Installed Strut Bar
Lexus Test Driver
Joined: Mar 2016
Posts: 9,507
Likes: 2,575
Thanks, suspected that.
But... doesn't it appear that the design is a bit... flimsy?
I don't mean the attachment points, they look quite sturdy in so far as they won't shift under load.
I mean the bar itself. Engineering 101: "a curved beam will continue to bend in either direction in the same axis when stressed", so the mere fact that it's curved is a negative.
Given that the height (center of the beam) is mandatory to clear whatever, shouldn't the attachment points on the strut towers be taller to use a straight beam?
Has anyone attached a GoPro with an LED under the hood to see how it deflects?
The stiffness (resistance to bending) of a beam is inversely proportionate to the cube of the length of the unsupported span (distance between fixed ends). E.g., if the beam length is 30" (link to link), cantilevering the mounts inward to re-locate the links by 2" each reduces the beam length to 26". The beam is now more than 50% stiffer with a very minor weight penalty (mounts are somewhat larger).
Was this factor examined when the design parameters were selected?
It appears that the absolute height is a combination of beam-to-hood and beam-to-valve cover, with the last dim the OD. This should always be as large as possible (disregard the weight change). The difference in stiffness between 2 beams of the same length, wall thickness and material, where one is 1" OD and the other 1.25" is huge: over 100% increase.
But... doesn't it appear that the design is a bit... flimsy?
I don't mean the attachment points, they look quite sturdy in so far as they won't shift under load.
I mean the bar itself. Engineering 101: "a curved beam will continue to bend in either direction in the same axis when stressed", so the mere fact that it's curved is a negative.
Given that the height (center of the beam) is mandatory to clear whatever, shouldn't the attachment points on the strut towers be taller to use a straight beam?
Has anyone attached a GoPro with an LED under the hood to see how it deflects?
The stiffness (resistance to bending) of a beam is inversely proportionate to the cube of the length of the unsupported span (distance between fixed ends). E.g., if the beam length is 30" (link to link), cantilevering the mounts inward to re-locate the links by 2" each reduces the beam length to 26". The beam is now more than 50% stiffer with a very minor weight penalty (mounts are somewhat larger).
Was this factor examined when the design parameters were selected?
It appears that the absolute height is a combination of beam-to-hood and beam-to-valve cover, with the last dim the OD. This should always be as large as possible (disregard the weight change). The difference in stiffness between 2 beams of the same length, wall thickness and material, where one is 1" OD and the other 1.25" is huge: over 100% increase.
would be interesting to see how a go pro video looks underhood... i imagine the flex is not enough to see without a visual indicator (like a needle that moves along a line) i thought about this years ago but still haven't figured out how i'll set it up. I did do an underbody video of my 3IS though:
And here's the stock RC-F engine bay... yes notice the straight bars that attach to the firewall. You guys should check to see if you have these mounting provisions behind that padding. If you do, this is obviously the best setup. Buy from the dealer.
Lexus Test Driver
Joined: Mar 2016
Posts: 9,507
Likes: 2,575
I would do this stock RC-F shock tower brace setup on my 3IS in a heartbeat. The RC-F and RC and 3IS seem to share the same firewall/front end (at least visually they look identical) but I'm scared to pull back the firewall padding on my car.. seems like it will break. I just want to peek behind it. lol
I would do this stock RC-F shock tower brace setup on my 3IS in a heartbeat. The RC-F and RC and 3IS seem to share the same firewall/front end (at least visually they look identical) but I'm scared to pull back the firewall padding on my car.. seems like it will break. I just want to peek behind it. lol
Lexus Test Driver
Joined: Mar 2016
Posts: 9,507
Likes: 2,575
oh well.. I bet someone could weld those plates on. of the stock RCF brace. Cut some padding. Install brace. Use a marker to mark where the brackets would sit. Trace it on the firewall. Sand some paint down on the firewall. Fabricate some mounting plates that are a little larger than the bracket to spread the load out. Seam seal. primer. Paint. =D Would be nice to see a closeup of the stock RC-F mounting point. Probably the area is reinforced and has threaded nuts to receive the bracket.
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