Roll Cages - Myths And Fallacies

[Beer Baron]

yes, turn 1 at ec is the widow maker. you must have some nice balls to be sideways at 208kph! the inside wall is mighty close to the track there, and plenty of people far more talented than me have hit it... hard.

I've seen up close what it did to my friends GT3 cup car and bear in mind this car has a fully integrated cage installed at the porsche motor sport factory. it was nicely rooted and unrepairable.

[ferni]

Thats only because it does.

Basically lateral acceleration increase with the square of velocity. basically acceleration = velocity squared dvided by corner radius. So if you are doing, say 160km/h (44.4 metres per second) through Suzuka 140R you get:

Acceleration = 44.4 squared/140

Acceleration = 14.1metres per second squared

Acceleration = 1.438 gees.

Same sum for 161km/h gives 1.456 gees.

Finding 1.27% more grip is a MASSIVE gain in a race car.

Which is why you need to bust your arse to do even 1kmk/h quicker through a corner than the next bloke. By the way the reason you can tell people are spanking themselves when talking about silly cornering speed is as follows.

Say we are doing 1 minute laps of a 1 mile long circuit.

This means we are doing 60mph, obviously.

If we do 61 mph the lap time reduces to 59 seconds.

So if some nugget tells you of a heroic speed through a corner you may suggest, in the words of Dave Allen: "Stop it or you'll go blind."

Ahhhh see my problem was i was pre-occupied with hanging on for dear life i couldn't get the calculator out

hahah naa thats good to know, but i don't really follow where the figures came from what is Suzuka 140R? wheres the 140 come from

and how did you get from

Acceleration = 14.1metres per second squared

to

Acceleration = 1.438 gees.

[Adz]

Troy,

Points taken.

It was turn 10 and EC not turn 1. Havent drifted turn 1 but that would be hella fast.

[Beer Baron]

holy shit! how you do manage to drift turn 10 at 208kph?! that is a mighty impressive effort. even a V8 SC is taking turn 1 at around 200kph and it's the fastest turn on the track.

[Adz]

Na na na its not exaclty like the car is maintaing 200 kph around the corner. The car induces its slide in to/prior the corner at 200kmh.

[Roy]

Does the drift box tell you what your actual corner speed is? It doesnt really matter for the sake of this chat, but often wondered just how quick they are going when they are fryign 3rd and 4th gear through bends. Wheel speed has to be around the 160-180km/h, but often wondered what the actual road speed was?

At the end of the day...i woudl think that the average drift guy will be beding his car more often then the average track guy...there are hundred of pointless cases where we could discuss the pros and cons.

Best bet is to weight up your needs and what you do with your car. Its corners like turn 1 at EC and the final turn onto the straight at PI that is makign me heavily consider a CAMS/FIA approved half cage for my R32. Thats me. Others will be different. Point is next month we can come along with our questions and get the whole story and how it impacts what you can do with your car

[djr81]

Ahhhh see my problem was i was pre-occupied with hanging on for dear life i couldn't get the calculator out

hahah naa thats good to know, but i don't really follow where the figures came from what is Suzuka 140R? wheres the 140 come from

and how did you get from

Acceleration = 14.1metres per second squared

to

Acceleration = 1.438 gees.

The 140R corner at Suzuka is a fairly famous & hairy corner that as of last year was taken flat in an F1 car - sort of destroyed the mistique really. It is named because its radius is 140 metres.

How did I get from one to the other? Well the accelration due to gravity is 9.81 metres per second squared. So if you chuck yourself off a building one second later you will be doing 9.81 metres per second, or about 35km/h. One gee is the same acceleration as that due to gravity. It is just a bit more user friendly is all.

[djr81]

Does the drift box tell you what your actual corner speed is? It doesnt really matter for the sake of this chat, but often wondered just how quick they are going when they are fryign 3rd and 4th gear through bends. Wheel speed has to be around the 260-280km/h, but often wondered what the actual road speed was?

At the end of the day...i woudl think that the average drift guy will be beding his car more often then the average track guy...there are hundred of pointless cases where we could discuss the pros and cons.

Best bet is to weight up your needs and what you do with your car. Its corners like turn 1 at EC and the final turn onto the straight at PI that is makign me heavily consider a CAMS/FIA approved half cage for my R32. Thats me. Others will be different. Point is next month we can come along with our questions and get the whole story and how it impacts what you can do with your car

The drift box is really just a GPS system. It works out your speed by working out the change in latitude & longitude as you drive around. Hence it is independent of wheelspeed. The downside of this is you cannot then detect wheelspin via the data log. Which limits its usefullness for people not wanting to drift.

The most common serious damage I see to cars is when they slide off the track sideways. I have seen a couple of people do this on sprint days, but oddly never seen a drift car turn turtle. It is actually quite surprising how slowly you can slide off the track sideways & still end up upside down. I think the sprint guys tend to do it more often because they are carrying more speed through the turns & particularly on corner exit - which is where some people get sideways & run out of talent to coin a phrase.

If you think about it properly a sprint car should always be going quicker than a drift car simply because it is using all of the tyre available grip whereas a drift car wont be because the driver is intent on getting wheelspin. Sliding friction < static friction. Immutable law of nature & pretty hard to argue against.

[ferni]

If you think about it properly a sprint car should always be going quicker than a drift car simply because it is using all of the tyre available grip whereas a drift car wont be because the driver is intent on getting wheelspin. Sliding friction < static friction. Immutable law of nature & pretty hard to argue against.

Exactly.

And your previous answer about gravity 9.8m/s makes sense now... i should of realised.

[Roy]

So guys, this is happeneing this coming meeting.

After cheating a big accident at Sandown im mor ethen ever looking at getting something sorted for my car.

[Roy]

Dont forget tonight, i fyou want to know anything about roll cages then tonights is the night to get the facts

[Russman]

Bummer I'm not there again... I'll be picking your brain sometime in the future Bris.

[Al]

Fark this rental bullshit, i totally forgot about the meeting

[R31Nismoid]

Great work Troy.

The best speaker we have ever had at a meeting without a doubt.

Maybe because i was interested totally in the topics and info, but it was the best ive heard.

Thanks for organising it mate.

[JAGR33]

Totally agree, was very informative and has answered a lot of questions I had on roll cages in street cars..

Looks like I'll be visiting Brown Davis very soon....

[R31Nismoid]

If the Bris doesnt organise a group buy.

Then im willing to organise it.

I would suspect after a cost approx $750 with removeable bars and stuff... That will sell people instantly.

And thats a Roadworthy cage to boot (as long as you get an engineers cert @ around $550)

Cant beat a basic cage, installed, legalised for under $1500

The cost vs benefit... probably the best value i have ever seen :sorcerer:

[Ronin 09]

did someone say brown davis???

:sorcerer:

[Do-Luck]

Agree with Ash. Thanks heaps for organising it Troy.

Definately learnt a lot of facts about legalities, and construction of cages and so forth.

I'll definately be putting a half cage in my car now, particularly that it's pretty inexpensive, offers more protection, and is both CAMS and Vicroads compliant.

[R31Nismoid]

Marcus (and others) is that the GTR he was talking about?

I forget the guys name already

[JAGR33]

Marcus (and others) is that the GTR he was talking about?

I forget the guys name already

Yep, that's Drew Jorgenson's car...

That cage is a work of art...