Suspension dilemma
 

Hi, I'm looking to get new suspensions on my BRZ. I'm quite new to this so I've been looking around for options and wanted to get some inputs. ^^; I use my BRZ mainly for DD but want to lower it for performance to turn more tightly around corners and of course for looks :thumbup: I am considering anywhere from 1.5"-2" (38-50mm) drop.

Still deciding on whether to get springs or c/o's =/

If I were to go springs, I'm thinking either Eibach Pro-Kit or Tein S Tech.

If I were to go c/o's, I'm thinking Blistein B14 or KW V1 since it seems like they are made for ppl who don't know much about suspensions like me :lol:

So as I stated before, I'm still learning about suspensions so any explanations, links, references, etc. would be greatly appreciated :thumbup:
On that note, would I need LCA? or new shocks for the springs? or anything else for that matter? :bonk:

Oh and as for the budget, ideally anything below $2000

Thanks in advance.

On a $2000 budget you have a pretty large selection pool. Go for the KWv3s. If you're looking into getting something cheaper so you can also get aftermarket top hats or LCAs, try Bilstein B14s, KWv1s, or Fortune Auto 500s with Swifts.

You'll want the LCA if you want to correct camber in the rear. With a drop that much, you're looking between 2-3 degrees of camber. If that's too much for you, start looking for LCAs. For your front camber some coils like the FA500s have a top camber plate while the Bilsteins and KWs don't. There's a good market for aftermarket camber plates as well. Grab OEM crash bolts and you'll have about a degree in the front. With a camber plate as well, you'll have it adjustable to about 2 and a half degrees.

the KW V3's get too technical and i feel like i'm not educated enough to know how much spring rate and etc. i need or want. so that's why i'm opting for B14's or V1's.
so basically if i drop to almost 2" i'll require LCA's,camber plates, and crash bolts to support the 2 degree of camber?

KW V1's or RCE T0's would work really well. The have a slotted front strut, and if you got the OEM crash bolts, at the ride heights you want to be at, you would have no problem getting -2.5 degrees (probably more) in the front (with the stock tophat). This would help offset the camber in the rear from the drop (so you wouldn't need camber plates and may or may not want rear arms depending on where your rear camber is at).

Everyone's different when it comes to alignments after suspension changes. With around 1.8 inch drop on my Fortune Autos, my rear camber brought me to 2.3. My front with camber bolts brought me to 2.5. I've seen numbers range from 1.5 to 3 degrees in the rear.

And if you can afford, the v3s will be worth your money. You can learn suspension. But if you get the v1s and decide later you want the v3s, you'll be out a good chunk of cash. Out the box they're perfect already and when you're ready you can dial the suspension as you please.

EDIT: There have been a lot of people parting out lately and I've seen multiple sets of v3s on the FS section with less than 8000 miles. Plenty of other coils as well. Just note that often times the warranty does not transfer with new owner.

is there a rule of thumb or something to decide how much camber i need for the amount of drop in height? so LCA's and plates are not necessarily needed? but i'm guessing it would be beneficial...

when you say 'dial the suspension' i assume you're referring to the stiffness not the height? and i also assume with the v3's you can adjust the height whenever i need to?

also i was looking into sway bars and how do i determine what size to get? i get the basics of the bigger the sway bar the stiffer the sway bar. i don't want to overkill and waste money by getting the largest one.

I will say it sounds like you're solidly in the coilover camp with the kind of drop you're looking for. That's really too much for the stock struts to handle and anything going that low is not being designed with performance in mind.

The issue is if you lower with something like springs, you can end up with a lot of rear negative camber and very little negative camber in the front. When dropping, the rear gains -ve camber a lot more than the front so if you drop an inch, you might be at -2 in the rear and maybe -1 in the front, if that, if you don't have any other camber adding hardware. This gives more grip to the rear relative to the front.

So to even things out, depending on what you want to do with the car, it's a good idea to get a camber plate or camber bolt or something for the front. A lot of coilovers slot the upper hole of the knuckle interface so it has additional camber built in, making an aftermarket bolt of plate unnecessary (depending on how much you want).

If your primary concern is looks, less -ve camber in the front will be better for tire wear. If your primary concern is handling, you probably want at least as much -ve camber in the front than in the rear.

what do you propose is the ideal amount to drop for performance?

You can drop as much as you want, but you introduce certain problems as you go lower and lower. These problems can all be remedied with enough money, but at the extreme end you essentially are building a slammed race car and customizing the chassis to compensate, etc.

The consensus I've found is that 1" (maybe a hair more) is the limit for optimal handling performance without too much sacrifice in the chassis dynamics. Too low in the rear and you first introduce excessive negative camber. Too low in the front and you first don't have enough negative camber. Camber bolts and Whiteline tophats will allow plenty of camber adjustment for the front, and LCA's will allow camber adjustment in the rear (or camber bushings, but they're tricky to use).

Going really low can result in too little bump travel and the roll center getting screwy, as well as some other issues. Roll center is the imaginary point that the car's body rolls around. This is where you need an excessively stiff setup to prevent the slammed suspension geometry from further ruining the car's handling. Slammed cars are typically no good at the track.

I think -1.5 to 2.5 up front and proportionally -1 to -2 in the rear is a reasonable range to start with. The more you have up front, the more you'll want in the rear to promote balance, but typically more up front. If you never drive the car aggressively, or it's rare, you'll probably want a bit less. The more aggressive you are, the more negative you want. Ideally you want just the right amount of camber for your driving style that provides even tire wear.

I'd say around an inch on stock struts. Anything beyond that and you're just going to overly wear the struts because they just aren't designed for that kind of drop. The two most popular performance oriented springs IMO (RCE and swift) drop the car about 0.80 and 1 inches respectively. If you want much more, just go coils.


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So you're suggesting that once I go lower than 1" I should start thinking about camber adjustments?