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Old 07-31-2011, 02:06 PM   #5
Butler Cox
Join Date: Jul 2011
Posts: 7


Results with PV cap off: Low end was great, pulls like a trooper. Upper end goes through the 11,700 - 12,500 "dead - zone boggy like before except perhaps it pulls through slightly better/faster, but still ratty. Signal bore is as clean as can be determined with picks and lights, as is cleaned every 10-15 laps. Valve moves freely. Haven't yet put a camera in there, though.

I also noticed that with the cap off, performance was a bit cleaner at water temps between 140 (F) and 148. Above that to max 153 the dead-zone is wider and boggier.

When the cap is back on evey PRM range is just not as "snappy" no matter how many clicks, even with different springs (factory fresh).

Something else that bothers me and which is why I keep coming back to the PV: It doesn't give me the "extra-gear" kick at 7,500-8,000 *every* time. Sometimes it does, but mostly it doesn't, no matter what click setting. Doubly puzzling is that this occurs with a couple of different speced PVs from race karts that run well.

Also tried manually pushing shaft in and out while on track: When pushed in performance is logier from 5600-12,000 and motor wouldn't rev as easily through the "dead zone" as with the PV fully out.

Based on previous tests, with a ratio of 12/78-79, which is what puts my lap times where I'd like them (before the issue started), if I return to 12/78-79 (from the 12/83 where I'm testing), it will not pull through this dead-zone at all within the confinement of our straightaway lengths.

Everyone is still stumped. Hopefully we'll get a leak-down on it in a week or so, as well as get it on a dyno and see what these show.

I'll keep updating this THD as we go along, but it'll be a few days before I can get back to the track (Grand Junction Motor Speedway

Last edited by Butler Cox; 07-31-2011 at 02:24 PM.
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