rxforspeed

iTrader: (3)

I've been hunting various suspension/steering/brake components for my '83 GS (will soon have COMPLETE '84 GSL-SE suspension) and have only run across a few strut tower bars. I'm eventually going to run a complete adjustable suspension and would like to find a strut bar with an adjustable center tube. For all who respond and have strut bars, please indicate the manufacturer along with it's features, pro's & con's, and your overall opinion of the part. If I can't find what I'm looking for, I'll have an ex-coworker CNC plasma cut the blanks I need to fab up an adjustable bar of my own with adjustable firewall tie bars. I'd jump on ReSpeed's in a heartbeat if you could adjust the tension between the strut towers...

Example-Racing Beat's looks like flat aluminum plate! No adjustability and likely not to fit with my DCOE intake set up. Theirs seems WAY too flexible and overpriced!

I'm also interested in how many of you are running rear bars. I've only seen one in the classified section of this forum and none elsewhere, so I figured that would be a custom fabbed piece for my '7. Thanks to all who reply and help with this topic!

-Adam Collins

justint5387

iTrader: (1)

Why does a strut bar need adjustablility? My RB strut bar works great, it stiffen up the chassis and made the front a lot more stable.

Seniorchief

+1 for the RB strut tower brace. I have had an RB on my RX-7 for the past 9 years. Car handles like it's on rails with this strut brace installed.

slowautoxr

iTrader: (6)

A straight bar is not going to flex. I guess adjustable strut bars were created to adjust between cars. I see it as a weak link in the bar.

Rear bar? I guess you're talking rear sway bar. My autox only RX-7 with panhard rod and tri-link has an adjustable rear sway bar. My other RX-7's with stock style setups do not have the rear sway bar.

rxforspeed

iTrader: (3)

I'm just **** about my car's performance. It doesn't have to be adjustable, but I want mine to be. With an adjustable bar you can put more pressure between the strut towers than you ever could with a non-adjustable bar, and that affects a small aspect of handling performance, similar to adjustable sway bar endlinks or other minor adjustments. I'm not a suspension engineer, so I can't explain exactly how it works to you. I'm just looking for fellow enthusiast's input on the parts they currently own. I'm most likely going to fabricate one for my car unless I can find a less time-consuming option that somebody else on here is running (if it's not overpriced). What kind of strut bar are you running, Justin?

rxforspeed

iTrader: (3)

No, I'm refering to a rear suspension brace that mounts inside the cargo compartment. My adjustable rear sway bar from Racing Beat should be waiting for me by the time I make it home tomorrow. The part that I'm refering to is not actually a "strut bar" for the rear (since there are no struts), but basically serves the same function-to strengthen the area around the mounting points of the suspension to reduce chassis flex and improve cornering power.

justint5387

iTrader: (1)

A strut bar is designed to prevent chassis/strut tower flexing during cornering, an adjustable bar would actually be weaker than the strut bar that you can't adjust. I am running a Racing beat strut tower brace.

rxforspeed

iTrader: (3)

That RB piece looks great installed, but have you ever tried any others to compare it to? I believe a tubular bar would probably perform better due to it's higher structural rigidity and tensile strength. I'm not putting you down for running it, just trying to weigh my options before I buy or start to fabricate anything. Like I said two posts ago, I'm just **** about my car's performance and am looking for every bit of adjustability I can find...

-Adam Collins

rxforspeed

iTrader: (3)

Not if properly designed. Take for example, the RB bar. Hold a piece of 16ga steel or aluminum plate horizontally between your hands and bend it. It's going to be flexible. But roll that into a cylinder and you can no longer bend it with even three or four times the force it takes to bend the plate made from the same material and thickness!

An adjustable bar, properly designed, will perform better than it's non-adjustable counterpart. Are adjustable suspension links (the kind used in four links and ladder bars suspensions weaker than non-adjustable stock pieces? Possibly, depending on how they're designed and manufactured, but usually not. Using the right materials and having a center bar that's set up with 1/2" or 5/8" left and right-hand threaded inserts, studs, jam nuts, etc. does not compromise integrity.

I didn't start this thread to argue with people. Just because it says "RX newbie" under my name doesn't mean I'm some dumb punk kid that knows nothing about what I'm writing, I just wanted people's opinions on what they're running. Thank you for your input Seniorchief. You too, Justin.

Do you see what I'm refering to now? I'll have to fabricate one myself and send you guys pics so you'll understand. An adjustable flat bar that has slotted or elongated holes for adjustability WOULD DEFINATLEY be weaker than your RB bar, but that's not what I'm talking about. I've never even SEEN a FLAT strut bar before seeing RB's product. Maybe it's stronger than what I can imagine-maybe I'm missing something here. But an adjustable tubular bar PROPERLY DESIGNED and manufactured would still be stouter than a FLAT PLATE. Hell, even a cheap tubular bar would be stronger than a flat plate. The entire strength of ANY product is only as good as it's weakest link, and in the case of the RB strut bar, it's the material itself that's the weak link. An adjustable bar, like the one I've tried to describe, would most likely have it's weakest link in the area where the tubing attaches to the flat plate around the strut tower, but even that can be cured by careful engineering and proper reinforcement. Do you see what I'm talking about now?

-Adam Collins

justint5387

iTrader: (1)

You need to show us a pic or a sample of one, the adjustable bar that i am thinking about is the regular strut bar that is is available on ebay(I used them before). For the RB strut bar, it is very hard to bend, so i don't think the material is actually weak.

Re-Speed.com

iTrader: (3)

This is a properly designed strut bar that has adjustability in the main tube that does not create a weak link in the bar.

http://www.mrcmfg.com/respeed/catalo...c3890e48e40832

A rear bar will do absolutely zilch. The pickup points for anything worth supporting are no where near where you could pickup from inside.

My opinions of course.

-billy

dbragg

iTrader: (7)

the RB brace isnt going to bend. i have one and that thing is a monster.

heres a good strut tower brace thats FULLY ADJUSTABLE:


http://www.mrcmfg.com/respeed/catalo...b1e8e827015fc9


damn billy, you beat me to it

rxforspeed

iTrader: (3)

I'm not saying the material is weak, but it is the weakest link. A tubular bar made from the same material and thickness would be a LOT stronger though. I believe I'll have to fab one up just to illustrate my point-I haven't seen one for the FB like I'm trying to describe. But if I were to buy a non-adjustable bar, I would pick ReSpeed's over RB's because of the strength. You can use tubing that's less that half the material thickness of flat plate and it will still be stronger. Like I stated earlier, I'm no engineer (well, I don't have a degree anyway) but I've been welding for almost ten years and have worked in steel yards, fab shops, and the like, and I completely understand material strength and designing components that will withstand abuse. I've worked on cars (and specialize in suspension and chassis work-mostly customizing) for as long as or longer than I've been welding, mostly as a hobby but I've held jobs where I've combined my skills, too. Thank you guys for your input, but I won't be getting RB's strut bar. I'll get the measurements and dimensions I need when I get home tomorrow and have the blanks CNC'd for me. I'll gather the materials I need and start this project, then post pics of the finished product when completed, most likely over a month from now due to my current job in the communications industry keeping me away from home four and a half days a week. When I'm home, I've usually got my seven-year-old son so it's kind of hard for me to find time to start a fabrication project and finish it in a timely fashion. Nevertheless, I'll post pics when finished...

Anyway, anybody else using a different bar? ReSpeed's maybe? I'd love to see some better pics of theirs (thanks for the great pic of the installed RB bar, Senior). Or rear suspension braces/"strut" bars-anybody running one of those? Thanks again to all who reply...

-Adam Collins

Jeezus

iTrader: (4)

This is my rear strut bar. I have not gotten around to fitting it in yet.

rxforspeed

iTrader: (3)

Bwaits and aws140, I was typing while you replied. Thank you. I misunderstood the description of your bar, bwaits. I see now the jamb nuts on the driver's side of the center tube. I would probably order this from you, too, but I've got an obligation to fabricate one now. I'd really prefer a piece with left- and right-hand threads, each on opposite sides of the bar for adjustment without removal and allowing more force to be applied between the mounting points, but your product is an excellent example similar to the type I've been trying to describe. Over half of my suspension/steering components are eventually going to come from you anyway, so I might as well add at least a custom touch of my own with the strut bar.

Thanks for the input about the rear bar, bwaits. I'll have to study the mounting location of the links and shocks to see if I can't add some extra support without adding much weight. I'll be visiting a local shop with corner scales a whole lot while weighing the corners of my car, shooting for a 50/50 balance. I know I'll have to make multiple adjustments, add a bit here, taken from over there, ect-that's one reason I'll be running your front and rear coilover kits besides the basic ride height adjustability. What's the closest you've come to perfect balance on any of your cars, and approximate weights of the corners if possible? Thanks!

I've fallen in love with this car and want only the best in terms of performance and reliablility for it. Jeezus-let me know if you notice any kind of difference after installing that. Did you get that from another member of the forum in the classifieds? That looks like the bar I saw posted for sale along with a few other items earlier this month or so-I can't remember exactly when it was. I was interested in it, but I didn't see the thread until the bar was already sold.

Again, thank you to all who reply with information or opinions. Your feedback and experiences are very helpful in persuading my decisions on many aspects of this car!

-Adam Collins

Jeezus

iTrader: (4)

Will do. Probably wont be much, but I will keep you posted! I got it from another member a few months back though. Havent gotten around to it, but I have an extra black set of rear speaker covers to cut up and see where I need to make the final slices on it.

speedturn

iTrader: (1)

Adjustable spherical rod end bearings on each end of the brace make the overall design much more flexible than a brace that is rigidly bolted in. The goal is rigidity, not flexibility. Most mass-produced strut braces use those spherical rod end bearings to allow for the slight differences in dimensions of mass produced cars.

I have not seen a mass produced strut brace that beats my home made strut brace. Sorry for the cluttered photograph, but my strut bar is fabbed from 1" steel box tubing. There is a 1/4" thick plate welded to the tops of the strut towers, with ears that protrude slightly forward of the strut towers. This keeps the lateral strut bar forward of the alternator pulley with a little clearance. The strut bar bolts onto the the 1/4" thick plate, so that the bar can be removed for engine R&R.

To really make this strut bar the stiffest, notice the diagonal brace running from the lower frame rail on one side up to the strut tower on the other side. This completes this struture, creating two triangles in what used to be an open U structure. This design is stiff, and cheap; I built it all myself from a few dollars worth of steel.

rxforspeed

iTrader: (3)

I'll not be using heim joints on mine, and it won't be flexible. The adjustability will not hinder the stiffness of the bar. My finished product will most likely resemble ReSpeed's, just with a center bar that has machined wrench flats and threaded to accept left- and right-hand STUDS (like all-thread or threaded rod) that will be solidly mounted (fully welded and reinforced) to the plates that bolt to the strut towers, which will have an additional support to tie into the firewall. It will have at least three points that attach to the strut plate for increased stiffness, and I may borrow the idea from you and tie it into a lower structure of the car also. Using a jamb nut at each end of the center bar and plenty of threads cut into the bar itself will assure there is no way for the adjustment to back off, or weaken the structure. With the tension I'll apply between the towers, it's purpose will serve me better than a non-adjustable bar and will still be just as strong as a solid bar. Trust me, the piece I fabricate will be structurally sound, excessively rigid, and far superior to a flat plate type brace. I've even got a hydraulic tubing bender to ensure each individual component of the finished product will be made from a single tube-bent for any needed clearance-and not hacked up and welded together forming weak stress points. I know exactly what I'm doing...

-Adam Collins

slowautoxr

iTrader: (6)

Here's what's on my blk/wht RX-7 and what's on my autox only car.

resjsu

I was trying to sell this but no one wanted it....

Morey987

My strut towers are raised. I want the respeed one, but it looks like it might hit my hood. Hey Slow autoxr what kind've intake is that? I've never seen one come straight out like that. How's the heat from the header?

Rx7carl

Dont discount the RB unit. Its like a tank. Its not flat steel, its rolled up along the edges, giving it great rigidity. And the triangulation makes the front STIFF. Only complaint is access to some components. But the carb should be fine for you.

The MRC bar is similar to the one I have on the IT car (minus the legs to the firewall). It was from Mazda Motorsports, and yes with the center adjuster turnbuckle. Stiffening was good, not as good as the triangulated RB unit. I suspect the MRC one will help that. My only criticism of that bar is the firewall tie is at a shallow angle. While giving great fore aft stiffening, a steeper angle would give more lateral stiffening, which is whats most important. IMHO the adjuster has no material affect on the stiffness.

Nice setup Tom! Give us the backstory on those jackstands! And how do you get the car up that high? Oh and a precarious place for that Coors Light bottle. Cant have any alcohol abuse.

Re-Speed.com

iTrader: (3)

Agreed. Increasing the angles gets in the way of most stock stuff like air cleaners though. Since all our parts are done in house we can accommodate custom bits if the customer has the clearance.

-billy

slowautoxr

iTrader: (6)

The short intake straight out the side is marked Atkins Aviation. There's a heatshield around the header.

woodonastick

iTrader: (1)

i use a 1 piece bar from mazdatrix. its just me but when something is adjustable and is suppose to be stiff, kinda defeats the purpose...but thats just me. :shrug: