Make a 240z safer.

[asuly]

So you are saying to pad up the doorpanels with dense foam? or literly inside the door directly behind the door skin? So to integrate the foam into the door panel would I put in behind the cardboard panel or in front of the cardboard panel?thanks

 

 

I have to agree with John C on this one---the wrong thinking is to reinforce the door.

What you need to do is stop the acceleration zone between the door and your body. Note all the interior panels are SO MUCH CLOSER to you now in 'bigger' cars? A Linclon Town Car has me rubbing my knee on the dash bolsters and door, where I'm free to flop all over in the Z.

 

That's what gets you injured.

 

Volvo knew long ago that putting cardboard in the doors gave a deformable structure to spread out the time of impact and transfer of force to anything soft that impacts them in an impact. The best thing you can do is put dense foam on the inner door panels to a point that you don't have more than 1" of movement of any extremity from the door.

 

When you are hit, you only accelerate for that inch, then start compressing the foam and dissipating energy. You feel a large "push" when you get hit, not a "BANG-WHAP-SH*T!" response like in the car without padding.

 

Most of the internal panels these days move the deformable pressboard and foam very close to you so when you are hit, you deform the panel and stop your limbs from accelerating.

 

Like this photo, the acceleration from the steering wheel to the dashboard allowed for a cracked metacarpal. Had that been a pre-1967 dashboard, it would have been a broken wrist...or worse!

 

I agree what John C says: the forces are being misunderstood and the approach to mitigating them is totally wrong. You do not need any more stregnth than a 73 or later door has---it transfers side impact to the rest of the chassis, preventing spot-intrusion of the door to the driver. What needs to be done to 'improve' the survivability is get proper dense foam padding on the door panels that will cushion you when this happens. That is the #1 thing to do. The transfer of energy from door to A and B pillar is already accomplished with the latch mechanisim and door bar already in place. The 6/76 an later internal latches are slightly better at this than the earlier, but it's a minute amount.

 

What you need is elimination of hard impact points, filling of space to prevent limb acceleration, and putting deformable structures in place to spread out the force of impact over a second, instead of a millisecond.

 

There was a group of guys with Mercedes that were human crash dummies---they would crash the cars into things. They would all place pillows and foam so they couldn't move hardly at all save to move the wheel to steer into the target. Belted and thusly isolated, they rarely got injured, and they were impacting at HYPER velocities!

[BLOZ UP]

A safe car is the largest one you can get.

 

That's assuming all cars are built equally safe. I suppose now large SUVs are required to meet the same safety standards of cars, but that wasn't always he case. An H1 may fair better against a Honda Fit, but if two H1s collide, you're both screwed.

Edited November 19, 2010 by BLOZ UP

[Pharaohabq]

Well that's interresting... I guess it makes sense though, I've seen how they make body moulded seats for race cars, formula one. the have a beanbag of foam pellets that they seat the driver in, then they pour in a foam glue hardener. they driver seats on place and gets comfy while it dries, then they pull him out, and clean up the foam, taping it up and carving it out for freedom of movement, but the fact is that he can't move more than an inch or so. It's not really practical for Daily driving. but you're right, I can see that adding foam to lessen your accelleration while the car absorbs the impact really sounds like a good idea. My door bar idea was more to try to prevent the impactor from intruding too far into the cab. So perhaps a combination of the two would make for a safer vehicle. Now what type of foam to use? Regular expanding foam, "Great Stuff"? We'll be getting into redesigning the interior here, so this might become a conversation for a different section of the site.

 

Phar

Edited November 19, 2010 by Pharaohabq

[Tony D]

"It's not really practical for Daily driving."

 

Actually, those seats are very comfortable for long term driving. You will find you don't get shoulder fatigue driving long distances. If the seat fits you, the need for 'cushion' is eliminated.

 

"My door bar idea was more to try to prevent the impactor from intruding too far into the cab."

 

As stated, this exists on all S30's from 73 onwards. Retrofit of 73 doors to earlier models will accomplish this in a proper manner, and not through some ham-fisted addition that will likely do more harm than good.

 

"So perhaps a combination of the two would make for a safer vehicle."

Perhaps? It's current standard design philosophy. The days of supposition or guessing are gone--it works and it's incorporated on all new vehicles currently sold here for street usage in the USA/North America.

 

"Now what type of foam to use? Regular expanding foam, "Great Stuff"?"

This gets to the complexity of design and engineering---FOAM is only one suggestion, you can not get blinders and fixate on semantics, the crash mitigation design of a car is a system integrated throughout the vehicle. Like I said, Volvo found rolled bits of cardboard tubing inside door handles dissipated energy very effectively. Stunt men routinely fall into corrugated boxes piled on the ground as they collapse at a know rate with a known surface collapse weight---if you have ever landed from height onto these boxes, it feels more like some big guy running into you and pushing you till you hit a wall softly instead of like falling out of bed onto the ground...WHUMP!

 

My suggestion of foam would ideally be some multi density stuff like rollbar padding, perhaps even stiffer like Ensolite or wrestling mat. It all depends on what body part you are intending for it to hit. Softer less dense foam in a layer nearest the extremity, with a layer of denser foam under that of a given thickness, and under that even more dense foam---like a progressive spring. Meaning when a small impact occurs, you 'bounce off' and no deformation of the panel occurs. Under heavier impacts, you could progressively compress the foams until the underlying sheetmetal is starting to deform from your 'immovable object' extremity working against the force of the impacting vehicle coming from the other way.

 

I would not use HARD foam like 'good stuff' as a primary impact agent. It will deform upon impact and will then require replacement. Like the foam inside a helmet --- ever look in there? Styrofoam! Same stuff you guy at home depot. Not particularly strong, but it WILL compress. Rollbar padding over that maybe... And a layer of thinner very soft foam or covering material for the door would all work to mitigate the impact.

 

I would stay away from anything you can't move with a HARD press of your thumb, or that doesn't somewhat spring-back. And stay away from anything that makes the doors underlying structure more rigid and unyielding. It needs to be able to move from external impacting vehicle, and from internal occupants which will hit it.

[Tony D]

"It's not really practical for Daily driving."

 

Actually, those seats are very comfortable for long term driving. You will find you don't get shoulder fatigue driving long distances. If the seat fits you, the need for 'cushion' is eliminated.

 

"My door bar idea was more to try to prevent the impactor from intruding too far into the cab."

 

As stated, this exists on all S30's from 73 onwards. Retrofit of 73 doors to earlier models will accomplish this in a proper manner, and not through some ham-fisted addition that will likely do more harm than good.

 

"So perhaps a combination of the two would make for a safer vehicle."

Perhaps? It's current standard design philosophy. The days of supposition or guessing are gone--it works and it's incorporated on all new vehicles currently sold here for street usage in the USA/North America.

 

"Now what type of foam to use? Regular expanding foam, "Great Stuff"?"

This gets to the complexity of design and engineering---FOAM is only one suggestion, you can not get blinders and fixate on semantics, the crash mitigation design of a car is a system integrated throughout the vehicle. Like I said, Volvo found rolled bits of cardboard tubing inside door handles dissipated energy very effectively. Stunt men routinely fall into corrugated boxes piled on the ground as they collapse at a know rate with a known surface collapse weight---if you have ever landed from height onto these boxes, it feels more like some big guy running into you and pushing you till you hit a wall softly instead of like falling out of bed onto the ground...WHUMP!

 

My suggestion of foam would ideally be some multi density stuff like rollbar padding, perhaps even stiffer like Ensolite or wrestling mat. It all depends on what body part you are intending for it to hit. Softer less dense foam in a layer nearest the extremity, with a layer of denser foam under that of a given thickness, and under that even more dense foam---like a progressive spring. Meaning when a small impact occurs, you 'bounce off' and no deformation of the panel occurs. Under heavier impacts, you could progressively compress the foams until the underlying sheetmetal is starting to deform from your 'immovable object' extremity working against the force of the impacting vehicle coming from the other way.

 

I would not use HARD foam like 'good stuff' as a primary impact agent. It will deform upon impact and will then require replacement. Like the foam inside a helmet --- ever look in there? Styrofoam! Same stuff you guy at home depot. Not particularly strong, but it WILL compress. Rollbar padding over that maybe... And a layer of thinner very soft foam or covering material for the door would all work to mitigate the impact.

 

I would stay away from anything you can't move with a HARD press of your thumb, or that doesn't somewhat spring-back. And stay away from anything that makes the doors underlying structure more rigid and unyielding. It needs to be able to move from external impacting vehicle, and from internal occupants which will hit it. It has to be harder than you think, as stuff too soft will not do anything. The soft layer is maybe 1-2mm just for 'comfort and abrasion' getting into and out of the vehicle or incidental contact. Gives the impression of a cushy interior, but underneath the harder foams or corrugated cardboard will actually provide the actual crash-crush structure. Take apart some Volvo Doors in the junkyard and you will be amazed at what is inside them! Rolls of cardboard tubing...Currugated cardboard and a stiff outer shell of the inner door panel---you hit the inner panel, the panel is sufficiently stiff to spread your impact out over the whole roll, and then the whole roll collapses acting as a decelleration/braking mechanisim. Very well thought out---and deceptively dangerous---after a crash people carp about inner door panels 'that look fine' being listed on the repair order---there is a reason: they are EXPENDED. They may LOOK fine (now they tend to fracture so the complaints go away...) but the integral crash structure is completely used in the accident and will not work for a second impact. Like a helmet---one use and throw away.

 

Kinda like the 240 in my photo...

Edited November 20, 2010 by Tony D

[Pharaohabq]

Thanks Tony-d, for your input on this.

 

I understand what you're saying in that any panel we'd make would need to be single use only much like your metaphore of the motorcycle helmet. Likely we would not want to reuse any panel anyway, after an accident. we're just trying to see what improvements can be made to an S30 to improve safety.

 

My comments about the seat moulding are valid, in that it'd be a lot of work to put into a daily driver, not that it would be uncomfortable, but just that a moulded foam seat would be difficult to get into and out of on a regular basis( I'm talking race car F1 driverseat type tightness.. My example was to demonstrate I understood the concept of limiting a body's accelleration in an impact, based on the earlier comments.

 

Improving the door panel as you've mentioned sounds like a good and workable solution. Layered cardboard (foamcore) much like they use in architectual modelling (see image)

 

This could be glued to the inside of the panel, shaved and shaped for asthetics and fit around seats and elbows. Outer layers could be slotted to lower resistance, then the whole panel would be covered with 1/4" foam rubber and vinyl to make a nice looking interior panel. Some type of shrink vinyl would be best. You could even integrate a cup holder. Foamcore would likely hold up better than cardboard with any humidity, but both could be sprayed with a sealer to protect it.

 

I know this would not guarantee no injuries as compared to the stock S30 panels, but it does seem that it would not add to an injury either. Your point was to limit the accelleration inside the vehicle while the S30 chassis absorbs the impact. I certainly would be willing to drop some 100LB weights on some foamcore and cardboard to test this theory. Unfortunately I do not have a bunch of dead S30's to crash test, nor high speed equipment to document with to go furthor than that.

 

It does seem the vital areas would need to be hips ribs and shoulders would benifit most from being built up, with less in between for arm movement and comfort. Without airbags you cannot do much passively about head movement and people are just not going to wear a helmet while driving to work. (not to mention if you did wear a helmet, and got in a wreak at fault or not, some lawyer would imply you were driving unsafely, since who but race drivers wear helmets?)

 

 

I looked at a bunch of pictures of car doors today too, most modern ones have a lot of padding at the hip and a ridge at the shoulder (much like the Z32) but not so much at the rib section, I guess the thinking is that a person's arm would take up some of the space. I also noted that in a lot of newer cars it seems that the B pillar is moved forward a bit more; not that S30's really have a B pillar.

 

I've also noted a lot of the seats have wider sides to the seatbacks which I could see when someone is belted inplace could help limit movement as well. I'm really liking the Rx8 seats, I wonder if they're on the list for fitting in the S30, I'll have to check.

 

Phar

[johnc]

IMPAXX foam from Dow. Its what NASCAR uses and below is the technical drawing for the NASCAR COT installation. You can purchase the foam from BCI.

 

http://www.rollbarpadding.com/downloads/NAS-COT-DM.pdf

[Pharaohabq]

That foam looks pretty good too. I don't know how hard it is to cut and cover, but certainly using a foam that's designed for the application is a positive idea. I'm not sure I exactly understand the drawings though. The Impaxx foam is softer at low speed, but crushable at higher speeds, that's awesome.

 

Phar

[getoffmyinternet]

Thinking along these line though, another option could be finding a way to monitor peoples driving, other than police officers and cameras. But deep down do we really want that? Sacrifice freedom for safety. My guess is people would say no.

 

 

Big brother?? What like monitor your speed and have a printer built right into your dash so every time you go over the limit your own car faxes you a fine? How about cops just pull people over for good reason instead. I've always thought that it would make more sense for the price of a ticket to reflect your income. I always see rich people weaving in and out of the carpool lane etc. because it's not that big of a deal to them, whereas a poor person has good reason to be afraid to leave their house because they might get dinged on something minuscule.

Edited December 3, 2010 by getoffmyinternet

[getoffmyinternet]

ugh..

Edited December 3, 2010 by getoffmyinternet

[getoffmyinternet]

ugh..

Edited December 3, 2010 by getoffmyinternet

[getoffmyinternet]

ugh..

Edited December 3, 2010 by getoffmyinternet

[MX500]

Please do us (and all S30's) a favor by learning how to drive a larger, less performance oriented car until you are very confident in your abilities. No disrepect intended whatsoever, but the 240Z is a performance oriented car with ZERO driver assists. Say you come around a corner going to fast, and your dog is in your way, you hit the brakes, but due to lack of experience tyou can't modulate the pedal well enough, lock up the brakes and kill your dog (or it could have been your neighbors kid too!). A modern car with ABS (anti lock brakes) could have helped prevent that. With time, you can learn to modulate brakes right up to the traction limit and not lock them up, but I sure as hell couldn't when I was your age. ABS would have saved me from my first two real crashes. I wouldn't worry about the safety features of the Z, I'd worry about the driver, a safe driver can help prevent some accidents in the first place.

 

Now this is why I said that:

At age 16, I attempted my first drift in my '68 Cutlass, I hit a 90* corner going 15-20 MPH in the snow, then floored it... I overcorrected 4-5 times, nearly hit a telephone pole, but ended up not hitting anything. It was a close call and a reminder to not be stupid/

 

First accident: also Age 16 (still didn't learn). Going 100 MPH in a civic, came around a blind corner (in my lane, I was never dumb enought to cross the yellow lines), there was a dipshit in a car halfway blocking my lane going about 5MPH. I swerved to the right, hit the brakes, the right tires were on gravel, they slid, the left tires grabbed, This made the car to a VERY quick spin to the left, I countersteered in time to keep it from spinning out and guided the car past 4 trees and drove it up an embankment and through a fence. I put ripples in the roof because I hit so hard. However, I missed every potentially deadly object, did not hit the other car, and me and my passenger were unscathed.

 

Second accident: Age 16, bumped into an explorer in a parking lot

 

Third accident: age 17, in my first 240SX, bought some crappy "performance" tires from Les Schwab (F--- those guys, they lied to me)I had hit this same corner with bald tires at the same speed the same morning with no issues. I hit the corner again with the new tires (after driving 30 miles to wear off the slick mold release compound) and I slid straight across the corner and up a curb. I ended up with a steel pole stuck through my passenger side of the windshield, if I had a passenger, they would have came close to losing their life.

 

I've got in about 7 more "accidents" but don't feel like listing them. I havent had an at fault collision in four years, I'm now 21. I may have been more reckless than most, but please take my advice because I learned from experience. DON'T drive like an idiot! Also, it is a good Idea to have a sacrificial first car. Most people I know crashed their first car in one way or another. Buy a Z after you have a few years experience under your belt. There aren't many of these cars left and it would be a shame to crash one.

 

 

Try a Civic or a 240SX if you want to have a good handling first car, they are a bit better in accidents than the 240Z and had anti lock brakes as an option, some years also have airbags which you seem to have been concerned about. Of those options, the 240SX would be WAY more structurally solid than the civic, I was Tboned by a camaro in my first 240SX, I ended up with only a dented fender, he ripped apart the whole rear bumper and damaged the tail light and rear valance of his car. That idiot floored his car in reverse and hit me when I was driving down the road, there was no intersection, I had the right of way.

[bjhines]

If you want a slightly more modern/safer car. Then get into a BMW E36 325i or an earlier BMW E30. That have a lot of safety features that the Datsuns did not.

[Pharaohabq]

WOw MX you've crashed a lot... You know they do have driving courses out there, might help on the insurance side...

 

The modifications to an S30 to make one safer is what we're talking about. Not any particular person's driving skills. This could actually be a valuable thread if we work out some ideas.

 

Phar

[bjhines]

HOLY crap.. I must drive like an old lady. When I was 18, I tapped a minivan when she stopped suddenly to make a last minute turn with no room and no blinkers or any kind of warning. I was following too closely and that was the last time I ever tailgated. The only other time I have ever even scratched paint on any car was a tirewall due to squishy brakes at VIR. That was also the LAST TIME I ever used drum brakes on track. I have avoided countless wrecks because I look at it as "everyone else is TRYING to kill me out there". If I have any kind of incident with a vehicle I completely rethink what I am doing and address the problems immediately. Tree-limbs have done FAAARRRRR more damage to my vehicles than any other possible event. My poor BMW M3 hashalf a dozen dents from the damn trees.

 

You can retrofit a modern brake system with 4 wheel antilock brakes. Traction control and stability control are great in the wet or slippery conditions. You could also retrofit an airbag by replacing the steering column and adding the appropriate sensors, seating, A-pillar and knee bolsters.

Edited December 4, 2010 by bjhines

[bjhines]

jimminny christmas the thing hangs up when I try to post.... double post on hangup.

Edited December 4, 2010 by bjhines

[getoffmyinternet]

I havent had an at fault collision in four years, I'm now 21.

 

 

Well that's nothing to be proud of. If you've averaged two accidents per year then you should probably not drive at all. Public transport isn't as bad as it used to be.

 

It's like bj said, drive like everyone is out to get you. More often than not a not-at-fault accident just means legally you weren't liable even though clearly you played your part (it takes two to tango). There are even no-fault accidents for situations where the law is too gray to determine who made the bigger mistake.

 

 

jimminny christmas the thing hangs up when I try to post.... double post on hangup.

 

Try quadruple post!

[Pharaohabq]

Okay, So say re refit the door panels with a nice hard foam like Impaxx, Aside from driving lessons and all, what other things can we reasonably do to improve the safety of our S30's? The Wreaked Z picts out there are pretty heartbreaking, but most seem to take hits pretty well.

 

Adding airbags is out of the scope of most of us on here. Though it would be a good idea, there's a safety issue with them as well in that airbags are usually sized for the vehicle they're in, so if we added them, and made them work properly with the right sensors and all that, it's still possible they could cause more injury than not having them in place. This is a difficult ideal mainly in that we're not trained to know what Airbags require.

 

A Roll cage is certainly an idea though, how well will one really help you in a daily driver situation. Sure the Rollbars will be padded, but you can still hit your head. Does the risk of that make a car More or Less dangerous for having one? Most of us take off the heavier 260/280 bumpers. How much difference do those really make in a higher speed accident?

 

The Stock S30 seats (73+). They're okay so far as safety. but a newer bucket seat with wider side bolsters to bucket you into the seat, sure seem like they'd be better, in that they too would prevent body accelleration assuming, you were buckled in.

 

 

I guess what I'm getting at, is that maybe we could make a list of mods we could do to an S30 Daily driver to decrease the likelyhood of injury when someone hits you, or if you hit anyone...

 

 

So far we've got:

 

Learn to drive - drive like people are trying to kill you (easy advice, but not really a car mod)

Door bolsters - To limit body accelleration in a crash.

Rollcage - Does this really help in a daily driver?

Seats - Newer seat design can hold a passenger to help prevent body accelleration

ABS - Haven't seen anyone put in in an S30 yet. Are ABS calipers much different than standard calipers? I have an 350Z ABS pump. might be interresting to try out.

 

If you've got more ideas aside from ranting that people can't drive, then please speak up. This could literally be a matter of life and death.

[Tony D]

" More often than not a not-at-fault accident just means legally you weren't liable even though clearly you played your part (it takes two to tango)."

 

Someone claiming to be in SoCal posting that boggles my imagination! In the land of Illegal-Alien Swoop-and-Squat Predators I find that an offensive comment---ESPECIALLY since I have been a swoop-n-squat target!

 

Sometimes (and in more cases that you would think, especially in larger metro areas) it really ISN'T your fault, and in more cases than you think, it's outright felonious activities bumping up the accident statistics!

 

Curiously, 'Swoop-n-Squat' is unheard of in some states with No-Fault Insurance. Meaning you get into an accident, your insurance pays for your damages. And the other party pays for theirs. The Insurance Companies work out subrogation of the claims---it ceases to be an income source for the poor who can afford to buy a car at lein sale and then go cruising the interstates looking for a commercial vehicle that has signs on it that signify "WELL INSURED CORPORATE VEHICLE VICTIMIZE ME AND YOU WILL WALK AWAY WITH AT LEAST $50K"

 

 

The biggest safety device in the vehicle is the driver. Period. Drive like everybody is out to get you and chances are you will go quite a while before someone succeeds in getting you!

Edited December 8, 2010 by Tony D