Better handling by removing/reducing swaybars?

[MGPAX]

I'm trying to get a bit more rear end rotation in my spirited daily driving with stock suspension parts. '14 BRZ
My tires are stock and at 50% or so and wearing perfectly, so I don't want to
change the alignment setup too much.
I'm putting on an adjustable rear sway (Perrin 16mm 30%-100% increase approximately)
And Whiteline top hats that will be set to add .75 degrees additional caster without adding camber. (Total caster would then be 6.5 I believe.)

I'm hoping to get a subtle increase in rotation without any snap oversteer or uneven tire wear.

Seem like a decent plan?

[Captain Snooze]

Originally Posted by MGPAX

I'm trying to get a bit more rear end rotation in my spirited daily driving with stock suspension parts. '14 BRZ
My tires are stock and at 50% or so and wearing perfectly, so I don't want to
change the alignment setup too much.
I'm putting on an adjustable rear sway (Perrin 16mm 30%-100% increase approximately)
And Whiteline top hats that will be set to add .75 degrees additional caster without adding camber. (Total caster would then be 6.5 I believe.)

I'm hoping to get a subtle increase in rotation without any snap oversteer or uneven tire wear.

Seem like a decent plan?

Rear toe has a huge influence on rear end stability: the more toe-in the more stable. From dodgy memory @CSG Mike runs zero toe at the rear but he knows how to drive. Myself 0.5mm a side. BUT don't forget compromise! Reducing toe-in makes rotation easier but affects stability. Adjust little by little.

[CSG Mike]

Originally Posted by Captain Snooze

Rear toe has a huge influence on rear end stability: the more toe-in the more stable. From dodgy memory @CSG Mike runs zero toe at the rear but he knows how to drive. Myself 0.5mm a side. BUT don't forget compromise! Reducing toe-in makes rotation easier but affects stability. Adjust little by little.

I run zero on stock or near stock cars in the rear, but myalignment preference will change depending on what exactly is on the car.

As a general rule of thumb, I recommend 0 for stock/near-stock cars for experienced drivers, and 1/16" total toe-in for most modified cars.

[venturaII]

I run zero rear toe as well, and a slight bit of toe out up front. Yes, the car will wander a bit on the highway and is very responsive to input at any speed, but I like the ability to get it to rotate at will, and it makes a nice compromise between a super aggressive autocross alignment and one dumbed down for minivans. If I were going to Bonneville, I'd go a little more conservative, but I feel like it really wakes the car up, which is why I bought it in the first place.

[MGPAX]

Here's my suspension.
Toe is virtually zero all the way around from the factory.
I'm going to fix the small difference in left right rear toe...which is already
just barely off zero. (Is this just odd or is rear toe always measured from the
back of the car?...as is reverse of front?)

I'll have it checked again once parts are on.

PAX

[wparsons]

Originally Posted by Shankenstein

Roll by itself isn't inherently evil. The side effects of roll can lead to reduced handling.

Redistributing weight (tire loading) can reduce the available grip. Flex in the bushings and chassis can lead to poor geometry.

Too much roll for the suspension geometry can really compromise the contact patch too. On a car with good camber gain, roll isn't so bad. On a car with poor camber gain (or zero, like our front ends) it's pretty bad, and requires more static camber to compensate.

[Racecomp Engineering]

Originally Posted by MGPAX

Here's my suspension.
Toe is virtually zero all the way around from the factory.
I'm going to fix the small difference in left right rear toe...which is already
just barely off zero. (Is this just odd or is rear toe always measured from the
back of the car?...as is reverse of front?)

I'll have it checked again once parts are on.

PAX

I wouldn't be so happy with that alignment. The rear toe would bother me.

More front negative camber would help your rotation issues as well, even on stock tires.

EDIT: I'm also not sure what you mean by "Is this just odd or is rear toe always measured from the
back of the car?...as is reverse of front?"

- Andrew

[MGPAX]

Originally Posted by Racecomp Engineering

I wouldn't be so happy with that alignment. The rear toe would bother me.

More front negative camber would help your rotation issues as well, even on stock tires.

EDIT: I'm also not sure what you mean by "Is this just odd or is rear toe always measured from the
back of the car?...as is reverse of front?"

- Andrew

*This alignment check is the first one since buying the car over a year ago. I thought it was pretty good for stock after over a year of sliding around!

Thanks for your input. And the rear toe is what I'm talking about.
The little picture next to the setting is saying that a positive number is
actually taken at the rear of the rear wheel (rear of wheel's distance from center) thus it is actually toe IN. (Which I always thought was a negative number)
Am I right?

The Whteline top hats have a .5 degree setting to add neg camber. But I thought with all the caster on this car I may be over doing it if I add more camber also. You think I should add the camber also?

Thanks for your input!

[strat61caster]

Originally Posted by MGPAX

Here's my suspension.
Toe is virtually zero all the way around from the factory.
I'm going to fix the small difference in left right rear toe...which is already
just barely off zero. (Is this just odd or is rear toe always measured from the
back of the car?...as is reverse of front?)

I'll have it checked again once parts are on.

PAX

I cannot overstate how much camber has transformed my car, I would rethink the tophats you just got and get camber plates, no noticeable impacts to NVH on my car and like I said, transformed from what I would call an understeering pig to something that actually rotates. And I've still got toe-in on the rear because I do significantly more street and highway miles than speedy driving. I'm around -2.5 degrees now, some guys are up over -3.

Even just camber/crash bolts to get you up over -1 degree up front will be a noticeable difference.

[Chad_W]

On other cars I've run zero toe and -1.5 camber upfront and while I really enjoyed the handling, I would wear out the inner shoulders of my tires 30-40% quicker than the outers. How has that alignment held up in terms of tire wear on the BRZ?

[Racecomp Engineering]

Originally Posted by MGPAX

*This alignment check is the first one since buying the car over a year ago. I thought it was pretty good for stock after over a year of sliding around!

Gotcha, that makes sense then. We just never really like factory alignments or "in spec" by the book alignments.

Originally Posted by MGPAX

Thanks for your input. And the rear toe is what I'm talking about.
The little picture next to the setting is saying that a positive number is
actually taken at the rear of the rear wheel (rear of wheel's distance from center) thus it is actually toe IN. (Which I always thought was a negative number)
Am I right?

Toe in is positive, toe out is negative. I'm not following on the where you measure it thing. I'm trying to find a good picture for you but gotta meet with someone in a sec.

Originally Posted by MGPAX

The Whteline top hats have a .5 degree setting to add neg camber. But I thought with all the caster on this car I may be over doing it if I add more camber also. You think I should add the camber also?

Thanks for your input!

Yes definitely! You will see a big improvement especially on stock suspension. Even 0.5 degrees more than what you have would be on the lower end of what I would recommend. See strat61caster's post.

- Andrew

[strat61caster]

Originally Posted by Chad_W

On other cars I've run zero toe and -1.5 camber upfront and while I really enjoyed the handling, I would wear out the inner shoulders of my tires 30-40% quicker than the outers. How has that alignment held up in terms of tire wear on the BRZ?

I'll take wearing out the inner shoulders over many DD miles over wearing out the outer shoulders over a few track miles. I've also planned on buying a set of tires per year on nice 200TW competitive tires in OEM size, so far I think I'll get two seasons out of the ZII's.


I plan on adjusting my camber before and after events, my current setup seems to have little impact on toe when adjusting the camber, takes all of ten minutes to pull the jack out, make the adjustment and put the jack back.

[Racecomp Engineering]

-1.5 is not excessive at all IMO for these cars. Consider that from the factory they have about that much or a little more in the rear...while the front is a macstrut set-up with wheels that turn....

- Andrew

[stugray]

Originally Posted by MGPAX

Here's my suspension.
Toe is virtually zero all the way around from the factory.
I'm going to fix the small difference in left right rear toe...which is already
just barely off zero. (Is this just odd or is rear toe always measured from the
back of the car?...as is reverse of front?)

I'll have it checked again once parts are on.

PAX

I would say that ALL of that is suspect if your RR tire pressure is ZERO PSI