My BRZ seems to be going airborne

[Fastbrew]

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.

[tahdizzle]

[Fastbrew]

Originally Posted by tahdizzle

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



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

[tahdizzle]

Originally Posted by Fastbrew

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?

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.

[P@ul]

Need more droop, main spring + tender spring.

[OICU812]

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.

[Fastbrew]

Originally Posted by tahdizzle

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.

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.

[Dezoris]

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.

[Fastbrew]

Originally Posted by OICU812

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.

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.

[Fastbrew]

Not too low

[OICU812]

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.

[Dezoris]

Originally Posted by OICU812

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.

[wparsons]

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

[Fastbrew]

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.