blonde_man
05-01-2001, 11:35 PM
This is appealing to me because I have my rear konis set pretty stiff (not the stiffest) and it is not real comfortable. In fact my WRX sport tuned stock suspension is way more comfortable than the SVX now. I thought about a rear strut tower, but the rear deck seems enough. I was thinking about stiffening it further by having tubing welded crossways just behind the rear seat, attaching from the strut tower top to the center of the floor (diagonal) This is a setup used on the Cobb tuning WRX used for Autocrossing.
If you install the Koni's and stiffer (GC) springs in your. You probably would benefit from stiffening up your frame.
Originally posted last year over at the Yahoo SVX Club(http://www.subaru-svx.net/archive/article.php?message=26350):
I just read something VERY interesting in the latest Sport Compact Car magazine (June 2000) that addresses this concern.
In their "Projext 300ZX TT" article (pages 236-242) they talk about stiffening the chasis, "In any high performance car, it is impossible to make the chassis too stiff. The stiffer the chassis, the higher it's 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 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."
So stiffening the chassis must be difficult and expensive huh? No not at all. SCC found a simple and inexpensive way of stiffening the body. They "injected the chassis with catalyzed rigid strutural polyurethan foam. Structural foam, in the 2lb per cubic foot density, that we used, can stiffen the chassis members up to 40 percent. Higher densities of foam can increse stiffness by up to 300 percent. 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 other premium cars. In fact, the foam we chose is the foam recommended to repair damaged Q45s."
Just get the magazine. The article has too much to type. In short they "were amazed at how this simple procedure improved the performance of the car." They claimed that "the chassis now almost feels like it has a roll cage!!! Even though the Z already has a pretty tight chassis, it feels more solid. The ride has been improved and road noise has been reduced noticeably. If you even just want a smoother ride, foaming is a worthy, easy to do modification."
Foamseal is the name of the product they used. They warned against using the cheap hardware store alternative, because it won't dry, and it isn't endorsed by I-CAR (national cerification group for quality auto repair). FOAMSEAL's kit uses a two-part catalyzed polyurethane foam, that quickly cures into a rigid, waterproof, closed cell foam.
It takes some some prep work to get the car ready for the work. The foam is nasty stuff if you get it on paint, interior pieces or your skin. It's IMPOSSIBLE to clean off anything. So remove and tape everthing, and wear old clothes and gloves. They injected the foam into the rocker panels and frame rails of their Project Z through existing bolt and drain holes. It quickly expands to fill the empty space, and begins to cure in about a minute. So you have to work quick and put in just the right amount.
They filled all of the Z's unibody frame members using 5 foam kits. Also, make sure you relocate all the wires and lines going through the chassis, or they will be entombed forever.
That's about it. It all sounds pretty logical. The stiffer suspension made the chassis the weak point, so it (and you) gets beat on. Stiffen the chassis, and the suspension has to do the work just like it was supposed to! Get the issue for more info. If this sounds like too much work for you, I'm sure any body shop could do it easily enough, since they all should be familiar with the product already.
I'm definitely going to FOAMSEAL my car, unless IMP will retool custom parts to redo the entire body. I don't know about that one!
Sorry this was so long, but I hope it helps!
If you install the Koni's and stiffer (GC) springs in your. You probably would benefit from stiffening up your frame.
Originally posted last year over at the Yahoo SVX Club(http://www.subaru-svx.net/archive/article.php?message=26350):
I just read something VERY interesting in the latest Sport Compact Car magazine (June 2000) that addresses this concern.
In their "Projext 300ZX TT" article (pages 236-242) they talk about stiffening the chasis, "In any high performance car, it is impossible to make the chassis too stiff. The stiffer the chassis, the higher it's 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 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."
So stiffening the chassis must be difficult and expensive huh? No not at all. SCC found a simple and inexpensive way of stiffening the body. They "injected the chassis with catalyzed rigid strutural polyurethan foam. Structural foam, in the 2lb per cubic foot density, that we used, can stiffen the chassis members up to 40 percent. Higher densities of foam can increse stiffness by up to 300 percent. 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 other premium cars. In fact, the foam we chose is the foam recommended to repair damaged Q45s."
Just get the magazine. The article has too much to type. In short they "were amazed at how this simple procedure improved the performance of the car." They claimed that "the chassis now almost feels like it has a roll cage!!! Even though the Z already has a pretty tight chassis, it feels more solid. The ride has been improved and road noise has been reduced noticeably. If you even just want a smoother ride, foaming is a worthy, easy to do modification."
Foamseal is the name of the product they used. They warned against using the cheap hardware store alternative, because it won't dry, and it isn't endorsed by I-CAR (national cerification group for quality auto repair). FOAMSEAL's kit uses a two-part catalyzed polyurethane foam, that quickly cures into a rigid, waterproof, closed cell foam.
It takes some some prep work to get the car ready for the work. The foam is nasty stuff if you get it on paint, interior pieces or your skin. It's IMPOSSIBLE to clean off anything. So remove and tape everthing, and wear old clothes and gloves. They injected the foam into the rocker panels and frame rails of their Project Z through existing bolt and drain holes. It quickly expands to fill the empty space, and begins to cure in about a minute. So you have to work quick and put in just the right amount.
They filled all of the Z's unibody frame members using 5 foam kits. Also, make sure you relocate all the wires and lines going through the chassis, or they will be entombed forever.
That's about it. It all sounds pretty logical. The stiffer suspension made the chassis the weak point, so it (and you) gets beat on. Stiffen the chassis, and the suspension has to do the work just like it was supposed to! Get the issue for more info. If this sounds like too much work for you, I'm sure any body shop could do it easily enough, since they all should be familiar with the product already.
I'm definitely going to FOAMSEAL my car, unless IMP will retool custom parts to redo the entire body. I don't know about that one!
Sorry this was so long, but I hope it helps!