328 GTS structural rigidity compared to GTB | FerrariChat
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328 GTS structural rigidity compared to GTB

Discussion in '308/328' started by 3@32off, May 11, 2006.

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  1. 3@32off

    3@32off Rookie
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    Feb 10, 2006
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    Saint Paul, MN
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    Chris Borgeson
    #1 3@32off, May 11, 2006
    I've been searching around trying to find out if the GTS version had anything added to it to make up for the removeable roof. Keith Bluemel's book says remarkably little on this topic. I know that many modern convertibles add lots of additional structural components and heavier gauge steel etc. to try to control cowel shake and vibration.
    So for those of you have taken door skins off or performed extensive restoration work on both models, is there much of anything added to the GTS to compensate for the lack of a roof structure?
     
  2. hardtop

    hardtop F1 World Champ

    Jan 31, 2002
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    Dave
    #2 hardtop, May 11, 2006
    I've had them both (still have the GTB). For the GTS, a big reinforcement is done in the door sills. They are significantly higher in the GTS. Additionally, there is a lot of meat in the B pillars into the roof rear hoop. You should know, however, that even the GTB's are not particularly stiff. A good bump will reverberate through the chassis. However, the GTS's are pretty flexible. This flexibility bothers some people more than others. It bothers me a lot. I had a QV GTS and a 328 GTS before buying a 308 GTB. Every Ferrari I have had since (4 more) has been a closed car. But, modern cars of every brand have gotten a lot stiffer as well.

    Dave
     
  3. 3@32off

    3@32off Rookie
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    Chris Borgeson
    #3 3@32off, May 13, 2006
    Thanks Dave, my GTS twists noticeably when turning up into a driveway or other uneven area where one wheel begins to climb significantly higher than the other three. I never really noticed it until I recently drove my brother inlaw's M3 converible in to the driveway the same way. It's night and day difference in feel even at such slow speeds.

    That said, I would never expect a 17 year old car to compare to a modern well engineered convertible. Sounds like the factory did the best they could and short of welding the doors shut on my GTS (ain't ever going to happen) I've got to live with it.
     
  4. Perfusion

    Perfusion F1 Rookie

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    Aaron
    #4 Perfusion, May 13, 2006
    There is a similar (flexibility) issue in Corvettes of the same age. I know, because I have one (C4 generation). The coupes with a removable roof become noticeably "twisty" with the top off. Things like pulling into a parking lot off the main road with a steep incline, taking speedbumps diagonally, or any uneven roadway was enough to make you think the car was going to split from all the flexing.

    To combat this same phenomenon on the C4 convertibles - even less structurally rigid - the factory used an "X" brace that bolted in 4 locations to the underside of the car. Because the same frames were used for all cars, the mounting holes are there on the coupes as well. An company began making aftermarket braces for the C4 coupes, and those who have them on their cars (though I do not) say that the structural rigidity with the top off is DRAMATICALLY improved.

    The company is R-D Racing (http://www.r-dracing.com - click on "Cross Frame"). Although I'm nearly positive the brace won't fit a 328, I just through it out there for those of you "inventive" types who may want to try a similar approach on your car.

    Best -

    Aaron
     
  5. hardtop

    hardtop F1 World Champ

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    Dave
    #5 hardtop, May 13, 2006
    Pretty much all cars have gotten much stiffer. Modern convertiblesa are stiffer than my 328 GTB.

    Dave
     

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