Interior 1st Gen Most liked posts in thread: #848 Interior Project

It turns out there's quite a bit to worry about with the airbag system:

*front airbags [2 ohms]
*side curtain airbags [2 ohms]
*the seats {thorax bags [2 ohms], seatbelt pretensioners [2 ohms], driver seatbelt buckle Hall sensor [450mV on signal line] ['02-'04 only, after which is more complicated]}
*battery pyrotechnic [2 ohms] that blows the battery-to-starter cable when any airbag is fired
*side impact sensors underneath the rear seats [79 ohms each]

I'm assuming the airbag module has the longitudinal g-force sensors since I can't find anything else. Others that have measured the airbag loads have come up with upwards of 4 ohms, though their cars have been later model years, so things may have changed over the lifespan of the chassis. From '05 onward the passenger seat started using a full Hall sensor for the seatbelt along with an occupant detector mat in the bottom seat cushion. Thankfully I don't have to worry about those things!

Since I'm keeping only the front airbags and battery pyro, all other loads have resistors on them. I built a simple voltage divider for the seatbelt buckle sensor. It appears it's a Hall effect sensor with 5V and gnd fed to it with a signal wire returned to the airbag module. Testing showed that the signal wire [blue/yellow] output 0V with no buckle and 450mV buckled. The voltage divider is a 390KOhm and 39KOhm between 5V and gnd. This outputs 450mV between them, perfect for the sensor wire.

 

The Autopower fits good enough. The bar doesn't mount to very structural parts of the chassis; the rear corner of the floorpan and the rear fender inner liners, but it's better than nothing. The instructions tell you to just crank down on the fasteners and any creases in the sheetmetal will be smoothed out, which is highly ghetto. I opted to use fender washers to keep the floorpan structural/acoustic creases intact, however this necessitated buying proper hardened locknuts instead of a double nut jam situation. Also, the passenger rear diagonal bolts need to be installed with the head in the fender and the nuts in the cabin in order to clear the charcoal canister within the fender. No biggie, just something I had to figure out on my own.

The rollbar does allow me to fit my 205/45-16 Hoosiers in the rear seat vacancies with perhaps a 1/4" clearance between them and the harness bar. Close fit!

 

Thanks Nitro

Nathan; the main reason I went with the Autopower is because it allows me to keep using the rear seats to hold my race tires to and from the track. The SD bar you have would block that ability, unfortunately.

 

Words of wisdom, thank you very much for the comments DixonL2!

This is exactly why I didn't go for a full cage; because I still drive my R53 on the street and didn't want to increase street-driving risk w/out a helmet. The combination of my seat positions and rollbar place any steel far behind and out of harms way from the occupants heads, a critical facet. The rear-ward slope of the Autopower bar helps facilitate this easily.

I progressed a bit more tonight, but since the Red Wings game is on tomorrow :cornut: , it'll be a few more days before I realize any significant progress.

 

Update!

Tearing apart the wiring harness: This is the driver side looking toward the firewall


More wiring harness, this time the rear section driver side. The wires for the rear wiper, washer tube, power outlet, and airbag system wires all were removed.


Here is my voltage divider for the seatbelt hall sensor:


The new Remote Keyless module location, behind the tachometer. The loose wires are for the module but haven't been shortened yet. I did this on MM2urbo and the keyless performance actually improved!


I finally found a good use for the headliner!


Cheers, and thanks for the kind comments so far!
Ryan

 

Thanks! I removed the rear wiper in MM2urbo, so I know it's not that big of a deal to not have it. It's worth the 3 pounds. :devil: The headliner is in the garbage!

UPDATES!
Things are going smoothly; as smoothly as this sorta stuff can go. :mad2: The wiring harness is complete and the interior is painted! I still have to apply the headliner cardboard fabric, rear seat fabric, trim the main carpet for the rollbar and battery to clear and then I can start installing things.

Locating the battery underneath the driver seat. I'm retaining the lower air vent to keep good cabin circulation.


Welding up the new battery box. I used 9/16" zinc coated steel and created a 4 sided rectangle. 2 sides will be used as leverage to hold down the battery in the z-axis with industrial 3M velcro [you'll see that later!] After the battery box was welded up I painted it for anti-rust.


A shot of the seat rails before they were painted. I started with Sparco universal steel seat rails and welded 1/8" thick angle steel with 1.25" legs that is used as anchor points for the anti-submarine belt eye-hooks. This should be plenty strong.


Sparco Evo waiting in the perimeter ;D


Paint! I'm painting all exposed interior sheet metal "Black Night Metallic" which turned out to be a rockin' choice.


Here is the roof so far. I plan on covering the cardboard with a cool fabric, tbd.


Cheers,
Ryan