Understeer on '22 BRZ

[Fletch]

I have a '22 BRZ with camber plates, RLCA's and brakes - otherwise stock.

Im currently running with -3 camber in front and -2 in rear as I *think* that was the recommended setup from some fairly respectable drivers - i could be wrong here.

I've been getting LOADS of push mid-corner. It's extremely hard to get the car rotated for exit. Initial turn-in is basically fine though, so it's not like the rear is too soft or anything so I don't really understand it.

The issue is more or less the same running on the stock 18" rims + tires and also with Toyo RR's 225/45/17s (semi-slicks).

Do others experience this? What are my options to dial it out (cheaply)?

[strat61caster]

How’s the tire wear?

[TommyW]

Are you on the gas before the apex or possibly putting too much load on the front tires ?

[Pat]

What are your tire pressures?

[ZDan]

Stock springs? Too soft for track work on decent tires, more body roll and loss of front camber in cornering. You might think about stiffer/lower springs. And/or front and rear swaybars. Also could stand more camber (particularly with stock spring rates), try -3.5/-2.5.

[Icecreamtruk]

Originally Posted by Fletch

I have a '22 BRZ with camber plates, RLCA's and brakes - otherwise stock.

Im currently running with -3 camber in front and -2 in rear as I *think* that was the recommended setup from some fairly respectable drivers - i could be wrong here.

I've been getting LOADS of push mid-corner. It's extremely hard to get the car rotated for exit. Initial turn-in is basically fine though, so it's not like the rear is too soft or anything so I don't really understand it.

The issue is more or less the same running on the stock 18" rims + tires and also with Toyo RR's 225/45/17s (semi-slicks).

Do others experience this? What are my options to dial it out (cheaply)?

Sounds like a driver problem. Your setup isnt exactly the best (assuming you have stock springs since you didnt mention ratios) but you should be able to get the car to rotate more than enough with proper trail braking. My guess is that the car is pushing all the way thru, not just mid corner, and you are unloading the front tires too much, too early when you get on the gas and it gets worse (and then it bothers you where before it didnt).

[ZDan]

As lauded as these cars are for handling, they are abysmally nose-heavy and severely punish the front tires even with a half-decent setup. My BRZ is my daily as well as my track/time-trial car, so setup is pretty compromised. I'm running 4.4F/5.3R Swift lowering springs with Bilstein B8s, -35mm lower than stock, -3.7F/-2.9R camber, Eibach sway bars front (soft setting) and rear (stiff setting), on 245 or 235 A052/RE71RS/CR1 tires. Have taken efforts to "fix" weight distribution, my TT-legal setup is ~53F/47R (vs. 55/45 stock). And I still have more mid-corner understeer than I'd like...

My previous street/track cars (240Z, S2000, V8 FD) all worked the rears harder than the fronts. I kinda miss that...

[Pat]

Originally Posted by ZDan

As lauded as these cars are for handling, they are abysmally nose-heavy

Yeah....I'm going to have to disagree with that. Are they heavier in the front than what you've used previously? Sure. Are they a couple percentage points more front-biased than some other front-engined, rear-drive sports cars? Yep. But to say they are "abysmally nose-heavy" I think is overstating it. They have a greater percentage of weight over the rear axle than the vast majority of cars sold today.

[ZDan]

Originally Posted by Pat

Yeah....I'm going to have to disagree with that. Are they heavier in the front than what you've used previously? Sure. Are they a couple percentage points more front-biased than some other front-engined, rear-drive sports cars? Yep. But to say they are "abysmally nose-heavy" I think is overstating it. They have a greater percentage of weight over the rear axle than the vast majority of cars sold today.

What I'm stating is my actual experience tracking the platform, not just an opinion. Even with a half-decent setup, it tremendously overworks the fronts and underutilizes the rears. For a performance-oriented rear-drive car, 55F/45R is pretty bad in actual practice. 50/50 is of course a lot better, and 45F/55R better still.

55F/45R is suck-town for a rear-drive car for track work. And my S2000 was also WAY better in the snow as well!

edit/addendum:
OK, I probably *am* overstating it! I do love the car, and if buying a new car it would be a BRZ or GR86. Every car is a host of compromises, and the weight distribution is the one big compromise in this car (to me anyway). My druthers, there'd be a 2-seat version with the rear wheels shoved forward a good 10" or so, that would for the most part fix the weight distribution, remove weight, and reduce polar moment of inertia in one swell foop. Maybe I should pull out the sawzall...

[Fletch]

Thanks for the answers. I really messed up by not checking the RR's wear straight after the last session. I ended up having to drive 100 miles home (super sketchy) on them as I found my street tires were badly corded when i took them off. So im limited what I can read from the RRs. The inside is predictably worn from the ride home. The outside is pretty good. A tiny bit excessive on the edge of the sidewall but not really enough to indicate im rolling over them badly IMO - but I could be wrong.

Yes the springs and shocks are stock. I'd really prefer to keep them that way. I think they're pretty damn good for what it is and i use the car on the street a lot.

On my race car we'd soften the front sway bar to dial out this kind of understeer (or stiffen the rear), but I had an alignment guy trying to tell me its the opposite with 'this type of suspension'. I'm an idiot mechanically so im not sure what's correct or not. If this is something that can easily be fixed with a sway bar that would be a good option for me.

I guess my big question though is do others experience this with comparable camber numbers??? From the answers it seems no, which maybe points to something being wrong somewhere with my setup.

[Fletch]

Originally Posted by Icecreamtruk

Sounds like a driver problem. Your setup isnt exactly the best (assuming you have stock springs since you didnt mention ratios) but you should be able to get the car to rotate more than enough with proper trail braking. My guess is that the car is pushing all the way thru, not just mid corner, and you are unloading the front tires too much, too early when you get on the gas and it gets worse (and then it bothers you where before it didnt).

Yes im trailing the nuts off the thing. Even with comedy levels of brake+steering angle the rear wont come around like it should. The fronts just overload and push forward way past the apex.

[Icecreamtruk]

Originally Posted by Fletch

Yes im trailing the nuts off the thing. Even with comedy levels of brake+steering angle the rear wont come around like it should. The fronts just overload and push forward way past the apex.

Sounds like you are trailing too hard (too much pressure, too much steering angle) or the electronic aids are blocking you off, are you on track mode or pedal dance (either works)?

[strat61caster]

I use more camber in an autox setting, which has less sustained cornering loads, I would increase front camber if it was my car but your tire wear points to something different, or you drive a lot of street miles.

-4.3 F and -2.5 R here, with stiffer springs, might change some parts to get more for next season. When I was on stock coilover I was decently happy with -3/-2 but it was a compromise setup that could have used more. If you have video post that up.

[Racecomp Engineering]

Originally Posted by Fletch

I ended up having to drive 100 miles home (super sketchy) on them as I found my street tires were badly corded when i took them off. So im limited what I can read from the RRs. The inside is predictably worn from the ride home. The outside is pretty good. A tiny bit excessive on the edge of the sidewall but not really enough to indicate im rolling over them badly IMO - but I could be wrong.

How much toe do you have?

Originally Posted by Fletch

On my race car we'd soften the front sway bar to dial out this kind of understeer (or stiffen the rear), but I had an alignment guy trying to tell me its the opposite with 'this type of suspension'. I'm an idiot mechanically so im not sure what's correct or not. If this is something that can easily be fixed with a sway bar that would be a good option for me.

I guess my big question though is do others experience this with comparable camber numbers??? From the answers it seems no, which maybe points to something being wrong somewhere with my setup.

With semi-slicks, the stock suspension is far from ideal even with -3 degrees camber. And right, I certainly wouldn't recommend softening the front bar.

- Andrew