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Thread: Strut brace......

  1. #1
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    Strut brace......

    My friend put on a new upper front strut brace on his car & now is telling me that I've just got to get one.He dosen't drive really hard or quick , so I can't see what he talking about or what improvement it has made in his car(Lexus SC /400). So why should I get one.... other than to add some "BLING".I rarely drive my Z3 hard, but the two of us dice it up every now and again in an old shopping center parking lot, SCCA style.
    Your thoughts.....

  2. #2
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    It's really mainly for show. If it were really necessary, the engineers would've added it from the factory. There are a lot of aftermarket suppliers providing upgrades for the car so it's ultimately a business.

    If you rarely drive your Z3 hard then I don't think you need one. There's a purpose for it and that's to make it a bit more stiffer, but if you don't need it then I don't suggest you get one, unless you want to just have it to have it. It does look impressive under the hood.

  3. #3
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    The general theory is that the bracing prevents the upper strut mount from flexing in relation to the lower mounts and the opposing tower during aggressive cornering, which allows the suspension geometry to remain constant and allow the pivots to do their job and maintain the desired movement arcs, etc.

    Some chassis may benefit more than others, and common wisdom is that they must help some. Personally, I do not believe you are going to see enough improvement to "feel" it. It is such a minor gain if any, only those who've driven their cars at the limit for years would notice if anybody.

    Lately kinematics machines used to test every manner of chassis performance aspect have come down in price to the point where not just OEMs have them. Performance shops that do work for NASCAR and such can now afford the modern, relatively inexpensive ($300,000) piece of equipment these days. Since OEMs are traditionally mum on chassis details such as this, we're now seeing the first credible streams of information coming out of these performance shops. As of yet, I'm told they have not found a single aftermarket front strut tower bar to provide any structural/suspension/performance benefit.


    I have one each front and back on my noodlely SE-R. I have yet to even consider one for the Coupe. Both see plenty of track time.
    Last edited by BenFenner; 05-14-2014 at 04:56 PM.

  4. #4
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    Quote Originally Posted by IgotBMW View Post
    It's really mainly for show. If it were really necessary, the engineers would've added it from the factory... There's a purpose for it and that's to make it a bit more stiffer...
    Many performance cars have strut bars from the factory, usually not across the engine, but triangulating back to the bulkhead (firewall). Like the Z4. In a convertible, especially a Z3 with the struts so far ahead of the bulkhead, a strut bar stiffens the front end and reduces cowl shake on bumps. And if the car is driven and cornered hard enough in autocross or racing, especially on bumpy surfaces, the strut bar can also improve handling by reducing deflection in the strut tops which changes camber.
    http://store.uucmotorwerks.com/artic...ement_math.htm

    I added a bar from Strong Strut, customized for the M44:
    http://i49.photobucket.com/albums/f2...ps992d7f62.jpg
    I thought it made the car feel more solid hitting bumps and railroad tracks. That was a year ago, and the new has long since become the normal, but I remember thinking the strut bar was worthwhile.
    Last edited by Vintage42; 05-14-2014 at 02:46 PM.
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  5. #5
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    Quote Originally Posted by Vintage42 View Post
    I thought it made the car feel more solid hitting bumps and railroad tracks. That was a year ago, and the new has long since become the normal, but I remember thinking the strut bar was worthwhile.
    I agree with that.

  6. #6
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    Triangulated strut supports (often seen on vehicles from the factory) help with torsional rigidity, which is a worthwhile goal.

  7. #7
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    Quote Originally Posted by Vintage42 View Post
    Many performance cars have strut bars from the factory, usually not across the engine, but triangulating back to the bulkhead (firewall). Like the Z4...
    I think the triangular brace is used because a brace straight across the engine requires too much clearance; it would raise the hood line. (The straight strut bars that so easily span the engine of a 6-cylinder Z3 do not fit between the 4-cylinder engine and the hood.)
    The triangular braces in the Z4 and many recent performance cars -- at 45º to the strut towers -- vector away half of their effectiveness versus straight between the towers, but they are designed to be adequate without raising the hood line.
    Last edited by Vintage42; 05-14-2014 at 03:14 PM.
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  8. #8
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    If you live in the world of perfect road surfaces - I'd say nah. I'm NYC , home of the pot hole. Strut towers DO crack and deform ( ask me how I know) from this kinda shyte. One of my front upper shock mount bolts had to be banged back into alignment BEFORE I could fit a strut brace on. And repaired cracked weld on one shock tower. Heed the warning on clearance though, not all braces are equal in thickness/height over the engine and MAY dimple your hood if there is not clearance.
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  9. #9
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    I had an experience that very clearly illustrated chassis flex in my Z. Was on a winter morning, had parked the car outside on a drizzly night and the entire convertible top was coated with a thin sheet of ice. Pulled into a parking garage and was cresting the top of a ramp at an angle. As soon as my leading front wheel crossed over the transition from the ramp to the level part of the slab I could hear the ice breaking away in sheets from the convertible top. IMHO I think that a strut bar could help with chassis stiffness and suspension response...
    Last edited by dkindig; 05-14-2014 at 04:24 PM.

  10. #10
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    On a roadster, the feel is night and day as far as cowl shake goes. Will it improve handling? probably not to a noticeable degree.

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  11. #11
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    Quote Originally Posted by dkindig View Post
    I had an experience that very clearly illustrated chassis flex in my Z. Was on a winter morning, had parked the car outside on a drizzly night and the entire convertible top was coated with a thin sheet of ice. Pulled into a parking garage and was cresting the top of a ramp at an angle. As soon as my leading front wheel crossed over the transition from the ramp to the level part of the slab I could hear the ice breaking away in sheets from the convertible top. IMHO I think that a strut bar could help with chassis stiffness and suspension response...
    this is sarcastic right?

  12. #12
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    The Z3 wet noodle effect is certainly made more rigid by the addition of the strut brace.
    Now in E92 M3 ZCP -- Absolute beast

  13. #13
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    I agree, roadster is very flexible. Try to put hard top without front screws (or one) and drive a little and you will be very surprised how flexible it actually is. On roadster strut bar makes big difference when cornering and on bumpy roads.

    You don't have to buy expensive like Dinan bars, they are strong and look cool, but even cheaper bars from ebay will make a big difference.

  14. #14
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    I have used one on both my MRoady`s and the feel was definitely noticeable on bumby roads and in turns with a bump or a drop in it. Also going over RR tracks. Worth the addition to me.

  15. #15
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    Quote Originally Posted by wrench13 View Post
    ... Heed the warning on clearance though, not all braces are equal in thickness/height over the engine and MAY dimple your hood if there is not clearance...
    That only happens from installing a brace on a 4-cyl and slamming the hood shut.

    There is plenty of room over a 6-cyl engine for a brace. What can dimple the hood are the brace mounts added on top of the struts. But all braces have beveled mounts to avoid that.

    It is the 4's that have the problem. There is so little room over the intake that the usual 4-cyl braces bend around behind the engine in a weak U-shape that must flex like a bow. Only the Strong Strut is a solid bar that goes across the engine, but as originally sold, it's the same bar as for a 6, shimmed so high to clear the engine that the ends of the bar would indeed dimple the hood, unless the hood was first raised by adjusting the rubber bumpers and the latches. Unwittingly slamming the hood shut without raising it, will dimple each side over the struts. Strong Strut provides instructions and modeling clay to set the clearance.

    To make my Strong Strut clear my 4-cyl without shimming the bar ends and raising the hood, Strong had to mill the underside of the bar to clear the front of the engine. The center of the bar was milled to half its depth, for half its width, a 25% reduction in cross section. The solid bar is so over designed that the reduction is negligible.
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  16. #16
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  17. #17
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    I have a Mason Engineering aluminum bar.. great bar, but not sure it's worth $400+. I bought mine used for $140. Definitely made a small difference on my roadster, but it's no miracle worker. I'd say the difference is worth about $200-250 for me.
    Cyrus Mistry

  18. #18
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    Quote Originally Posted by BenFenner View Post
    I have one each front and back on my noodlely SE-R. I have yet to even consider one for the Coupe. Both see plenty of track time.
    Ben, Did you ever do the structural foam inside the rocker panel reinforcement that Mike Kojima did to a 300ZX?

  19. #19
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    I can add that I added the strut bar and though I noticed a difference right away. As far has track/high performance driving benefits; I'm not so sure. I have received a couple of compliments that it looks cool under the hood.
    -Dustin


  20. #20
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    Quote Originally Posted by spacecowboy View Post
    Ben, Did you ever do the structural foam inside the rocker panel reinforcement that Mike Kojima did to a 300ZX?
    No... Only one SE-R guy has actually done it. I'd love to do it, but it is just not worth the time for me right now (ever). I'll link you his thread in a bit.
    I've sat in the car, but never driven it. Maybe I'll make a point to drive it when I see him again in June.

    Edit: Here yah go: http://www.sr20-forum.com/brakes-sus...g-chassis.html





    Last edited by BenFenner; 05-15-2014 at 08:42 AM.

  21. #21
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    Thanks.....Strut brace.

    What a well educated group of Z3 owners. Thanks for all of your replies. I think I'll get one just for the 'BLING'
    factor.Can't hurt.......

  22. #22
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    Quote Originally Posted by BenFenner View Post
    No... Only one SE-R guy has actually done it. I'd love to do it, but it is just not worth the time for me right now (ever). I'll link you his thread in a bit. I've sat in the car, but never driven it. Maybe I'll make a point to drive it when I see him again in June.
    I'm curious to know if that foam also acts as an adhesive. Do you have any idea if it's on permanently once it sets up?

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    Quote Originally Posted by spacecowboy View Post
    I'm curious to know if that foam also acts as an adhesive. Do you have any idea if it's on permanently once it sets up?
    I've used it before. It is adhesive (you have to chip it off of the metal) and will slightly break down over time. Works wonders in convertibles but you have to be careful of putting it in sills and block off any drainage going through them. The foam will trap any moisture and accelerate rusting. http://www.asahi-net.or.jp/~VS6N-MRY.../urethane.html

  24. #24
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    So a front strut bar will help with cowl shake ? mine is so bad at highway speeds all the mirrors vibrate on the yellow car.
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  25. #25
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    Quote Originally Posted by amancuso View Post
    So a front strut bar will help with cowl shake ? mine is so bad at highway speeds all the mirrors vibrate on the yellow car.
    That sounds like it may be a different problem. Cowl shake is negligible on a smooth road like a highway. Its an issue over rough roads, potholes, etc.

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