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-   -   Steering issue on long sweepers (https://www.ft86club.com/forums/showthread.php?t=120989)

Spence96 08-04-2017 09:51 PM

Steering issue on long sweepers
 
I will post the link to a video I have uploaded to Google Drive. Pay close attention to both of the right hand turns I go through. Traction control is off (I did not do the pedal dance), but the traction still kicks in with very little steering input. It required countersteer to avoid going off road. This does not happen during autocross, only on roads like the video or highway on ramps.

What you might like to know about my car:
Tein S-Tech lowering springs with stock struts
XXR 530's 18x8.75 +33 on all 4 corners
245/35/18 Contiental Extremecontact DW on all 4 corners
Open Flash Tablet tune (idk if it affects the steering or not)
Stock everything else as far as chassis/suspension goes

Video link:
https://drive.google.com/drive/folde...zg?usp=sharing

Edit:

My front left ball joint was not completely tightened down, and the front left wheel bearing was replaced under warranty. The car now handles great again.

tyler_win_photo 08-04-2017 11:15 PM

Has it been aligned? Could possibly be a rear toe issue

Spence96 08-05-2017 12:35 AM

Quote:

Originally Posted by tyler_win_photo (Post 2957223)
Has it been aligned? Could possibly be a rear toe issue

Car has been aligned twice since I put the springs on March 2016. It's been doing it ever since I have had the Teins. Possibly bad springs/struts? Installation was done by a Subaru dealer so i don't think it is due to a poor install.

wparsons 08-05-2017 04:35 PM

What are the exact alignment specs, did they give you a printout? Have you verified tire pressures are good all around?

Watching the video, the slip indicator doesn't come on at all on the second right hander, just the first one.

What are your feet doing when it comes on in the first corner? Braking at all? How hard on the gas?

There's a patch of rough looking pavement near the entry of the first one, could just be too fast for the conditions? You were going ~85mph, but I can't get a good sense of what the pavement is like.

mav1178 08-05-2017 05:19 PM

Your alignment is basically causing the car to think you are losing traction at higher speeds.

I used to have this problem when I had a fairly aggressive alignment for street use and any turns above ~50MPH sharper than an onramp would trigger traction control.

Either you have to readjust your toe or just do pedal dance. Saying "I got it aligned twice in last year" doesn't tell us much about what work was done.

Oh, my problem went away after I put the suspension back to stock.

-alex

Spence96 08-05-2017 06:01 PM

Quote:

Originally Posted by wparsons (Post 2957462)
What are the exact alignment specs, did they give you a printout? Have you verified tire pressures are good all around?

Watching the video, the slip indicator doesn't come on at all on the second right hander, just the first one.

What are your feet doing when it comes on in the first corner? Braking at all? How hard on the gas?

There's a patch of rough looking pavement near the entry of the first one, could just be too fast for the conditions? You were going ~85mph, but I can't get a good sense of what the pavement is like.

Alignment specs as of 3/4/2017 F and B are front and back. L and R are left and right
-.7 camber FL / -.8 camber FR
5.6 caster FL / 5.8 caster FR
-.04 toe FL / .05 toe FR


-2.5 camber BL / -2.5 camber BR
.10 toe BL / .13 toe BR

stevesnj 08-06-2017 12:48 AM

Quote:

Originally Posted by Spence96 (Post 2957257)
Car has been aligned twice since I put the springs on March 2016. It's been doing it ever since I have had the Teins. Possibly bad springs/struts? Installation was done by a Subaru dealer so i don't think it is due to a poor install.

Did they reset the Zero Point Calibration?

tyler_win_photo 08-06-2017 05:25 AM

Could possibly one of your struts be blown?

wparsons 08-07-2017 01:29 PM

Quote:

Originally Posted by Spence96 (Post 2957515)
Alignment specs as of 3/4/2017 F and B are front and back. L and R are left and right
-.7 camber FL / -.8 camber FR
5.6 caster FL / 5.8 caster FR
-.04 toe FL / .05 toe FR


-2.5 camber BL / -2.5 camber BR
.10 toe BL / .13 toe BR

That's the after?? Not great at all, but I still think you were simply above the limits of grip based on the video and how the pavement looks.

I'd still want the toe set better... I like it to be bang on 0* up front, and 1/16" total toe in (1/32" per wheel) in the rear. In degrees, that's 0.14 total or 0.07 per wheel. That'll be looser than what you're currently running though. At the very least you want to make sure you don't have toe out one side and toe in on the other like you currently have on the front, and that it's equal side to side.

wparsons 08-07-2017 01:36 PM

Actually, watching in slow motion.. did you drop a tire off the inside of the pavement a little?

-Willis-86touge 08-07-2017 01:41 PM

Quote:

Originally Posted by stevesnj (Post 2957628)
Did they reset the Zero Point Calibration?

What exactly is zero point calibration? I heard it used before but nobody ever goes into detail

Spence96 08-07-2017 03:10 PM

Quote:

Originally Posted by wparsons (Post 2958163)
Actually, watching in slow motion.. did you drop a tire off the inside of the pavement a little?

I almost did, because the steering snapped in that direction. Hence why I had to countersteer slightly. I did not apply any steering, throttle or brake input, but my car randomly snaps in the direction I am turning. It happens on smoother on ramps for highways as well so I don't think it is because of the road surface. I am leaning towards it being more of an issue of blown struts, cheap suspension with unbalanced front and rear spring rates, or something might be loose or bent under the car.

stevesnj 08-07-2017 03:43 PM

Quote:

Originally Posted by -Willis-86touge (Post 2958165)
What exactly is zero point calibration? I heard it used before but nobody ever goes into detail

Yaw rate sensor and acceleration sensor zero point calibration.

Basically it set's to 0 (zero) or re-calibrates the way the car determines when to apply the VSC based on your current wheel, suspension, Alignment setup. The VSC is based on many values , speed, position of car on X,Y Axis and calculates if and when to apply the VSC. The values are affected by the overall tire height, alignment of the suspension changes. If these values are changed from the factory configuration of stock wheels and alignment with taller overall wheel height, camber bolts, etc. the values don't match the factory calibration thus will activate or won't activate the VSC properly and can cause loss of vehicle control or just over react and turn on more often.

Basically when you mod your suspension, wheels, tires, suspension parts, alignment (post). The Zero Point Calibration should be performed.

Spence96 08-07-2017 04:49 PM

Quote:

Originally Posted by stevesnj (Post 2958224)
Yaw rate sensor and acceleration sensor zero point calibration.

Basically it set's to 0 (zero) or re-calibrates the way the car determines when to apply the VSC based on your current wheel, suspension, Alignment setup. The VSC is based on many values , speed, position of car on X,Y Axis and calculates if and when to apply the VSC. The values are affected by the overall tire height, alignment of the suspension changes. If these values are changed from the factory configuration of stock wheels and alignment with taller overall wheel height, camber bolts, etc. the values don't match the factory calibration thus will activate or won't activate the VSC properly and can cause loss of vehicle control or just over react and turn on more often.

Basically when you mod your suspension, wheels, tires, suspension parts, alignment (post). The Zero Point Calibration should be performed.

Where would I get this done? The dealership that installed my springs?


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