How functional is the X brace?

[androo007]

Hi guys,

Thinking about cleaning the engine bay up, and although I like the originality of the X brace it does make it look cluttered.

Was considering replacing with a tower strut brace (like the normal ones you see) - but has anyone noticed any difference? Does the X brace offer a noticeable improvement?

Obviously don't want to mess up what Toyota got right if so. ....

[Ryan S]

Something I've often wondered.

[outrun]

Hopefully it does more than the cancer bars.

[JD]

It seems like the 4 point bracing of the cross brace, bracing rear towers against the bulkhead, would likely provide more torsional rigidity than just a 2 point tower brace that only braces the chassis across the strut towers. You would need to do some real testing, but having that extra flex resistance may also have a positive effect during weight transfer under acceleration and braking. I might be talking sh111te but it's an interesting topic anyway. I only run a tower brace in the bay.

[gnzyza]

I don't have the cancer bars or brace in the bay because I'm still tinkering. It's fine as is atm and Ive driven it hard, will see if I notice a difference when I put it back on.

Though it's good to have the extra structural rigidity that ties in the otherwise gaping hole.

[androo007]

That's a good point regarding the firewall mounting points.

With the mid engine etc I was trying to think where the flex would be - and that seeing as they applied it to the mk3 as well it must be more than just a novelty piece.

I hadn't thought of the weightshifting torsion too, that's a good point.

[C35Rob]

I don't think any of us are good enough drivers to notice any difference to how the car feels, but Toyota spent R&D money and obviously identified that it does do something, otherwise they wouldn't have fitted them cause they're not exactly a cosmetic improvement, even back in the late 80's there will have been some computer modelling identifying flex in the chassis

[pbmr2]

Used to have a sloped driveway, reversing up it you could hear and feel the chassis flex when hitting the ramp (2mph) in reverse at a diagonal angle. If the chassis is moving that much at super slow speeds, imagine what it's doing blatting round a corner at 70.

Also the engine mounts are fixed to the rear towers, so the weight of the engine is moving around attached to more-or-less the same part as the cross brace.

The odd things is that the brace isn't a tight fit on the bolts, so any hard movement could move the brace under the bolts anyway. But the bolts would limit that movement and resist it a little.

There are probably better ways to brace a chassis but keeping it easy to work on might have been in the thinking of the designers.

[C35Rob]

The brace doesn't need to be a tight fit over the top mount studs, if the nuts are correctly torqued then the clamping force exerted on the brace will be more than enough to stop it moving, you never want any lateral loading on studs like that, their job is to provide axial clamping force.

[androo007]

Good points.

OK in that case I think I'll spruce up what's there instead.... thanks!

The only real upgrade then is the TRD bar - but at rates now way over priced. There are some rough looking copies around but I guess original is best.....

[acf8181]

Oh yeah...my X brace is still in the loft...forgot about it....kinda says it all

[HighwayStar]

I think the fact the TRD brace exists in the shape it does and the factory brace is installed at cost and shares the design answer the OP's question.

I recently saw one of the TRD copies on a TRD kitted car at a MR2DC meet and it looked pretty good to me the owner of an original...

[aussieGT]

Good points.

OK in that case I think I'll spruce up what's there instead.... thanks!

The only real upgrade then is the TRD bar - but at rates now way over priced. There are some rough looking copies around but I guess original is best.....

I was lucky enough to buy one of the last TRD rear braces brand new and in it's box, some of the welding on it is a bit rough looking in places, so maybe the copies are trying to emulate that as well.

[kirk]

I love the design of the TRD brace. I have one myself which is currently off for powder coating. The only thing that concerns me is if I want to fit a GT4 charge cooler I may have to get rid as I have my doubts it will fit unless anyone knows the answer?

[jon]

I love the design of the TRD brace. I have one myself which is currently off for powder coating. The only thing that concerns me is if I want to fit a GT4 charge cooler I may have to get rid as I have my doubts it will fit unless anyone knows the answer?

I've got a ST205 chargercooler and TRD brace. Fits fine, although I have polybushed engine mounts to reduce engine movement which probably help.

[kirk]

I've got TRD engine mounts all around. Not quite as sturdy as poly bushes but certainly stiffer. I take it clearance is quite tight so too much movement and it's likely to hit it?

[androo007]

How much is a powder coat?

[2mad]

I drove my car after work with no x-brace .. the back of the car was like jelly .... refitted mine pronto

[jon]

I've got TRD engine mounts all around. Not quite as sturdy as poly bushes but certainly stiffer. I take it clearance is quite tight so too much movement and it's likely to hit it?

There's about 1cm of clearance at the closest point. I've actually got poly inserts rather than full polybushed mounts, so there's still a bit of engine movement. No signs of the chargecooler rubbing against the brace after a couple of years.