WTB: NB steering wheel w/ airbag

[MC70]

FWIW I have very little doubt it'll fire, however I think it is prudent to test. And the lack of indication that there's a problem only indicates that there's enough resistance in the system to keep the indicator from tripping. I have a resistor in my car, so I'm pretty sure the airbag in my woodgrain Nardi Classico will fire; darned if I can figure out where it is though. They must have really packed it tightly into that horn button!

What the test will do is to confirm that the stock NA wiring is capable of firing an NB airbag. Since I'm slaving it into an NA using NA wiring (with the exception of the connector swap to make the two work together) it is as real a test as possible since I'll be firing it using the sensor (which I think is just a plunger switch, or a frangible switch; if it is the latter I'll have to short the wires if there aren't any secondary electronics housed therin. If there are, I'll need to source a replacement from somewhere.

I'm not attacking you for your decision; don't get your panties in a wad. This question has come up a few times on a few different boards and the best we can do is hope it will work. There may be variables in there that we're unaware of at the moment. Doing this test will alleviate a lot of those concerns. You can be happy with your decision all you want, but wouldn't you feel better that it had been tested? Feeling one way and having evidence to support your belief/hope should be reassuring.

[Bob_MX5]

Of course I'd feel better if tested. FWIW, I am confident the NA wiring is capable of firing an NB airbag for the fact that I have no airbag system codes. A true test would be great, but you cannot duplicate a real world test with a simple wire/fire. If your test works and I am sure it will, all you can say is, "In my test it worked." You cannot say, "In my garage test it worked so in all real world cases it will work too."

In a real world crash, the decision to fire, the decision to send the proper amperage to the bag to fire, is not something you can duplicate in the garage. Let's be honest, the air bag system is much more complex than a light-bulb connected to a battery with an on/of switch. We know this because the system can detect several system problems. Also, the lack of airbag light indication is much more than only indicating there's enough resistance in the system. Hence, the numerous different codes that could be displayed by the "flashing" airbag light.

Also, your comment did have tones of "attack" with, "My question to you is: will it fire when you need it? Prove it will. "

I don't need to prove it will. It's my bag in my car and my decision affecting only me. And this wasn't a question of "should it be done", but rather "could it be done". I provide a reply that it could be done. As I note, the "should" is an individual decision. Nothing you or I do or say should be the cause for someone else's decision.

And for the record, my panties fit fine and are not in a wad. Thank you for your concern.


cheers

[Rogue]

And for the record, my panties fit fine and are not in a wad. Thank you for your concern.

Priceless, quote of the Month!

[OZMDD]

Kinda sounds like you're just looking for an argument there, mc70. Bob's posts are rational and accurate, while you're starting yet another pissing match with a stranger. Wtf? Kinda seems like the waitress at Keller's that everyone gets along with except you.

Is this lack of people skills why you always keep a packed suitcase on your trunk?

[MC70]

The Kellers thing kind of showed the cliques here and how defensive everyone is. I posted both times because I thought it was funny, even suggesting that maybe I looked like an ex of hers or something. Then all the measuring started.

And while Bob is a nice guy (I'm pretty sure we've met a few times now), I am not sure he is an electronics tech. In a strange twist of fate, one of the primary and fundamental duties I had in the military was maintaining and developing chaff/flare system which also bled into turbine squib start systems. This is exactly what happens in an airbag system. The system in our cars appears to be less complex than Bob has suggested. However as soon as I get into it this weekend I will know for sure.

I'm not picking arguments with anyone, though I have noticed that the way I communicate and the words I write with to my friends and family back east have to be modified for communication here; I admit I seldom do that. Similar words and inflections have different meanings or inferences.

I mean, think about both instances of Kellers... Folks here were there; did I seem anything but affable and easygoing? I wasn't anything but happy and enjoying myself.

[altiain]

Of course I'd feel better if tested. FWIW, I am confident the NA wiring is capable of firing an NB airbag for the fact that I have no airbag system codes. A true test would be great, but you cannot duplicate a real world test with a simple wire/fire. If your test works and I am sure it will, all you can say is, "In my test it worked." You cannot say, "In my garage test it worked so in all real world cases it will work too."

And for the record, my panties fit fine and are not in a wad. Thank you for your concern.

cheers

As an engineer I'd put a lot more faith in a physical sytem test than I would the absence of a warning light. The multi-million dollar machines my team designs can transmit several thousand different diagnostic codes back to my computer from anywhere in the world (which is nice, because I hear Siberia sucks this time of year) yet for some silly reason we still choose to manually validate safety critical systems with direct testing, even if that testing is a simulation.

MC70's test isn't a perfect real world simulation - nothing short of running an NA with a swapped steering wheel head on into a tree and seeing what happens would be a perfect simulation - but it's pretty damn close. Depending on how the test was conducted I'd certainly put a lot more faith into his test results than the absence of a fault code.

As for panties, I prefer them black and lacy. Yours might fit perfectly fine, but I'd argue the second part. Most of the people participating in this thread remind me of why I gave up surfing the pointy board a long time ago. You're all getting very close to sounding like my 3 year old son when he's been up far past his bedtime.

[Dave04]

happy and enjoying myself.

We are NOT that kind of board....

[Mr.E.G.]

Are you guys suggesting that you will detonate the airbag inside the car as part of your test?

I've seen hundreds of deployed airbags and a good many of them busted the windshield. Any concern about that?

[Mr.E.G.]

Also, thanks for answering my original question about whether or not the NB steering wheels will bolt into an NA. For the record though, I didn't plan on plugging the airbag in since I just assumed they would be different.

[Titus]

I'm not picking arguments with anyone, though I have noticed that the way I communicate and the words I write with to my friends and family back east have to be modified for communication here; I admit I seldom do that. Similar words and inflections have different meanings or inferences.

Folks here hate Yankees. Heck, they barely tolerate Kalifornians like me.

[MC70]

Technically I'm a Californian by birth but lived in VA (which is South of the Mason Dixon line, so not a yankee). But I get your meaning. It really is strange how differently we communicate; a praise or obvious humor there is often seen as offensive here. Difficult. Especially difficult when you are going out of your way to try to be nice.

[MC70]

Are you guys suggesting that you will detonate the airbag inside the car as part of your test?

I've seen hundreds of deployed airbags and a good many of them busted the windshield. Any concern about that?

That is exactly what I'm suggesting but this will be tested in a wrecked 97 in my garage. A lady pulled out in front of my son. Both of his airbags deployed. The passenger side broke the windshield already. The wheel I will test is a donor from an NB.

The connector is different from NB to NA, and that has caused some speculation if they were incompatible because there were different firing conditions required or if it was just a different plug to identify a later version/manufacturing variances/etc. We know they will fit, and the connector is easy enough to swap, but the question of whether or not it will work in conjunction with the NA Airbag module remains. That's what I want to find out before I put this into my son's car.

[Bob_MX5]

.... We know they will fit, and the connector is easy enough to swap, but the question of whether or not it will work in conjunction with the NA Airbag module remains. That's what I want to find out before I put this into my son's car.

If I may be so bold to ask: what is your plan for actual detonation? How will duplicate/produce/measure the exact amperage (too little it won't work, too much and you've exceeded firing threshold/real world conditions) necessary to fire the bag as a simulation of real world conditions. Do you have the necessary equipment to properly test the sensors/modules/wiring to ensure all are in working condition? Has your test equipment been calibrated by a reputable, independent, test company?

If this were just a "fun" experiment, answers to the above may not matter. But, as this concern's your son's safety, you may want to know these answers before you do or do not install the bag in his car based upon the results of your experiment.



cheers.

[MC70]

Bob, the first thing to understand is that the amperage requirements are determined by the device; the system simply has to be able to handle that amperage. I think you are thinking of current or voltage.

I've been doing more research today on the system and it turns out that it literally shorts wires to trigger the firing pulse. The threshold is determined by a set of mechanically activated switches in concert with a comparitor circuit which is set up in an 'and/then' mode instead of a much more complex 'if/and/or/then' mode. The firing does not appear to have any particular pulse requirements. In fact it really looks as though the fire pulse is a constant-on with intent of the trigger being pointedly expendable.

I believe you were suggesting that the system somehow measures impact forces and then calculates whether or not the system will fire. It doesn't. Also, the force of impact has no bearing on the signal characteristics sent to the module or the firing pulse that the module sends to the airbag. There are bumper switches which are gated via a switch near the firewall. If any one of the bumper switches is activated in conjunction with the firewall switch the airbag will fire. All of the switches are a gold plated ball-in-tube type switch. The ball is held away from the contacts (keeping the circuit in an open condition) via a magnet; this keeps the conductive ball at the aft side of the car and the contacts are in the fore end of the car. Given the weight of the ball and the force of the magnet on the ball it is easy to determine the impact force required to trigger the system.

Once the switches are activated a 12 VC signal is routed to the airbag module where the comparator circuit goes active. I am not sure if it is a 12VDC signal shunted to the airbag trigger (I expect so) or an internally developed signal. I need to study the schematic with part numbers.

The point of the explanation above is to dispel any myths about an actual collision having any determining factor in whether the NA system will fire an NB bag. I will either reset and re - trip the switches to detonate or I will shunt the 12VDC into the switch end of the module. Both have precisely the same effect as being involved in a collision. There is no electronic inertia sensor in the 1990-1997 Miata.

If the airbag deploys, it will confirm that the NA module can provide an adequate pulse to fire an NB airbag.

[black roadster]

Interesting read. I'm interested in the out come. I think what MC70 is trying to determine is if the NA airbag computer will send a proper signal to detonate the NB air bag. That's the only change you are making in the system so the trigger is inconsequential. The real question is will the NA computer be able to detonate the NB airbag.

Another thing to consider though, if you're actually concerned about it as a safety device is the seat belts in conjunction with the airbag. The NA seat belts have a sewn in tear-away section while the NB do not. The NB2 use explosive seat belt real locks as well. How these play into the safety operation of the airbag, I have no idea but I thought I'd bring up the question.

[MC70]

^ I also discovered that during my research today and realize that since I do not have an airbag I need to undo this feature. I had already been looking at replacement belts but now there is a bit more urgency.

[OZMDD]

I can report that the NB wheel and airbag work perfectly in a 96. I retrofitted the wheel for the NA clock spring, built a harness to connect the NA connection to the NB airbag, then spliced on the NA horn harness to the NB horn wire lead.

I rammed several parked cars with no airbag deployment, so I was concerned, but once I took the impact speed above 25 mph, she blew in my face like KenO's PE teacher! Tastes salty, but a great success!