Been looking at some mods on my Mk2 and of course strut braces are in the frame. I looked at the cobalt 3 point one, which secures onto the bulkhead, and the two suspension points. The bulk head itself is quite flimsy, so I cant see what extra stiffness it would add, and the angle of the braces would indicate from an engineering point of view that they are not going to help much.
Looking at the straight across versions, these would be great if the engine wasnt in the way, and the rods/tubes were straight. However because of the stand ups from the suspension points and bends in the tube itself, their effectiveness is greatly reduced, so again my question is how much difference do they really make?
(Looked at this with my engineer neighbour, and he concurred that unless the brackets and tubes etc were massive structures (and they appear not to be) its hard to see that they add any significant strength)
I’m also an engineer, and I can see no benefit in these devices, other than they look quite impressive in the engine bay. My car had one fitted when I bought it, so it was difficult to be objective about the benefits. However at some point I removed it to do a job on the top of the engine and forgot to put it back, I didn’t realise it was missing for about 2 weeks and then only because I missed something to lean on with the bonnet open. I have since fitted a supercharger and most of these bars will not fit, I still have not noticed any difference. I strongly believe that when owners fit them and remark on some improvement, that it is a placebo effect
Couldn’t disagree more. The triangulated braces do not load onto the firewall; they bolt through the firewall onto a stout bracket that is attached to the scuttle. Copies or used braces might be missing this important brace. What you will notice, if you fail to fit the scuttle bracket properly, is that over time, the holes in the firewall will oval, and rip, indicating the amount of movement transmitted from the shock tower tops.
Mine regularly comes off, and I do notice when its missing. I’ve had 4 different Roadsters and 3 different brace; generic Freedo, factory steel,and RS Aizawa brace. The Cobalt copy is rather inferior in design to the RAS (Mazdaspeed) brace.
it makes your engine bay looks sportier and that’s it I guess they might be useful to some proper racing cars which are heavier, bigger power and used for proper track racing
but well, its only a 30quid addition to your car and will make your engine bay looks better. why not?
The effect may be small and it may be unnoticable to most people under normal driving conditions but car manufacturers don’t (for the most part) bolt loads of bits on a car for nothing. My 02 2.5 sport has a front strut brace, its black and visually unimpressive, but I’m sure it does something. That car also has lots of bracing underneath that the basic cars do not have, combined effect must be more stiffness, equals more controlled handling etc. etc.
On the other hand I fitted my nice roadster orange strut brace on my MK1 and honestly can’t tell the difference, but it does look nice… [Y]
Would be interresting to do a proper with and without test on a track…
I mostly noticed the difference on mine when going over rough roads with the 17" wheels and lowered suspension. The car used to shake, rattle and roll all over, now Elvis has left the building to an extent.
Steering seemed more precise too, but this could be the placebo effect. The smoothing over railway crossings etc. can’t be placebo.
I’ve used a Mazdaspeed alloy brace on all of my Mk 1s and latterly an Arizona, and it definitely works for me. Takes out some, if not all of the front end quake that you get over bumps. You still get some shake on bigger bumps, but the brace seems to damp them down more quickly.
I’m now looking for a suitable brace for my Mk3 as the wobbly front end is starting to annoy me a bit!
Im on my 4th mx-5 and have had variosu stages of braces on and off.
My cars have always had good suspension geometry’s and suspension choices etc etc and I have always found the brace to be very noticable.
It is my opinion that a 5 less well set up would find poorer returns. I found it made the front end feel tighter and steering sharper, especially wih a front under brace added if its an early mk1 without one.
iv had one on the mx5 since i bought it but my fiesta didnt have one on, i fitted one that cups the top strut/chassis part and i actually didnt like the way it made the car feel in the corners as i might have tightened it up to much as it felt too stiff in the corners but i got used to it and now you can throw it in to corners (not as much as the mx5 though hehe)
Car feels more stable over bumps and uneven road. An extreme example is going over a railway crossing - without the brace is very violent, with the brace it is much more smooth.
Steering does feel a little more responsive, but not a lot.
I fitted one and I tend to think of it as a body brace rather than a strut brace as a strut brace is designed to help keep front end geometry constant whilst cornering. This was a problem on cars fitted with McPherson struts as with this design of suspension the lateral loading on the top mounts gets quite high in fast corners.
Most of them brace one coil over top mount against the other to prevent lateral flexing of the inner wings…
All MK 1/2/2.5 (Possibly MK3’s too, I can’t be bothered googling for the info at the moment) MX5’s have double wishbone suspension mounted on a separate sub frame up front, This is bolted to the chassis rails at the bottom of the inner wings. There’s minimal lateral loading at the top mounts. There’s quite high vertical loading as the dampers try to keep the wheels on the ground over bumps, But a “Strut brace” can’t help against vertical loading (And to be honest, The inner wings don’t really need any help with vertical forces). The only other job the top mounted do is supporting the car’s weight via the coilovers.
The second type that tie into the bulkhead are a slightly different story though, These triangulate the inner wings and bulkhead together to prevent body flex in this area (They just happen to bolt to the top mounts as they’re conveniently located and structurally robust enough to take the loading). This flexing is caused by the mass of the body wanting to continue going in a straight line when the front sub frame is trying to pull it around a corner. The body wants to flex at the point where the inner wings meet the bulkhead but this type of brace resists this force and helps to maintain a consistent front end geometry in relation to the rear wheels.
From an engineering point of view thats all there is to it, But if I’m missing something here feel free to prod at me with pointy sticks. [:D]
Well I have to say, there has to be a case of ‘no sense, no feeling’ about drivers who can’t tell if the brace made a difference.
Just fitted my long awaited ebay purchase, and what a difference! I swear the effect is comparable to sizing up 2" on the front tyres for the way the front end suddenly seems glued to the road. I can notice straight away that the car is less willing to bump-steer and rattles less on the same roads that I drive every day to work (I’ve started forming minor bump/pothole avoidance habits that I never bothered with newer cars) especially noticeable on level crossings and roads with many bumps and uneven surfaces.
It’s the basic version that came on the special editions or dealer fit option, with the adjustment threaded bolt about two thirds the way across the length. Adjusted to pull the two struts as advised at 12Nm. (no torque spanner, so adjust till tension is felt +2 flats of the hex) And I think that is the difference, if the bar is a straight fit (like the £30 ebay jobs), it just rests on the car, but by being in tension, the car is already being affected standing still, therefore more likely to stay tight over the dynamic forces applied during driving.
But that’s just me. I expect a suspension expert like the guys at WIM would have a professional opinion that is really worth listening to!
I have the same strut brace as Waz, with the adjuster screw in the middle. Should I pull or push the sturts, I assumed it should gently push them as this is resisiting the force generated while cornering.
Any advice greatfully recieved as it’d be pointless having it fitted but adjusted wrongly.
I’ve had to do some work on it recently and had to take the strut off. Following some debate with the old chap (retired mechanic) I put it back on ‘neutral’ so just as I took it off, I just re-threaded the bolts on the ends and locked em up. I have to say, I think i prefer it. I had to do a test drive with it off completely and I still maintain there’s a difference, it’s just that slightly pulling it seems not to be necessary. I’d hate to overstress something!
As a mechanical engineer, that makes excellent sense to me.
My Mk3 OP didn’t come with an engine bay brace (if I may call it that) and I wanted to reduce scuttle shake. The Nengun brace is much sturdier than the Mazda one, being a substantial, one-piece triangulated aluminium tubing fabrication, rather a bolted assembly of small steel pipes, so that’s what I fitted.
Fitment is not a trivial exercise on non-Sport models. I had to source new bulkhead panels (standard Sport components, but much cheaper imported from Montogomery Mazda in the USA than buying in Britain) and dismantle a lot of the engine bay bulkhead to fit it. As Mr Reman says, it is the diagonal bracing from the inner wings to the bulkhead which is probably more important than the bracing from one wing, over the engine to the other wing.
It did reduce the scuttle shake quite a bit, but the biggest change to the handling was the totally unexpected, much sharper and more sudden turn-in on corners. Not really sure why this should be, but it’s unlikely to be a “placebo” effect since I wan’t expecting that or looking for it!
And an added bonus for those who care about such things - the substantial, shiny Nengun brace looks dead cool … especially compared with the Mickey-Mouse assemby fitted as standard to Sport versions of the Mk3.
It is easy to forget how much the body shell of even a well-built, good-handling car like an MX-5 flexes, and I suspect that such braces reduce vibration and resonances as much as limiting any absolute relative movement. And if you look under the bonnet of even an expensive, highly-regarded convertible such as the Jaguar XK, you will see similar diagonal tubular braces between the bulkhead and the inner wings. They aren’t very prominent and they aren’t particularly pretty, so they’re obviously not there for decoration.
