Sidesteps - what issues with removing them

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Re: Sidesteps - what issues with removing them

Hi desmond,

The strength issue is the problem not the sensors themselves. The deployment of the air bag is under the control
of a ECU. The ECU takes into account the speed of the car, the de-celeration rate and a few other inputs into account
and using this information decides on the optimum point to deploy the airbag if need be.

Also taken into account is the known energy absortion or "crumple rate" of the vehicle ascertained by calculation and
crash testing. By strengthening the side of the vehicle you are altering the "crumple rate" and this will have an effect
on the airbag deployment timing and worse, may cause the airbag to deploy when not needed.

The same applies to bullbars etc and is why they are certified as airbag complient, they are designed to crumple in sever
impact to maintain the cars original specs. This is why ARB bars for instance have the corragated crash cans whereas Toyota
have solid crash cans. The Toyota bullbar crumples and absorbs energy whereas on the ARB bar the crash cans crumple and absorb
the energy. I bet the seller of the skid bars is not prepared to give you an airbag complient certificate?

The bottom line is you should consider insurance aspects. In this day and age if a passenger was injured in
your car you could be leaving yourself open to legal action if you have changed the safety aspects of your car.

Cheers

LeighW

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Sidesteps - what issues with removing them

The strength issue is the problem not the sensors themselves. The deployment of the air bag is under the control
of a ECU. The ECU takes into account the speed of the car, the de-celeration rate and a few other inputs into account
and using this information decides on the optimum point to deploy the airbag if need be

I think your overstating the sophistication of the system.... speed and de-celeration are NOT taken into account with side air bags and there are NO other inputs other than the side airbag sensors... infact the side airbag will go off if you are fully stationary and someone plows into the side of you.

The only reason this is a grey area is because no one has followed through the engineering and approval process (Not made it known to the public atleast)

When people don't understand how things work (airbags, VSC, TRC) they think it can't be modified or mods will render it un-safe. In many cases when modifications are made with sound engineering they enhance safety.

Mick

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Re: Sidesteps - what issues with removing them

Hi MickL

I'm not interested in getting into an argument, just trying to supply some info.

Here is a little lite reading, the same system is used for either front or side are bags, only difference
is side airbags have to inflate a lot faster and may also incorporate a roll detector to trigger airbags
in a vehicle roll over.

In the case or a station vehicle, acceleration will cause the airbag to inflate, the computer knows the car is stopped
therefore rapid sideways acceleration/deceleration (side ways into a tree for example) must be an impact.

Also, in a side impact there is a lot less time for the system to react therefore timing of the airbag inflation is more
critical.

All impact sensors these days work on inertia change principle, most using a pizzo sensor to detect changes in inertia.

The following is from a technical info document:


Airbags



Vehicle crash strategies are primarily concerned with restraining vehicle occupants, and absorbing collision energy that would otherwise be transferred to the occupant.

The primary method of occupant restraint is the seat belt. However airbags are used to supplement the effect of the seat belt and have proven to be very effective in reducing the likelihood of severe head injuries.

How they work
A front airbag system includes a large nylon bag, which is inflated and deflated rapidly in the event of a severe frontal collision. The drivers airbag is housed in the centre pad of the steering wheel, and the passengers airbag, where fitted, in the upper left of the dash.

The airbags deployment is controlled by several sensors that detect the occurrence and severity of a frontal crash. When the airbag controller determines that the airbag should be deployed, the system triggers an inflator unit that burns chemicals very rapidly to produce large volumes of inert gas to inflate the bag.

As the bag inflates, it splits open the covers on the wheel or the dash, ballooning in front of the occupant. At the same time the occupants head and upper body is moving with significant force toward the inflated bag. As the occupants head strikes the airbag, the bag starts deflating through vent holes in its base. This controlled deflation cushions the decelerating heads forward movement. The whole process occurs within about 100 milliseconds - about the same time as the blink-of-an-eye.

In the process of deploying, considerable smoke, dust and noise will be produced and the occupant may be unaware that the bag has deployed. This is normal.

When do they deploy?
For the driver or passenger airbags to deploy, the following minimum criteria must all be met:

A frontal collision has occurred while the vehicle was traveling at more than about 25km/h.
The angle of impact is within a window typically around thirty degrees either side of the cars centre line (around 60 degrees in total).
The deceleration forces produced are at least equal to those produced when the car collides head-on with an immovable barrier at approximately 25km/h.
If all these triggering conditions are not met the airbag will not deploy. Thus, a vehicle with a properly functioning airbag system could suffer significant frontal collision damage without airbag deployment.

Front airbags will not be deployed in the event of a side or rear end collision or in a rollover, as deployment would not enhance occupant protection.

Dual stage airbags
Not to be confused with dual front airbags, dual stage or adaptive airbags are a smarter generation of airbags that can optimise the level of airbag deployment to suit the severity of the crash. The airbag is of a variable volume and can be inflated in two stages depending on the severity of the crash. The level of occupant protection is improved accordingly and the risk of secondary injury reduced.

Side, curtain and knee airbags
Many vehicles offer seat mounted side airbags, and side impact curtain airbags mounted inside the sides of the roof frame. They are intended to help protect occupants against head, neck and thorax injuries during side impacts and rollovers. Knee bags protect lower limbs from injuries caused by impact with dash panels.

Airbags and bull bars
Inappropriately designed bull bars may interfere with the airbag systems ability to correctly deploy the bag. So its vital that any bull bar fitted to an air bag equipped vehicle is compatible with the system. Only bull bars that are certified as not affecting air bags systems can legally be fitted to later vehicles.


Cheers

LeighW

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Sidesteps - what issues with removing them

I'm not interested in getting into an argument, just trying to supply some info

Leigh,

It's good healthy discussion... hardly turning into an argument.

Your information is generic and applies to airbag technology in general, it's hardly vehicle specific.

My comments are directly related to the Prado. The side airbag system can be considered quite primitive... it's basically an electronic version of the first generation physical contact activated systems (as in the Volvo 850 for example)
There is no roll over activation feature, only a single sensor either side. No other inputs for side airbag activation.

The front airbags take signals from two front sensors as well as a speed sensor input and a G force sensor in the centre of the vehicle (under the console)


Anyway... how they work is not the point... the discussion is about sliders and there possible effects on side airbag deployment.

I stand by my earlier comments.... the area is gray as no one has (as far as I know) gone through the engineering process and proven anything (Either good or bad) and the various RTA continue to sit on the fence.

It wouldn't be terribly hard to engineer sliders that are airbag compliant. It's just someone has to foot the R&D costs which I would think is unlikely as the market just isn't big enough to recover the costs.

And...Even if there is and effect on airbag deployment there is still the potential to modify the system electronically. Not that long ago people many people thought EFI would be the end of engine mods... and look now... with a laptop and software you can program 3D fuel and ignition curves in real time, on the road, all for a couple of thousand dollars (Kalmar software and Bosch EFI systems for example)

It's not all doom and gloom... if you really want to do something, it can be done... it's just a matter of how much you want something and how much money you want to throw at it.

Mick

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Re: Sidesteps - what issues with removing them

Hi Mick,

No Probs, I'll think you'll find in the 2008 models on the airbag system may have changed as
they now have four lateral sensors, one on the drivers side and passenger side pillars and
one behinhd the rear door pillars on each side from memory.

Also Toyota in their documnetation now refer to two stage deployment which was on the
American models and now appears that it maybe on the the Aussie models. They also now
refer to detecting the weight of the front occupants and using that info in the airbag deployment
timing for the front occupants, again I think this was on the American variant and now appears
to apply to the Aussie model.

To cut to the chase, with regards to sliders, as are mounted so low I myself agree that I don't
think they would have any depremental affect unless your hit by a Lotus or maybe a motor bike and
could certainly be engineered to be airbag compliant.

It will be interesting to see what the recommendations of the vechile modification review come up with.

Cheers

LeighW

[MickL Addicted PP Member Find all posts View Profile Close MickL]

Re: Sidesteps - what issues with removing them

Leigh,

I'll have to trust you on what you say about the 2008 model. I based my info on the Toyota SRS wiring and conponent diagrams for the prado.. unfortunately the are dated 8.2007.

It will be interesting to see what the recommendations of the vechile modification review come up with

Jury is out on this that's for sure. I really haven't kept up with it and I hope that some of the people with their fingers in the pie show some common sense and don't paint all modifications with "Can't be done" brush.

I agree with stamping out dangerous modifications done by backyarders, but surely there is a place for mods that don't effect (and sometimes enhance) vehicle safety systems.

Mick

[mcbeater Lurker Find all posts View Profile Close mcbeater]

I notice most people leave the stock sidesteps on.
Also noticed that any 120 that's done any reasonable offroad work has bent sideteps.
I was thinking of just taking mine off and preserving them in good nick for when the vehicle is sold.
The fuel tank is still lower than the steps but it would give a bit more clearance at the sides.

What about stone chip damage to the mouldings and door panels - do the side steps prevent that, is that why people leave them on ?

Take them off. They sit wider and lower than your sills and they are made for little old ladies to step on not to protect your sills like sliders.
They are flimsy and weak and just begging to be bent, i reckon they create wind drag on the highway too.
They're like the third row seats... Boat anchors.

[ozwapet2 Advanced Member Find all posts View Profile Close ozwapet2]

Take them off. They sit wider and lower than your sills and they are made for little old ladies to step on not to protect your sills like sliders.
They are flimsy and weak and just begging to be bent, i reckon they create wind drag on the highway too.
They're like the third row seats... Boat anchors.

Yes they have been off for, oh, about 6 years now and not been any issues. I have not done any "heavy" offroad work as I am over all that, bedsides that is not what a Prado is for.

However I do get into the bush regularly.

And then when I do sell the vehicle I have pristine sidesteps to put back on.

[Scruffy Member Find all posts View Profile Close Scruffy]

Any idea how much the standard sidesteps weigh please? Just calculating how much weight a pair of 40kg sliders (20 per side) will add in real terms!

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Sidesteps - what issues with removing them

Bugger all on a 120. Maybe 3-4 kilos.


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