TAdriver

I would like to know what you all think is the best k member for clearance and strength.

DONAIMIAN

iTrader: (18)

For clearence, all of them are going to be about the same. Strength wise, they all suck on the street.....well lest the ones that are out right now.

WS6WRX

iTrader: (1)

My BMR broke after about 6 mos.

Cal

iTrader: (1)

I second this. There isn't a good one on the market yet.

Foxxtron

iTrader: (1)

From personal experience, the ones that are currently available don't seem to handle lateral gravitational forces well. For the weight lost, there is a large tradeoff in chassis rigidity, and some will say, "who cares if it isn't really that stiff." If there has to be a decision between stiffness and kerb weight, then stiffness will be the most sound physical option, as the chassis and suspension will operate in a more consistent manner when it has to handle road imperfections (turns and road artifacts).

I know that someone again is going to say "street" not "track", and that's okay to disagree, but what I disagree with the "street" part is that "street" is usually assumed to be performance within legal limits of what public road the vehicle is being operated. As illegal as it is (regardless of being caught), someone will eventually attempt to perform a track manoeuvre on the street (which I don't endorse or encourage, btw).

As far as clearance, even if you have to sacrifice some clearance (e.g. using front mounted turbos, long tube headers, etc.) the stock design still offers plenty of clearance for most designs. If a manufacturer decides to offer a quality product for the F-body, then consideration of the stock K-member design is usually factored into the design of their product.

Point of all that's stated, if the design allows too much risk of failure for whatever added benefit, then you should definitely reconsider as much as possible.

YellowToy/A

iTrader: (1)

Is that what hes said?

bmfcamaro

iTrader: (1)

spohn is supposed to be making one. there stuff is the strongest looking stuff i have ever seen.

Foxxtron

iTrader: (1)

"looking strong" is one thing, while actually proven to be strong is another. Not to flame, but there is always an assumption that if it is advertised to be "strong", it will be "strong." I would like to see its results of its performance in field testing as my "guinea pig" days are over.

I'm not too sure who engineers what for many aftermarket upgrades, however I was impressed by LG's aftermarket design, not so much by its proposed design, but also the fact of his RR experience and his education (believe he has a BS in Mathematics) would have much to do with his designs or choice of parts for his designs.

Foxxtron

iTrader: (1)

Yes sir. I would guess (which guessing is what I seldom do) is the K-member dilemma would make an interesting, well thought out sticky to clarify what aftermarket K-members would benefit from.

Sorry for the hijack, but it just came to my mind.

Foxxtron

iTrader: (1)

Affirmative Mitch. I was one of those persons who needed rehabilitation from "aftermarket candy syndrome."

I know who made those k-members that broke and deformed over a short time (3 months to be exact).

And I think you and I also agree that it sure isn't worth spending a lot of time (hard earned wages and labour to install the part) and money (1000 USD just to shave off 12-17 pounds) in favour of a negligible performance improvement.

sikws6

would you two get over patting each other on the back I think weve got the message and opinion both of you hold..

mitchntx

iTrader: (14)

Fine ... do your own freaking research ...

EPP

iTrader: (22)

I've had a BMR K Member on my Z28 for three years, with no problems. Maybe I've just been lucky, but we install quite a few of them and we've never had any problems, other than needing to tack weld the alignment washers after the alignment is done. Bob

silkey

do you think that chassis flex is causing this?if so would sub frame connectors help with this problem?if it cant move it cant crack,right?

WS6WRX

iTrader: (1)

Well I guess if you don't put much stress on the K member, they can last for a while. However if you use your car in any kind of handling performance events or even aggressive cornering on the street, they will break and no subframe connectors will save it.

Foxxtron

iTrader: (1)

Do everybody a favour and speak for yourself, and I will speak for mine. Let the moderators govern the thread, and leave your ego out of it. I was speaking from personal experience, and when he made a guess, then that's when I decided to respond.

mitchntx

iTrader: (14)

Thanks

Foxxtron

iTrader: (1)

That's the problem. The K-member is acutally a subframe itself. Not only does it serve as a stress bearing member for holding the engine and steering rack, it also bears the loads of the front part of the monocoque itself, also bearing the loads of the front suspension. This part is really more important than what would usually meet the eyes.

The current subframe connectors are only designed to be responsible for joining the two "sub-moncoque" parts togethor, therefore they are designed to reinforce the centre of the whole monocoque. Reiforcement of the front part of the monocoque is designed with the factory k-member in mind. I believe that some "vintage era monocoques" didn't have separate K-members, but rather an integral carriage for the engine itself, while the suspension was tied completely to the front monocoque.

If there were subframe connectors that were to remove the chassis flex from the front monocoque engine area, then there needs to be a design on it's own to reinforce the engine area, which there already is in the factory K-member which works in accordance with the front sub-monocoque. That's why many F-body drivers consider strut tower braces overkill.

silkey

i think i see now.so with subframe connectors you are still getting flex from the nonstock k member.kinda like a pivot in a pair of sissors,its locked in one way,but on the ends its still moving,for lack of a strong enough anchor.

Cal

iTrader: (1)

Put a simpler way, the stock K member happens to already be well designed. If you use a lighter one made with less steel, it will not be strong enough to take cornering loads. Which might be alright for a drag car with skinnys on the front. I think to significantly reduce it's weight without compromising strength you would need to make it out of titanium! And for the price of fabing one from titanium, you might as well buy a Ferrari Enzo.