Squishy feeling movement from rear end during hard corners

[gonzo]

Whenever I take long, hard (lol) corners my rear end feels like it's shifting sideways on the lateral axis. Not sure if this is considered body roll since it feels like just lateral movement of the body, not rotation on its longitudinal axis (which is body roll). The tires stay planted when it happens and I don't hear them reaching limits of grip (sliding or squealing sounds). It feels as if the tires are gripping a lot but the chassis is held to the suspension using soft bushings. So the chassis pulls sideways before the tires reach limits of grip. I feel it more in the rear than the front.

What is causing this lateral movement? And can I stop the movement without losing grip? Will roll bars helps?

I have michelin PSS, trd springs, tranny mount, rear subframe inserts, camber bolts, and aligned for max negative front camber (rear had even negative camber, toe is 0).

Thanks!

[strat61caster]

The bushings in the rear subframe are known to be very compliant stock, I believe there are a few options for upgrading those, definitely known to add some confidence in what the rear is doing.

[ame="https://www.youtube.com/watch?v=OKbZFknBzh8"]Team VCMC FR-S - AutoX Video 4: Rear Crossmember and Swaybar - YouTube[/ame]

[gonzo]

Originally Posted by strat61caster

The bushings in the rear subframe are known to be very compliant stock, I believe there are a few options for upgrading those, definitely known to add some confidence in what the rear is doing.

Thanks but I already have the kdt922 inserts! Maybe I should have gone with the kdt921 instead?
http://www.whiteline.com.au/product_..._number=kdt921



Will the KDA326 help with the lateral movement in the rear? Or is it only good for the camber adjustment?
http://www.whiteline.com.au/product_...CA326&sq=18543




Would the differential mounts help?
http://www.whiteline.com.au/product_...DT925&sq=18545
http://www.whiteline.com.au/product_...DT924&sq=18544

[Racecomp Engineering]

Originally Posted by gonzo

Will the KDA326 help with the lateral movement in the rear? Or is it only good for the camber adjustment?
http://www.whiteline.com.au/product_...CA326&sq=18543

IMO it helps quite a bit. WL also make a non-adjustable version if you already have adjustable rear LCAs. Makes life a little easier as no one likes using the rear bushings to adjust camber.

- Andrew

[SVLTE]

Do you find this happens more toward the corner exit when you're getting back on the throttle? I felt what might have been a similar sensation when I swapped the TRD rear bar back to OEM and had the rebound on my shocks set a little softer for street driving. Accelerating out of a turn the car would squat very noticeably on the outside rear wheel. Felt like it had plenty of grip, but it was just an awkward sensation. Slowing the roll rate with stiffer rebound settings completely eliminated it.

[gonzo]

Originally Posted by SVLTE

Do you find this happens more toward the corner exit when you're getting back on the throttle? I felt what might have been a similar sensation when I swapped the TRD rear bar back to OEM and had the rebound on my shocks set a little softer for street driving. Accelerating out of a turn the car would squat very noticeably on the outside rear wheel. Felt like it had plenty of grip, but it was just an awkward sensation. Slowing the roll rate with stiffer rebound settings completely eliminated it.

Sounds like it. So the suspension was set up for the stock tires. No wonder it's so fun with the crappy prius tires! Would the trd bars help me? No $ for coils right now.

[SVLTE]

I ran on TRD springs and bars with 245 PSS's for several track days before I got konis. Wasn't until I went with konis and changed the rear bar back to stock (it was a little too tail happy for autocross) that I got that weird feeling running closer to softer rebound rates, so the bars definitely help. You could go with the bars and/or get some nice shocks like koni, bilstein, or cusco to go along with those springs. Unless you really want to start tinkering with your setup, I don't think coilovers are necessary.

[gonzo]

Originally Posted by SVLTE

I ran on TRD springs and bars with 245 PSS's for several track days before I got konis. Wasn't until I went with konis and changed the rear bar back to stock (it was a little too tail happy for autocross) that I got that weird feeling running closer to softer rebound rates, so the bars definitely help. You could go with the bars and/or get some nice shocks like koni, bilstein, or cusco to go along with those springs. Unless you really want to start tinkering with your setup, I don't think coilovers are necessary.

So would you recommend Koni yellows with TRD springs and stock rear bar for autocross? Thanks a lot for the info and advice. I have 215 PSS's.

[SVLTE]

That's at least where the car felt best *for me with rival S's and RE71R's* for autocross. I thought it was better for the street when I had both TRD bars on and could run the dampers a little softer without getting that squat in the rear end.

[NissanGuy]

Occam's razor: Have you tried higher tire pressures?

I have to run 43+ psi on my car, though admittedly mine is a special case with coilovers and 205/55R16s.

[colin88]

Originally Posted by NissanGuy

Occam's razor: Have you tried higher tire pressures?



I have to run 43+ psi on my car, though admittedly mine is a special case with coilovers and 205/55R16s.

43psi ??

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