks good here, but look at the joint - amazing stuff!

 

Luckily it 'breaks off' the subframe easily. Thankfully.

 

All done, and re undercoated

 

Thank you cargo edition Maxima!