Asking for a spin
Thread Starter
Drifting
Joined: Sep 2005
Posts: 2,487
Likes: 42
From: Austin, TX
Asking for a spin
I was scratching my head the other day at the track, the car felt super sketchy on long corners where the rear was heavily loaded and I was on partial throttle. It just felt nervous, like it wanted to spin, but it was set and should have enough grip. It was like it was asking to spin, and I kept telling it no. My butt would send the alarm using my 3axis ***-cellerometer.
Everywhere else the car is perfect and confidence inspiring, but those damn longer corners.
Then it hit me, I looked at my adjustable toe arms. Nope, no locking plates. Ordering a set from Tarrett, let's see what happens.
Everywhere else the car is perfect and confidence inspiring, but those damn longer corners.
Then it hit me, I looked at my adjustable toe arms. Nope, no locking plates. Ordering a set from Tarrett, let's see what happens.
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Joined: Dec 2005
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From: New England
Thread Starter
Drifting
Joined: Sep 2005
Posts: 2,487
Likes: 42
From: Austin, TX
I wonder if I completely mis-understand the dynamic here. I was looking back at some notes from the spec boxster and we didn't run locking plates on that for whatever reason. That car would easily get it's toe out of whack. Like I said we where always aligning the toe between races/sessions.
I guess what I am pondering is that maybe I am feeling something else. It stands to reason that w/o the locking plate but with the toe arms any slip would be permanent and not just in that corner. It would slip and stay there, and not be a dynamic movement.
What I feel is in long corners where the weight is heavily on one side the car goes oversteer-y.
Could I be feeling rear bump steer instead?
I guess what I am pondering is that maybe I am feeling something else. It stands to reason that w/o the locking plate but with the toe arms any slip would be permanent and not just in that corner. It would slip and stay there, and not be a dynamic movement.
What I feel is in long corners where the weight is heavily on one side the car goes oversteer-y.
Could I be feeling rear bump steer instead?
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From: Columbus OH
I guess what I am pondering is that maybe I am feeling something else. It stands to reason that w/o the locking plate but with the toe arms any slip would be permanent and not just in that corner. It would slip and stay there, and not be a dynamic movement.
What I feel is in long corners where the weight is heavily on one side the car goes oversteer-y.
Could I be feeling rear bump steer instead?
What I feel is in long corners where the weight is heavily on one side the car goes oversteer-y.
Could I be feeling rear bump steer instead?
Rubber in the rest of the suspension?
LSD?
What you are describing could be a few things. Despite the fact that you have eliminated the rubber from the toe arm which is the first step, the rear of these cars still has rubber in the dog bones, the inner control arm bushing, etc. There can still be some deflection there causing the car to take somewhat of a delayed set.
Or could be that you have a proper and functioning LSD in the car and what you're feeling is the LSD locking up so that you can drive the car off of the rear wheels?
or tire squirm??? Nitto's, esp when full tread have quite a bit of squirm that you just need to get used to and drive around until they are a bit more worn down. Not the most confidence inspiring feeling but they love alot of slip angle so driving them in the beginning state gets you used to the feeling they need to really go fast.
Thread Starter
Drifting
Joined: Sep 2005
Posts: 2,487
Likes: 42
From: Austin, TX
Thanks for the replies guys. Good ideas...
Not tire squirm, happens on MPSC's too. I am pretty confident on this one. I drive way more slip than this on Nittos, but it's not a controlled slip like I am asking for, it's something else.
LSD is a guard unit, just refreshed and in good shape, I am pretty sure thats not it.
I am thinking it's dynamic (kinematic) tow or I am riding on the bump stops. I think the next step is to do measure with a bump steer gauge.
Not tire squirm, happens on MPSC's too. I am pretty confident on this one. I drive way more slip than this on Nittos, but it's not a controlled slip like I am asking for, it's something else.
LSD is a guard unit, just refreshed and in good shape, I am pretty sure thats not it.
I am thinking it's dynamic (kinematic) tow or I am riding on the bump stops. I think the next step is to do measure with a bump steer gauge.
Thread Starter
Drifting
Joined: Sep 2005
Posts: 2,487
Likes: 42
From: Austin, TX
Ok, just an update. Installed the locking plates and I gave the car an alignment. I went from -2mm toe in the rear to -4mm toe in rear. Problem seems to be gone, loads of grip in the 'trouble spot' on the track, in either direction. Had enough confidence to get my best laptime.
my thesis is I am getting just a bit of dynamic toe out and thus pushing the toe towards zero or positive. My butt senses it, and confidence drains. Need to measure it to validate.
my thesis is I am getting just a bit of dynamic toe out and thus pushing the toe towards zero or positive. My butt senses it, and confidence drains. Need to measure it to validate.
