Members Dustin M. Posted October 3, 2015 Members Share Posted October 3, 2015 I never ran this by Al, just throwing it up here as I've busted the 1 Oct deadline and it may be too late. We have tolerances for fuel pressure and ignition timing, I think we need to specify our tolerance for restrictor plates but I don't know what's reasonable. 3.11.1 Fuel Pressure Tolerance shall be +/- 2psi for EFI cars. Carbureted cars are not subject to a fuel pressure tolerance. 3.11.2 Timing tolerance shall be +/- 1 degree What do you guys think? Quote Link to comment Share on other sites More sharing options...
BADVENM Posted October 3, 2015 Share Posted October 3, 2015 Here is the rule currently: 7.21.4 All Cars may install a restrictor between the air filter and intake manifold to reduce horsepower and torque. The diameter and thickness of the restrictor plate orifice(s) shall be noted on the Dyno Sheet and must match at all times. Carbureted cars may install a mechanical throttle stop on the carburetor linkage for the same purpose. Throttle stop dimensions must be noted on the Dyno Sheet for inspection purposes and must match at all times. Quote Link to comment Share on other sites More sharing options...
Members Dustin M. Posted October 3, 2015 Author Members Share Posted October 3, 2015 Yes, but there's no +/-, I was thinking maybe .1mm? Just something to account for a different caliper being used to measure at the track vs in your garage. Quote Link to comment Share on other sites More sharing options...
Mach1 Posted October 3, 2015 Share Posted October 3, 2015 .1mm is pretty tight, i'd say .5mm Quote Link to comment Share on other sites More sharing options...
Members Dustin M. Posted October 3, 2015 Author Members Share Posted October 3, 2015 That may very well be the case if I'm reading the rules right, thanks to Glenn for pointing out the uber obvious. 3.11 Tolerances Unless otherwise specified, all published measurements infer a tolerance of +/- one-half of the last specified decimal place. All rounding will be done to the nearest decimal place that is specified in these rules. In a case where a measurement falls exactly on the halfway mark it shall be rounded up or down in favor of the competitor. 7.21.4 All Cars may install a restrictor between the air filter and intake manifold to reduce horsepower and torque. The diameter and thickness of the restrictor plate orifice(s) shall be noted on the Dyno Sheet and must match at all times. Carbureted cars may install a mechanical throttle stop on the carburetor linkage for the same purpose. Throttle stop dimensions must be noted on the Dyno Sheet for inspection purposes and must match at all times. Below from the dyno sheet: Restrictor size, # of orifices, diameters, thickness: The rules don't specify how accurately the restrictor plate's diameter must be annotated on the dyno sheet. If specifying within 1mm is OK, then I'm seeing a +/- .5mm tolerance which ought to be enough to account for variances in calipers. I've had this come up already and didn't know the answer, shame on me. Quote Link to comment Share on other sites More sharing options...
Mach1 Posted October 3, 2015 Share Posted October 3, 2015 On my sheet I just put "Medium" on the diameter, I hope thats ok! Quote Link to comment Share on other sites More sharing options...
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