custom subframes (cross members)

[7thgear]

The impreza has a small market, mainly for the pro racers and rally guys

but i'm wondering who will be the first to start producing these for the FRS

they are lighter, stronger, and allow you to relocate the inner pivot points of control arms and what not

[Anthony]

What would be the advantage of relocating the control arms?

[7thgear]

Originally Posted by Anthony

What would be the advantage of relocating the control arms?

same idea as the drop spindles/roll correction components

you get to drop the car while maintaing OEM geometry

[Anthony]

Ah, ok. I'd be sold on it just from the weight and strength benefits alone, assuming they were what I'd consider a good cost:benefit.

[7thgear]

Originally Posted by Anthony

Ah, ok. I'd be sold on it just from the weight and strength benefits alone, assuming they were what I'd consider a good cost:benefit.

you're probably looking at 1200-1500 per end, depending on who builds one and how quickly they do it.

i have seen documented step-by-step rocesses of people building these, it's not rocket science and if you keep it simple anyone that can weld would be able to make one.

MSI is the most well know for Subaru's (but also stupid pricey), they claim 50% weight reduction over OEM.

i'd post a link but i'm worried the mods are gonna hachiroku on my ass. You can google em, "MSI Impreza Rear Subframe" for more info.

[Turbowned]

Do want!! Thought about getting one to replace the rusting subframe on my STi.

[Anthony]

Originally Posted by 7thgear

you're probably looking at 1200-1500 per end...

Oooph! Maybe later...

[wparsons]

Giving multiple attachment points for the upper control arm also lets you tweak the camber curve as well, which can be a huge benefit to matching the curve to your suspension travel and spring rate.

A longer arm with the inner pivot further inboard will keep the same alignment, but give less camber gain, a shorter arm with the inner pivot further outboard will give more camber gain.

[solidONE]

I'm sure when the SCCA production racing guys (or any other amateur racing class that allows this) start playing with this car is when you start seeing these on the market.

[ciro]

Originally Posted by 7thgear

you're probably looking at 1200-1500 per end, depending on who builds one and how quickly they do it.

i have seen documented step-by-step rocesses of people building these, it's not rocket science and if you keep it simple anyone that can weld would be able to make one.

MSI is the most well know for Subaru's (but also stupid pricey), they claim 50% weight reduction over OEM.

i'd post a link but i'm worried the mods are gonna hachiroku on my ass. You can google em, "MSI Impreza Rear Subframe" for more info.

you could build a carbon fiber frame for that price.

[7thgear]

a frame what?

this is a rather critical part for the die hard handling enthusiast. Price isn't astronomical when you consider the benefits and the cost of all the smaller parts you would get to even come close to getting similar results.

[Anaxilus]

Originally Posted by ciro

you could build a carbon fiber frame for that price.

Don't really think so w/ that complexity and load requirements. You could certainly try but I doubt it would be safe let alone even begin to turn a profit if you could. That's assuming use of cheaper wet carbon which would likely be even heavier and more unwieldy than this piece. Dry carbon would be 4-5 times more expensive at least.

Why would you even want to? Are you trying to decrease relaibility? CF is not the answer to everything. Notice the absence of CF wheels in F1? Even Dymag's website doesn't even list CF wheels for cars anymore.

[Anthony]

Carbon fiber also flexes a lot more per thickness. To make it equally stiff, it would be so thick the weight savings wouldn't be nearly as substantial, plus the cost would go up. And yes, prepreg would be death-expensive.

[mike156]

Actually, uni-axial dry carbon with the right laminate design is stiffer then steel for a given thickness. But composites aren't about thickness anyway as, if you are smart, you fill layers of composites with super light material that simply keeps the layers spaced a certain distance apart. You would also build it as a monocoque type structure using surface loads instead of a spaceframe structure like you would with metal. But there is NO WAY IN HELL you are building a structural carbon subframe for $1200. Maybe you could overlay an OEM subframe with wet carbon for that much to make it look like a carbon subframe.


The fact that all the arm pivots are located on the subframe and not in the unibody is a BIG advantage here as you can do just about anything with geometry. Roll center, anti-squat, camber and toe curves...Everything can be changed.