NSX-Tech:
I developed a problem rather quickly at a recent track event at VIR and I need some solid technical input on this as it is a hard problem to diagnose, or so it seems. First of all, the car is in very good shape and had just passed two technical inspections before going to VIR this past Friday. I am throwing in some facts here also, which are likely irrelevant, but it can't hurt. My car is a 92 NSX with Basch Supercharger, Comptech 6 Speed and 4.55 R&P and Dali Racing Sways, currently the rear is on but the standard NSX is on front. It has been this way for a couple years. Drivng the car on street and highway for the last couple weeks has been event free. Everything about the car feeling especially good. So I went to VIR (South Track for those who know it. In the first run of the day about four laps in I detected kind of a rump-rump-rump sound when cornering at speed, equal to the rotation of the tires. I pitted and hypothesized, drove around the paddocks and the skidpad, not able to tell anything was wrong. I could feel this in the steering column as well as hear it.
I thought carefully about it and then thought, this only happens when cornering or going around a curve to the left and when the front right tire is fully loaded. In the second run of the day (I only ran one cautious lap-to test this), I went in with this hypothesis and it proved true. On this course there are two semi connected left curves, one on a downhill pitch...and it was during these turns that I proved it to myself, that there is a problem when cornering to the left. Also, because of the lie of this track, I also proved that it is not braking dependent.
So I took my NSX to the dealer today, informing them that they would not be able to reproduce this symptom, but asked them to check what might be the problem in the front right wheel. They could find nothing wrong. They said that the air dam might be flapping against the tire and seemed loose, but that didn't hold true to me when I also felt the rump-rump-rumping in the steering wheel. There only other alternative was the front right wheel bearing (and they were very reluctant to offer this, since they couldn't be sure anything was wrong with it and it is a $600+ replacement) as a solution. So now I offer it up to you NSX Track tech guys. Based on my description and your experience, what could it be? What might it be? And the tire and brake appear fine, and are doing fine in spirited city/highway driving.
Thanks,
Bill Harpe
Durham, NC
I developed a problem rather quickly at a recent track event at VIR and I need some solid technical input on this as it is a hard problem to diagnose, or so it seems. First of all, the car is in very good shape and had just passed two technical inspections before going to VIR this past Friday. I am throwing in some facts here also, which are likely irrelevant, but it can't hurt. My car is a 92 NSX with Basch Supercharger, Comptech 6 Speed and 4.55 R&P and Dali Racing Sways, currently the rear is on but the standard NSX is on front. It has been this way for a couple years. Drivng the car on street and highway for the last couple weeks has been event free. Everything about the car feeling especially good. So I went to VIR (South Track for those who know it. In the first run of the day about four laps in I detected kind of a rump-rump-rump sound when cornering at speed, equal to the rotation of the tires. I pitted and hypothesized, drove around the paddocks and the skidpad, not able to tell anything was wrong. I could feel this in the steering column as well as hear it.
I thought carefully about it and then thought, this only happens when cornering or going around a curve to the left and when the front right tire is fully loaded. In the second run of the day (I only ran one cautious lap-to test this), I went in with this hypothesis and it proved true. On this course there are two semi connected left curves, one on a downhill pitch...and it was during these turns that I proved it to myself, that there is a problem when cornering to the left. Also, because of the lie of this track, I also proved that it is not braking dependent.
So I took my NSX to the dealer today, informing them that they would not be able to reproduce this symptom, but asked them to check what might be the problem in the front right wheel. They could find nothing wrong. They said that the air dam might be flapping against the tire and seemed loose, but that didn't hold true to me when I also felt the rump-rump-rumping in the steering wheel. There only other alternative was the front right wheel bearing (and they were very reluctant to offer this, since they couldn't be sure anything was wrong with it and it is a $600+ replacement) as a solution. So now I offer it up to you NSX Track tech guys. Based on my description and your experience, what could it be? What might it be? And the tire and brake appear fine, and are doing fine in spirited city/highway driving.
Thanks,
Bill Harpe
Durham, NC