Summit Point Main With Riesentoter PCA Event Recap

Published: October 18, 2015

I ran my 2000 supercharged Miata this event.

Tires

I ran on 225/45/15 Toyo RRs I just installed for this event on 9" wide wheels.

I also realigned the car for this event, primarily increasing front camber from -0.6-0.8 degrees to about -2 degrees and zeroing out front toe.

The car felt more composed on RRs compared to Maxxis RC-1 of the same size. I was taking it a bit easier in the only full session I had to avoid shocking the tires in their first heat cycle, but even so I felt the car more planted exiting corners under power. Mid corner grip was improved as well; this change I attribute largely to more negative camber in the front.

An interesting observation here is that section width of 225/45-15 Toyo RR is smaller than section with of 225/45-15 Maxxis RC-1. I discovered this accidentally by stacking tires one on top of another - in case of Toyos the wheels made contact, whereas with Maxxis tires the tires were making contact.

Brakes

I flushed the brake fluid for this event and surprisingly the pedal was softer than ever before, and going even softer as the session progressed. I was still running Raybestos ST-43 pads on stock rotors. Not sure what to do about the brakes, perhaps bleeding them again is in order.

As I came off the first session - which was not even that aggressive - the left front brakes were smoking a litle. Considering that ambient temperature was about 50 degrees, this was surprising.

Engine

Around the middle of the first session the car started making a howling noise in right hand turns that went away in left hand turns. I checked the front wheels and tires for rubbing after the session and came up with nothing.

In the second session the noise became more pronounced and eventually it started happening in left hand turns too, at which point I came off track. That's when I noticed what sounded like a mean misfire/exhaust leak. Idling in the paddock the car was very rough; I looked at OBD-2 codes and got P0103 for MAF sensor and P0303 for a misfire in #3 cylinder.

Eventually I found out that at least 3 of the spark plugs were loose in the head and the #3 spark plug had a piece missing. Compression check in #3 cylinder returned exactly zero. It was suggested to me that that means the spark plug piece made a hole through the cylinder. I have also been told that the spark plug had gotten very hot, which is believable considering the car overheated on me at the very first event I ran it - but that was two events ago and at the last event the car was fine. At this event the car was running hotter with time but I came off track with the temperature gauge in the 3/4 toward hot range.

Next on my list of things to do: figuring out what to do with my fleet of broken Miatas.