240z + 1JZ-GTE (manual) | Page 28 | The Z Club of Great Britain
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240z + 1JZ-GTE (manual)

Discussion in 'Hybrid Z cars' started by johnymd, Sep 4, 2010.

  1. tel240z

    tel240z
    Z Club Member

    no loss of traction so nice and safe on dry days........ not a lot of power then :p don't suppose you got round to changing the prop flange ??
     
  2. johnymd

    johnymd
    Z Club Member

    Good point Terry, yes I need more power to break traction so an increase in boost is the order of the day. Now where's my laptop.

    Yes I have changed the prop input flange and had both props (one's a spare) rebuilt with rear UJ's to suit the new bolt pattern. Still not made my mind up on what to do about the half shaft axles. Had a specialist look at the broken shaft and in his opinion I should go for tn22 material and not have them hardened. The broken shaft was tested and had a hardness of R35 on the un-treated section and R42 where it was hardened and broke. He has quoted me £75 each to have new axles made. I'm no expert on these matter's so any advice or just input is always welcome.
     
  3. Ian

    Ian
    Z Club Member

    Hi John, hope all is well with your JZ-Z.


    I was just wondering if you noticed much difference in terms of shell stiffness after fitting the cage. I am considering fitting a half cage, primarily to further stiffen the chassis but as it would likely add nearly an extra 30kg to the car I want to make sure its worthwhile.
     
  4. Rob Gaskin

    Rob Gaskin Membership Secretary Staff Member Committee Member

    Hi Ian, the reason for fitting a cage and in your case a half-cage should be for safety reasons. If you are doing it for shell stiffness then I would think it less important. A welded-in cage that attaches to the pillars, roof and suspension top mounts (front and rear) would stiffen the shell but spoil it.
     
  5. franky

    franky
    Z Club Member

    The safety devices rear hoop should help with you car, as its a 4 point fixing and provides triangulation across the rear. The other thing to think about is the amount of torque your putting though the chassis, this is what'll cause twist in a 50 year old design, that was never meant to have anywhere near that much put though it. It can only help. They also leave plenty of room around them and don't get in the way.
     
  6. Ian

    Ian
    Z Club Member

    Well, safety is a big reason as well, but I'm running only a fraction under 500lbft, I want my shell to last so I reckon some reinforcements can't go a miss. Why do you say a cage would spoil the shell? Yes, it would have a cage, that might take away value, but as it will never be sold I don't see it as an issue. I would still plan to have the trim in the car even with a cage so it will still look nice inside.


    My thoughts. My chassis currently seems nice and stiff and handles the power perfectly, but I want to keep it this way as long as possible.
     
  7. racer

    racer Active Forum User

    I would have thought a good cage will look after your shell nicely by stopping it twisting. Therefore also looking after your paint job.
    I notice the difference in handling on the road in my car if, I leave off the strut braces, let alone the cage.
     
    franky likes this.
  8. Rob Gaskin

    Rob Gaskin Membership Secretary Staff Member Committee Member

    In my track-day car I had a 6 point cage with door bars and harness bar. It was installed by Safety Devices and they fitted the boxes to the sills and the plates to the rear arches.

    When maneuvering over the hump in my drive the shell would creek and I don't think it was any less than before the cage was fitted. So that's a reflection on my shell but also the fact that the mounting points are low-down and not attached to the suspension tops. If the cage was attached to the pillars by welded plates it would have been a lot stiffer. However that and tubes mounted to suspension tops would spoil your road car.

    Just my own experiences as always. I felt a lot safer especially from rolls or side impact but to be honest I wasn't good enough to notice any stiffness re handling.

    It's not going to make it weaker but whether a half-cage will give you any noticeable benefit is doubtful but as always it's my opinion based on my experiences.
     
  9. johnymd

    johnymd
    Z Club Member

    I think a rear cage would be a good option to stiffen up the shell Ian plus give you a little protection if you roll the car. I certainly wouldn't put a front cage in a road car as it is a bit intrusive. I ran the car for quite a few years without a cage but cant say I really noticed the difference when I fitted it. Matt seamed to think it stiffened it up but I don't consider I'm skilled enough to notice. Although I have given my a car an above average amount of abuse over the last 8 year, the shell has shown no signs of stress in any way. I had my car made just how I wanted it so it fits much better than the safety devices one. I have been considering fitting something to the red car and do have a spare safety devices rear cage that I considered fitting. As this is going to purely be a road car I may just look at light weight small tubular bracing at key points around the car. I will probably pick up on the strut top along with seat belt points to triangulate these areas and link to the factory rollcage mount point. There is a well known car that has done similar. He has built a lightweight modded 240z and wanted the stiffness without the weight. I'll have a dig around for his build info.
     
  10. johnymd

    johnymd
    Z Club Member

    Here's one lightweight 240z but not the one I'm looking for.
     

    Attached Files:

  11. johnymd

    johnymd
    Z Club Member

  12. Ian

    Ian
    Z Club Member

    Not a bad idea if I don't go for a half cage. At the minimum I could add a bar between the struts with perhaps an additional bar or two, perhaps like you sat to the factory cage mounting points (assuming you mean the ones higher up near the roof) I really don't want to add much weight and I am hoping connecting the chassis rails up to the rear subframe stiffens it up a lot.



    Thanks. Funny enough I had only seen exterior photos of that car on Sunday as I was researching Watanabe wheel fitment and his runs Watanabe F8's.

    I actually have the same type of bracing up front as he has fitted, interesting looking at the rear though.
     
  13. johnymd

    johnymd
    Z Club Member

    Here is how I did the rear section of mine. Plus a picture of the braces I will use in the red car in addition to the other bracing I'm considering. Cage 1.jpg zbrace.jpg
     
  14. franky

    franky
    Z Club Member

    the rails you mean are just floor support rails, I think they'll help reduce floor flex at the seat mounting point, however I can't see it stopping any chassis flex, I did mine to the rear of the floor to to strengthen the seat area.

    A factory fit type rear hoop/cage would be +10000 man points.
     
  15. Rob Gaskin

    Rob Gaskin Membership Secretary Staff Member Committee Member

    John, that cage (well the rear section on the pic) does look strong and I like the fact that it attaches to the turrets. It also appears that you have done some extra welding around the door opening.

    For your use of the car all worthwhile I reckon.
     
  16. Ian

    Ian
    Z Club Member

    But when connected to join up with the rear subframe its bound to make the whole chassis a good amount stiffer. They are fairly solid rails so joining them to the fairly rigid subframe can only make the rear more solid.



    Your cage looks good John. Similar to what I have in mind.


    I like variations of these, only without the front sections, yours like quite like the first one here:


    [​IMG]



    I think one like this would work well for me. Except I'd probably only have one diagonal bar instead of the cross to save weight.

    [​IMG]




    [​IMG]




    [​IMG]
     
  17. johnymd

    johnymd
    Z Club Member

    My car was once in a very bad way so had some pretty extensive reconstruction at Fourway before I bought it. The welding around the door was probably part of it.

    I stole most of my ideas for the cage from the silver Fourways car.
     
  18. Rob Gaskin

    Rob Gaskin Membership Secretary Staff Member Committee Member

    I visited Fourways a long time ago and they were building a cage that had a horizontal bar behind the seats and resting on the transmission tunnel. I thought that was a good way to help side impact protection and also stop the hoop punching through the floor in a roll (in the days before sill boxes).
     

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