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-   -   Fb sturt Bars? (https://www.rx7club.com/1st-generation-specific-1979-1985-18/fb-sturt-bars-557421/)

dj55b 07-08-06 01:48 PM

Fb sturt Bars?
 
Does anyone where this sturt bar might of came from ... doesn't look like its RB http://cgi.ebay.ca/ws/eBayISAPI.dll?...:EOIBUAA:CA:11

BridgePorted12A 07-08-06 01:52 PM

Custom...the guy probably made it himself, has access to a machine shop, etc

boog 07-08-06 02:01 PM

mazdatrix makes a fairly cheap one (120 i think) that makes a noticable affect on cornering/steering and looks cool too

peejay 07-08-06 02:19 PM

That looks like the CP Racing bar, but the mount plates are a little different.

http://img.villagephotos.com/p/2004-...-underhood.JPG

I don't know why anyone would make a strut brace out of stainless steel. There's no performance benefit to the different material whatsoever.

RacerX7fb 07-08-06 03:55 PM

"...Much lighter and stronger than regular carbon steel tubing and it will never tarnish or rust !!!!"

That could be why. Why use aluminum or carbon fiber for that matter.

peejay 07-08-06 04:21 PM

Stainless weighs close enough to the same weight as standard steel as to make no odds. The only way different steels can be lighter is in the use: stronger materials can permit thinner tubing/plate for equal strength.

He used 1/8" wall, 1" tubing. This is what the CP brace uses. They will weigh the same.

I have no data on strength of stainless, but since IIRC they use a high chromium content in the steel, it's probably similar to chrome-moly, meaning that while it is stronger, the elastic and yield limits are very close to each other, meaning a force large enough to bend it is just as likely to break it. Mild is much more forgiving. And, it's probably a hardcore bitch to weld, again if it's anything like chrome-moly.

Anyway, say it's some undefined "stronger". We're really splitting hairs here. So it deflects a third of a millimeter instead of a half millimeter, big deal. It's still going to be one hell of a lot less than stock.

bad 83 07-08-06 04:39 PM

Hey peejay, I haven't seen a triangulated CP strut bar on a car before. Looks good. Almost as good as mine!!!
http://img.photobucket.com/albums/v6...7/P6240007.jpg

Just kidding. I have seen these strut bars on E-bay for a while. When this seller first started listing them, they were listed as built in house. I don't know about buying stuff off E-bay over the border. Just had some bad experiance with a seller from Ontario. O'well.

David Dewhurst 07-08-06 06:34 PM

bad 83, tell us about your air intake. Manufacture, number & such for the entire deal including the filter.

Thanks ; )
David

peejay 07-09-06 09:38 AM

I realized something the other night. The M.E. for steels is pretty much the same no matter what. So a stainless bar, of the same wall thickness and diameter, will deflect just as much as a mild steel bar.

The difference only comes if you deflect it to the point where it yields, at which point you wouldn't be worried about strut tower flex so much as getting the insurance info from the guy in the truck who just T-boned you.

no_name 07-09-06 10:06 AM

Damn this guy is goood.

You know your stuff man.

stilettoman 07-09-06 10:07 AM

Triangulation has to have a triangle!
 
1 Attachment(s)
No one has mentioned that the strut brace on Ebay is advertised as triangulated, yet clearly is not. And no engineer would recommend stainless for a strut brace unless you want it for appearance purposes. A properly designed strut brace will have all the members in compression or tension under load. Indeed, the one I built is put together with heim joints, so there can be no bending loads.

If there is no triangle to the center of the firewall, then you are not getting much benefit. Numerous people on this forum have bragged about huge improvements in handling by simply bracing the two strut towers together. These people are fantasizing to justify the money they just spent. A strut brace without triangulation is mainly good for bragging rights, and that assumes you are bragging to someone who has no knowledge of basic engineering principles.

If properly designed, strength is not likely to be the issue. If the parts not loaded in bending, then it is only an issue of stiffness. Mild steel has the same stiffness as chrome moly steel. Both have excellent weldability, assuming you know how to weld. Notice that only the tower cap fittings are welded in my design. My braces are made of solid aluminum rod.

If you want to see triangulation, look at the rather complex chassis shown on page 5 here, which is built entirely of 4130 chrome moly:

www.cardomain.com/ride/646433

dj55b 07-09-06 10:48 AM

Hey how much would you sell a triangulated sturt brace like your? Iknow that you'd have to fabricate it but i'm interested. PM me about price and stuff.

bad 83 07-09-06 06:19 PM

For those who want to know about the intake, it's a one off piece that Robert (robs7) and myself made. Well, sort of. This is actually a E-bay piece that is setup for a Chevy truck. I just modified it to work. http://cgi.ebay.com/ebaymotors/88-95...06630494QQrdZ1
Sneeky, aren't I?

trochoid 07-09-06 07:57 PM

A strut bars main purpose is to limit the deflection distance between the strut tops, no triangulation is needed for this. If one went to extremes, the triangulation would be from one strut top across to the other lower frame rail.

Btw, I have an old Rotary Engineering stainless steel brace, with the firewall braces. They make a great place to tie wires too and the cross bar gives me support when leaning over the widebody fenders when working in the bay.

peejay 07-09-06 08:22 PM

Ah, but if you just go top to top, the chassis can still "lozenge" and the strut tops can move in concert with each other.

Triangulating to the firewall puts a stop to that. The firewall is one of the main anti-torsional flex points, so tying into that is a Good Thing. It also helps a lot with beaming flexure. Note that the Escort/Capri guys make a handy little triangular sheetmetal brace to go between the body rails and the firewall, might not be a bad idea for us either.


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