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mooney265 mooney265 is offline
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Join Date: Sep 2008
Location: New Orleans
Posts: 1,365
Wastegate Pops w. Flame at High RPM Shift?

I took a couple of "parade" laps at a PCA event a couple weeks ago. I [and all the fans in turn one] noticed that my car consistantly popped and blew a good sized flame [2 feet] out of the wastegate at shift from 2nd to 3rd. This occured 5/5 times as I rounded this corner under acceleration... Usually at 5.5k RPM shift...

I have a digital AFR meter and run 10.5 AFRs under boost. I use an Andial fuel enrichement dial and am locked in at 1.0 bar of boost.

I'm thinking this is a result of rich fuel hitting the turbo and re-igniting then passing through the wastegate... Is this possible?

Or, is it rich fuel/exhaust hitting the hot exhaust headers and re-igniting then taking the shortest path through the wastegate?

Either way, should this "flame/pop" be happening? I've included a pic of my exhaust routing...

LIVN80S - - Red '79 Porsche 930 Steel Slant Nose Conversion [in 1987] w. 46k miles 3.3L; 964 Cams; K27HF @ 1.0 BAR, with Garrettson Intercooler; Rarly Zork; CIS Flowtech Fuel Head & BL-WUR.
Old 12-07-2008, 07:09 AM
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