Folks, pardon my ignorance as my MR2 is pretty new to me, however, I read a lot about different types of braces for the car, front, rear, mid, etc, now, I must admit that on the few occasions that iv'e pushed the car a bit (04 reg) the only thing I noticed was the front end felt a bit "skittish", cant say the handling concerns me otherwise

Are you folks adding braces for track use or am I missing something

Rob

For me the under mid brace was a massive improvement for reduction of scuttle shake when the roof was down, any other benefit was an added bonus

The cars are deliberately set up with initial understeer by Toyota. It is safer than more neutral till hiher concering speeds and then oversteer.

The Face Lift cars are slightly more so still.
They also have a bit stiffer bracing btw.

To understand the bracing subject the crux is that the MR2 mk.3 is a cabrio. Open both doors and you will grasp the fundamental issue versus a fixed roof coachwork: A cabrio like the mk.3 is fundamentally more flexible. You can brace till you need stiffer springs to compensate for the weight    but unless you weld in a cross braced full roll cage, it stays a spyder.

What braces ´do´ is give the driver more direct info over what the car is doing. How much you need, what is the sweet spot?
That depends. There is no better really, not even a best.
The standard car is stiff enough to track true for even spirited normal driving and offers good creature comfort.

From there it is a debatable subject with the personal need/preference being the deciding factor. All the extra braces do have their effect but do add weight so if you don´t use the extra rigidity, why bolt it on?

An extra cross contamination is several owners having a 2ZZ engine or forced induction on the 1ZZ.
This means 180/190+ hp, thus more load, thus need for a stiffer tub. Their opinions, feedback, however valid, should be taken with this caveat if you have the standard engine.

I don´t race my 1ZZ engined car and over here nééd all the ground clearance and conformity I can realistically get.
My pre face lift car has the OEM shocks/springs, a front strut brace (supporting the McPherson towers), a Corky/Snelbaard belly brace (basically a stiffer version of the OEM bracket) and Dev´s door spacers (in effect making braces of the doors on the doorlocks).
Any more bracing would for mé be counterproductive.

And lastly, bracing can be adictive 

Many of us are adding them for road use 

General consensus is that a mid brace and a front strut brace are the two biggest improvements to the stock car. For the mid brace you can either get a full brace or a small breastplate (which just pulls the centre together).

@Snelbaard and @Carolyn on here produce and sell a mix of braces. You can put your name down for one if there's none currently available. If you search the forum for "braces" you'll find the relevant threads

You know what... That's the first time someone's actually asked why...

Here's one for the reference section perhaps then.

Front strut brace
Workings: Prevent either front strut tower from flexing inwards by rigidly binding them together.
Result: A more "pointy" front end, reacting to steering input quicker and making the front feel a bit more solid.

Rear strut brace
Workings: prevent either rear strut tower from flexing inwards. The stock cross-brace in the engine bay already does a lot of this. Also, there is the subframe.
Result: Not much. Its use other than as engine bling is yet to be found.

Mid-brace (TTE brace and then the replica made by MattPerformance)
Workings: Prevent flexing of the main chassis, primarily in the diagonal axis. So, front left to rear right and vice versa. Making the whole center chassis move more rigidly
Result: Known as the "night and day" bracing. Almost required for any MR2. Much improved lateral stability, more substantial feel over bumps, better communication between car and driver.

Then there are a number of other braces more intended for track purposes. @Snelbaard is producing some and this write-up covers a fair few as well
https://www.mr2roc.org/forum/index.php?topic=17955

Quote from: shnazzle on November 27, 2019, 22:56You know what... That's the first time someone's actually asked why...

Coming from a motorcycling background, you would be surprised how many fit XYZ because Joe on a n other forum says its the dogs nuts must have modification, when in fact is probably useless bling (obviously not all bling is useless

A good selection of answers for me at the moment

Rob

I don't track my car either.  It's a long-term keeper, so I don't want to truly thrash it, ever. I've done, and been around, a lot of racing and I have witnessed the mess going on the track can make of a road car.

When I bought my car, it already had front and rear TRD strut braces.  I tried it with and without them (one at a time).  The rear brace made little difference to the feel of the ride or the handling.  The front brace, on the other hand made a massive difference.  The steering is much more positive and precise with it in place.  The TRD brace is very rigid.  I don't think one gets the same benefit from an ally single-bar brace, especially ones with cross-bolts at each end (which belong in the 'bling' category).  When I designed my version, I tried to make it as rigid as the TRD, which, I think, I succeeded in doing.

I came across a TTE/Matt race at the breaker's and picked it up for a tenner.  (It was very scruffy but it cleaned up pretty well).

I was sceptical as to what it would do for me on the street, but for that price - what the hell!  I was very surprised to discover that it did make a very noticeable difference.  There was much less scuttle shake and a much smoother ride over the bumps.  Just made it a nicer car to drive all round.

I'm almost finished with my first batch of mid-chassis under-braces (I massively underestimated the development time involved). They not only tie the corners together but tie everything to the centre of the floor as well.  I expect they'll do a good job.

I later came across a TRD style ally front underbrace and installed that. Not a massive difference.

For me, for street use, the front strut brace and the mid under-brace are the ones to go for.







 

Our one MR2 has lots of bracing.  We have a TRD front strut brace, a TOM's front lower brace, a Corky's breastplate (like the one @Snelbaard sells), a steel Carbing real lower brace, and an Autopower roll bar. The roll bar was mostly for bracing, rather than roll over protection.  The 2 that made the most difference were the breastplate, which boxed the center tunnel into a torque box, and the roll bar which tied the chassis together just behind the seats.  A full mid brace like Carolyns would act similar to the breastplate.

On relatively smooth roads and steady state cornering, the bracing isn't really that noticeable.  Where it shows up is on rougher roads and transitions, like S curves that try to twist the chassis. Cowl shake is noticeably reduced. Without bracing, the chassis flex becomes an undamped part of the suspension so the car tends to move around a lot on rough roads.  With bracing, the suspension works a bit harder, but is more stable.

Bracing makes a bigger difference with stiffer suspension, as the suspension transfers more load to the chassis. 

I agree that many of the aluminum "braces" are more bling than structural.  The exception is the Corky style breastplate like @Snelbaard sells that is properly designed.  If you get any single brace, get a breastplate or mid brace.  Then get a steel front strut brace like Carolyn's or TRD

Quote from: Beachbum957 on November 28, 2019, 12:39Without bracing, the chassis flex becomes an undamped part of the suspension so the car tends to move around a lot on rough roads.  With bracing, the suspension works a bit harder, but is more stable.

This is actually why I do NÓT go any stiffer (strut brace, belly thing, Dev´s); the flex of the chassis/suspension álso = conformation, road holding. It is like longer suspension travel without the extra springyness of that.

Imo, for real world road use, you want the softest ´setting´ you can get away with stability wise. 

I found that the pas delete aids in pointing the car where I want it while wallowing-about; the heavy assistance makes me give extra, unneeded/unwanted, steering input. Same thing bucket seats.
A stiffened-to-the-hilt car will loose traction earlier. Lowering, stiffening suspension ditto.
Just imagine a series of esses on a narrow road with pronounced crown and patched tarmac.

All very informative

How does the addition of a hardtop effect things, its a kind of brace

Rob

Quote from: Zxrob on November 28, 2019, 22:32All very informative

How does the addition of a hardtop effect things, its a kind of brace

Rob

A brace with a mounting in rubber ;-)

The extra mass of it on the windscreen frame shifts the frequency of the vibrations but I have not noticed any increased stiffness, only added weight high up.
Now, firmly bolting the hardtop down (and deleting the then superfluous softtop) thát would add stiffness.

I am toying with the idea of hard-mounting my hardtop. On the other hand it is really convenient to be able to take it off to do interior work.. What reccomendest thou, Petrus?

Quote from: Petrus on November 28, 2019, 22:43

Quote from: Zxrob on November 28, 2019, 22:32All very informative

How does the addition of a hardtop effect things, its a kind of brace

Rob

A brace with a mounting in rubber ;-)

The extra mass of it on the windscreen frame shifts the frequency of the vibrations but I have not noticed any increased stiffness, only added weight high up.
Now, firmly bolting the hardtop down (and deleting the then superfluous softtop) thát would add stiffness.

I have to disagree, here, Petrus.  The hardtop definitely makes a big difference to the general stiffness of the chassis.  My car is noticeably better over the bumps with it on.  (Mind you, I still love my soft-top too.)  Mind you. my hard top does clamp down very tight.

Quote from: Snelbaard on November 29, 2019, 08:38I am toying with the idea of hard-mounting my hardtop. On the other hand it is really convenient to be able to take it off to do interior work.. What reccomendest thou, Petrus?

You can bolt it to the fixtures of the clamps; Remove the receivers on the window frame/door sill, replace the four clamps by brackets. Only a few bolts to undo for removing the hardtop then.

That's actually a pretty good idea. For some reason, whenever I have people riding along in my car, the first thing they do is fumble around with the roof latch. I'd rather they didn't do that.

[edit: are there brackets available for that purpose?]

Quote from: Snelbaard on November 29, 2019, 13:12That's actually a pretty good idea. For some reason, whenever I have people riding along in my car, the first thing they do is fumble around with the roof latch. I'd rather they didn't do that.

[edit: are there brackets available for that purpose?]

Barbed Wire?    

From what I've read on here the fixings for the roof latch to the windscreen surround are very difficult to remove, sometimes requiring drilling out as the Torx head is prone to strip. So, something not to be done if you want an easy life.

Quote from: Joesson on November 29, 2019, 13:37From what I've read on here the fixings for the roof latch to the windscreen surround are very difficult to remove, sometimes requiring drilling out as the Torx head is prone to strip. So, something not to be done if you want an easy life.

Would an air-gun sort that? Or perhaps they are Loctited, meaning a fine soldering flame on the heads would work wonders.

My understanding is that Loctite or similar some bonding agent is used in manufacture. Would need to be a fine flame, carefully applied to preserve the finish of the latch.

Unusually for Toyota, the bolts are made of very soft stuff.  They're almost impossible to remove... they have the dreaded blue thread tape on them.

I managed to butcher the head of one in my car.

One day, I will drill them all out and replace with better kit.