Okay then, that description is very similar to what I'm experiencing and trying to describe. Perhaps I need to find a different word than understeer to describe that the car is not balanced the way I need at that point in the corner.

It's not as if I'm "pushing" either, or would have problems making the corner, but rather since there's no power I don't have the balance that I want and then instinct makes my hands and feet want to correct the situation.

Since you describe it as the throttle cable being (effectively) cut but that you can still goose the throttle, I'm curious. Does this mean that your engine freely revs when you lift the inside wheel? That's the part that confuses me and makes me wonder if my problem is different. When I'm having my problem, my engine doesn't freely rev. Instead, it feels like my rear end is "bound up" when I'm not able to deliver power.

 

Yes, when you lift a wheel, the engine RPMs will rapidly climb. Since your problems seem to be specific to right hand turns, is it possible that you're getting excessive blow-by, robbing you of power?

 

If you keep your foot on the gas, even a little bit, your lifted inside wheel will pick up speed and when it finally lands it will send a jolt through the drive line.

BTW, Thats a great way to kill a diff.

Since you only experience this on right handers there is a good chance the engine is bogging due to oil ingestion through one or both of the breather lines. It might be time to install a catch tank/breather.

 

Yeah, throttle cable cut is a bad analogy; it's more like the car's in neutral -- engine revs up freely. Only difference from actually being in neutral is the inside rear wheel spins up along with the motor, and as davepk points out, that's a Bad Thing for your diff when traction is suddenly restored.

You can hear a couple decent examples in this vid of me at Sears Point (a brutal track for IRWS, with lots of cresting turns). "Best" example is in T2, the sharp right-hander at the crest of the hill after the front straight (same place where I lose it at end of vid):
http://www.gofastvideo.com/gallery/item/pr...-mccanless.html

Note that in my vid, I'd already removed my rear swaybar and tuned my shocks to minimize the effect; didn't help, as my diff blew a month later.

It's even more evident in RL's car in T2 and T3a (the following right-hander, over the next crest), since he still had the rear bar:
http://www.gofastvideo.com/gallery/item/pr...rd-laifatt.html

 

Something is not right. The AP2 ('04+) S2k should not have inside wheelspin with the 0.25" wall thickness gendron bar. When I ran one of these with 225/275 Hoosier A3S04s I only got wheelspin on the stock bar. The AP1s on the other hand are always fighting wheelspin. Mostly because the rear bar is bigger and picks the inside rear clean off the ground in corners.

I guess it is possible that you are getting so much more grip from the 245/275 Kumho that you get wheelspin, but that is highly unlikely. What is true is that the more grip you have from surface/tires, the more bar you will need to prevent wheelspin. And also the more bar you can use without creating horrible push. If you were expecting the same bar settings to work with street tires and V710s, you need to adjust.

Are you *sure* that you have it set full stiff? There should be 6 holes for the endlink to go in, 3 on each side of a gap. The rear 3 holes are accessed with the endlink mounted on the rear of the control arm tab, the front 3 with the endlink on the front of the tab. It is the hole furthest toward the front of the car (which makes the shortest arm length) which is the stiffest setting. Note that I am not questioning your intelligence in any way, just double checking the most obvious possibility.

Other possibilities are that your bar is actually not connected somehow (loose endlink nut or something) or that your rear bar is binding (unlikely if you never touched it).

I still don't think this is possible. The AP2 is like 1 million times easier to kill wheelspin in compared to the AP1. From my experience the 0.25" thick center is more than adequate for checking wheelspin, you might still want to experiment with the solid center for tuning balance though. That is a lot of extra weight to carry around for minimal gain in stiffness unless you really need it.

Peter

 

Dave,

Thanks for confirmation (or lack thereof) . I already have an oil catch can installed, and i wasn't losing any significant quantity of oil after most of a day of running.

I also need to investigate my rear inner CV joints, as I believe I have a case of what many refer to as "the shakes". Perhaps it's just CV related, but I really don't think so.

My gut feeling at the track was that it was diff related. It felt like my rear end was somehow binding, which was interrupting power delivery. The thing though is that it was sounding like I was feathering the throttle, or that the engine was bogging, though I was full throttle.

No matter, I have all winter now to diagnose it. I've arranged my last track day of the season to be in a borrowed (stock) Miata at Road America.

Steve

 

My bar is set full stiff.

There is no sign that the bar is not connected. How would I know that?

I see the inside rear wheel come off the ground when my son drives the car, and I feel the effects when I drive the car.

 

I don't question that what you are getting is inside wheelspin caused by lifting the inside rear. That much is clear.

What I am saying is that if your front bar was somehow not connected properly, the inside rear *would* come off the ground, as if you had no front bar. If it was the rear bar disconnected, you would get no wheelspin but a horrible push.

I stand by my statement that the behavior you are seeing is not normal. I have run Hoosiers with the bar set on the 3rd hole from full soft on the identical bar to yours, and got zero wheelspin, not even close. I have also driven a setup AP1 with a solid bar that had inside wheelspin, so I do know what it feels like. Hopefully BK or someone who has run the same Kumhos as you will chime in.

If I were you, I'd go back and double check the function of everything in the front and rear swaybar assemblies. Disconnect the rear endlinks and make sure the bar is free to move in its bushings. If it is sticking, lube with some regular moly axle grease (NOT white lithium grease!). In the front, make sure that all links are connected securely and there is no evidence of endlink binding (chewed up aluminum top hat spacers etc.) Make sure you don't have a blown/leaky front shock. I dunno, just check everything. I hope you can get this figured out.

Peter

 

Vehicle Dynamics Assistant

Use that to troubleshoot your handling quirks.

 

Thanks for the suggestions. I took of the front and rear endlinks. Both bars rotate in the bushings fine.

Nuts; I was hoping that was the problem.