[SFV1LE]

Originally Posted by NG329

It's flexible for a reason. Over uneven pavement that slight flex keeps the wheels planted and avoids bounce. If anything, it probably cost more to have stamped steel fabricated instead of a solid piece. GM strategically dialed in more compliance to allow better traction for an already uber stiff chassis.

Show me an exotic or top level race car with any stamped suspension parts like these--or sub exotic like a Porsche 911 or GT3.

It's a basic principle that a properly designed suspension itself, the shocks, struts, springs, swaybars, etc should be the only thing providing flex or compliance in a fully tunable or even dynamic way to "keep the wheels planted and avoid bounce" How do you tune/adjust the effect of a stamped suspension arm?

Doing this with unpredictable flexy/bendy pieces of stamped steel is not strategic. And stamped steel does not cost more than cast or machined billet aluminum or steel.

[Evansa22]

Originally Posted by NG329

It's flexible for a reason. Over uneven pavement that slight flex keeps the wheels planted and avoids bounce. If anything, it probably cost more to have stamped steel fabricated instead of a solid piece. GM strategically dialed in more compliance to allow better traction for an already uber stiff chassis.

My understanding is the shocks should control comp/rebound to keep the rubber on the road. Even with the stock suspension setup I was able to get all four wheels of the ground so not sure I buy the stamped steel arms do anything for that specifically.

[Mark R]

Originally Posted by SFV1LE

Show me an exotic or top level race car with any stamped suspension parts like these--or sub exotic like a Porsche 911 or GT3.

It's a basic principle that a properly designed suspension itself, the shocks, struts, springs, swaybars, etc should be the only thing providing flex or compliance in a fully tunable or even dynamic way to "keep the wheels planted and avoid bounce" How do you tune/adjust the effect of a stamped suspension arm?

Doing this with unpredictable flexy/bendy pieces of stamped steel is not strategic. And stamped steel does not cost more than cast or machined billet aluminum or steel.

I agree. GM saved money where most people would not see it, and that is OK. Every motor vehicle except maybe a Bugatti, Koenigsegg, etc, has some sort of weak spot, or a component where they could have done better, but cut costs.

Fortunately for us Camaro owners, the suspension arms are one of those things where many can choose to keep them stock, and others of us can upgrade fairly easily and in a straightforward way with stiffer suspension components.

But let's not pretend that the stock suspension arms are anything other than cheap stamped steel, with lots of bend and flex, that are detrimental to handling.

If you want to see those bendy steel arms flex, look at this video:

[Whitespeed]

Originally Posted by Mark R

I agree. GM saved money where most people would not see it, and that is OK. Every motor vehicle except maybe a Bugatti, Koenigsegg, etc, has some sort of weak spot, or a component where they could have done better, but cut costs.

Fortunately for us Camaro owners, the suspension arms are one of those things where many can choose to keep them stock, and others of us can upgrade fairly easily and in a straightforward way with stiffer suspension components.

But let's not pretend that the stock suspension arms are anything other than cheap stamped steel, with lots of bend and flex, that are detrimental to handling.

If you want to see those bendy steel arms flex, look at this video:

And if they had put in less compliant bushings, there would be endless complaints about the ride being too harsh. Compromises have to be made for all sorts of reasons. IMO, they did a pretty damn good job considering this car is competitive with cars costing 10's of thousands to even 100,000 more.

[Mark R]

Originally Posted by Whitespeed

And if they had put in less compliant bushings, there would be endless complaints about the ride being too harsh. Compromises have to be made for all sorts of reasons. IMO, they did a pretty damn good job considering this car is competitive with cars costing 10's of thousands to even 100,000 more.

I agree.

[synolimit]

BMR here, it rubs on my hood. maybe 1/16th x 3/4" long on both sides. didnt know it or hear it, just see the rubs on the hood now.

[NG329]

Originally Posted by SFV1LE

Show me an exotic or top level race car with any stamped suspension parts like these--or sub exotic like a Porsche 911 or GT3.

This is not an apples to apples comparison and it's not really relevant what Porsche does..... or any other exotic.

Originally Posted by SFV1LE

It's a basic principle that a properly designed suspension itself, the shocks, struts, springs, swaybars, etc should be the only thing providing flex or compliance in a fully tunable or even dynamic way to "keep the wheels planted and avoid bounce"

This is ABSOLUTELY not true. It's not a basic principle that suspension should be the ONLY thing flexing. The entire chassis flexes to some extent and spring rates are chosen to work best with the chassis that serves to be the foundation. This is true in any motorsports application. For example, in the motorcycle world, frames flex. Steel Trellis, as well as aluminum Twin spar all have flex properties that give the bikes their unique handling characteristics. Different metals with varying geometries, widths, etc can have their deflection properties easily measured. Take bicycle design for example. Frame stiffness can be increased in bottom bracket areas by increasing thickness, width, or even the angle where it joins the other componentry. A too stiff frame will fatigue the cyclist. In auto applications, a too-stiff chassis will burn thru tires like no tomorrow and likely not hook up under power or in less than ideal road conditions.

Originally Posted by SFV1LE

How do you tune/adjust the effect of a stamped suspension arm?

This is a fair question and in my opinion the right one. I'm pretty sure that the experts at GM had the proper data models to calculate deflection rates in the alloy that was chosen for the project. If I had to make an educated guess they probably had predetermined tolerances and deflection rates calculated before choosing the final design

Originally Posted by SFV1LE

Doing this with unpredictable flexy/bendy pieces of stamped steel is not strategic. And stamped steel does not cost more than cast or machined billet aluminum or steel.

"Unpredictable" is an assumption and implies that GM did not do their homework by not taking into account the deflection properties of the stamped component used. That's a tough sell with a 7:16 Nurburgring time.


By no means is the car perfect and it's not my intention to imply that it is the 'end all - be all'. I am saying that I would be careful before swapping out any chassis component randomly in expectation that it will make an improvement to an otherwise world class machine. This isn't your typical SS where you can throw the BMR stuff at it and transform the ride from good to great.


Just my humble $0.02

[NG329]

Originally Posted by Mark R

I agree. GM saved money where most people would not see it, and that is OK. Every motor vehicle except maybe a Bugatti, Koenigsegg, etc, has some sort of weak spot, or a component where they could have done better, but cut costs.

Fortunately for us Camaro owners, the suspension arms are one of those things where many can choose to keep them stock, and others of us can upgrade fairly easily and in a straightforward way with stiffer suspension components.

But let's not pretend that the stock suspension arms are anything other than cheap stamped steel, with lots of bend and flex, that are detrimental to handling.

If you want to see those bendy steel arms flex, look at this video:

I've seen this video and it really doesn't prove anything other than the metal bends when you put a bar to it. Unless a GM engineer chimes in and explains why they designed the part that way then it's anybody's guess at the moment.

Stiffer does not always equal better and most tracks are not smoothe. You do not want to increase stiffness on uneven/rough surfaces. You need compliance. Adding additional stiffness to a car that is already stiffer than most on the market (in spite of those flexy arms) might not produce the desired result -- faster lap times. This car virtually has no body roll. I personally can't imagine why anyone would pursue more stiffness.

I've actually had the chance to push the car a bit (hell, I've even totaled one). The chassis can be bouncy due to the stiffness over rough roads. Adding more stiffness to the arms will just exacerbate the sensation and ultimately make you slower.

[Drnick]

Thanks for all the informative info, sorry I opened a
“ Can of worms “, in regards to “tower strut brace”!
But when I did suspension mods on older gen
Camaro’s that was one of my easiest first mods!
Anyhow, 16-21 ft lbs on those bolts? Considering
It’s cast aluminum towers, I’d go with lower amount
But at factory, they were barely half that when I
Removed them!!!

[Evansa22]

Originally Posted by NG329

I've seen this video and it really doesn't prove anything other than the metal bends when you put a bar to it. Unless a GM engineer chimes in and explains why they designed the part that way then it's anybody's guess at the moment.

Stiffer does not always equal better and most tracks are not smoothe. You do not want to increase stiffness on uneven/rough surfaces. You need compliance. Adding additional stiffness to a car that is already stiffer than most on the market (in spite of those flexy arms) might not produce the desired result -- faster lap times. This car virtually has no body roll. I personally can't imagine why anyone would pursue more stiffness.

I've actually had the chance to push the car a bit (hell, I've even totaled one). The chassis can be bouncy due to the stiffness over rough roads. Adding more stiffness to the arms will just exacerbate the sensation and ultimately make you slower.

My personal experience swapping out the rear suspension components for stiffer and in most cases lighter ones is the ride has changed for the better. Not to say anything negative about the stock setup as I was skeptical there would be any improvement because it felt so great. It definitely feels more solid, their's no wiggle when the tires spin, no discernable deflection in the rear, feels like it hugs the road even more. I have no hard data, or track times to prove it, but my body tells me their's an improvement so I'm good with that.

[arpad_m]

Originally Posted by Drnick

Thanks for all the informative info, sorry I opened a
“ Can of worms “, in regards to “tower strut brace”!
But when I did suspension mods on older gen
Camaro’s that was one of my easiest first mods!
Anyhow, 16-21 ft lbs on those bolts? Considering
It’s cast aluminum towers, I’d go with lower amount
But at factory, they were barely half that when I
Removed them!!!

Well, the service manual does call for 21 lb ft, see below (I believe what you were referring to is the fastener named "front suspension strut upper mounting bolt").

[Drnick]

Correct, I’ll re-torque them, but when I originally
Removed those 6 bolts, they were hardly tight!
I’d say under 10 ft lbs! A 1/4” ratchet could’ve
Loosened them!

[NG329]

Originally Posted by Evansa22

My personal experience swapping out the rear suspension components for stiffer and in most cases lighter ones is the ride has changed for the better. Not to say anything negative about the stock setup as I was skeptical there would be any improvement because it felt so great. It definitely feels more solid, their's no wiggle when the tires spin, no discernable deflection in the rear, feels like it hugs the road even more. I have no hard data, or track times to prove it, but my body tells me their's an improvement so I'm good with that.

No doubt. Not to contradict my point from earlier, when you make the chassis stiffer you will make it more responsive and more communicative. All benefits. But you do this at the cost of increased tire wear and reduced compliance over uneven roads. On smooth surfaces, stiffer works fantastic. On uneven surfaces it becomes a handicap. I'd venture to say that GM may have even been able to beat that 7:16 Nurburgring time had the chassis been even more compliant.

If you get out of the ZL1 1LE and jump right into a Porsche GT3, the Porsche feels "softer" by comparison. It's just a more compliant platform. Having more compliance allows you to get on the power earlier coming out of most corners.

Think of it this way... if you've ever raced you know that you soften suspension settings in wet weather to maintain traction. You need more compliance. Stiffer settings tend to overwhelm a machine's ability to keep the tires glued to the ground. Same in the dry..... the closer you get to the limit the more compliance you need.

Lastly, Rigid setups are very unforgiving. The stiffer you make it, the less likely it will tolerate input errors.

Let's also take the C8 for example. It's down 150HP, and the chassis/suspension is very soft. Yet, it's very close in laptimes to the ZL1 in most tests while running street tires and not R compound. In spite of the understeer problems it still laps fast because the soft-ish chassis is very compliant. It's well mannered when it comes to putting the power down.

[MakCamaro]

As per BMR instructions, you should tighten the 6 x 13mm mounting bolts to 16 ft/lbs.