Install a Kirk racing 2.0 inches DOM roll bar. It's 70lbs.

I had problem with hatch squeaks so I replaced hinges, stoppers, lock mounting point to no avail.

The roll bar solved all that and now I can feel the rear suspension working w/o the hatch squeaking!!!

Next on my list is this under body chassis brace.

 

Here's the link to Cork Sport chassi brace:

http://www.corksport.com/main.php3?p...3Fcat%3D214925

 

I think this is the link to the chassis support:

http://www.corksport.com/main.php3?p...3Fcat%3D214926

 

NICE!

 

I did not notice the chassis stiffening up when I installed a Kirk Racing rollbar. But I did notice a major difference when I installed a U-Haul hitch.

 

mazdaspeed has those chassis braces also. jason at jt-imports.com can get them. i want them badly

 

yeah.. i should be getting my Kirk bar also and was also looking at the chassis brace.. but man.. the weight just keeps goin up!!

 

Does anyone have those chassis braces? It looks like they would possibly help, but I am not yet convinced they would make a major difference.

A cage is a 3D object that would help a ton, by resisting the twisting in 3 dimensions. But these braces are only a 2D object, i.e.- they look like they are laid out in a plane. They should help the plane to not twist, but they won't make as much difference as braces that lie outside the plane, e.g.- the cage.

Any experience?

Cheers,

Steve

 

No experience with these in an FD, but I did have a brace simular in an M3. It actually helped quite a bit. I think the 4 pt bar would help some but obviously the 6 pt cage would be even better.

 

What's the weight on the chassis brace?

 

They are slightly different in design.
http://www.jt-imports.com/MAZDASPEED_body_stifeners.jpg

Just from the pictures, it seems that the AUTO-EXE one would be more effective than the Mazdaspeed one.

 

This maybe alittle of subject but when I had my Del Sol with the roof off you could really feel the frame twist and move going over rail road tracks or around corners. What I did was injected the frame and alot of hollow spaces with a special foam that hardens after it mixed. It was a night and day differance and only cost about $80. The car didn't feel like a wet noddle any more.
Sport compact car mag did this with one of there 300zx projects about 2-3 years ago also with good results. There is a few side affect that I did come across. 1 was draining water. It most cars there are spots where rain will collect and the drain through a hole or tube and if your not carfull you can easly plug one of these up causing water inside the car. Also the increased chance of rust from trapped water.
If you guy want so more info I'll get the name and web site.

 

I have read that article but I think it would be difficult to do on an FD.

It is a unit-body and thus there is no frame, per se, like most cars and I don't really see where you would be able to inject the foam into otherwise.

 

I haven't look yet but I'm sure there is plenty of spaces. After you start taking off fenders and strippin interior parts you"ll find lots of space. The del sol is also a uni body but uner the car the are 2 2" wide strips on each side under the car. I believe the fd has the same.

 

Perhaps...

However, the Del Sol is a econo-convertible. It is going to have ungodly amounts of chassis flex in the stock form.
On the other hand, the 3rd gen RX7 is a sports car.
Although foam injection may be able to improve the chassis rigidity of the 3rd gen RX7, the improvement will be several fold greater with the Del Sol.

 

More info on the structual foam.

http://www.sae.org/automag/globalview_03-00/04.htm

The all-steel, welded unitary body meets the world's toughest crash regulations, according to Mitsubishi, including 55-km/h (34-mph) frontal barrier, 64-km/h (40-mph) 40% offset, 55-km/h (34-mph) European/Japanese side impact, and 56-km/h (35-mph) rear-end collision. Sturdy body frames are further reinforced by inserting high-rigidity foam blocks into the frame sections, filling the cavity on application of heat during the paint-drying process. Other parts are also filled with noise-absorbing foam and urethane foam materials. A senior engineer said that the Proudia matches the world's benchmark car, the Lexus LS400, in road-noise suppression.

I thought the subject was very interesting, just thought I would pass it along.

Also the SCC article:

http://www.sportcompactcarweb.com/pr...0zx/index.html

Foam-Filling the Chassis
In any high-performance car, it is impossible to make the chassis too stiff. The stiffer the chassis, the higher its natural frequency, making the energy imparted to it by bumps less likely to excite the body's structure. A stiffer chassis enables the use of stiffer springs and shocks without hurting the ride. This is because a stiff, non-flexing chassis transfers more force into the suspension where it can be dissipated by the springs and shocks instead of transferring the force to the occupants. A stiff chassis is also more responsive to roll rate tuning for balancing understeer and oversteer. This is one of the reasons why automotive engineers are continually investigating ways to stiffen chassis without adding weight.

In a final bit of reengineering to stiffen the body, we injected the chassis with catalyzed rigid structural polyurethane foam. Structural foam, in the 2 lb per cubic foot density that we used, can stiffen chassis members up to 40 percent.

Higher densities of foam can increase stiffness by up to 300 percent. Since we cannot retool custom parts to redo the Z's body, we figured that this would be an excellent, low-cost way of greatly increasing chassis stiffness. Injecting foam is not a new technique for chassis stiffening. The Infiniti Q45 uses this sort of foam in some of its chassis members to increase stiffness, as do a few other premium cars. In fact, the foam we chose is the foam recommended to repair damaged Q45s.

To get the correct foam for our project, we contacted Art Goldman, Foamseal's automotive product manager and author of an SAE (Society of Automotive Engineers) paper on the use of structural foam for the stiffening of automotive unibody structures. We used Foamseal's two-component foam kit, p/n 11-22 to fill the main members of the chassis. Like we mentioned earlier, Foamseal is the supplier that I-CAR, a national certification group for quality auto repair, recommends for the repair of damaged, foam-filled chassis. The Foamseal kit uses a two-part catalyzed polyurethane foam, which quickly cures into rigid, waterproof, closed-cell foam. To prep the car, we carefully masked off all painted areas anywhere where the foam could drip. As this sort of foam is a thermosetting catalyzed plastic, we realized it could be icky if it spilled on paint or any part of the car's interior. This foam is nasty stuff. It is impervious to all known solvents and cleaners.

Rubber gloves must be worn. Get some of it on your hands and it will stay there for more than 3 weeks--don't ask how we know. Do not get this stuff on your paint. Wear old clothes; we ruined ours while learning how to handle the product. We injected the foam into the rocker panels and frame rails of Project Z through existing bolt and drain holes. When injected, the foam reacts like shaving cream and quickly expands to fill the empty space. You can judge how much foam to add by watching its expansion progress through some of the holes. Once injected, the foam expands and begins to cure in about a minute so you need to work fast and plan how you inject the foam before you start.

The life of the foam kit is limited to a few hours once the seal is broken. We filled all of the Z's unibody frame members using five foam kits. When foaming a chassis, you must remember the wires and other lines that pass through the chassis must be relocated or they will be entombed forever.

We were amazed at how this simple procedure improved the performance of the car. The chassis now almost feels like it has a roll cage. A sloped driveway can be driven up sideways with nary a creak. Even though the Z already has a pretty tight chassis, it feels more solid. The ride has improved and road noise has been reduced noticeably. We bet that the car will be even more responsive to chassis tuning measures in the future. If you are a slalom racer, a road racer, have a lowered car or even just want a smoother ride; foaming is a worthy, easy-to-do modification. Foamseal has foams in densities as high as 10 lbs per square foot if you desire to make things even stiffer.

Do not--I repeat--do not attempt to use cheap, hardware-store canned foam. This is not the same thing, and if injected into your chassis, will form a gummy mass that won't dry. Foamseal foam is a professional grade foam, which although it is a little unforgiving to cleanup mistakes, has superior mechanical properties and catalytic curing so it will dry even in an enclosed space.

 

I know how much ppl like sae, so here is an article from their site:
http://www.sae.org/automag/material/...1-111-4-71.pdf

 

Steve, I know that you're looking at the braces as two dimensional parts, but you have to consider that the transmission tunnel is three dimensional, and as a "hoop" in the centerline of the body, could be prone to flexing more so than other parts of the floor pan. These braces basically turn the transmission tunnel into a long, rigid, three dimensional brace by tying all the mounting points together at the rear of the car, and adding additional bracing at the front. That said, I'm pulling this straight out of my *** and don't have any real evidence to back it up, but that's my belief.

My best argument for this is that the C5 Corvette has an aluminum panel attached with 36 bolts which acts as a brace in the transmission tunnel from one end to the other. To get to the slave cylinder, you have to remove the exhaust, remove this panel, and then you expose the bellhousing, torque tube, and slave cylinder. Bleeding a slave cylinder on a C5 Corvette is therefore a 4-5 hour job, more or less.





At any rate, I just ordered one of the Cork Sport braces, so we'll find out what one weighs at the very least.

I'll probably end up chopping up the rear brace, because my Cobra 8.8" brace already covers the rear subframe, but the area in front, where the rear two cross-braces were located, I need to do something about. Not only did Grant "Jimmy Hoffa" my aluminum cross-brace for the front position, but I also need to figure out how to mount a driveshaft loop in the transmission tunnel, and that point was a perfect location. So basically I'll end up with a "box" brace that ties those four mounting points together and gives me a mounting location for a driveshaft loop. Not sure if I'll try to tie it into the Cobra cradle or not, but that would be ideal.

My cage (OK, rollbar) ties the rear floor pan cross brace to the front of the rear strut towers, so I'm covered from above as well. Since it's made of chromemoly, it only added about 40-45 lbs.

 

Update... it's a special order part, so expect about a month and a half for delivery, with a 20% non-refundable deposit up front.

Mine's ordered, I'll post updates when it shows up.

 

Sounds like a perfect opportunity for a group buy if you ask me.

 

OK, I got off my fat *** and called Derrick at Corksport and he will look into a group buy pricing for the AUTO-EXE body stiffener if we can get about 10 people or so. Please PM me or reply here if interested. LaBreck's order will be counted so we need 8 more interested parties.

Oh, in the mean time, I will aks Jason if it's OK to post a group buy thread.

Ed

 

If you look on the corksports picture, I have the brace to the right(rear subframe brace). I installed it along with a 5 pt cusco roll bar, 4.777 final gear and a Cusco LSD and the car feels so SOLID now. I'm not sure if it was the rollbar or the subframe brace, but the combo of both makes the car feel so rigid.

 

I will probably be interested in the GB as well.

 

how much weight is this stuff adding? Isnt that a big concern to performance fiends?

 

I'm interested if the GB pricing covers both the front and rear.

On another note, I got to stop spending money on this car, the economy is going down the *******, our clients are going bankrupt and our Top Gun President is pushing for a $750B tax cut (which allegedly will create 1.4 million jobs, i.e., $500,000 subsidy to create one of those jobs). Someone stop me from spending money ... please ....