Post "wheel alignment" issues...are they related?
 

Hi guys

Need some technical help

2012 Toyota 86 GT Manual
Was recommended Bridgestone RE003s to replace worn stock 1s so got them. 1st bad decision - hard ride then stocks.
They managed to talk me into getting a wheel alignment too. 2nd bad decision.

Have adjustments from the 1st change in the 1st photo. Issues were car was pulling right at speed than pulling left with braking. And my steering radius to get the car to turn into corners seemed really excessive.
Took it back and they "set it up again from scratch" - doubt they know what they are doing since the original settings for the fix I would have thought would be the same post the 1st change but there were differences already. Well it sorted the pulling right issues mostly but still slightly pulls to the left at speed. Turning radius issue seems slightly better but I am used to a smaller turning circle which I am pretty sure is what the 86 does.

I am taking it back to Toyota to really start from scratch.

But was hoping to find out if the turning circle issue is related to the changes the f***ers made over the 2 adjustments.

Thx

Sorry

Photos are here

You got camber and possibly a little toe thrust from the rear axle. Since the camber isn't supposed to be adjustable that's been there since the factory slung in the subframe. Toe us adjustable and must be as close as possible to the same left and right. But the camber needs sorting first.

Subaru actually supplies crash bolts which can be used to adjust rear camber. My mechanic fitted some to mine and got negative camber to about 1.8 degrees left and right. He also checked the rear subframe alignment left to right as he was fitting Whiteline subframe bushing inserts at the same, time which I highly recommend btw.

Then set the toe. Your rear toe is close enough but since toe alters with camber change as the rear suspension compresses under acceleration and rises under braking it can amplify your camber thrust which is pushing the rear of the car to the left, more under acceleration and less under braking. Personally, I'd ask for more front toe in but that's a very personal decision. With front toe set as it is your steering would be more lively with sharper turn in and the trade off for that is a bit more front end wander especially under hard braking. Many people prefer that and are willing to put up with the need to steer the car more actively when driving in a straight line.

Not sure I follow your description of the steering radius, that isn't really adjustable if the front toe is in spec. In my experience the turning circle for these cars is very poor, probably due to the Impreza front wheel drive design the chassis comes from and the different position of the steering rack from that initial design.

Possibly that's why Subaru designed in such easy to find oversteer. 8-)

The numbers on the second start out in a place consistent with where the first left them, minus the steering wheel being turned a little one way vs the other (may still feel straight, and maybe they're not centering the steering wheel properly) and a little bit of settle (maybe their toe plates are a touch sticky in the back, or they only slide and don't turn).

The rear camber isn't uncommon, and isn't adjustable stock. It shouldn't be related to the driving issues.

Hmm? Can you tell a bit more info what are those camberbolts for rear? :/
First time hearing about such. At which point they are used? What part numbers they have?

Canadian part # 264-3641, which looks more like a phone number than a part number.
I assume but don't know that the camber bolts go in the outer LCA to hub joint.

Checking my alignment charts shows the rear camber on my car is more negative on the right than the left, cross camber net number is 0.7 degrees. My car tracks perfectly.

The other possibility for the OP is bad luck getting one defective tire.

This can be isolated by moving one tire across the car on one axle and see if the problem reverses. If not then move one tire acriss the car on the other axle.

Road force balance is also a good check on tire quality.

What?

The BRZ is basically a sawed off Impreza. Exactly 3 inches were taken out of the wheelbase. Track is the same, allowing for the wider wheels on the BRZ. The shorter wheelbase takes only 7 inches out of the turning circle. At 35.4 feet the BRZ has a big turning circle for such a short car.

The front LCA are installed backwards. The steering rack is behind the engine and that's why the engine is so far forward. The rear suspension is basically pure Impreza. I think even the roll bar swaps right in. If you like instant oversteer.

The orginal Impreza way back when was fwd. The BRZ was developed from the awd version. I think you can see blanking plates covering the holes in each front hub where the Impreza would have drive shafts.

There may be a handful of parts bin parts but the platform itself is not Impreza. All new design and most certainly not sharing anything with the 20 year old FWD version.

http://www.ft86club.com/forums/showthread.php?t=5274

Well, you can dream if you want but that is simply not the case.

The BRZ and the fourth gen Impreza are the same car. The Forester is a bigger version. (Same wheelbase as the Impreza). I recognize the last Impreza built as a fwd was some time ago, I was referring to the front suspension and steering layout which have not changed in a long time.

The Impreza is a very good design, no need to reinvent the wheel. The BRZ is only about 150lbs lighter, that's the three inches they chopped out of the floorpan.

Not dreaming, it is well documented that it is it's own platform. Proof of your assertion?

Have you looked under a 2012 Impreza?

What documentation are you referring to?

I linked it for you already.
Based on is not the same as made from. They could look similar that does not make them the same platform.
OK I am out since we are taking this way off topic in the tech section.

I think you'll find, if you read your link carefully enough, that in amongst all the pr bumpf the test mule for the BRZ was a sedan: that was the Impreza.

Toyota had very little to do with the development of the BRZ from the Impreza.

You can still have the last word if you want. You could check the alignment specs for the Impreza first though . It could be educational for you.