Outer Limits 4x4 Board

Hey guys,

I bought a Suzuki Jimny recently - 2006 model and have just fitted a small suspension lift and some slightly larger tyres. Anyhow, they are scrubbing a little so I just wanted a little extra clearance to prevent this, and figured a bodylift would be my best and cheapest option.

I was just curious though about how bodylifting newer cars affects the air bag systems, and whether there is any illegalities or danger involved in doing so?

It doesn't appear from what I can see that any airbag sensors are attached into the ARB bullbar, but I guess I don't really know what to look for in that regard.

Anyhow, it would be great if you could be of assistance!

Cheers
Chris

the airbag deployment system used by suzuki would be ok with a bodylift, but finding someone to sign-off on that modification will be the hard part.

why is that joe?

From my understanding a bodylift was a relatively basic mod? In terms of signing off on it I thought it wouldn't have been too much of a hassle...

I just wanted to sort it all out before going ahead to purchase the kit, as I am trying to make the car as re-sellable as possible for later on, so preferring to not go to the gaurds with a chainsaw!

Is it more a case of engineers being over-cautious of something?

Thanks for your response!

If you could by any chance explain to me how the system actually works that would be awesome.. that way I could forward that information on!

Cheers

Basically, regardless of the vehicle, or the method and location of the airbag sensors, bodylifting any airbag equipped vehicle, is, as far as I can tell, a big no no legally.

You can argue with the umpire's descision, but them's the rules.

If you can find an engineer who is willing to set the precedent, that's great.

The key issue is that any modification that has the potential to have any effect on the deceleration of the body of the car in crash is a problem.

That's why ARB, as an example, had to do masses of engineering and actual barrier tests to prove their bars didn't mess with the timing of the bags deployment.

Obviously, if there has been a modification between the body and the chassis, there is a potential that the timing of the airbag deployment will have been effected. A timing mismatch might see the bag trigger early or late, either negating it's effect or potentially adding to injury.

We an all postulate that ant timing change won't be significant, but until someone pays the money to physically prove it, bodylifts and airbags are going to stay a no go zone for engineers.

That's my understanding currently.

Steve.

Great Steve thanks!

Not what I wanted to hear... But it was what I needed to hear.

I have heard of a few people doing it, so it would be interesting to see why they chose to do this, particularly to vehicles under factory warranty etc but atleast now I know the reason for it being a no go.

Cheers

why twisty got aproval to do it to his new hilux and that has bags so see why he can then?

That will depend on where and how the Jimny airbag sensors operate.

If it's the same configuration as hilux then it might be easy. For QLD, at the moment.

If it's different, then you'll be starting from scratch.

I'm not aware, for instance, that airbagged cars are being legally BL'ed in Victoria.

Steve.

Steve,

Yeah some of the reasons I was looking into it was I had heard of approvals.

I had also heard that the newer Series 3 (05? Onwards) jimnys operated off a new type of sensor for the airbags - that was like a motion/speed reduction sensor that is attached to the body, hence lifting the body wouldn't effect this as it sets the bags off based on the bodys impact alone.

Apparently the older ones used more basic crash sensors, which was the reason this was not possible.

Keep in mind what I have just said above is all 'what I have heard' and not based on fact, which at the moment I have had trouble tracking down.

I think I will ring QLD transport tomorrow and see what they say.

If you can confirm that the system relies on a decelleration sensor in the body rather than contact on the chassis, then you may well have a case, for now, in QLD. which is great.

You can understand the reluctance of engineers to sign thise sort of issue off though.

Steve.

oh totally.

I will be ringing and finding one before I go doing anything thats for sure.

Thanks again.

I rang the transport department this morning.

They told me I could submit an application and it would probably be approved subject to the conditions that it doesn't effect the steering, airbag systems, other vehicle mechanics etc..

SO they said:

Ultimately it is your responsibility as the driver that you ensure that whatever modifications you do do not impede with the manufacturers specifications, or cause the vehicle to not operate as the manufacturer intended.

This being said, they said it can be done and it would have to be looked over in the pits upon completion, but they said the only way to ensure it won't damage the airbag system is to speak with an engineer initially, or contact Suzuki and get their view on the matter.

I got my written approval to allow me to fit a 50mm body lift to my sierra today. the second point of the conditions of approval is:

Installation of the body lift kit must not interfere with manufacture's specifications or the continuing compliance of any Australian Design Rules appicable to the vehicle including the electronic stabililty control (ESC) system or the deployment of supplementary restraint systems or SRS airbags.

This doesnt effect me as it is a sierra, but as it came straight from the Department of Transport, and it is current, I thought it could be handy.

Cheers

Most modern cars use accelerometers to trigger air bag deployment.

So the vehicle "crush" rates play a huge role in the accurate timing of air bag deployment.

Anything altering those crush rates will have an effect on the system and without extensive testing it will be difficult to determine the negative effects (if any) of the body lift.

From that point of view many engineers may not want to touch it for fear of the unknown.

I would like to hear hoe you get on as a point of interest.

Me personally I would mot want to do such a mod on a modern vehicle.

I would rather chase the extra lift required via a suspension lift.

I'm going to set aside the airbag legality issue for a moment.

I think what you meant by "I would rather chase the extra lift required via a suspension lift" was "I would rather fit bigger tyres to my car by lowering the bumpstops"

A body lift doesn't improve ground clearance and is only a tool for clearing bigger tyres. As such, it's a much better idea than adding extra suspension lift for that purpose, and here's why.

a 2" body lift will require the bumper mounts to be modified, and maybe the low range shifter boot.

to have the same effect on tyre clearance, you'd need 2" of extra suspension lift, 2" bumpstop spacers, possibly different shocks, custom springs ( or hassles with rate etc) caster correction, driveshaft mods, possibly adjustable/custom panhard rods, and then you've ended up with a car with worse suspension geometry (as it's well beyond design ride height) and a higher COG than the same overall height and tyre with 2" less suspension lift and 2" of body lift.

Bodylifts have their place. They are a VERY useful way of adding tyre room.

My guide is that you bumpstop space, body lift and cut guards to clear the tyre. You play with suspension to add travel. You don't add suspension lift to fit a tyre.

Note, these are general comments and no specificly related to the jimny. I've body lifted over a dozen suzuki's over the years.

Steve.

I got the ok from an engineer to body lift a 99 Pajero for a customer he said we could do it as it was pre 2000 build (not sure what this has to do with it, probably adrs at the time ), the airbag sensors were in the body. and the type of sensor it was. but i'm in nsw . Not sure if this helps you as it aint a 2006 jimny.

thanks guys, all the information helps..

I have tried to contact suzuki, so hopefully they get back to me at some stage to clear things up!

Steve no thats not what i meant adding suspension lift is far more complex than a body lift due to the added "corrections" required to have a funtioning system.

As you stated depending on the size, type, way you lift the suspension an equal bump stop mod must be performed.

What i meant was i would rather modify the suspension correctly to be able to run the tires desired rather than perform a modification that may compromise an integral part of the vehicles function.

For instance if a 2" coil spacer is fitted either the the shock mounts must compensate for the height increase or a longer shock must be fitted and the bump stop must be lowered 2" to match.

The above scenario results in a suspension that is 2" higher yet can also facilitate a larger tire due to the correctly applied bump stop adjustment.

I guess my point is if that you're already at, say, 2" of suspension lift (and 2" bumpstop spacing) then a BL is a far better option than trying to go to 4" of suspension lift.

I think I'd rather BL a new jimny than run 4" suspension lift (so long as the legality can be resolved)

Steve.

I agree with you Steve on the merits of a body lift.

I just to not agree with the effect a body lift may impose on such a new vehicle.

If it were mine i would stick to a sensible off-the shelf lift and decent tires and drive accordingly.

There is no real issue with a body lift as I see it. Air bag sensors work on magnetic switch. For the amount of force required to open the two magnets inside the sensor block to activate the system has to remain the same to be legal. Hence ARB etc having to engineer the hell out of their bars. 'Cause if the new bull bar on impact gave a bigger inital jar to the vehicle than the original bumber, (as original absorbs more of the impact) the magnets would open ealier and cause the bag to be triggered too early causing injury.
With a body lift, the impact and crush force to activate these switches will not change. I have seen many cars that I have towed in thinking, why didn't the bag go off, car looks rooted. This is because they have to be hit square on for the bag to go off. Most airbag sensors are mounted on the radiator support panel, except for side curtains..

Hope this helps Chris72.