Alternative to lowering
 

If you wish to maintain stock ground clearance but get most of the advantages of lowering springs fit a set of these:

https://mcasuspension.com/traction-mod

Then crash bolts front and rear to get the static camber settings you want.

Cheaper and as effective.

Lowering the CG by an inch really doesn't affect handling much.

What about combining these with some moderate lowering springs (TRD, Eibach Pro-Kit, RCE Yellow) on stock shocks? Best of both worlds?

And I didn't know we could use crash bolts in the rear. Part number? I would like to reduce the negative camber in the rear.

Whiteline offer a camber bolt kit to adjust the rear camber.

OR go with RCE yellow, it only 20mm and I have never ever scrape on anything so far.

then camber bolt in the front.

and LCA arm in the rear.

This. RCE yellows, camber bolts up front and SPC rear lower control arms.

That mod doesn't increase spring rate, which is the goal of lowering springs for some people...

Not knocking it, but it definitely isn't a replacement for most people.

You could increase the spring rate while maintaining stock ride height and using the MCA brackets. The BRZ has a pretty effective spring rate from the factory. The lowering springs have to increase the spring rate.

Why do you want to reduce rear camber? Factory camber is pretty good, just not always equal right to left, which is the main reason my mechanic fit crash bolts, to equalize rear camber. I asked him to also max it out so it's about 1.8 degrees each side now.

Doesn't the rear gain negative camber upon compression? So to optimize the contact patch in a corner you would want to have little static negative camber to keep as much tire width on the ground as possible. Correct me if I'm wrong! I thought it'd be best to get a lot of front negative camber and close to zero rear negative camber.

I never knew people got lowering springs for anything other than lowering before this.

The chassis is Impreza which is awd. Removing the drive from the front axle means the engineers needed to dial in more understeer.

You want around 1.5 degrees rear camber and about zero front camber for normal street driving. Rear axle camber gain helps stabilize the chassis as you feed in more power. The front axle is limited somewhat by the strut design, although the Porsche Boxster/Cayman initially used four wheel struts and was a superb handler.

Lowering changes the static alignment. The reduction in roll moment from lowering the CG is pretty modest. You need higher rate springs when you lower the car to prevent bottoming out.

The MCA traction aids reduce anti squat almost exactly as lowering would do, though MCA recommends their brackets regardless of suspension height.

What the heck is anti squat?

I can see how the MCA suspension mod can maybe lower the rear end a little, but what do you do about lowering the front end?

I wouldn't go with lowering springs because 1) this car doesn't need higher spring rates 2) shorter springs means less suspension travel which negates anything good about a lower CG 3) blown dampers. But I could see moving the pickup down to lower the car and maintaining the stock suspension travel being a good thing if you can lower the front too.

It is the force applied to the chassis by the alignment of the suspension arms in a longitudinal direction. It is essentially the same as roll resistance provided by the roll centres but that is across the car.

A quick google will get you a diagram.

Weight transfer is carried into the body by springs acting on the suspension arms. Those suspension arms generate leverage. If the leverage is angled up into the body (as the rear trailing arms on the BRZ are) then weight transfer under acceleration is resisted by the springs but that resistance is partly direct by the spring acting on the spring perch and partly apportioned to the body by the angle of the trailing arm.

Fitting MCA traction aids reduces this leverage effect.

The benefit is gained in transitions, such as accelerating harder out of the corner. More of the weight transfer goes directly through spring compression and less through the trailing arm. The ride is softened, the contact patch is stressed at a slower rate and, if the geometry change is correct, more grip is available to accelerate and corner the car.

MCA did a lot of work testing their brackets to ensure the desired effects actually occur. They do. These brackets make the BRZ easier to accelerate out of the corner. You get more power down to the road earlier. Lowering the suspension has a similar effect.

The drawback is more suspension movement for a given weight transfer. Fitting higher rate dampers to the rear reduces this negative. Lowering springs are stiffer so achieving this effect by lowering springs automatically reduces spring compression effects.

I use my BRZ year round for daily driving. I like the softer ride to the point that I also fitted rear springs from the 2017 model year. That helps traction also. The Edelbrock Supercharger can develop enough torque that reducing anti squat can deliver more grip allowing more throttle to be used earlier.

Another benefit of the MCA brackets whether lowered or not is the transitions effects on the springs are slowed down a bit which, depending on how you like to drive, can make you faster. Some may find this makes the chassis less responsive for the same reason.

There is no perfect setup, just a perfect setup for a particular driver.

MCA traction aids have no effect on ride height. That is why they were thought of in the first place. Fitting these brackets is the only way to reduce anti squat without lowering the car.

The body end of the trailing arm is lowered. The spring perch remains at the same height.

What changed is the arc of travel of the trailing arm. It begins more horizontal which reduces anti squat leverage. That's all it does.

Your reasoning is why I fit these devices and also softer rate rear springs from the 2017 model. The 2017 factory car handles better than previous model years for this reason: more front roll resistance and less rear roll resistance. This pattern has been consistent at the factory beginning with the initial differences between the FRS and BRZ in 2013. In fact I'd be willing to bet that all the really good aftermarket spring sets up the front spring rate more than the rear % wise. Certainly fitting a stiffer front bar always improves the handling balance. Every tuner producing a better BRZ chassis goes this route.

This is consistent with what I've read elsewhere. Stiff front, soft rear, with big bar up front and little bar out back. It's a proven path for setting up the handling of a front engine, RWD car. Makes sense in theory as well.

I'm still wondering about optimal camber front to rear. I'm thinking with front crash bolts and camber bolts you could get -2+ degrees of camber up front with stock suspension or moderate lowering springs (~1" drop) and a big front bar and then something like SPC rear LCAs and less camber, maybe around -1.5 degrees out back plus the MCA traction mod sounds like a super solid, somewhat affordable setup.

Edit: Also, do these control arms achieve the same effect as the traction mod? Although they mount at the stock location, it has some drop integrated into the arm. Idk, just thinking out loud! http://www.stance-usa.com/main/produ...ith-60mm-drop/

Dont know if you are a shill or trying to justify your $350 bracket purchase by making bold claims, but I smell so much BS in this thread.

Do you guys even track your cars to suggest BRZ needs more roll stiffness in the front? Steady state cornering behavior of the BRZ is already mild understeer, which gets more recognizable with higher grip tires.

2017 cars have softer rear springs but stiffer rear swaybars.

Nothing you change with the camber and suspension links will provide the same reduction in lateral load transfer as a 1" lowering would provide.

Ask our Australian friends who do track this MCA mod successfully. That's how I found out about these brackets. Some hard numbers are posted here:

http://www.ft86club.com/forums/showthread.php?t=112859

You can make of this what you will. The described improvements are real.

Modified LCA do not usually change the anti squat because they do not change the body mounting point.

They could do so if the hub end were made sufficiently high relative to the body end but they generally make these only to accommodate a lower spring mount.

There's a lot more to it than that... you have to consider motion ratios to get wheel rates, and frequencies. Once you factor in wheel rate on a stock FRS or BRZ, the rear is effectively softer than the front even with stiffer spring rates out back.

Not even slightly. The MCS mod lowers the front pivot of the trailing arm, not the overall ride height. Those arms just lower the shock mounting point to lower the car.

MCA brackets also eliminate wheel hop. I fit my summer tires today and did a controlled wheelspin standing start, no wheel hop at all and also a nice chirp when into second.

Powerslides are now also very smooth and controllable, no tank slapper return to straight ahead.

My bad, I need to read up more on wheel rates and motion ratios. Not trying to spread any misinformation.

Yeah I figured those RLCAs were different than the traction mod. Thanks for the clarification.

The mention of motion ratios reminds me to also mention the "jacking" forces induced by the angled of the suspension arms at any given point in their ranges of motion. This is how anti squat and anti dive forces are created. Roll stiffness is also affected by suspension arm angles, in this case it is described in relation to roll centres. Lowering springs change the effective range of motion and thereby also the initial roll and jacking forces. The biggest effect of lowering springs comes from the reduction in ride height effects on suspension arm angles. The effect on weight transfer torque of a 12-25 mm drop are minimal in reality.

MCA brackets create in effect a softer spring rate in relation to spring compression because more of the weight transfer torque is carried directly by the springs. MCA suggests increasing the rear damper rate if the transient effects of their brackets create faster roll rates than desired, just for example.

There is a lesson here: making your own suspension modifications is tricky. Bottom line is only the actual driving experience will allow you to find the correct set up for your driving style and environment, be it aggressive or track oriented or occasional canyon runs.

Consider how you like the car to behave and where you will be driving it. Then find the parts suppliers who have been there and done that and buy their stuff. The price of those parts should include the cost to the maker of some heavy duty road testing. I know Bilstein for example won't build after market shocks until there is an aftermarket and then they build a specific shock for a specific application. Even their adjustable kits are designed for your car specifically.

MCA did the same and extensively tested their brackets to ensure the stated results set achieved. Whether you want those results is the only question to ask yourself.

That's a direct result of the reduced anti-squat. It lets the rear suspension work more under acceleration forces.

That's what our Ozzie friends are saying in their introductory thread. That's why I bought a set.

Everyone who makes their BRZ faster ends up moving roll resistance to the front axle. These MCA brackets are the only mod that addresses the unfortunate legacy (har har) which resulted from fitting the Impreza rear subframe assembly into the BRZ virtually unchanged.