Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB

Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB (https://www.ft86club.com/forums/index.php)
-   Tracking / Autocross / HPDE / Drifting (https://www.ft86club.com/forums/forumdisplay.php?f=39)
-   -   goin reverse stagger, maybe... (https://www.ft86club.com/forums/showthread.php?t=145380)

ZDan 05-18-2021 11:39 AM

goin reverse stagger, maybe...
 
I'm thinking about going 255/40-17 front with 235/45-17 rears for Palmer next month, maybe even 255/225 :drinking:

I get a mid-corner push in some corners on 245-square with my unadjustable-except-front-camber setup, and wear the fronts much quicker than rears. Seems like it's worth a shot to try to beat the Miata that got me by less than a tenth at NHMS!

Anyway, just throwing this out there to get ridiculed and then do it anyway :cheers:

TommyW 05-18-2021 12:51 PM

Quote:

Originally Posted by ZDan (Post 3433743)
I'm thinking about going 255/40-17 front with 235/45-17 rears for Palmer next month, maybe even 255/225 :drinking:

I get a mid-corner push in some corners on 245-square with my unadjustable-except-front-camber setup, and wear the fronts much quicker than rears. Seems like it's worth a shot to try to beat the Miata that got me by less than a tenth at NHMS!

Anyway, just throwing this out there to get ridiculed and then do it anyway :cheers:

Can you stiffen up the rear bar? Is front camber maxed? Wondering if you decide on a reverse stagger if you can't just run something softer in front instead?

ZDan 05-18-2021 01:16 PM

Quote:

Originally Posted by TommyW (Post 3433756)
Can you stiffen up the rear bar? Is front camber maxed? Wondering if you decide on a reverse stagger if you can't just run something softer in front instead?

Stock non-adjustable sways, front camber at -3.5/-3.9.
Springs are Swift Spec-R: 4.4 F, 5.3 R (kg/mm), Bilstein B8 struts/shocks.
Car is 1.25" lower than stock all around. I think I'm soft enough that I'm riding on the outside front bump stop during hard cornering.

Icecreamtruk 05-18-2021 01:17 PM

It'll make what you think it'll do (make car more tail happy) but it will do so by removing grip from the rear, not adding to the front. I dont think it'll be faster, my opinion, I have 0 experience behing a reverse stagger in RWD applications.

In other ideas, have you tried using spacers to change track width at one end only?

Icecreamtruk 05-18-2021 01:17 PM

It'll make what you think it'll do (make car more tail happy) but it will do so by removing grip from the rear, not adding to the front. I dont think it'll be faster, my opinion, I have 0 experience behing a reverse stagger in RWD applications.

In other ideas, have you tried using spacers to change track width at one end only?

TommyW 05-18-2021 01:28 PM

Quote:

Originally Posted by ZDan (Post 3433760)
Stock non-adjustable sways, front camber at -3.5/-3.9.
Springs are Swift Spec-R: 4.4 F, 5.3 R (kg/mm), Bilstein B8 struts/shocks.
Car is 1.25" lower than stock all around. I think I'm soft enough that I'm riding on the outside front bump stop during hard cornering.

The camber seems about as much as you'd want. Ultimately you want to work on the end that is troublesome however it sounds like you've done about all you can do with the front of the car. At that point the rear needs to be considered. Balance is balance. Even though you'd be taking grip from the rear you may reduce push enough to make it worth it.

ZDan 05-18-2021 01:36 PM

Quote:

Originally Posted by Icecreamtruk (Post 3433762)
It'll make what you think it'll do (make car more tail happy) but it will do so by removing grip from the rear, not adding to the front.

Going from 245 square to 255/235, for same overall tire points for classification (i.e. same competition weight).
So yeah, I am effectively trading rear grip for front grip and not just throwing away rear grip.

Or I could go 255/225 and shave off a few pounds!

Quote:

I dont think it'll be faster, my opinion, I have 0 experience behing a reverse stagger in RWD applications.
Neither have I, but in this case, given modest power, 53.5/46.5 weight distribution, and a setup that *obviously* overloads the fronts and underutilizes the rears, seems like a decent approach.

Other pertinent related info: 245/40-17 A052s won't be available until after event at Palmer, but 255s, 235s, and 225s are in stock...

Quote:

In other ideas, have you tried using spacers to change track width at one end only?
I have 3mm spacers, so not really enough to make a difference. With stock-length ARP studs I wouldn't/couldn't go any more than that, so the answer is pretty much no adjustability here.

M0nk3y 05-18-2021 01:52 PM

Quote:

Originally Posted by ZDan (Post 3433760)
Stock non-adjustable sways, front camber at -3.5/-3.9.
Springs are Swift Spec-R: 4.4 F, 5.3 R (kg/mm), Bilstein B8 struts/shocks.
Car is 1.25" lower than stock all around. I think I'm soft enough that I'm riding on the outside front bump stop during hard cornering.

Unless you zip tied your shocks to confirm you're on bumpstops that is a very broad assumption.

I'd rather play with rear camber and/or toe to your liking rather than take away tire...

Besides that, sounds like you need a shock revalve

Petah78 05-18-2021 01:52 PM

I have no insightful knowledge to share but it will be interesting to learn of the outcome if you go through with this idea. But I agree that the car does tend to push at the limit.

Quote:

Originally Posted by ZDan (Post 3433743)
I'm thinking about going 255/40-17 front with 235/45-17 rears for Palmer next month, maybe even 255/225 :drinking:

I get a mid-corner push in some corners on 245-square with my unadjustable-except-front-camber setup, and wear the fronts much quicker than rears. Seems like it's worth a shot to try to beat the Miata that got me by less than a tenth at NHMS!

Anyway, just throwing this out there to get ridiculed and then do it anyway :cheers:


ZDan 05-18-2021 01:56 PM

Quote:

Originally Posted by M0nk3y (Post 3433770)
Unless you zip tied your shocks to confirm you're on bumpstops that is a very broad assumption.

In the end it doesn't matter whether it's that I'm into the front bumpstops or something else, but running out of front travel was a real issue with the Sachs struts, less so with Bilsteins but I'd bet I'm into the stops a bit. Which is actually a *normal* thing with these cars anyway...

But long/short, I need more front grip and this is one way to get it, whether the "problem" is lack of front bump travel or not.

Quote:

I'd rather play with rear camber and/or toe to your liking rather than take away tire...
Again, I'm not "taking away tire" overall. I'm adding tire to the end that's WAY into the nonlinear/non-productive portion of the load/grip curve, and taking away a smidge from the end that doesn't need it.

Rear camber and toe are where I want them, don't have the sheet in front of me but rear camber is -2.75ish and rear toe is in the zero to 0.1 degrees total range.

Quote:

Besides that, sounds like you need a shock revalve
It's a mid-corner push, it ain't the shocks...

strat61caster 05-18-2021 02:33 PM

I too have removed grip from one end of the car to adjust balance, it never resulted in a faster time unless I was driving like an idiot before and then decided to drive less like an idiot, but it was always more fun to drive.

If you gave me your car to make quicker I'd toss a front sway bar on it (19-20mm), zero the toe, and stay 255 square. The front sway bar has shown to improve the front end grip and responsiveness over and over again.

That is assuming there isn't a driving issue that can be worked around. All this internet advice will pale in comparison to someone who knows their shit taking your car for a few laps.

M0nk3y 05-18-2021 02:40 PM

Quote:

Originally Posted by ZDan (Post 3433774)
In the end it doesn't matter whether it's that I'm into the front bumpstops or something else, but running out of front travel was a real issue with the Sachs struts, less so with Bilsteins but I'd bet I'm into the stops a bit. Which is actually a *normal* thing with these cars anyway...

But long/short, I need more front grip and this is one way to get it, whether the "problem" is lack of front bump travel or not.

Again, I'm not "taking away tire" overall. I'm adding tire to the end that's WAY into the nonlinear/non-productive portion of the load/grip curve, and taking away a smidge from the end that doesn't need it.

Rear camber and toe are where I want them, don't have the sheet in front of me but rear camber is -2.75ish and rear toe is in the zero to 0.1 degrees total range.


It's a mid-corner push, it ain't the shocks...

That's weird, I don't have bump stop issues at all...

You're running a compromised setup trying to maintain point compliance.


IMO rear camber is too high especially if you're having mid-corner push. Shocks on entry can help you with aiding rotation, because that's really what you want in the end right?

To each their own, but this is a very backwards way to deal with a setup issue.

ZDan 05-18-2021 02:53 PM

Quote:

Originally Posted by strat61caster (Post 3433803)
I too have removed grip from one end of the car to adjust balance, it never resulted in a faster time unless I was driving like an idiot before and then decided to drive less like an idiot, but it was always more fun to drive.

One more time, I'm *adding* grip to the end that needs it. Outside front is well into the nonlinear portion of the load/grip curve, outside rear not so much... Adding front tire and taking away the same amount of rear tire should give an overall INcrease in grip. Critically, it should allow me to get harder on the gas sooner exiting critical corners without the front end washing out as much, which should benefit me all the way down the straights.

Tires ordered so we'll see!

Quote:

If you gave me your car to make quicker I'd toss a front sway bar on it (19-20mm),
That would take away front grip and exacerbate the problem. Thing to do would be bigger *rear* sway bar, but then I'd have to add 41 lb. and possibly get into the realm of unloading the inside rear too much for the Torsen to deal with.

Quote:

zero the toe,
Rear toe is near-zero. Don't have the sheet in front of me but it's a bare smidge of rear toe-in, in my experience (and I've experimented with rear toe a lot, intentionally and unintended "blind" testing) 0.1* isn't hugely different from 0.0* for mid-corner balance. It's around 0.05* total IIRC. There's nothing *magical* about zero rear toe, optimal toe is a range and -0.05* to +0.15* doesn't make all that profound a difference. Particularly for a relatively softly-sprung zero-downforce street car on "street" tires...

Quote:

and stay 255 square.
I've never run 255 square. 245 square at the moment. I've also run 235 and 225 square.

Quote:

The front sway bar has shown to improve the front end grip and responsiveness over and over again.
Maybe for autoX, but it's gonna hurt mid-corner front grip for sure.

Quote:

That is assuming there isn't a driving issue that can be worked around. All this internet advice will pale in comparison to someone who knows their shit taking your car for a few laps.
He already has ;)

TommyW 05-18-2021 02:54 PM

Also maybe look at your throttle input and see if maybe too early?


All times are GMT -4. The time now is 09:24 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
User Alert System provided by Advanced User Tagging v3.3.0 (Lite) - vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.


Garage vBulletin Plugins by Drive Thru Online, Inc.