Originally Posted by bbundy
(Post 493710)
Go Park your car on some flat ground takes the roof off or put the top down open both doors and look at it from the side.
Other than the sills, the trans tunnel, and the wimpy so called frame rails it already is a flat plate trough the center of the car. To make it stiffer it needs added section modulus in the vertical direction to reduce vertical bending and torsion. A flat plate structure on the bottom of the car dosnt give section modulus in the correct direction. Spindly tubes replicating the flat plate is harldy better. Door bars do ad a huge amount of vertical section modulus though not as much as a real roof or a cage would. Also Converting the Trans tunnel from an open hat section to a tubular section also would significantly change the section modulus in both vertical bending and especially torsion. Mazda I think was pretty on track on the Mazdaspeed as seen in the pic but I still think it can be done better. Bob |
Re: MSM
When I added the butterfly to my 2000, I could swear it ended up stiffer than my friend's MSM. |
Originally Posted by mgeoffriau
(Post 493804)
I know this is probably short-sight, since one's interests and tastes change over time, but does anyone else feel like they will keep their Miata forever? Mine is rust free with a straight body. Motors and parts are plentiful. I don't see any automakers building a similar car that would be within my budget. Within a few years it'll be virtually worthless, so there wouldn't be much point in selling it.
|
Originally Posted by gospeed81
(Post 493798)
Car sure will be nice when I'm done though.
Originally Posted by mgeoffriau
(Post 493804)
I know this is probably short-sight, since one's interests and tastes change over time, but does anyone else feel like they will keep their Miata forever? Mine is rust free with a straight body. Motors and parts are plentiful. I don't see any automakers building a similar car that would be within my budget. Within a few years it'll be virtually worthless, so there wouldn't be much point in selling it.
|
Originally Posted by mgeoffriau
(Post 493804)
I know this is probably short-sight, since one's interests and tastes change over time, but does anyone else feel like they will keep their Miata forever? Mine is rust free with a straight body. Motors and parts are plentiful. I don't see any automakers building a similar car that would be within my budget. Within a few years it'll be virtually worthless, so there wouldn't be much point in selling it.
Bob |
Originally Posted by JasonC SBB
(Post 493823)
Re: MSM
When I added the butterfly to my 2000, I could swear it ended up stiffer than my friend's MSM. Frame rail reinforcement + soso making a tube out of the transmission tunnel > making a slightly better tube out of the transmission tunnel. I don’t know for sure that is just my best guess. Bob |
Yes, FM's butterfly requires that their frame rails are in place. I installed em all at once.
And yet the door bars made a more dramatic improvement. I suspect though that with the door bars, removing the butterfly/frame rails would be very noticeable. IOW they both help. BTW I posted months ago on m.net that an easy way to measue stiffness would be to look for the dominant resonant frequency in the chassis motion in the left-right direction in an accelerometer mounted on the rollbar. The higher, the stiffer. In my car it was 17 Hz IIRC, with all the bracing in place. I don't have any before/after numbers though. P.S. Here it is http://forum.miata.net/vb/showthread...=accelerometer The 17 Hz resonance is by far the largest resonance in the car, and it is largest in the left/right axis on the rollbar. This agrees with the butt-o-meter in that the chassis shudder feels like the seatback and the steering wheel are vibrating left-right (I'll bet, in opposite directions, due to chassis twist). |
P.P.S. I wish there were a door design wherein when you close it, some kind of strong mechanism latches in and makes the door a load bearing member, to make it part of the structure. Would work great for convertibles.
|
Originally Posted by mgeoffriau
(Post 493804)
but does anyone else feel like they will keep their Miata forever?
__________________ Best Car Insurance | Auto Protection Today | FREE Trade-In Quote |
Originally Posted by bbundy
(Post 493710)
Mazda I think was pretty on track on the Mazdaspeed as seen in the pic but I still think it can be done better.
Bob |
If mine doesn't get totaled or something catastrophic doesn't happen to it..im going to keep it as long as I live and I'm going to keep modding it..:D
1990 78k Original Miles, original paint, lots of Original stuff, 2nd owner.. Nomie |
Originally Posted by mgeoffriau
(Post 493804)
I know this is probably short-sight, since one's interests and tastes change over time, but does anyone else feel like they will keep their Miata forever? Mine is rust free with a straight body. Motors and parts are plentiful. I don't see any automakers building a similar car that would be within my budget. Within a few years it'll be virtually worthless, so there wouldn't be much point in selling it.
There's no substitute for my car...and track rubber is only $600 a pop. |
Originally Posted by JasonC SBB
(Post 493891)
P.P.S. I wish there were a door design wherein when you close it, some kind of strong mechanism latches in and makes the door a load bearing member, to make it part of the structure. Would work great for convertibles.
I always end up thinking I'd be better off doing everything else first, or just putting in a real cage for the effort. |
Originally Posted by JasonC SBB
(Post 493891)
P.P.S. I wish there were a door design wherein when you close it, some kind of strong mechanism latches in and makes the door a load bearing member, to make it part of the structure. Would work great for convertibles.
|
If this thread has taught me one thing, it's that I need to sell the Butterfly sitting in my garage and pick up a pair of door bars...
Good stuff. |
Originally Posted by cueball1
(Post 491673)
Hard Dog bolt in bars right?
Great review and good to know it makes a difference. Boss Frog slams them so much I was waffling. Got a set coming for the holidays now. In what way do they slam them? on installation or just function? because they seem to be in the game now: Miata Performance http://www.bossfrog.biz/Miata_Performance/IMAG004.JPG http://www.bossfrog.biz/Miata_Performance/IMAG006.JPG http://www.bossfrog.biz/pdf/BF.DoorB...tions.0912.pdf |
I'm no engineer so I can't comment on their functionality, but aesthetically they look utter garbage.
I had door bars with my old Carbing cage, I miss them, (but not the loss in legroom!) |
What size tubing is that? Looks small. To me, that design looks like it will crumble on side impact.
|
Seems like I recall BF slamming door bars unequivocally...until they introduced their own, then suddenly they were only slamming the other designs. The page explains their use of 1" tubing and sheetmetal instead of larger tubing.
It's ugly, but I could live with ugly if it was a truly superior design. They just lost some credibility with me when they changed their story about door bars (especially when consumer reviews of other doorbars are almost universally positive, even more so than roll bars, frame rails, butterflies, etc). |
Without looking at their page, their design could be stiffer for the same weight or the same weight for the same stiffness. The plates would increase beding stiffness considerably in the plane of the plates (vertically as installed). Also it can be narrower with the smaller diameter tubing.
Nice idea from a purely mechanical standpoint but I do not like the look at all especially with the lettering cutouts. I still prefer the ones I have. OK read the description.. Traditional single-tube door bars with two mounting points do little to stiffen the frame Clearly that is not true. Marketing-speak. |
All times are GMT -4. The time now is 03:38 PM. |
© 2024 MH Sub I, LLC dba Internet Brands