. Bottom line is that the top 6 qualifying cars (from 4 different engine builders) were correctly Whistled at the SIC with the new procedure and all 6 failed.
There was no announcement of the change, nor did it appear in fastrack, as it is not a rule change, but rather a change to the test procedure. My recommendation is for everyone to have their engine's Whistled to the new procedure ASAP!
Three cars were whistled under protest. I was not there( nor was Dan) and not fair for me to comment on anything other than our entry. The engine in the Buras car( our engine) did NOT fail the whistler, nor was an RFA written on the car at any point. It whistled 10.0-10.1 with the valve cover removed, which is the limit when testing with the whistler on an 01 up car. With the valve cover on, it whistles 9.5-9.6, as do all compliant 01 up cars.
I agree with Dan, all should check their engines whistled with the valve cover off. I have found( as have all other engine builders) that those numbers mirror the actually cc numbers much closer ( IMO, exactly) the real compression ratio. It is fair to say that in the race to be competitive, all builders have pushed the boundaries... It starts with 'Hey Engine builder X , they whistled my car this weekend and it was only 9.2, WTF? They whistled Y and Z and they were 9.5... I want mine there as well. Whistling the cars with the valve covers off is the correct way to do this. I am confident all engine builders will make sure that their engines are compliant by both CC and by the whistler with valve cover removed(which IMO is the same number). All engine builders and competitors want to win and beat each other, I truly believe 99% want to beat each other fairly and compete under the same rules. This gray area with compression and valve covers made uncomfortable choices for all of us as racers and engine builders and needed to be corrected. This is/was an issue that needed to be resolved. I think it is safe to say that all engine builders ( myself included) will be checking all their engines to make sure they are compliant by CC and Whistler with no valve cover on. In the long term, this will be an improvement in the class and the rules which is what will all want.
With CRB hat on...
This inconsistency with valve covers is not a miata specific problem. It is a problem FOR ALL overhead valve cars with recessed spark plugs including the integras, hondas and most every other as well. It became apparent in SM as we are all so close, so many being built and tested and obviously I have first hand experience here. It is important to state the rule has NEVER changed, the RULE has always been your compression needs to be 9.0, 9.4, 9.5 or 10 or less depending the year of the car. The revised testing procedure does not state "the valve covers MUST be removed" it simply says it may be necessary in overhead valve cover vehicles. The Whistler procedure is a generic procedure for EVERY car tested in the SCCA, not a miata or Sm specific procedure. Perhaps a miata specific procedure should be written? Perhaps we should throw the whistler away as it seems apparent that yet again there were discrepancies in the results. I will say, as someone who has used the whistler many times, it is a VERY accurate tool. There is no good reason to get varying results. But the tool is only as accurate as the person calibrating and testing the car, just like every other tool. That is not to imply anyone did anything wrong, again, I was not there. Jim Creighton posts here, so perhaps he may clarify what happened?