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-   BRZ First-Gen (2012+) — General Topics (https://www.ft86club.com/forums/forumdisplay.php?f=23)
-   -   corner exit traction (https://www.ft86club.com/forums/showthread.php?t=37377)

autobrz 05-24-2013 10:36 AM

corner exit traction
 
I've noticed the brz rotates very well under throttle, better than the mr2 I used to own. the mr2 being mid-engined tended to push under throttle. I didn't "tune it out" because I wanted the stability for a rear heavy car.

The main difference I'm noticing on corner exit is how easy it is to get the brz's tail to slide under power. In the mr2 that had a lot more torque, with the right alignment and tires, it was almost impossible to break the rear lose. It just hooked up and went.

I see 4 main differences though between the cars.
1. weight distribution favors mid-engined cars on corner exit traction
2. suspension setup - mr2 had aftermarket shocks and camber bolts
3. tires - 235 width fk452 vs 215 width prius tires
4. differential - mr2 had open diff that would spin the inside tire, a limited slip would dump the power on the outside tire if the inside tire had no weight on it.

Now, I want to say the brz is actually very good on corner exit. It's just a different kind of experience from the mr2 where I had absolutely no worry about losing rear traction on dry pavement. Wet pavement is a completely different story. :bellyroll:

So can any of the above differences be addressed?
1. no
2. yes
3. yes
4. I've never driven a car with a limited slip before. I can say it definitely helps on the very tight corners where an open diff would just spin the inside tire. On higher speed corners, I might like the an open diff better for the added slip allowance or I just need to drive better. :)

corner entry and transitions is where the brz really shines above everything else though...

WolfpackS2k 05-24-2013 10:51 AM

I'm assuming you are just talking about 1st and 2nd gear? Or maybe 3rd gear on a less than ideal grippy surface, since the car doesn't have enough power to slide the tail at a high speed.

Also please stop referring to the tires as "prius" tires. They are Summer Grand Touring tires with a W (186mph) speed rating and a 240 wear rating. Just because they're offered as an option for the Prius in EUROPE doesn't mean they're whimpy crap tires:sigh:

If you want it to grip better on corner exit use a staggered tire set up, with 225, 235, or 245 section width tires in the back instead. Just be aware that under other situations your car will be more prone to understeer.

autobrz 05-24-2013 11:01 AM

yes, I'm talking about 1st and 2nd gear.

I don't mind being able to break the rear loose. it's actually pretty fun to do once in a while. I did notice the 240 wear rating which surprised the heck out of me when I looked at the tires. Let's see how long they last with rotation. :)

I'm wonder though does the rear have enough camber gain stock? Anyone with experience have studied their tire wear? If not, I might have to go out and drive really hard for a while with the right amount of air pressure to see if the rear needs more camber because it could be the tires have more traction, it just doesn't have the contact patch.

WolfpackS2k 05-24-2013 11:05 AM

I like the tail out antics in 1st and 2nd gear as well. It's much more controllable than doing the same thing in my previous car (S2000). That car would snap back too quickly (prob b/c of it's 255 section width rear Dunlop Z1 Star Specs, haha).

I'm looking forward to taking the car to the track with these Michelins, for some oversteer fun :P

CSG Mike 05-24-2013 11:13 AM

Keep in mind the BRZ also comes with almost zero toe in the rear from the factory ;)

autobrz 05-24-2013 02:14 PM

After checking the track forum, it doesn't look like many people are dialing in rear camber and also saw report of a lot of camber gain for a little bit of lowering. They're mostly going with a stiffer front sway bar which I hate for driving feel. I would only go the direction of losing the rear sway bar or going stiffer springs up front because if you've driven a car with more spring vs a car with more sway bar, you will understand. But class rules must be followed in order to stay competitive :burnrubber:

autobrz 05-24-2013 02:17 PM

Quote:

Originally Posted by Marchy (Post 957733)
um, they're pretty crappy tires, i can slide the ass out in 3rd in the wet :burnrubber:. IMO the car should not do that.

in the wet, you can break the rear loose in any gear if the tires have enough lateral load... it's physics

Porsche 05-24-2013 03:55 PM

Quote:

Originally Posted by WolfpackS2k (Post 957140)
They are Summer Grand Touring tires with a W (186mph) speed rating and a 240 wear rating. Just because they're offered as an option for the Prius in EUROPE doesn't mean they're whimpy crap tires

Furthermore, I believe they are OEM tires on some Audi, BMW, and Mercedes models.

Porsche 05-24-2013 03:59 PM

Quote:

Originally Posted by autobrz (Post 957749)
in the wet, you can break the rear loose in any gear if the tires have enough lateral load... it's physics


Bet you can't do that in SIXTH gear in the automatic! :D

Have you looked at that ratio? Lordy! I figure you guys need to change down from sixth when encountering a slight grade on the interstate. ;)

Porsche 05-24-2013 04:02 PM

Quote:

Originally Posted by autobrz (Post 957737)
But class rules must be followed in order to stay competitive :burnrubber:


Yep. Changing class can REALLY up the ante to remain competitive! :D

autobrz 05-24-2013 04:25 PM

Quote:

Originally Posted by Porsche (Post 958003)
Bet you can't do that in SIXTH gear in the automatic! :D

Have you looked at that ratio? Lordy! I figure you guys need to change down from sixth when encountering a slight grade on the interstate. ;)

I bet if I get to top speed in 6th in the auto, I can just turn the steering wheel a little bit and get the rear to slide :lol: something about increasing speed and the tendency to oversteer... not sure how to explain it... :lol:

Porsche 05-24-2013 04:31 PM

Quote:

Originally Posted by autobrz (Post 958059)
I bet if I get to top speed in 6th in the auto, I can just turn the steering wheel a little bit and get the rear to slide :lol: something about increasing speed and the tendency to oversteer... not sure how to explain it... :lol:

FINAL oversteer? At top speed of around 140 mph?

It should not be designed to permit that; it should understeer at high speeds when cornering.

But you might be right.

And since you have an auto, whereas mine's a manual ... you go first!

We'll watch.

Tell us what happened. ;)

Porsche 05-24-2013 04:37 PM

Actually, you cannot reach top speed in SIXTH gear in the auto, I don't believe. It's too tall a gear and that 2 liter just hasn't got the grunt to pull top speed in sixth.

IIRC one needs fifth gear for top speed in the auto. Even that gear is taller than sixth in my manual gearbox BRZ.

But go ahead and max it out in sixth, whatever the speed, and make it oversteer if you can with additional throttle. Bet you can't. ;)

Not without doing something dumb.

Again ... we'll watch! :)


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