Hey folks, just wondered if anyone has had any experience with this strut brace? As my 1.5 doesn’t have the factory brace it doesn’t have the firewall mounts. However this one connects the two towers…
What you think? Worth buying?
My race car doesn’t have one.
I fitted one and all it did was add weight….
You can buy and add the factory firewall mount too you know? Which will then open up your options as to which strut brace you fit.
If you like the looks then why not, but note the reply from ‘rodders’ regarding any performance gains.
Your race car has a full roll cage which may negate the benefits of a front struct brace. Having said that, the Global MX-5 Cup car still has one fitted which is completely different to the optional factory version.
@pikeg123: If it helps, my car had the factory three piece struct brace and had it swapped for a lighter one piece, primarily for easier access to the damper adjustment knobs. With the factory version on bumpy roads, the car had some scuttle/cowl shake which is not as noticeable since fitting the one piece version.
I have been looking into this, and I can’t see the point in a transverse connection between the towers but I may be missing something. It seems to me that the towers only take the vertical loads from the spring-dampers. All lateral load goes through the wishbones straight into the subframe, then into the rest of the chassis at low level. Indirectly the towers could be braced to increase the overall torsion resistance of the front end but this is not achieved with a transverse connection and requires diagonal shear bracing, e.g. from each tower back to the scuttle.
For racing, has anyone tried bolting the bonnet down?
The roll cage probably only stiffens the cabin area, so there would still be advantage in bracing the relatively flexible bonnet area
I think I read somewhere that on both the NC and ND the factory brace was fitted to improve scuttle shake rather than to brace the top suspension towers? Anyone know the answer?
I think that is a very good point alben!
OK, can you explain “scuttle shake”; I am not aware of it on my NC1?
From Wikipedia;
Scuttle shake** (sometimes called cowl shake in the [US] is the term used for the phenomenon experienced in many [convertible or open top [automobiles where, due to lower [structural rigidity caused by the lack of a roof, the middle section of the chassis flexes, causing the bulkhead in front of the passenger compartment to move and vibrate when the vehicle is subject to uneven road surfaces. Passengers feel it as a noticeable vibration and shudder. To some extent this is reduced by the rigid girder section connecting the front and rear subframes on the mx-5.
In the MX5 ‘Scuttle Shake’ is a phenomena that only the top 0.1% of exceptionally gifted and talented drivers can discern so don’t worry about it!!
I’m neither gifted or talented but i can detect scuttle shake especially with the top down!
Re: Scuttle shake: putting aside the rattling of the many plastic parts that sit in the position of a traditional scuttle panel, this phenomena sounds like the distortion of the engine bulkhead, because it is fixed across the beams that run from front to back and floor pan. The shear forces, that are usually taken into the roof via the A pillars, cause S bending of the bulkhead, which has low rigidity in that direction. Any bracing that improves the overall torsional stiffness will help.
See Alben’s post above.
Thanks, Blue and Alben, I was reflecting on that, i.e. scuttle shake is part of the mode shape for the torsional ocsillation of the body, which is reduced considerably by the roof of a saloon compared with an open sports car, primarily because the overall structure is stiffer.
I read recently that scuttle shake is very definitely evident in convertible cars. Apparently Saab have a massive problem with it. I have an nd1 & I have noticed a slight problem. Having said that a tower brace is pretty u.s. the better alternative is the mx 5 parts one. They can supply a new scuttle panel that connects to the tower strut that they also supply. This is the route I’m going to go. Anybody interested take a look on mx5 parts. Those that have a factory fitted brace don’t need to worry about it.
Where did you source the cross brace.
The strut brace is made like that (from Carbing in Japan).
