Who makes the best strut bars?
 

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

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.

+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.

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.

I'm just anal 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?

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.

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.

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 anal about my car's performance and am looking for every bit of adjustability I can find...

-Adam Collins

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

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.

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

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 ;)

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

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

http://i14.tinypic.com/66xbi40.jpg

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

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. :)

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.

Please try to understand!
 

:wallbash: 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

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

http://i178.photobucket.com/albums/w268/resjsu/two.jpg
http://i178.photobucket.com/albums/w268/resjsu/six.jpg
http://i178.photobucket.com/albums/w...sjsu/three.jpg
http://i178.photobucket.com/albums/w268/resjsu/one.jpg

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

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?

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. :eek:

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

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

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:

Thanks again to all who've replied with pics and info. RX7Carl, thanks for the insight-I never really saw any *good* pics of the RB bar, and couldn't tell that the material was rolled at the lip/edges. I was under the impression that it was made from flat aluminum plate and beveled at the edges, not rolled. Carl-you really seem to know what you're talking about-do the mounting points on the firewall need to be closer to the center of the car for better lateral stability? That would be my guess. Any hints/tips/tricks/ideas to help strengthen up the rear suspension mounting points?
Slowautoxr-OMFG, that's yet another kick-ass idea that I may be able to incorporate in my bar-camber adjusters! I'm going to have my strut tower plates CNC plasma'd (and probably milled to finished off the slots now), so I should be able to "borrow" that idea and save almost another $200. Thank you! BTW-what kind of carbs are those, ICH series webers? That is truly a unique set-up. I'm having problems downloading this morning, I'll have to check out the pics a little closer in the next few days to figure out how I'll pull it off.
Morey987-raised strut towers? Was your car lowered that way? I've channeled trucks before, but I'd personally be afraid to cut into a unibody car myself to lower it. Unique idea though.
I greatly appreciate any comments, pics, ideas, or suggestions from anybody, even constructive critisism. I'd hate to have to make more than one of these (for myself) if I don't have to. Keep the pics and comments coming, along with any fresh new ideas to build into a strut/suspension bar. Thanks!

-Adam

It's a racing beat kit from what I can gather. Helps eliminate the bottoming out.

You mentioned that you want left/right handed threads for adjustability, right? Doesn't that describe the MRC bar? I just re-read their description to be sure, and it sounds like it's exactly what you are requesting. Am I missing something? :)

Sounds like you're on you're way to building a very nice ride...

it's pretty much the same thing, but i think instead of the turnbuckle, hes wanting to thread both ends of the tubing. thats what i got out of it.

:icon_tup: Exactly. I want to be able to add pressure between or away from the mounting points. To adjust the one I'm going to build, you'll only have to loosen one left-hand-thread jamb nut and one right-hand-thread jamb nut from each side of the center tube (which will have machined wrench flats) and manually rotate the center bar itself, leaving the strut tower plates fully attached to the strut towers. Even with the "turnbuckle" style pictured on ReSpeed's website, you'd still have to remove the bar (at least one end completely) to adjust it. I want to build mine with both positive and negative possible adjustments for the main reason being I don't have much experience with strut-sprung vehicles. Most of my suspension work and modifications have been performed on dual wishbone (double "a-arm") type front suspensions and I'm not exactly sure of the repercussions of exerting pressure outward on the strut towers or away from them and the adverse affects either will have. I'm sure this adjustment would (one way or the other) affect camber gain/loss entering or exiting corners a great deal more than just a non-adjustable straight center bar/tube, or even an adjustable bar that can only be adjusted off of the vehicle.
Personally, I don't really care if it takes me a year or more to get my suspension 100% dialed in to my exact preferences-but by having every little possible aspect adjustable ensures that I WILL eventually reach my goal and remain satisfied with it's performance for years to come. Sure, I could buy a non-adjustable bar or something other than what I desire, but as engrossingly anal as I am about the small details like this I would NEVER be satisfied and continually wondering what would be possible with this or what impact this feature would have on my suspension system. I don't NEED it, but then again I don't NEED the car either. I just want it...

This is not a true statement. The turn buckle and threaded tubes ends are LH and RH threaded. Break the jam nuts loose and turn the turn buckle to adjust.

If you move forward, and have cad data on your parts. I would be happy to quote the laser work for you. I know you mentioned plasma but I can beat ANY price on laser or plasma in mild steel sheet and plate. Plus you wont have the nasty edges with laser bits.

-billy

Just remember is some classes the triangle connection back to the firewall is a no-no and the bar can only go between the two strut towers.

I'm sorry man, I saw the pic and the only adjustable part I could see was located on the driver's side so I assumed this was the case. Again, I apoligize. I shouldn't have assumed. I figured the fully adjustable LH and RH threads were incorporated into the firewall ties, which is also what I plan to do with mine. I'll send you a PM with the info to discuss the laser cutting. I ran a CNC plasma for over a year and a half, so I know exactly what you're referring to when you mentioned the "nasty edges".

TG-thanks for the reminder. I had also noticed the warning on ReSpeed's website, but I don't plan on racing this car. I realize I'm sinking quite a bit of money into just a high performance street machine, but I've fallen in love with this little car and don't want to set any type of performance limitations on the suspension. I'll not compromise more streetability than I can afford to lose in the engine compartment (only adding a few pounds of boost with a 7" Camden supercharger), but I believe my goal of high eleven second 1/4 mile times will be easily reached when an agressively street ported and supercharged four port early 13b (from my SE with 12a side housings) finally finds a new home between my GS's strut towers.

My suspension will be a totally different story though-with no shortcuts, compromises, or generic components at all to hold it back from it's full potential. I can live with the harsher ride I'll inherit from a low 35- or 40-series 17" tire sidewall, the higher spring rate I'll have with the additionally cut RB springs (at least until I get my ride height within the range I'm shooting for to figure out the spring rates and free heights of the coils to order with ReSpeed's front and rear coilover kits), and the stiffer dampening qualities of the Illumina's higher settings. By running all adjustable components, I'll be able to change the dampening/rebound rate of the struts/shocks, the ride height, caster/camber/toe settings, swaybar preload, and other adjustments to smooth out the ride if I wish to drive it up here to Pittsburgh (or where ever else I may be) to bring it to work for a week or two, then change it back to more performance-oriented settings for the winding country back-road driving it'll see more of around home. To put it bluntly, I'm not going to build the car to be legal in any certain racing class, I'm going to build it to fit my driving style and to be more compatable with the types of roads I most often commute. Don't get me wrong-I'm not saying I'll be street racing it, but I may have to push it to the limits once in a while to help me avoid the other idiots on the road...

Kentetsu-thanks man. I've already put quite a bit of blood, sweat, and tears into this project and I've got much more to go, and even more money to spend on it!

Again, thanks to all who've shared opinions and ideas! Keep 'em coming!

why dont you check out the strut tower bar from rx7.com

rxfo, thanks for the compliment. That RB bar is heavy steel. Exactly, going to the center creates the best triangulation possible, and as a bonus, you have the mount for the hood latch there already. But that causes small but manageable access problems for mx. To stiffen the rear suspension mounts I would look to seam weld the areas and maybe add some gussets and/or doublers where the links mount. But the rest of the chassis will still flex a bit. One area that you might want to seam weld also is the c channel that runs inside the car left to right behind the seats.

Maybe if you really exerted pressure you might affect the camber, but thats something you should be able to adjust if you run plates anyway.

tg, thats why the IT car has a straight across bar, triangulated isint allowed in IT.

Thanks for the info, Carl! My storage boxes are already out of the car as is the carpet, so I'll have to break out the welder once I get a bit of time off to spend back home and weld up the "c" channel and gusset the rear suspension mounts in critical areas. The only other option I could think of as I was disassembling the SE was to add a roll cage and incorporate the rear four cage mounts directly over the factory sub-frame/body-mounted link bar mounts to further increase COMPLETE chassis rigidity. I don't really plan on racing the car, only a few drag strip passes at the most, and I don't plan on it being fast enough to require a 'cage at the strip but am seriously considering one for the additional strength and reduced flex it could provide.

I don't have much experience with unibody cars, either. I'm used to full-framed domestic cars and trucks, so I'm not really sure where the common roll cage attachment points are in these vehicles. For my purposes, I believe tying the front subframe/suspension into the rear suspension/subframe would be the best possible placement for a 'cage. I'd use DOM .090" 1.5" OD tubing and build a six-point 'cage with additional attachments to each rear upper shock mount if I were to do this, unless one of you guys has a better alternative.

One more thing, does anybody have any experience experiementing with "subframe connectors"? The subframes on both the front and rear of these cars look to be integrated with the body (unlike most older domestic "unibody" cars with bolt-in subframes-Camaro's, Fox-bodied Mustangs, etc). Has anybody sucessfully attempted to weld in additional braces between the front and rear-extending the entire length between them? I may have to ditch my "full look" interior idea to keep the car at 2400lbs if I add the 'cage and subframe connectors...Thanks again for the help guys!

-Adam Collins

Well if your serious, your not that far from St. Louis. This guy builds the best cages for a 1st gen Ive ever seen. http://www.izzyscustomcages.com/Home.html He's a 1st gen guy whos expanded. He's a member over on Mazspeed and a good guy from my dealings with him. My road race car has a Kirk cage. Its ok, like any bolt in cage, ala autopower. Legal but not that great. ISC does cages but not to the saftey, engineering and quality of Izzy's. If I ever get back into road racing, I'll build a new car and I will tow the shell up there to have him do the cage even though ISC is only down the road. No offense to Mike at ISC, hes a good guy and does good work, but Izzy's cages would make me feel safer.

http://www.izzyscustomcages.com/MJYP2CageInstl.html

I dont think anyone has tried a "subframe connector" as theres really no frame to tie in. Seam welding is the trick to adding stiffness to these unibody cars. Search the net for seam welding. Theres lots of examples to learn from, especially the rally guys. They beat the hell out of their chassis.