X-brace?

[96TSi_Chris]

Well first off i am in no way a suspension buff, so if this questions is stupid, refrain from flaming.

Now my question is, ive looked around and couldnt find any results which means they probably dont make x braces for our cars. Im sure people who know what im talking about have seen the honda hatches w/ x-braces in the rear of the hatch which stiffens up the chassis and in turn inproves handling and straight line acceleration b/c more energy goes to the tires rather then into the frame and chassis itself. Anybody have any ideas on this b/c my rear seats are out and replaced w/ rx-7 storage bins and i was going to do the traditional strut tower brace, but a friend of mine brought this up and frankly i didnt know much about it for our cars. Any input would be great.

Chris

 

[Defiant]

Eh, DSMs aren't whippy little H-car shitboxes. Which is a lot of why the damned things weigh so much, and Hondas don't.

Still, anyone who's done it will sing to the heavens about the astounding gains, while those of us who'd never bother will say it's a waste of steel. It would serve well to make our modicum of storage space completely worthless, however- finishing the job a tower brace only begins.

 

[14.5 drift]

wow, that was almost poetic defiant.........I would agree with defiant on this. Just by installing the rear strut bar, the rigidity difference is astounding, I'd imagine any further streangth would only improve handling, how many fold is a good question......

 

[PaulPDX]

Even the benefit of strut bars is debatable. The front strut bar will probably help some... but unless you drive competitively on the track, you probably won't know the difference aside from the psychological kind. Given the weight of DSMs, rear bars are probably mostly for looks... but it shores up the rear enough to minimize some body creak. IMHO, strut bars are something one can go with or without. Not enough difference to matter. Most strut bars are improperly designed to be effective anyway. Not trianglulated. For a strut bar to really work as it should, it needs to be bolted to the firewall as well as the strut towers to make a rigid link between the bulkhead and the towers. The bars we are sold have pivot points at either ends of the bar. What's the point? The towers can still move independantly of one another, even if the movement is more limited than without the bar, it's movement nontheless.

If you dig around on the web for an OMP E36 M3 front bar, you'll see that it's a solid (i.e. no pivots). It's really a beefy hallow steel pipe welded to two metal plates/collars. Bars like this cost more to make because everything has to be precise (length of the bar, location of the bolt holes). The DSM aftermarket bars have adjust to fit pivots cheap to manufacture... poor job of bracing.

 

[IMMORTALSPYDER]

The spyder's have a x-brace built into the body.

The part numbers are 76020R and 76020L. Plus there's 2 other parts in the diagram which are supports for the braces I think. I can't remember on my car. The part numbers for them are 76070R and 76070L.

Next time I take my trunk apart I'll let you know whether they're bolt in or weld in. But I'm guessing weld in. I wonder how much Mitsubishi wants for the pieces?

 

[DSMeclipse4G63]

our cars are already stiff enough for everyday driving...very stiff, puting this in would only help if your making extrem power to flex the chassis or if your going to autocrosse. If you are going that route then a rool cage will do a much better job and will also be more funtional.
Andrew

 

[PaulPDX]

Basically what I said... and a drool cage too. :laugh:

 

[14.5 drift]

Sorry but you guys are flat out wrong, that or perhaps i happened to get one of the only low milage grandma driven sloppy chassid gsx's around. I have to say in my personel experiencs that my car benefited severly from strut bars. I can even feel it when I go sideways over a speed hump, before the car would form to the bump, now it feels like a square frame rolling over a bump if that makes any sense.


Here is my testing conclusions.

Personaly I am kind of a night owl, and often take my car out for pointless cruises at odd hours of the A.M. Right in my area their are a bunch of freeway over passes (any one in socal OC) should know what I'm talking about). There is the 55 freeway, the 22 freeway, 57 freeway, and 91 freeway all kooked together in about a 8 - 10 square mile radious. At night i would throw the car in cruise control at about 75 miles per hour keeping it at 75 through the freeway banks, not one time but many times over the passed 6 months. 75 seemed to be the point where the car was comfortable, and so was my passenger (my girlfriend likes to cruise with me through the banks). There was minimul tire squeel and marginal room for error at these speeds, but thats how fast we were going through the banks before the bars.


After the bars (bars installed correctly that is) I have been able to produce speeds 5 to 7 miles an hour faster through the same banks, with zero tire squeel and a much more confident grip and steering feedback. Turn in sharpness has increased, response has increased, and overall lateral grip, not to mention this is with a 50 dollar ebay set with all the flimsy adjustable ends. There are locking nuts for every adjustable piece so every thing is fastened very securely, and the bars feel very solid. When I first installed them I put them on just the way that fit, and the car didn't really feel that good, and the bars seemed flimsy. Once i figured out they were adjustable, i spun the rear bar so tight (preloaded it) that the brackets were nearly bending at a sit still. After I preloaded both the front and rear bars WOW!!! what a difference in handling. I live in OC california and these bars are very simple to take on and off (maybe 20 minutes to unload and take off and 30 to put back on and preload again) if you want to come test ride my car with and with out the bars, you are more than welcome.

50 dollar ebay strut bars = best 50 dollars spent on my dsm



If you havn't noticed by now I am really into the handling of my car so I notice these things alot. maybe others that dont give as much of a crap wouldn't care about an extra 7 mph through the corners but if your anal like me you probably will...........

 

[leet]

I think your gains were psychological, 14.5.

I put them on my car both before and after I had coilovers, and I noticed no difference. I left them on though, if the gains are there, they are minimal on a street car.

I would love to test out a triangulated STB, but I haven't seen any around for a DSM.

 

[jtmcinder]

Most people are not interested in the "data" from some guy's butt dyno, but very few of us have access to a skidpad and a consistent driver, so here's something to try.

Remove the front STB (if you have one).

Lift your car by the nose and then tie a string across from the top of one shock to the other. Use string that isn't elastic, but tie it nice and tight. Then lower the car back down.

If your car is/was like mine, the string is now loose.

Repeat with front STB in place (if you have one). The string does not become loose.

If merely putting the static weight of the car onto the front wheels is enough to bend the unibody, imagine what happens when you are cornering on decent tires.

Note: there is also a lot of flex at the lower half, making a lower front stress bar worth something, too. It's just hard to get any string down there to measure it.

Now, repeat the process in the rear: nothing happens at all, with or without the STB.

As to triangulated STBs ... have you looked under your hood lately? Where, exactly, were you planning for this thing to connect to the firewall? And how sure are you that our firewalls are strong enough to take this?

As to the idea that DSMs are stronger than Hondas ... I'm not so sure if you are correct. The torsional stiffness of a 2G sucks. Nothing like a WRX or Evo. And those older Civics were damned stiff, too. Let me put it this way: if you asked me which car needed all four jackstands -- a 97 TSi AWD, a 2000 WRX, a 2002 Evo8, or a 1989 Civic DX -- it would be the first one, no question.

- Jtoby

 

[leet]

Interesting point JTM. I'm going to try that tonight and see what the results are!

 

[NDgsx]

Let me put it this way: if you asked me which car needed all four jackstands -- a 97 TSi AWD, a 2000 WRX, a 2002 Evo8, or a 1989 Civic DX -- it would be the first one, no question.

- Jtoby

Being the proud owner of a 89 civic LX I must say that it also needs 4 jackstands. However I did wreck it so the body isn't in "perfect" shape
Evos are definetly more torsionally rigid than DSMs. I only use one lift point on the front to lift the whole side of the car for putting widebands in. The only DSM I can do that with is mine with the cage.

 

[cait sith]

EVO's/Sti's also have seam welded chassis (Chassii?), and a number of bracing points vs. their stock humble Cedia/Impreza platforms guys, so keep that in mind when you're comparing a econobox sports coupe to a purpose-build, performance holmogation shell.

 

[ldstang50]

Even with the stock v-brace behind the seat of the evo, they still flex. There have been many of times the inside rear wheel has come off the ground when I've been running it hard. That was all stock. The Evo also comes with two bars going across the bottom front acting as lower tie bars. I have replaced those with a cusco lower tie bar, not a HUGE difference. But it did tighten up the front end a little and gave better feedback. A few weeks later I installed a rear cusco triangle brace. It attaches itself to the top of the rear struts and then to the floor of the car with a bracket that is drilled throught the floor and held in with 2, 14mm nuts. That I will tell you, made a big difference. The torsion flex in the rear is almost none now. I'm really looking forward to this winter when I more than likely put in my cage.

 

[Evan K.]

If you are interested in strut bars I would personally recommend the RRE bars. Solid ended rigid bars which are far superior to the bolt end/adjustable bars.
If you want to test the effectiveness of the strut bar you have or are considering stand it up straight on a hard surface(your garage floor). Put your hands at the top. Now put all your weight on it. Bounce a little if you can. Feel the flex? Now lay it down flat with the ends supported on cinder blocks. Push with as much force as you can on the middle. Again note the flex ( if any). If it flexes make a fishing pole out of it Put something better on instead.
My personal experience is order of importance:
-Rear bar
-Lower front bar
-Upper front bar
With a quality set of tie bars you can't not notice the improvement.

As a test (mentioned earlier) try jacking your car up. Stock 2g DSMs will require a lot of jacking to get the side of the car up using only the front jacking point, if you can do it at all. This is due to all the chassis flex. With a well tied chassis it becomes an easy task.

 

[ldstang50]

I agree with the above except for the laying it on the floor and pressing in the middle. Have you ever pressed on a titanium strut bar that goes in the Evo's? The flex in the middle. The strut bar is meant to stop the flexing of the strut towers during cornering. That is why its so important to have the third attachment on the frame or firewall. The titanium strut brace might bend in the middle but when it comes to torsional flection it is very very rigid.

 

[jtmcinder]

You guys know that an upper STB is only meant to keep the outside-of-the-turn upper suspension points from moving outwards when cornering -- i.e., they're under tension when working -- such that whether it bends in the middle when you sit on it is totally irrelevant, right?

- Jtoby

 

[ldstang50]

You guys know that an upper STB is only meant to keep the outside-of-the-turn upper suspension points from moving outwards when cornering -- i.e., they're under tension when working -- such that whether it bends in the middle when you sit on it is totally irrelevant, right?

- Jtoby

jtmcinder. thats the point i was trying to make. i noticed that the titanium strut braces flex in the middle. but thats irrellevant. The STB is to keep the shock towers in place. They are basically useless without the the third point to attach to. The tower under pressure with a STB on it but no third attachment point will put all its pressure on the other tower, thus allowing for some flection. The third point on the frame will absorb the pressure cause its a 'non-moving' point thus adding to structural rigidty

 

[ldstang50]

You guys know that an upper STB is only meant to keep the outside-of-the-turn upper suspension points from moving outwards when cornering -- i.e., they're under tension when working -- such that whether it bends in the middle when you sit on it is totally irrelevant, right?

- Jtoby

jtmcinder. thats the point i was trying to make. i noticed that the titanium strut braces flex in the middle. but thats irrellevant. The STB is to keep the shock towers in place. They are basically useless without the the third point to attach to. The tower under pressure with a STB on it but no third attachment point will put all its pressure on the other tower, thus allowing for some flection. The third point on the frame will absorb the pressure cause its a 'non-moving' point thus adding to structural rigidty

 

[ldstang50]

You guys know that an upper STB is only meant to keep the outside-of-the-turn upper suspension points from moving outwards when cornering -- i.e., they're under tension when working -- such that whether it bends in the middle when you sit on it is totally irrelevant, right?

- Jtoby

jtmcinder. thats the point i was trying to make. i noticed that the titanium strut braces flex in the middle. but thats irrellevant. The STB is to keep the shock towers in place. They are basically useless without the the third point to attach to. The tower under pressure with a STB on it but no third attachment point will put all its pressure on the other tower, thus allowing for some movement of the towers. The third point on the frame will absorb the pressure cause its a 'non-moving' point thus adding to structural rigidty

 

[jtmcinder]

"Useless" is way too strong a term to use when describing non-triangulated STBs.

What these bars are designed to prevent is the upper end of the outside-of-the-turn suspension from bending outwards (under the inwards force on the lower end). There is very little force on the inside-of-the-turn suspension. So, by connecting the upper ends together, you are effectively giving twice the strength to the outside-of-the-turn suspension ... it's own strength plus the other side's strength.

Yeah, sure, triangulated would be stronger, but here I first have to ask a question: do you really have the lateral grip to make the added strength of triangulated (over plain) STBs useful? Unless you're on R-compounds with decent shocks and springs, I doubt it. And even if you do have the grip to make triangulated useful, there are two other issues to consider: is there a good place for the triangulation to mount? and do the rules under which you compete allow this? In the front of a 2G, there's nowhere to put the chassis point. In the rear of a 2G, you don't need triangulation. And, if you're doing this because you autocross, then take note that triangulation is illegal in Stock, Street Prepared, and Street Modified; a full X-brace will bump you to F/Prepared. And lot's-a-luck there!

- Jtoby

 

[ldstang50]

The 2pt STB will not deflect as much flexion as the 3pt will. Just like a 6pt cage will allow more rigidty than a 4pt cage. But you're right the 2pc still offers deflection. As far as mounting points on the firewall of a 2g, you would have to make them. My car came with a front and lower STB stock, granted I dont' have a technical DSM, its still has a 4g63 damn it!!! Anyways, as far as daily driving is considered, no one would notice a difference between a 2pt and a 3pt STB. But the people that drive autocross (maybe not SCCA) will notice a difference given they have some gumball tires on there. I know I noticed a BIG difference when i put my rear triangle brace in vs just the bar. I have yet to run without the front STB yet. Granted I am using Dunlop SP Sport FM901. They have a LOT of stickiness to them. As far as street tires for the money I have not found a tire even close to it for performance per dollar. Tires, suspension and components all compliment each other given the right set up.

 

[Evan K.]

You guys know that an upper STB is only meant to keep the outside-of-the-turn upper suspension points from moving outwards when cornering -- i.e., they're under tension when working -- such that whether it bends in the middle when you sit on it is totally irrelevant, right?

- Jtoby

My only reason for suggesting that form of a flex test was so that some of the readers who might not be able to stand the bar on end might have an alternate method to check their bar(s). You are correct and I should have been more clear in my explanation.

 

[Revolution]

Are you by any chance refering to the x brace wich bolts up inside you'r cabin bay?
This x brace bolts in using the driver and passenger side top mounted seat belt bolts then connect to another bar wich is bolted into the rear top mount seatbelt bolts. Now correct me if im wrong but that same bar has a flange for the cockpit bars and another set of bars that bolt into the trunk area , thus creating an x shape.

I've heard of those bars and personall I would buy them a because i dont have rear seats and two because theirs nothing wrong with making the car more rigid.

But how more rigid is the question , is it worth the extra weight?

I'll try and find the company name but , I have seen quite a few auto cross cars have them.

 

[96TSi_Chris]

Are you by any chance refering to the x brace wich bolts up inside you'r cabin bay?
This x brace bolts in using the driver and passenger side top mounted seat belt bolts then connect to another bar wich is bolted into the rear top mount seatbelt bolts. Now correct me if im wrong but that same bar has a flange for the cockpit bars and another set of bars that bolt into the trunk area , thus creating an x shape.

I've heard of those bars and personall I would buy them a because i dont have rear seats and two because theirs nothing wrong with making the car more rigid.

But how more rigid is the question , is it worth the extra weight?

I'll try and find the company name but , I have seen quite a few auto cross cars have them.

Ah yes sir, you are correct, thats exactly what i was talking about. It just seems like w/ my FWD, the back of the car seems "loose" when cornering or launching. Ive seen em in autocross cars and thats exactly what i was wondering. I just want to know if its worth fabbing up or if someone makes em.