Thread: L322 Bullbar development! Finally

Originally Posted by Tombie

Indeed good advice.

The big difference with the RRS using a Disco bumper is that at the least, the chassis dynamics are the same. So crash pulse would be very similar if not exact.

The FFRR is a very different beast under that skin, and a custom bar could trigger too early or too late, both can have fatal consequences (think chest crushed)

Yes I agree - Ron (P38Rover) snapped this pic about 10 years ago - as he indicated at the time is a nice fit - is a ARB D3 bar so while a little work is required the D3 bar does fit. But your point is valid concerning air bag activation etc - hence my comments about the big bar manufacturers not making bars to suit - they would have the resources to sort this out but choose not too, so I doubt the little guys can do it.

As far as I'm aware, the AirBag sensors are accelerometers that are computer controlled to deploy if a certain deacceleration figure is experienced.

The airbag compliance, is more so to do with the actual timing effectiveness of the sensors. This is largely achieved in the crush can or deformation zones where the mounting points are although they are not directly related to the airbag system per se, they would affect the forces distributed through the chassis and to the sensor.

It would be in the larger manufacturers commercial interest to state that they are the only legal/approved way forward, alot of articles appear to be bent that way. However, it seems to me that a well designed crumple zone on the mounting points would allow for compliance. I think this is what smaller shop rely on.

An interesting article on the matter where Toyota rep basically says that outside of full scale crash testing you'd be guessing as noone apart from them has the detailed design data. This appears to be saying that no other manufacturer has it right... so go figure, everyone is competing for the business.

Bullbar safety up in the air (drive.com.au)

A wee thought experiment: If i covered my front bumper with cardboard, or a plastic cover, or paint protection(!) would this mean i have to crash test it?

At what stage does it become a bar?
How can i demonstrate legally that cardboard doesnt affect the airbag system?
Can i remake the exact design of my bumper in alloy is that legal if its the same design?

My thoughts are that if it distributes crash forces to the correct place, and that place (mounts) have a slide-style crush box to prevent low speed impact airbag activation, then this would be a demonstrated design characteristic for not adversely affecting airbag conditions.

Even in saying this, airbag deployment at speed (real crash/head on etc) would not be adversely affected with a full solid steel bar mounted directly to the chassis as the deaccell and airbag controller conditions would be met easily.

Small shops have this worked out I reckon and understand exactly what would be required to not interfere with critical airbag timing. Even if it did, HOW WOULD YOU KNOW (noone has access to the vehicle manufacturers actual design characteristics)? The only real way appears to be full scale crash test of a vehicle and ARB and TJM DO NOT do this for majority of vehicles outside of supplying factory delivered ANCAP ratings.

I personally would have no problem in strapping a full alloy bar on the front end as long as it didn't take me overweight if a supplier who would know much more about this stuff than i do, states that it has been built correctly.

______

EDIT: Re mounting, and why i think that the mounts are the thing that actually matter here

"The test is recorded using high-speed cameras and sensors fitted all over the test rig, and the results are checked to ensure the airbags only trigger when they’re supposed to and not earlier or as a result of an impact less than designed for.

The high-speed footage, when played back in slow motion, also allows the TJM testers to check deceleration rates. Measurements are also taken of the bar deformation and how far it has moved within TJM’s patented mount system. This mount system is designed to absorb the energy of the impact, thus minimising how much of the force of impact gets transferred to the occupants within the vehicle, as well as how much load transfers into the chassis itself."

Engineering ADR-compliant gear (whichcar.com.au)

_____

Happy reading!

Reuben

More from a guy that says he works doing crash tests:

ADR verification (fjcc.com.au)

Crash Test.jpg

At this stage I'd settle for a Smart Bar, they are now doing them for other 4x4's and also have winch versions I'll send them an e-mail and see what happens

Tough, Lightweight & Seriously Safe | SmartBar SpartanBar Bull Bars

There also is a video on the site showing 4x4 V's a calf ! All survived, but a good indication of the quality of the bar.

Superior Safety Without The Weight | SmartBar Bull Bars

Laurie

Originally Posted by irubix

Slightly more than a brush bar id say, looks fairly rigid!

Attachment 167544

sorry i thought the last posts were about another bar

Originally Posted by vbrab

Have been to Perth and had initial fit for bar, and had my queries answered regarding compliance and how they intend to mount it.

Bar is to be mounted via some pretty solid looking steel mounting brackets that attach to front subframes (through holes cut in bumper).
It appears that it will be not that difficult to unbolt should I need to remove bar for major repairs.
Also asked them to enlarge the front ventilation, which is not as restricted as I had thought and it appears that airflow won't be impacted very much (if at all).
After initial fitment, they have re-fitted front bumper (see pic) while bar is sent to powder coaters who are closed for Christmas and beyond.
It will be fitted over the existing front bumper with fog lights and park sensors fitted to roobar.
Heading back in 2 weeks for fitment.
Only real issue is that limited colours available from powder coaters, so have to live with sort of silver grey.
Attachment 167475

Hi,
Great work on bull bar. As for colour mine l322 is silver, so it's perfect for me. Like to know final cost for purchasing.

Jason

Originally Posted by landie56

Hi,
Great work on bull bar. As for colour mine l322 is silver, so it's perfect for me. Like to know final cost for purchasing.

Jason

They gave me a price of $2900 fitted (which I thought was bit OTT, but cheaper than a Roo strike.
Seems that either way powder coating or polishing the aluminium, adds up to about the same labour/price.

Originally Posted by irubix

As far as I'm aware, the AirBag sensors are accelerometers that are computer controlled to deploy if a certain deacceleration figure is experienced.

The airbag compliance, is more so to do with the actual timing effectiveness of the sensors. This is largely achieved in the crush can or deformation zones where the mounting points are although they are not directly related to the airbag system per se, they would affect the forces distributed through the chassis and to the sensor.

It would be in the larger manufacturers commercial interest to state that they are the only legal/approved way forward, alot of articles appear to be bent that way. However, it seems to me that a well designed crumple zone on the mounting points would allow for compliance. I think this is what smaller shop rely on.

An interesting article on the matter where Toyota rep basically says that outside of full scale crash testing you'd be guessing as noone apart from them has the detailed design data. This appears to be saying that no other manufacturer has it right... so go figure, everyone is competing for the business.

Bullbar safety up in the air (drive.com.au)

A wee thought experiment: If i covered my front bumper with cardboard, or a plastic cover, or paint protection(!) would this mean i have to crash test it?

At what stage does it become a bar?
How can i demonstrate legally that cardboard doesnt affect the airbag system?
Can i remake the exact design of my bumper in alloy is that legal if its the same design?

My thoughts are that if it distributes crash forces to the correct place, and that place (mounts) have a slide-style crush box to prevent low speed impact airbag activation, then this would be a demonstrated design characteristic for not adversely affecting airbag conditions.

Even in saying this, airbag deployment at speed (real crash/head on etc) would not be adversely affected with a full solid steel bar mounted directly to the chassis as the deaccell and airbag controller conditions would be met easily.

Small shops have this worked out I reckon and understand exactly what would be required to not interfere with critical airbag timing. Even if it did, HOW WOULD YOU KNOW (noone has access to the vehicle manufacturers actual design characteristics)? The only real way appears to be full scale crash test of a vehicle and ARB and TJM DO NOT do this for majority of vehicles outside of supplying factory delivered ANCAP ratings.

I personally would have no problem in strapping a full alloy bar on the front end as long as it didn't take me overweight if a supplier who would know much more about this stuff than i do, states that it has been built correctly.

______

EDIT: Re mounting, and why i think that the mounts are the thing that actually matter here

"The test is recorded using high-speed cameras and sensors fitted all over the test rig, and the results are checked to ensure the airbags only trigger when they’re supposed to and not earlier or as a result of an impact less than designed for.

The high-speed footage, when played back in slow motion, also allows the TJM testers to check deceleration rates. Measurements are also taken of the bar deformation and how far it has moved within TJM’s patented mount system. This mount system is designed to absorb the energy of the impact, thus minimising how much of the force of impact gets transferred to the occupants within the vehicle, as well as how much load transfers into the chassis itself."

Engineering ADR-compliant gear (whichcar.com.au)

_____

Happy reading!

Reuben

Just on this - ARB (it’s the only one I can speak certain of) does get the crash pulse data from the manufacturers when developing its bars.

It also does do the sled testing after all the FEA modelling is completed.

The mount system (also known as crush cans) is instrumental in the timing of crash pulses, as are chassis crumple zones.

Anything that impacts the above can have detrimental consequences to the vehicle.

Get it wrong one way and the bags trigger late - which means they’re inflating as they impact chest/face.
Go the other way and they’re already deflating and you hit the steering wheel or get more whiplash.

If they over increase the sensitivity threshold you could find an impact that shouldn’t have set off the bags now writes the vehicle off.

It’s not anywhere near as simple as “we are confident” - it should be “we are certain”.