Various Chassis Braces?

[Roadcone]

Which braces do you feel do something beneficial and which braces do you think just take your money?

The TRD member brace kit all seems legitimate to me. The rear bumper brace doesnt apply to USDM cars as we apparently have a beefier bumper 'cuz 'murica.

[wparsons]

What are you trying to achieve with the braces? Without knowing what you want it's really hard to say if they're worth it.

Does the car see track time? If yes, what tires and spring rates?

[Roadcone]

This was more a hypothetical question. Like fender braces, do you think they do anything or is it just taking your money?

if you just need a scenario here's two. Pikes Peak umlimited class aero, third member suspension and 335 slicks on all four corners. another would be a street car running something like a super sport that sees mountain use on a set of lowering springs.

[strat61caster]

The rear subframe bushing inserts (I have whiteline, I think there's other brands though) are well worth $50 for a car on public roads

A racecar would likely go for solid metal to replace the subframe bushings

I also have differential bushing inserts but I felt like it over-stiffened the rear and am considering removing some of those inserts.

TRD looks like overpriced bling to me, imho everywhere that brace kit connects is where a subframe attaches to the chassis, if that piece of sheetmetal is adding significant rigidity between those points then this chassis is as floppy as an NA Miata.

http://www.ft86club.com/forums/showthread.php?t=117053

[Roadcone]

braces. not bushings. Metal, not rubber/poly



I've driven a car with and without this kit. It's noticeable.

[strat61caster]

Originally Posted by Roadcone

braces. not bushings. Metal, not rubber/poly



I've driven a car with and without this kit. It's noticeable.

Then why ask if you already know?

Brace kits aren't common for this chassis, it was already designed to be stiff. It's not the 90's any more, you'll get more bang for your buck out of bushings.

Good luck!

Edit: To be clear, I'm not saying they don't matter, I'm saying the improvement is small.

[jamal]

None of that has ever really impressed me. "hey, check it out, we bolted one part of the floor to another part of the floor!"

I have heard pretty knowledgeable people say they make a difference but I haven't seen a lot of quantified data. Like maybe you take a chassis and twist it and measure force vs deflection with or without different braces.

If it's a race car, you are welding in a cage.

[norcalpb]

The front crossmember brace makes a huge difference imo. Same with a front strut bar.

Keep in mind these will make your ride less comfortable as the force of hitting pot holes will be transferred to you instead of the chassis.

A NASCAR chassis engineer said both the front and rear suspension should have any equal amount of support from braces, but adding too much stiffness from braces can exasperate understeer/oversteer depending on the current balance your car.

Like others have said, adding bracing to the rear suspension/subframe won’t do much and you should try bushings there if you want to make a bigger difference.

Perrin steering rack brace is also great, but if I could it again I’d privablt go for the Cusco steering brace.

[Gunman]

It's going to depend on how hard you drive the car. If you are pushing it, to where the torsional compliance is an issue, they the braces will help. General rule of thumb is to remove chassis compliance, so you can isolate it to the suspension, and tune it as needed.

That said, I have worked on a NASCAR cup car, which we had to remove braces to get it to turn. During the big coil bind era, the chassis needed some compliance, because the suspension didn't have any.

[Roadcone]

Originally Posted by Gunman

It's going to depend on how hard you drive the car. If you are pushing it, to where the torsional compliance is an issue, they the braces will help. General rule of thumb is to remove chassis compliance, so you can isolate it to the suspension, and tune it as needed.

That said, I have worked on a NASCAR cup car, which we had to remove braces to get it to turn. During the big coil bind era, the chassis needed some compliance, because the suspension didn't have any.

which is part of why i'm asking this on here. Cusco sell braces that are 100% absurd, there's zero reason to tie the subframe to itself in the rear yet they've got a brace for it.

[venturaII]

Originally Posted by Gunman

That said, I have worked on a NASCAR cup car, which we had to remove braces to get it to turn. During the big coil bind era, the chassis needed some compliance, because the suspension didn't have any.

+1 and that's really the only scenario where adding chassis stiffness would cause understeer/oversteer. If a car has sufficient suspension stroke, a stiffer chassis is always better.

[churchx]

venturaII: just that improvements are rather slight and there are better parts/areas more worth investing into. And i wonder if those slight improvements are enough to offset weight gains.

[Gunman]

Originally Posted by Roadcone

which is part of why i'm asking this on here. Cusco sell braces that are 100% absurd, there's zero reason to tie the subframe to itself in the rear yet they've got a brace for it.

Agreed, I've looked at some of them, and wondered what they thought they were stiffening?

[venturaII]

Originally Posted by churchx

venturaII: just that improvements are rather slight and there are better parts/areas more worth investing into. And i wonder if those slight improvements are enough to offset weight gains.

The gains on car with any sort of streetable suspension would be virtually unnoticable, in terms of measured performance. NVH will certainly change (and degrade overall) and is certainly the source of 99% of claims that the car has been 'improved'. But I'd expect that reducing overall chassis flex could result in better durability over high mileage and/or hard use. All that said, 25 pounds isn't a whole lot to be adding. A lightweight battery would fix that if you were worried.