subframe questions

[bradze]

the OEM subframe is there for crashes, correct? i was thinking of having a subframe similar to this from gorilla offroad company made,

or would i be able to make a piece to mount a winch to the front of my subframe? because the plastic was getting destroyed up front, i cut it and changed it around to give me slightly more clearance til i can afford a nice looking plate bumper. here is a pic of the side of my ghetto setup. i wish i had photoshop to make it clearer of what i have intended.

 

[dajeepman]

See this is the only reason i dislike my outback... its approach angle sucks compared to the departure angle. When i took my outback to colorado I did a number on my bumper and the undercarriage plastic. That's why i stopped offroading my Daily Driver outback.. I love the Gorilla stuff but it currently out of my budget.

 

[bradze]

yeah, mine was trashed so i cut it up and changed it to get a little more clearance, but it still sucks.

 

[Ratbag]

^ Do be aware that putting in something like this will dramatically change the way the seatbelt pre-tensioners and air bags work, specially if you have a front end accident .

 

[bradze]

so i guess that idea is out and i need to start saving for a custom front plate bumper.

 

[Ratbag]

Yeah, Bradze, that sort of thing looks like a good idea, until you realise what it does to the safety systems of the car.

In Oz, it is unlawful to do that sort of modification.

When I was looking at sump guards for Roo2 ("skid plate"), our mechanic of some 15+ years, Ross Hallett, told me that he would have to state on the service invoice/s that the car was unroadworthy because of it, unless the sump guard was air bag approved.

This would have had the effect of voiding both our personal injury insurance and our comprehensive insurance. IOW, hurt someone; lose your house ... .

He also pointed out that anything at all that slows down crumple rates during impact by as little as a few microseconds would cause the pre-tensioner seatbelts and air bags not to deploy properly - i.e., instead of saving your life, they might contribute to killing you.

Sort of pulls one up short ...

BTW, the OEM subframe is there to provide strong mounting points for the engine, gearbox, suspension, etc. It is also designed (along with all the panels) to crumple in certain ways and at certain rates to try to help you survive a crash. Changing it in any way changes how all that works ...

 

[El_Freddo]

the OEM subframe is there to provide strong mounting points for the engine, gearbox, suspension, etc. It is also designed (along with all the panels) to crumple in certain ways and at certain rates to try to help you survive a crash.

While they have certain conditions to adhere to for crash results there is no possible way that vehicles can be built for every crash situation. Who knows, there might be a situation were you crash and this frame helps you out.

For example, a good friend of mine's dad was in a major accident where he rear-ended a flat bed truck - it turned out to be the truckie's fault. He only survived due to taking his triton 2wd ute that day, it had a ladder chassis front to rear. If he took their Lancer that had all the safety bells and whistles for that time they reckon he wouldn't have been here today.
Basically the strength of the chassis saved his life in this case - if he puckered up to kiss his wife he would have been kissing the back of the truck. The rescue crew were in the mindset that they were cutting a body out of this wreck - he survived and with a lengthy recovery period in hospital he's able to live without disability to tell the tale.

So really, if you're going to hit something so hard that you move subframes etc you're already in a world of who knows what. Many crash tests happen at low "urban speeds" of 60km/h - many crashes occur at a much higher speed with many many different impact angles and objects - many that could never be predicted by the car manufacturers. The urban speed is where your air bags are going to make most of the difference. there are many high speed crashes where the air bags do not deploy.

Thought I'd put that out there - play devil's advocate...

Cheers

Bennie

 

[Ratbag]

Yeah, I know, Bennie ...

A friend of my brother's went under the tray of a truck, decapitating his passenger. These days, most trucks have run-under bars. Tilt-tray tow trucks don't appear to ... .

OTOH, I have seen many, many accidents:

• where superior roll over resistance and suspension design prevented the vehicle from rolling;
• where side intrusion bars and double welded box section sills prevented the other vehicle from penetrating into the passenger cabin cell;
• where seat belts kept the driver behind the steering wheel, instead of sitting on the passenger's lap - or vice versa;
• where the predetermined crumple rates prevented the engine and transmission (or petrol tank ... ) from perforating the passenger cell;
• where the rear bonnet locking tabs prevented the bonnet being deformed and torn off its mountings, then usually shoved through the windscreen;
• where better designed steering, brakes and suspension allowed the driver to remain in control of the vehicle in emergent situations when it would not otherwise have been the case;
• where stronger roof structures and pillar design stopped the roof caving in, in either roll over crashes, or those where the vehicle was flipped;

etc, etc, etc ... ad infinitum, ad nauseam

Unfortunately, I have also seen the results of accidents before any of these things became a commonplace.

Perhaps you should not be quite so quick to write off the design attributes that are included in almost all modern vehicles - particularly those that we take for granted in our Subies built since about 1993 ...

Perhaps you do not have the length of experience to see the before and after results that flow from these gradual improvements in design. Some of us have, and understand these things only too well from personal experience ...

Sorry, but I have been to too many funerals ...

ONE fortuitous occurrence doesn't really have very much effect on the population statistics as a whole, and the latter absolutely refute the position that you have posited. Sorry.

I am not playing the Devil's Advocate role ...
Too many people and friends have died because these things didn't exist in my youth. I'll leave it at that, but the ripples spread far and wide, and can have lifelong consequences for all those within the circle of effect. I have been one of those latter people.

 

[Rally]

It almost sounds like that for the 99 accidents you will survive using the car as is, this might be outweighed possibly by using an un tested modification which was not designed with safety in mind, but something altogether different. There are reasons road tolls around the world are declining and have done so for many years. It's not that the quality of drivers is any better, or because they have reduced the speed limit to near walking pace. It is a combination of better roads, RBT and better designed cars and the mandatory use of seat belts. No one can say with any certainty that being in the Lancer would not have been survivable because no one has tested that scenario against the Triton. I tend to doubt it myself as most utes- apart from say Falcons and Commodores- perform particularly badly in testing and they don't need to meet the same safety standards. So they don't try to make them safe because they don't need to. Once you get above a certain speed, and it is not that high, you have a sudden stop type crash and no car will be able to protect you.

Air bags do not deploy because of the speed of the accident but the g forces of the crash. In an under ride situation, where the structure of the car is not involved in the accident, I could understand why the air bags would not go off.

Without knowing all the details of one particular crash, one can only generalise. So unless this is an under ride situation, which is then just a matter of ride height, the thing that will kill you will be the sudden stop. And in those utes, it is far more of a sudden stop than a Lancer. Where such a car might be an advantage is where say a Landcruiser impacts the Lancer. The Cruiser, apart from it's weight advantage, uses the Lancer as the crumple zone. Even so, I have seen a fatal accident involving a late model Patrol and a smaller vehicle in a head on- no roll over- and the occupants in the smaller car survived and the Patrol driver sadly did not.

Some interesting things emerge from testing- there is some inconsistency in the results, so you have to average out the results over numerous tests And if you wish to increase your chances of surviving, be small. Smaller people are more likely to survive or receive less serious injury.

 

[NachaLuva]

The Cruiser, apart from it's weight advantage, uses the Lancer as the crumple zone. Even so, I have seen a fatal accident involving a late model Patrol and a smaller vehicle in a head on- no roll over- and the occupants in the smaller car survived and the Patrol driver sadly did not.

Its all about energy. A car impact has enormous energy & something has to absorb it. Either the vehicle or the occupants

In a well designed vehicle with well designed crumple zones, most of the energy is absorbed by the metal deforming. The rest is absorbed by the human bodies inside, hopefully not enough to cause serious injuries.

4WDs dont have much energy absorption, so therefore a lot of energy is absorbed by the occupants bodies. All too often you see a 4WD in a fatal accident on the news with moderate damage but a fatality inside. Yet the other car is a total mess, barely recognizable, but everyone survived. People can also suffer fatal internal injuries with minimal broken bones as the soft tissues absorb the energy.

Have you seen a big accident in an F1? It looks like it explodes as pieces fly off, yet the driver gets out & walks away, even in a 300kmh accident! This is because as the car "explodes", the pieces absorb vast amounts of energy as they break off. The science behind this is extraordinary...every bolt & every component has a predetermined failure rate to absorb the maximum amount of energy possible. It never ceases to amaze me...

 

[Rally]

Spot on. If I wasn't so tired last night I should have written what you did.

 

[mr turbo]

Have you seen a big accident in an F1? It looks like it explodes as pieces fly off, yet the driver gets out & walks away, even in a 300kmh accident! This is because as the car "explodes", the pieces absorb vast amounts of energy as they break off. The science behind this is extraordinary...every bolt & every component has a predetermined failure rate to absorb the maximum amount of energy possible. It never ceases to amaze me...

Spot on.

Ditto.
That is so very true.

Regards
Mr Turbo

 

[Ratbag]

I agree absolutely, NL.

Like braking, where one converts the kinetic energy of the car into heat, which is then radiated away by the brakes.

In a prang, one converts the kinetic energy of the car into shrapnel, twisted metal, etc - just so long as one can get the energy down to minimise what has to be absorbed by the occupants when they hit the seat belt, air bags, etc.

Of course the car manufacturers cannot test for, or design for, every possibility - BUT they can design the entire system to absorb and dissipate as much energy as possible, regardless of what happens.

The crash testing cannot test for every possibility either - BUT they can point out specific weaknesses in the design of the cabin, doors, restraints, etc that need to be addressed.

The "Active Headrests" in the later models are there to help prevent whiplash injuries - BUT BE WARNED: They only work if the head rest is up away from the rear squab of the seat! They do not work if the head rest is all the way down. It says so right there in the Owner's Manuals ... .

If you are hit by a train, or a B-Double, pretty well nothing will save you - that's just the way it is, folks ...

 

[mr turbo]

The "Active Headrests" in the later models are there to help prevent whiplash injuries - BUT BE WARNED: They only work if the head rest is up away from the rear squab of the seat! They do not work if the head rest is all the way down. It says so right there in the Owner's Manuals ... .

Another way to (help) prevent whiplash (for non active headrests) is to make sure the top of the headrest is above your eye line & not below it :iconwink:

Regards
Mr Turbo

 

[Ratbag]

Thanks for adding that point, Mr T. Quite right.

IIRC, it also said something along those lines in Roo1's OM. It didn't have any of this sort of technology in it, but was still a very safe car in every respect. A car doesn't have to have pre-tensioning seatbelts, or air bags, in order to have both primary (accident avoidance capability) and secondary (what happens if you don't avoid the accident ... ) safety. BUT all these things help. Sometimes dramatically.

The accident I was in in the family's Austin 1800 was potentially horrendous. Run off the road by a semi-trailer at over 95 mph (not deliberate on the semi's part, just the way the road was made). The primary safety characteristics of the car helped the driver to stay in a straight line. The pre-determined crumple rates, seat belts and structural integrity and strength of the body saved its occupants from serious injury or more probably, death.

Every aspect of a car plays some part in its safety, no matter if it is insignificant in any particular prang. In the next one, it may be critical to survival or avoidance of serious injury ...

The car is a disposable item, its occupants are irreplaceable.

 

[bradze]

i have changed my mind on wanting a totally new subframe. i want to put a winch in front of the subframe, now i have no welding skills or equipment so i would pay to do it. could a mount be made extending the subframe or should something be made extending down from the bumper beam? im thinking about some kind of tube bumper to give me some headlight protection and not have to worry about plastic scraping on anything. you lucky aussies have such easily accessible options