My BRZ seems to be going airborne
 

Now that I have put on my Feal 441 coilovers, lower control arms and other suspension bits + changed to 17x9 wheels and 255/40/17 tires - I have noticed a change:

My traction control is coming on in situations that it did not before and surprising me. I can't easily break the car loose from a standstill (good thing until I add HP) BUT - if I am driving fast on the highway and on entrance/exit ramps - the car must be catching a little air.

This gives me pause and makes me think about things like droop. I am pretty sure I shouldn't be seeing the traction light come on since I believe I was hammering the BRZ pretty hard before the modifications.

Question: Is this typical after making these adjustments or is this a symptom of a potential issue with high speed maneuvering? In my mind, it is obviously not a good thing to have added all this rubber and have it off the road. I suppose this is where things like proper ground effects can help keep the tail down. It just seems weird that I would start noticing it now. It could be that I am just driving the car differently too.

:popcorn:

Oh come on -

It's a simple (if not slightly stupid) question - does anyone else have the TC light pop on during highway speeds and should I even spend any time thinking about it?

PS: No -it is not like the Isle of Mann
http://www.ft86club.com/forums/attac...7&d=1339523170


I can't even feel a loss of traction. That's what is bugging me.

I have no idea how to answer anything you post. You are saying that you are getting your traction control indicator while driving aggressively.... Yup.

A man walks into a doctor's office and says: "Doc, it hurts when I do this."
The doctor replies: "Then don't do that."

Don't mean to offend, but everyone gets a traction control indicator when they drive this car aggressively.

You are saying that you are getting the indicator in situations where you hadn't before.
Well need a bit more detail before any real assumptions can be made.

Need more droop, main spring + tender spring.

There's much to be considered here that you haven't shared.


1.) how much lower are you from stock now?
2.) what settings in coils have you changed in regards to damping and rebound?
3.) did you purchase toe links band LCAs?
4.) what is your current camber, caster and toe from alignment you had done when installing these items?

All these affect how the car feels and reacts when lowering and diverting from stock and are all important to have within proper ranges for car to drive effectively.

Thanks for the response.

My main concern is that I have perhaps lost droop/traction by upgrading the suspension. I cannot picture any of my highway driving resulting in lifting one of these larger wheels off the ground to the point where it slips enough to kick that light on.

I guess I will get it on the lift and check to see if everything is operating correctly. In the meantime - I will watch out for low flying geese.

You never answered how low you are compared to stock. The TCS will be freaking out more with a lowered suspension and what you probably are feeling is your suspension set way too firm as that air/bounce feeling is tied to overly damped suspension.
Which could also be causing your TCS to activate.

Street suspensions need travel and damping.

1) 3.5 inches ground clearance at the front lip in the tire well. I was aiming for about an inch max and leaving reasonable gap in the wells for the tires
2) Feals for BRZ = 7K front 6K rear swifts - one-way adjustment at 1/2 the range
3) Yes GTSpec adjustable toes (will have to dig up the settings for caster/toe)
4) 3 degrees camber on the rear wheels / damping is set to the middle of a 30 click range - a somewhat stock ride / FEALS are one-way and Odi says that the control mainly alters rebound to make it "easy to tune"

The main thing is I will head in to the shop and get it checked. My feeling is that something needs adjusting a bit because I shouldn't be losing traction like that.

Not too low :)
http://i.imgur.com/VDtVmWQ.jpg
http://i.imgur.com/xb1ywie.jpg

Ok at this point results from your alignment are needed.

(-3) degrees camber on rear is extremely aggressive to say least. However as many will say (toe) is most important to wear and also how the car will react.

Are you racing regularly this car or plan to? If not you should be more like -1.3 to -1.5 rear and -1.7 to -2 up front zero toe all around. That would be far more realistic for a sporty street driving car with natural feeling. Alignment is #1 and within ranges then you can properly adjust coilovers to suit your needs. Until the alignment is good and within specs of intended use no need to assume or try anything else IMO.

Also ya you're pretty low as Dezoris mentions lowering that much on it's own will affect (a lot). -1.5" lower then stock seems to be the breaking point where one should consider other things past that low if want to retain a good feeling and driving car. Ie: roll Center front bushings, axle risers etc. I'm lowered -1.4" from stock and will not go lower for those exact reasons.

Start with alignment need to get rid of that extreme camber in rear as mentioned. Keep toe near zero front and rear. You want those dampers at 8/10ths soft. Possible that may even be too firm. If that does not help you will need to raise the car to get more suspension travel. Could be a problem with not enough stroke namely in the rear.

I would bet that it's all in the rear alignment, -3 static is a ton of rear camber...

Thanks for the info - eyes are also pointing at the rear sway bar being a bit stiff. Basically, lifting the inside wheel and putting the weight on the outside where it should be. I hadn't thought about that yet. But, then again - I am learning a ton with this vehicle. The car is being setup to find a happy medium between street/DD, some autocross and a bit of HPD at the track for fun.

I am going to get it on a lift soon and check settings with the pros. It's not bad the way it is - just a little odd to see the TCS bitching at high speeds on slightly contoured straights and curves.

Anyways - thanks again for the great pointers.

are you sure everything is installed correctly? I would be suprised if a 1" drop would cause in-lift with a stock rear sway bar.

With more significantly lowered cars, roll center is usually to blame for inlift.

don't try to fix in-lift with tender springs. Get better/longer main springs if your springs are too short and don't get you to full droop.

Have you tried playing around with the damper adjustment? If the adjuster only alters rebound I am guessing that would be a good place to start. It's free and easily repeatable.

That's where I am going to start. Also totopo, it's not a stock sway bar. It has an adjustable Whiteline + the brackets. It's setup pretty stiff. I think between these two items the rear wheels will stay down a little better...

You can also reset the system in tech stream as you're supposed to do when you lower the vehicle. :) might make the difference.

Wouldn't it show up with a warning light just rolling around 'regular' if it needed it? I have a trip to the dealer planned for a stab at cricket removal. I will ask them if that needs to be done too...

Thanks!

uhhhhh..... aren't those spring rates like double the stock ones? If so why are you running stiff anti-roll bars? Definitely loosen that rear anti-roll bar. If you want to change the balance, then I would think it's better to loosen the front anti-roll bar.

I think they are 2.7K front and 3.5K rear as stock on the BRZ.
And these are 7K and 6K. So, quite a bit of difference.

I want it flat as hell in tight cornering so I guess I am getting what I wanted. It's job is to lift my inside wheel and that's what it is doing.

I will take it out and run some cones and take it to the track, I think.

Honestly, this is the most dialed in sports car I have ever owned so some of what I am experiencing is probably driving a properly setup car for the first time.

It just threw me for a loop at higher speed. I hadn't thought about that yet!

Tweak and learn, I guess.

Can't wait for my first HPDE at the track.

Given the motion ration at the rear OP has gone much softer at the rear than front.
Standard f/r spring rate at the wheel is approximately 2.4k/1.97k.
After market is 6.3k/3.4k which is quite a difference f/r. I would have thought that a stiffer rear bar would have been appropriate in this case.
I understand this is not addressing OP's problem.

You know, I have been thinking about it this evening and I am not sure this is a problem. It's just different than what I am used to and I am not used to a suspension dialed in like this. I think playing with the Feal settings a little and taking it out to the track with an experienced driver (friend happens to be an instructor - woot) and letting them give it the once over on the track and around some cones will be more beneficial than me making guesses.

I think making sure that the options are set correctly in TechStream is a good idea. I will check with someone who has it running (dealer or my tuner) or maybe delve into it myself. Looks cool and I am an IT guy by trade.

Anti roll bars are more important in autox w frequent transitions that road courses. Roll doesn't really do much for road courses. Don't sacrifice real traction for subjective roll. The stiffer suspension you have, the lighter anti-roll bars you need. Taking out your rear Anti-roll bar to prevent inlift will help traction more than having less roll.

Roll does not equal weight shift. It means nothing in static cornering and only really has meaninings in transitions and driver subjective preference.

Did you ask the feal people what antiroll bar you should be running? I have a feeling those spring rates are set up for stock Frs antiroll bar.

Super flat handling is NOT ideal, or else race cars wouldn't have suspension.

That's a great point - I am going to get the car parameters set straight in techstream - do a little driving to be able to reproduce the behavior - there is an exit ramp near home that has done it twice - see if it changes after the techstream. In the meantime - I will fire an email off to Odi at Feal and tell him the config/behavior and see what he says too.

Thanks for the responses!

Are you coming from a FWD car? The last thing you want to do on a RWD car is lift the inside rear tire. Lifting an inside wheel on a FWD car isn't ideal, but it's usually the only way to get them to rotate.

Forget everything you know about setting up a car if your only experience is FWD, you're working with a totally different beast here.

No - a Jeep and before that a WRX. I think the bar in back might be a tad big. Fun stuff! Cool to have a car that is adjustable.

It needs it even if you lower the car just 3/4" ...

Here's a few tidbits from toyota:

Perform VSC sensor neutral memorization

- While obtaining the zero point, keep the vehicle stationary and do not vibrate, tilt, move, or shake it. (Do not start the engine)

- Be sure to perform this procedure in a level surface (with an inclination of less than 1 degree). DO NOT PERFORM THIS PROCEDURE UNLESS YOU CAN CONFIRM YOU ARE ON A LEVEL SURFACE LIKE A CALIBRATED ALIGNMENT LIFT.

When VSC sensor neutral memorization is performed, the yaw rate and acceleration sensor and the steering sensor zero point calibration are performed at the same time.

(E) connect the techstream to DLC3

(h) enter the following menus: chassis/ ABS/VSC/TRAC / Utility / VSC Sensor Neutral Memorization

So I can ask for this to be done at my dealer ship next time I take it in? I havent had these issues really after my sportlines install but I can break traction easier, since im planning on adjusting my setup to include coils, lcas and toe arms, I wanted to be prepared for what to expect.

Good luck OP.

why so much rear camber, you absolutely do not need that. i keep trying to take more out and add more in the front. currently i'm at -1.5 rear -2.1 front. rear toe in, front toe out. car handles like an animal.

i'm also running 6k front 7k rear (AST) and have zero issues at high speeds. seems like something is off here for you...

Rechecked - it's running -2.5 camber at rear. The Racecomp (not whiteline) was set at full firm in the rear. Pulling that back to midway to match the front.

The front camber is tapped out on the Feals at about ~-1.7/8 - I am looking to add Vorshlags to get it to more closely match the rear.

Why this much camber? I like the way it corners / feels /looks (other than my inside tire lifting due to the overly stiff rear sway which should be tweaked this afternoon) - I like the way it handles without needing to brake. I just don't like losing traction when accelerating out of corners! (Or at high speeds over contoured pavement!) It looks really good too :)

Tow is 1/2 degree out at front and 0 at the back.
Caster is currently not adjustable in my current setup. I believe the Vorshlags add in a degree of positive caster on the front plates.

It's fun playing with this stuff. Once I get the rest of the car dialed in with the turbo, etc - I am looking forward to corner balancing it to dial it in perfectly.

Thanks to everyone in this thread who has responded and offered advice. Suspension is something I am just learning. I know what I like but how that translates into physics, mechanics, settings etc is really awesome to dig into.

Stating the obvious here perhaps, but have you checked your tire pressures in case they're over inflated? Also -2.5 rear camber is quite a lot for a street car that doesn't see the track often.

TP is good. I spoke with Odi at Feal and he mentioned a couple of things -
1) the amount of camber in the rear is not a great matchup for cone dodging.

Basically, he said that if you ran the car through the cones with limited camber and the factory sway bar - he is guessing that the time would be faster than with the current setup. I believe he is right!

He also pointed out that there is a little extra front camber adjustment at the bottom of his setup with the little cam bolt.

Anyway - I had the rear sway bar set to medium (may go to totally soft later). I am going to adjust his one way system to have more rebound - that should stick the tires down better.

I am going to drive it awhile as is and then modify as needed.

The car is beautiful as is from the factory. It is soooo much fun to play with!

I will probably end up reducing the camber rear and front, softening up the rear a bit to increase traction and get ready for adding the turbo. I want the rear to be planted for that. It will be an interesting puzzle to get dialed in for daily driving and "just for fun" cones and tracks.

You want less resting camber in the rear than the front. If you're going to go with ~-2* up front you'll want about -1.25* to -1.5* in the back. The reason is that the front struts don't gain any real camber during compression but the rears do, so under cornering you'll be getting even more unbalanced camber.

toe in the rear...it will make it more stable. put the bar to full soft in the rear (it will still be stiffer than stock)

take out rear camber to like -1.5 and dial in front to somewhere around -2/2.3. toe out the front. i promise you that will handle really well. i thought the car handled like crap when it had more than 2 of camber in the rear...at one point when my old suspension was settling i was at -3.1 and i did not like that at all.

Yes.

As a side note - I stopped in to the dealership (Subaru) today to let them have a crack at cricket removal. I brought up this procedure and they looked at me like I was from the moon. One of the managers stepped in and said he was interested in learning more (Amazing!) and thought this might be a Toyota thing.

I am going to send him some info and see what they say. (I am sure that whatever applies to the GT/FRS goes for the BRZ.)

I was expecting the same type of response followed by "it will void your warranty" lol

We shall see I guess.

I sent him the link to TechStream on the Toyota site. Also - the info that someone provided earlier in the thread. I asked him - "Do you have the tool and a level surface?" He said he would get back to me. I told him not to sweat it too hard as I could probably figure this out with Toyota/Scion and a phone. Or - just not worry about it :)