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Strut bar Design Comparison

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  • Strut bar Design Comparison

    I recently had a chance to do a back to back test on track with no other changes on the car except changing out the front strut bar. I thought I'd share my findings, as it's a "simple" thing, but as everybody knows, the devil is in the details on putting together a fast and easy to drive car.

    There are two types of strut tower bars typically found:

    1. Bolted type that uses bolts to hold the mounting plates to the bar

    2. Welded type that is fully welded as one piece


    The main difference between them is that the bolted type allows the mounting plates to rotate about the bolt, and the welded type resists the mounting plates, and thus the top of the strut tower, from rotating. Obviously the welded type is superior in transfering loads between the strut towers and keeping the top of the towers from translating as well as rotating.

    The first strut tower bar was the bolted type, a typical GReddy style bar, with a tubular aluminum bar and steel mounting plates. Nevermind the fact that half the engine bay is taken apart, this was taken during turbo install.

    Impressions were that the car handled well, and I was curious as to if there was any sort of benefit noticeable to the driver.




    The second strut tower bar I ran 2 weeks later on track was a Stealth-Custom Fab bar made by Jonnie Fraz. This uses a tubular steel cross bar welded to laser cut mounting plates. The main thing I noticed with this bar is excellent attention to detail. The plates are all hand deburred and the preweld fitment was obviously very good. Welds were very even with good penetration. I deal with high dollar parts every day in my "day job," so it's very nice to be pleasantly surprised when you open the box to a car part and are impressed with the quality.

    One potential problem of a welded bar is that the postwelded fitment needs to be spot on since the bar is one rigid piece. Thankfully the Stealth Custom Fab bar has absolutely spot on fitment without excessively oversized holes. It was literally a 2 minute bolt-on job, which is always nice when working on a car!



    Good penetration and fitment on welds:




    Initial impressions on the street were that the front end was a bit quicker to turn in and react, but the true test was on the track where you really feel the chassis moving around. I was also excited to feel if the master cylinder brace would improve brake pedal "crispness" during threshold braking (drive a new BMW M3 or something like that with a very stiff firewall for an example of this).



    On the track the Stealth Custom Fab FSTB made a large impact on front turn-in feel and it particularly made the car more stable during the long carousel that has tons of bumps and hussling the car through the tight chicane (T8/T9). The MC brace made braking at the limit much better, and as evidence, I had far fewer lockups trying to threshold brake as the firewall wasn't flexing all around with all the pedal pressure. I was really digging the small nuiance of bracing the MC gives - it made the car feel more like an M3 under braking where it's very easy to flirt with threshold braking with the more rigid structure.

    Video of the bar in action (no, it's not a video of the bar hanging out in my engine bay, it's in-car video of the old rickety S-chassis being pushed to the limit):

    http://www.youtube.com/watch?v=wrL0b6bavRk

    My car has quite a few braces on it, but every time I add more chassis stiffness I really enjoy how the car feels in comparison to the floppy chassis it was at the beginning of its "track life." For a rough qualitative feel on how much "better" the Stealth Custom Fab bar is over the bolted GReddy style bars is about 4-5x the apparent difference. I could honestly leave the GReddy bar off and it'd be difficult to really feel from the driver's seat. The welded Stealth Custom Fab bar makes an immediate and apparent change.

    I'm kicking myself for running such a crap FSTB for so long. At least now I've answered my wondering on if a rigid welded FSTB would make a difference - and that is YES.
    '18 Chevrolet Volt - Electric fun hatch for DD duty!


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  • #2
    I had an ebay bolted type bar on my previous s13 with really soft springs (Tein s-tech, 180-ish lb/in). Even with that and crappy tires I felt an improvement in response especially during slalom.

    On the current s14 I use a DC Sports welded bar, 300# front springs, and RE01R tires. Yet I don't think I've ever felt a difference.

    So either the DC Sports bar is crap, or the s14 front end is a lot stronger.

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    • #3
      To have a full comparison, you need to try a triangulated firewall/strut tower bar. ....might even help with the brake feel a bit.

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      • #4
        The s14 overall just has much much greater torsional rigidity.
        My Blog | Unfriendly Garage | Endurance Motorsports

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        • #5
          Originally posted by sil8y View Post
          To have a full comparison, you need to try a triangulated firewall/strut tower bar. ....might even help with the brake feel a bit.
          That would be the "next step," but unfortunately lots of stuff is in the way to do that.
          '18 Chevrolet Volt - Electric fun hatch for DD duty!


          DefSport Koni Sleeve and Spring Perch Buy!!!
          http://www.nissanroadracing.com/showthread.php?t=5902

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          • #6
            Ahh, BS. One brake booster line and a little brake hard line minipulation and you're there.

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            • #7
              Nope, rednec... I mean NASCAR coolant surge tank going on the passenger side now. Going to be a bit full in the engine bay.
              '18 Chevrolet Volt - Electric fun hatch for DD duty!


              DefSport Koni Sleeve and Spring Perch Buy!!!
              http://www.nissanroadracing.com/showthread.php?t=5902

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              • #8
                So is mine. I have my expansion tank sitting right in between my wiper motor and intake manifold(Greddy) and my strut towers are triangulated. But I just made my bar though. I can't afford to buy one. ...its amazing what you can do with a little bit of angle iron and 1" stainless tubing. ...and don't tell me that 1" is too much realistate.

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                • #9
                  I am running this type of bar. Its an adjustable welded bar, but it only attaches to two bolts per strut. You can't complain about the fact that you can work on the engine without removing the bar every time :P.



                  Sorry for the messy engine bay :P. That was 3 years ago :P.

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                  • #10
                    I personally love my DC sports strut bar, it's welded and beefy as hell.

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                    • #11
                      How much clearance do you have underneath your new strut bar to the valve cover?

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                      • #12
                        ^ stealth has pics here http://www.stealth-custom-fab.com/pr...stb/index.html

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                        • #13
                          Yeah I looked there, was more looking for a measurement But thanks.

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                          • #14
                            Originally posted by e1_griego View Post
                            Yeah I looked there, was more looking for a measurement But thanks.
                            I'll take a look tomorrow. Just going from memory it's quite a lot. Not anywhere close to clashing with the VC.
                            '18 Chevrolet Volt - Electric fun hatch for DD duty!


                            DefSport Koni Sleeve and Spring Perch Buy!!!
                            http://www.nissanroadracing.com/showthread.php?t=5902

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                            • #15
                              Back when I used to autocross an AE86, I removed the FSTB and loaned it to a friend who was competing in a rallycross event. I had forgotten that I had loaned out the STB and that the car no longer had one installed. At the next autocross event, the front of the car felt mushy and unresponsive. I thought something was broken in the steering/front suspension. When i opened the hood, i was reminded that I loaned out the fstb. I was truely surprised how much of a difference it made!
                              I know it isn't an S13, but I thought I'd share anyways. :P

                              Thanks for the review/comparison between the 1pc welded bar and multipeice bolted bar. It is good to know that there is indeed a big difference.
                              -Dennis
                              92 240SX Coupe
                              93 MR2 Turbo
                              75 Celica GT
                              07 CBR 1000RR

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