Unstable suspension

Sam85

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many factors lead to the "squirmy" behavior.. off the top of my head (In order):

1. Bad Alignment
2. Wrong tire/wheel size
3. Adjustable springs (not corner balaned, or height is not properly adjusted)

doubt its anything major.

 

Motojunkie

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Definitely having meaty tires on rims not wide enough like @FuzzyRev85 stated causes issues. I used to work for Steeda. We would get guys coming in with GT500's that would stuff 305 and 315 drag radials on 9.5in stock rims asking why the car would get all over the place on the highway under power. Been in a few 700-800 wheel gt500's and it was scary how violently unstable they would get at high speeds under WOT pulls.
 
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FLtrackdays

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Bit off topic but… with these sticky tires and great alignment, my car feels incredible! All the cars nannie’s are off (separate issue) and she squeals in 3rd gear with the JB4 custom map on. But still feels stable as hell and easily controllable. This wasn’t the case on stock tires and prior to my latest alignment.
 

razorlab

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Bit off topic but… with these sticky tires and great alignment, my car feels incredible! All the cars nannie’s are off (separate issue) and she squeals in 3rd gear with the JB4 custom map on. But still feels stable as hell and easily controllable. This wasn’t the case on stock tires and prior to my latest alignment.
Def all about the alignment. I have done things on track with my current setup that would have had me spinning like a top when the car was stock. Like lifting off mid turn/power.

Also notice that you never hear about the whole "OMG SUPRA BUMP STEER ISSUES!!!!!" anymore.
 

JoshuaQ

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I'm running a pure 800, catless dp, and a ecutek tune. Pushing very high torque numbers low 6XXs whp..
I am also running the hks adjustable springs and on PSS fronts and back 275/295
Whenever I floor it in 3rd-4th-5h at around 100km or more the car feels squirmy? if that's the right term? It wants to slide right and left slightly. I don't know if its the crappy PSS that cant handle the power or is it a suspension issue and coilovers would fix that problem.

Any idea from the guys running big power?
You have 600+ whp and you're wondering why it may be squirrely? You probably won't find a tire aside from slicks that handle that power well. I'm no expert, but in the cold, mine can barely handle the 450 whp or so. Summer/warm time it grips great, but now the roads are cold af and mine gets a little squirrely now.
 

TNZupra

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I'm running the new Bridgestone RE-71RS in 275/35/18 FR and 295/35/18 RR. Very nice tire compared to the PSS and the Yokohama Advan Apex V601 I ran. Lateral grip is insane, and the car hooks up without any issues (stock turbo and MHD stage 2 OTS).

You can get them in the stock sizes for the 19", or you can size up the rear to 285/35/19.

Same goes for the Yokohama AD09, which is also a brand new 200TW tire. Both these and the aforementioned Bridgestones are very sticky, but were optimized for endurance racing, so you should see decent mileage on the street.

Just make sure you don't drive in temps below 30 or so, can cause damage to the compound.
 

TNZupra

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I'm running the new Bridgestone RE-71RS in 275/35/18 FR and 295/35/18 RR. Very nice tire compared to the PSS and the Yokohama Advan Apex V601 I ran. Lateral grip is insane, and the car hooks up without any issues (stock turbo and MHD stage 2 OTS).

You can get them in the stock sizes for the 19", or you can size up the rear to 285/35/19.

Same goes for the Yokohama AD09, which is also a brand new 200TW tire. Both these and the aforementioned Bridgestones are very sticky, but were optimized for endurance racing, so you should see decent mileage on the street.

Just make sure you don't drive in temps below 30 or so, can cause damage to the compound.
Forgot to mention that also, a taller sidewall can help with straight line hookup, as the sidewall is able to flex as opposed to a lower profile tire.

What you gain in straight line traction, you slightly lose in initial turn in.

Sorry for all the extra info lol
 

sams2k

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Def all about the alignment. I have done things on track with my current setup that would have had me spinning like a top when the car was stock. Like lifting off mid turn/power.

Also notice that you never hear about the whole "OMG SUPRA BUMP STEER ISSUES!!!!!" anymore.
more camber?
 

FLtrackdays

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more camber?
I would get a spec alignment and only add more negative camber all the way around (like me) if you’re going to track (harder/more turning = greater contact patch with the road). If you’re interested in drag racing, definitely ask @zrk.

CFB592F4-EBC4-40B6-A029-428DFCFB46B0.jpeg
 
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zrk

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