Eric - Plug Guy

Running through the mountain twisties this weekend, I noticed a couple times while pushing hard (not overdoing it, just good fun), that I was in full power mode in tight twisties, maybe 3rd gear, did not have a chance to 'see' the psi, and the power seemed to drop for a microsecond just a bit, then back on. Not total power drop, just very slight, almost as if you lifted slightly, then back on.

Not really sure what that was or if that would be common in tight cornering or other modes. Not sure if it has anything to do with blow off valves, pressures, altitude, etc. Was not alarming since it was a microsecond, but I noticed.

No other issues rest of the trip.

Anyone care to chime in?

Macster

You sure you didn't lift slightly? I know the few times I've taken my Turbo over some twisty mountain roads the car's so damn quick and unaffected by the steepness of the grade if climbing one of course and even at altitude not really impacted all that much by any significant loss of HP that I can find my speed at the next corner a bit higher than comfort dictates and I lift a bit. Going down a grade is complicated by the car's weight and momentum which of course is not shed as much even by lifting the throttle like it is going up the mountain.

Just a bit of a lift will cause boost to fall off some and this of course represented by the engine suffering a bit of a dip in power for an instant or two.

If you did not lift then the only thing I can think of is the engine controller detected incipient detonation and dialed back ignition timing which resulted in the brief drop off in power, not so much a drop off as a dip in power output but given the circumstances and timing feels like a drop off vs. just a brief dip.

At the point this occurred the engine could have experienced near max. boost and max. cylinder filling and this a good time for detonation to appear. At full throttle the engine controller can go open loop and feed more gasoline to increase the mixture's richness which helps to prevent detonation and of course help the engine meet the torque demand from the driver.

A very long shot is the E-Gas throttle is acting up. They can develop a temporary or even permanent dead spot which if you happen to hit it just so can cause the engine to cut out a bit cause the throttle begins to close a bit. I have never felt this from my Turbo but I have had this happen now once within the last couple of months when I'm driving my 02 Boxster (the one with nearly 240K miles). I suspect in the case of my Boxster the E-Gas pedal is wearing out. Try as I could though I was unable to reproduce the symptom so until I can I'm going to continue to drive it with the orignal E-Gas hardware.

Sincerely,

Macster.