Chassis Brace Theory Q...

[formeRiceR]

so recently I've formed an obsession on bracing:

I'm sure you've seem my posts on Foam, Spot welding, and etc.

my question today:

would it be useful or worth the trouble (time & money) of bracing the frame before the front struts (ie radiator area) or bracing after the rear struts (ie trunk area) will that help at all????

other than the obivous of better handling what other bebnefits are thee to stiffening up the chassis?
thanks again:w00t:

[krustindumm]

nismo power brace has proven that bracing in front of the struts helps, i'd imagine the same theory could be applied to the rear. my only semi-logical argument for this is that the flexing occurs at suspension mounting points, so the further you get from them, the greater the change. The brace will have a leverage advantage to be further from the point of the force, but, it will be ineffective in stopping the deflection if it is too far away.

If you are so keen on reducing chassis flex though, why not just go to a full cage that ties into the mounting points.

[McRussellPants]

Nismo Power Brace, Inner Fender Braces, Strut Tower, Good Cage.


Done and Done, don't waste money on shit tons of hinged bars, if you really want to get ritzy reinforce your subframe and such.

[formeRiceR]

so this will be a street car so having a cage in there is not going to happen, I will not be wearing a helmet 24/7 and I don't want my head sheared off in the event of an accident. I was wondering what are my other options other than a full cage. Rigidity without compromising saftey.

[Dousan_PG]

4 point cage w/ side bars is fine for the street

other then that what McRussell said.

[kandyflip445]

RXB is better than STBS.

[swifty949]

I have always been interested in the NAMS and Do Luck stuff. I'd like to get it all some day

EDIT: This is Big Bad BH Brian Harte

[91gst]

to stiffen the chassis dont waste your money on any kind of strut bar or lower tie bar that has hinges because those just flex with the car. get something that is solid like the carbing strut tower bars or dc sports.

[reflexdb]

the only real reason that you would need to stiffen the chassis is if you thought that the chassis was flexing while you were driving. it won't be flexing much unless you are driving hard (say, at a track). One of the ways that you might arrive at the conclusion that your chassis is flexing is if you make suspension adjustments to correct for handling problems that should work, but they do not work. overall, i would say that for street use, the chassis is prob plenty stiff enough without additional bracing.

[ThatGuy]

Do you really need to start a new thread everytime you come up with a new idea about bracing? Wouldn't one thread have been enough, and then you could just add your questions as they came to you?

[phreze]

Do you really need to start a new thread everytime you come up with a new idea about bracing? Wouldn't one thread have been enough, and then you could just add your questions as they came to you?

I was thinking the same thing, maybe a nice mod can put them all in one place?

Any reason why sway bars have not been mentioned or are they not considered to be chasis bracing? Those seem to be beter on the car then strut tower bars. Althought the carbring does look like a nice piece and a rear strut bar is very helpfull on fastbacks.

[reflexdb]

sway bars are not chassis bracing. they are suspension links.

[pablo180]

would it be useful or worth the trouble (time & money) of bracing the frame before the front struts (ie radiator area) or bracing after the rear struts (ie trunk area) will that help at all????

other than the obivous of better handling what other bebnefits are thee to stiffening up the chassis?


It depends totally on the type of racing that you are going to do. Since this is going to be a street car then most of the mods that you have already should be more than enough. But if you are obsessed then you would want to stiffen up the whole chassis as much as possible. Think of the chassis as a spring. If you can get the chassis stiff enough you can neglect the effects of torsion on the chassis when choosing a suspension to ride on.

[formeRiceR]

that's a good idea.... will do sir:bigok:


Do you really need to start a new thread everytime you come up with a new idea about bracing? Wouldn't one thread have been enough, and then you could just add your questions as they came to you?

I've also been wondering the "roll" in rollcage. is that for eliminating roll in the car or for safety when you car rolls. Also this will be driven on the road, but mostly will be used for spirited driving and sanctioned events (Auto-X). I was looking into a roll bar (4-point), I know there are 3 options: Autopower, Cusco, and Custom.

Do these bars help that much stiffness? Which offers the most safety? Can I use them at Auto-X????

[ManoNegra]

overall, i would say that for street use, the chassis is prob plenty stiff enough without additional bracing.

For S14s perhaps, S13s on the other other hand are like arthritic creaky old men.

[crazy9ceguy]

i just installed the nismo power brace today and wow what a difference in the steering response, its much more crisp, so crazy.

[1Via!]

Nismo Power Brace, Inner Fender Braces, Strut Tower, Good Cage.


Done and Done, don't waste money on shit tons of hinged bars, if you really want to get ritzy reinforce your subframe and such.
He speaks the truth.

Any bracing beyond this probably isnt needed.

Front end bracing(as suggested) is always a good idea for s-chassis no matter what you're doing. These front ends are floppy as fuck. I've a power power brace, strut bar, shakitto plates and some custom fender braces on the way, and I can say that all these braces respectively make a marked improvement in general handling and response.

Bracing the rear of the chassis is best left to a cage or roll bar(weld them please). Buying trunk brace and underchassis bracing isnt as cost effective as even a custom cage would be.

[formeRiceR]

custom fender braces that sounds interesting, did you fab them up yourself, any pics???

He speaks the truth.

Any bracing beyond this probably isnt needed.

Front end bracing(as suggested) is always a good idea for s-chassis no matter what you're doing. These front ends are floppy as fuck. I've a power power brace, strut bar, shakitto plates and some custom fender braces on the way, and I can say that all these braces respectively make a marked improvement in general handling and response.

Bracing the rear of the chassis is best left to a cage or roll bar(weld them please). Buying trunk brace and underchassis bracing isnt as cost effective as even a custom cage would be.

[91gst]

the only real reason that you would need to stiffen the chassis is if you thought that the chassis was flexing while you were driving. it won't be flexing much unless you are driving hard (say, at a track). One of the ways that you might arrive at the conclusion that your chassis is flexing is if you make suspension adjustments to correct for handling problems that should work, but they do not work. overall, i would say that for street use, the chassis is prob plenty stiff enough without additional bracing.


i dont know about that, a s13 hatch's chassis has a lot of open space inside of the car. especially if your car has a moon roof you lose some rigidity. when i pull my car in the driveway sharply from the street going about 2mph i can hear the moon roof lift a bit, so i know the chassis is flexing. my car however is completely stock so i guess that is expected but still i think any stock car can use some bracing (i.e. strut bars etc) if you do "spirited driving".

[radhaz]

Is there any feasible way to quantify the gains made by any one piece of chassis bracing?

I love my butt dyno and take it everywhere I go but to be honest I've never really calibrated it to ensure the system is within specifications. In fact if you ask my friends and coworkers they might even say it's out of tolerance and emits strange random odors that are quite unpleasant.

Uhm so back on topic, would an actual skid pad work for quantitive measurements? Does anyone have actual experience in this field that could shed some light on the topic for me?

[kandyflip445]

For me, I installed braces to get rid of squeaks and noises. lol It's worked so far and the driving feel (butt dyno) is better to me. I dunno about anyone else.

[formeRiceR]

bump for the Autopower / Cusco safety question... The reason I ask is because I've searched the forum I've been getting mixed answers and it seems like people are saying that they both suck...

I was watching some old videos and I saw a s13 flip and pretty much flattened like a pancake ... it's got me all frazzled....

[EchoOfSilence]

Cusco isn't SCCA legal, Autopower is. think about it

[Chrischeezer]

I have a weld-in/bolt-in 6 point cage rdy to go in...(300 bucks shipped on eBay)
-it has the main hoop the harness bar across two bars going to the rear strut towers, two bars running right next to the seats going as far forward as they can. and a diagonal support bar that runs across the two rear bars. I know for a fact its going to stiffen the crap out the car. think of how many ways the car flexes and moves inside and out... Inside has absolutely nothing to prevent the cars "flex" (but that's the way cars are made, perfectly normal) by adding an internal structure, that's solid, will generate smaller movements of the cars body if not preventing it all.

-another thing... i have a C piller bar and a front and rear strut tower bars. all ebay. by welding up the "joints" of these bars it made a noticeable differance...
-i too, sware by the nismo power brace.. good quality piece.

[formeRiceR]

-another thing... i have a C piller bar and a front and rear strut tower bars. all ebay. by welding up the "joints" of these bars it made a noticeable differance...
-i too, sware by the nismo power brace.. good quality piece.

That sound like a good idea:bigok:

[formeRiceR]

not to bring this thread back from the dead, but I heard that bolt-on roll bar kits don't do much to stiffen up the chassis because they are linked to weak parts of the chassis. is this true? how else can I stiffen up the back, would it be viable to weld the roll bar plates?

[chmercer]

roll bars are saftey devices, not strut bars. saftey.

[formeRiceR]

Cusco isn't SCCA legal, Autopower is. think about it


Cusco is made of Chrome-moly and Autopower is made of DOM.....

"Chrome-Moly is stronger than DOM and DOM is stronger than ERW" says the IO Port site...

[RalliartRsX]

Personally, I wouldnt get any bolt in cage.

Second, there is no way in hell I am running a cage on a street driven car!! The cage itself poses a safety issue if in an accident to occur on the street. Padding or not, if you hit your head on one of those bars, your certain to have a very serious concusion (thats unless you like wearing a helmet to the grocery store and back).

Weld/bolt in roll bars on the other hand, is not such a bad idea for the street as pretty much it acts like rollover protection and the bars arent as intrusive. Think about function from the point of verts like the SLK, miata, etc.

As far as bracing, it seems things like strut bars,c pillar bars, floor braces and the sorts dont have a real serious effect on handling. Feel, maybe, but I would prefer to spend my money on good tires, proper lightweight wheels and real damn good spring/damper combo and a real good alignment. But however, some braces like the tunnel brace and nismo power brace seems to have proven to yield acceptable results in chassis stiffening. If you want it done correctly, just weld various seems around the car. Thats probably your best (and in some cases cheaper) bet. Perfect example of this is comparing a regular Integra gsr to a type-r. The type r has various intricacies of chassis bracing in the rear and other parts as well as a more agressive damper setup and tires and it has to be one of the best front drive (if not overall) handlings cars still produced today (atleast, the DC chassis variants)

[EchoOfSilence]

Cusco is made of Chrome-moly and Autopower is made of DOM.....

"Chrome-Moly is stronger than DOM and DOM is stronger than ERW" says the IO Port site...
Yeah, it's stronger, but at what thicknesses? the Cusco bars are small diameter while the DOM bars are larger. That's more important