C/B Pillar bars ? RICE or actually work

[fatboyz39]

People don't admit that there wrong. Blitz ii would leave it at that, we know that it works and help with body rigidity.

Here's a test, jack up the car on one side, you'll see the car flex (very notceable on old cars), then add all the bars b/c or whatever and see the difference then.

[BlitZ]

he is more real life honda examples...

http://www.honda-tech.com/zerothread?id=795829

One day I was about to get out of the car while it was raining and the passenger got out before me. When she opened the door, I saw a drop of water fall from the windshield. I couldn't belive my windshield was leaking
On another day my g/f was driving caddy-corner over a speed bump and I put my fingers where the windshield meets the headliner and it flexed as we went over the bump!!! If it was able to flex like that then there was not alot holding the windshield on at that corner. I pushed on the top of it from the inside and the whole corner moved outward about 1/8th of an inch!!! The glue holding the windshield in failed and allowed it to seperate from the car.


Another Example of windscreen cracking on track because of flex..

I cracked the windshield many years ago on my ITA CRX by hitting the berm a hard lick (Turn 13, the off-camber left hander at Mid-Ohio) and that car had a full six point weld in cage. It was one of the Kirk prebent, weld in cages. The crack was just an inch or two long at first and started on the driver's side edge about halfway up the A-pillar. As the race ran and the weak point was there, it migrated the crack a few more inches as the chassis was stressed. I am sure that it was from chassis flex even with the cage, not from a lack of flex. I know when I used to autocross my old Omni GLH Turbo and I had high autocross tire pressures and my shocks set really stiff on stock springs, when I drove the car to the hotel overnight I could windshield squeek as the chassis was flexing over the normal city streets. The suspension and tires were so stiff that they were not being compliant and transferring the need for motion to the next most compliant part- the shell of the car itself.

[Muzz]

People don't admit that there wrong. Blitz ii would leave it at that, we know that it works and help with body rigidity.

Here's a test, jack up the car on one side, you'll see the car flex (very notceable on old cars), then add all the bars b/c or whatever and see the difference then.

Roll my ****ing eyes!

I dont doubt at all that flex is seen in these members, and that bracing them would reduce it. I do doubt that reducing this flex, with a single unsupported and hinged member, in a single plane across the chassis will effect the torsionl rigidity at all. Leading me right back to the first fact i stated, this is not my opionion, it is solid fact.

So what theory, information, anything at all, do you have to support your thoughts more than my car feels stiffer, which i dont doubt at all?
Please respond to this question....

[BlitZ]

Since you are becoming an engineer.. I think this would make good discussion..

http://en.wikibooks.org/wiki/Nissan_..._Strengthening

Extract from Mr WIKI...

C-Pillar Bars

The s13 hatch in particular has a fair amount of flex in the C pillar area due to the extensive size of the rear opening. A viable upgrade would be a C pillar reinforcement bar that bolts to the rear seatbelt mounts. It should be noted that the mounts on the s13 zenki ('89-'90) are more towards the glass and the s13 chuki ('91-'94) hatchback seatbelt mounts are parallel. A solid metal bar may be economically produced by measuring the distance between the 2 points and drilling mounting holes for this model.
Note: These bracings are produced as well for coupes but in those instances tend to mainly just be cosmetic since its not a weak point for them.

doesnt meant it doesnt do zero..

[Muzz]

he is more real life honda examples...

http://www.honda-tech.com/zerothread?id=795829

One day I was about to get out of the car while it was raining and the passenger got out before me. When she opened the door, I saw a drop of water fall from the windshield. I couldn't belive my windshield was leaking
On another day my g/f was driving caddy-corner over a speed bump and I put my fingers where the windshield meets the headliner and it flexed as we went over the bump!!! If it was able to flex like that then there was not alot holding the windshield on at that corner. I pushed on the top of it from the inside and the whole corner moved outward about 1/8th of an inch!!! The glue holding the windshield in failed and allowed it to seperate from the car.


Another Example of windscreen cracking on track because of flex..

I cracked the windshield many years ago on my ITA CRX by hitting the berm a hard lick (Turn 13, the off-camber left hander at Mid-Ohio) and that car had a full six point weld in cage. It was one of the Kirk prebent, weld in cages. The crack was just an inch or two long at first and started on the driver's side edge about halfway up the A-pillar. As the race ran and the weak point was there, it migrated the crack a few more inches as the chassis was stressed. I am sure that it was from chassis flex even with the cage, not from a lack of flex. I know when I used to autocross my old Omni GLH Turbo and I had high autocross tire pressures and my shocks set really stiff on stock springs, when I drove the car to the hotel overnight I could windshield squeek as the chassis was flexing over the normal city streets. The suspension and tires were so stiff that they were not being compliant and transferring the need for motion to the next most compliant part- the shell of the car itself.

hahahahhahahhahahhahahahhahahhahahahhahahahhahahah hahahhahhahahhahahahhahhahahahhaha, a question for you mr blitz, is the windshiels in a single plane across the chassis???

You havnt answered any of my previous questions to you, this ones an easy one, go for it!

[BlitZ]

You havnt answered any of my previous questions to you, this ones an easy one, go for it!

thought it would have been pretty damn simple for an an engineeering student..

centrifugal force, forces car to move outwards.. but tyres are pulling car back in...


so u have force from to top, mid, and lower sections to move outwards...
tyres come from the bottom/mid section to pull it in... therefore you roof could potentially flex.


Seriously ... why do u think having no sunroof is better than having sun roof in a race car..
Cause the roof flexes... B pillar brace would assist the same..


Damn man.. I seriously hope an engineering student who wants to get into motorsport has a better explaination to the theroy than an IT bum

[Muzz]

Since you are becoming an engineer.. I think this would make good discussion..

http://en.wikibooks.org/wiki/Nissan_..._Strengthening

Extract from Mr WIKI...

C-Pillar Bars

The s13 hatch in particular has a fair amount of flex in the C pillar area due to the extensive size of the rear opening. A viable upgrade would be a C pillar reinforcement bar that bolts to the rear seatbelt mounts. It should be noted that the mounts on the s13 zenki ('89-'90) are more towards the glass and the s13 chuki ('91-'94) hatchback seatbelt mounts are parallel. A solid metal bar may be economically produced by measuring the distance between the 2 points and drilling mounting holes for this model.
Note: These bracings are produced as well for coupes but in those instances tend to mainly just be cosmetic since its not a weak point for them.

Wow, great find! let me repeat myself for the 3rd time now.

I dont doubt at all that flex is seen in these members, and that bracing them would reduce it. While you may be able to feel the increased stiffness I do doubt that reducing this flex, with a single unsupported and hinged member, in a single plane across the chassis will effect the torsionl rigidity at all. Leading me right back to the first fact i stated, this is not my opionion, it is solid fact.

Before going out and trying to find more information to support your views that it does infactincrease the torsional rigidity, id really love to see some skid pan testing of peak lateral g's before, and after installing a pillar brace.

Even better would be some data, of a chassis torsional resistance to twist before and after adding a pillar brace, every car designed is tested in this manner.

[Muzz]

thought it would have been pretty damn simple for an an engineeering student..

centrifugal force, forces car to move outwards.. but tyres are pulling car back in...


so u have force from to top, mid, and lower sections...
tyres come from the bottom/mid section.

Ok so the force is pushing the roof outwards, thats correct. Lets say your cornering at 1g, and the weight of the roof is 80kg, that means that there is an 80kg force pushing out on the roof. This force is combated by six seperate pillars and six windows. Yes im sure the might be a couple of mm of flex at most, which brings me right back to my point for the fourth time, ill use bold for it ok.

I dont doubt at all that flex is seen in these members, and that bracing them would reduce it. While you may be able to feel the increased stiffness I do doubt that reducing this flex, with a single unsupported and hinged member, in a single plane across the chassis will effect the torsionl rigidity at all. Leading me right back to the first fact i stated, this is not my opionion, it is solid fact.

Do you understand the concept of torsional rigidity?

[BlitZ]

Even better would be some data, of a chassis torsional resistance to twist before and after adding a pillar brace, every car designed is tested in this manner.

hahah yeah great one.. Ill just do that tonight with my GTR computer at the local carpak


It isnt all about TORSION .... there is also FLEX rigidity to take into consideration..

Stop emphasising on things and sit back and open you eyes to the bigger picture...


if you car flexes the weight transfer is mutipled.. I honestly give up...

believe what u like.. cant argue with people who doesnt want to listen

[Muzz]

Seriously ... why do u think having no sunroof is better than having sun roof in a race car..
Cause the roof flexes... B pillar brace would assist the same..

Id say its got a hell of a lot more to do with the fact that its adding weight at the highest possible point above the roll centre, rasing the centre of gravity, increasing the torque causing bodyroll, also amplifing the weight transfer between the wheels in breaking, acelerating and cornering, reducing the cars traction capacity.

[Muzz]

hahah yeah great one.. Ill just do that tonight with my GTR computer at the local carpak

Nar, youd be much better off searching for articles from SAE reguarding torsional rigidity, im sure plenty of tests and studies have been carried out reguarding bracing to resist torsional twisting.

[BlitZ]

have u heard of cars that are so powerful that they buckle their roofs...
Mine does and cracked my sunroof