While at the track...

Friday afternoon. Exiting turn 7 at Lightning (NJMP). Drop to 2nd gear at just under 60 mph so i have some grunt. That means just under 6 grand on the tach. Heal/Toe, engage, smooth, nail it.

Holy $h1T!!! What's that blue/white cloud behind me? Did i just drop a motor?

Engine happy. No lights. Torque available. Apparently not. Reports of my death are greatly exaggerated.

A bit more smoke, car ran fine. Smoked again, lightly at restart later. Drove to dinner. Back to motel cheap, next morning, nothing. Oil level perfectly stable. Drive rest of track weekend without incident, although i also never downshifted into that corner again! Cost me seconds a lap. $H1T.

Consensus was (Wil DiGiovanni, Mike Carr, me, etc.) that the AOS was likely going. Watch oil. As noted, i watched a big nothing.

So....... is it? Or did something odd occur? Did Jupiter align with Mars as i exited turn 7?

Did a gremlin drop some WD40 into my intake? And vanish onto the wing of that plane from the Twilight Zone?

If it is the AOS, exactly how involved is this job? I know i can do it, but i'm rather busy at the moment, am blessed with good mechanics i can use, and don't want another "project".

What say the assembled gurus?

Grant

ps: Lightning is fun. Lots of elevation change. Evidence on youtube - search "SunR4" and "Lightning"



Edited 1 time(s). Last edit at 09/13/2011 10:15PM by grant. (view changes)

It sounds to me that you are going into to low of a gear and probably overreving the motor. Your should be exiting the corner at 4000 which is where the torque is ,at 6000 your almost on the rev limiter. If you are overeving you will get blue smoke coming out of the car. downshifting into to low a gear puts tremendous stress on the motor. Drive the track like you would drive on the highway,gradually increase your speed, you should be able to tell anyone which gear and the rpm you were turning in any corner.When I raced motor cycles my first year I rev ed the hell out of the bike, braked to hard to late, went sideways exiting corners and way to slow in the fast corners. Smooth is the key .My 3.2 pulls strong from 4000 to 6000 this is the rev range I would use.If you ever look at a dyno chart most motors drop off power if overreved. .With a dyno chart and some time you could probably calculate the perfect shift point for each gear. Shutting the throttle at high rpms will cause very high vacuum readings which will suck oil from where ever ,Aos ,valve guides or rings. Remember when you downshift hard the crank slow immediately and wave of slack develops in the cam chains. Lots of motors blow at the end of the straight. .I hope I haven't sounded like some kind of know it all its just I learned all this the expensive way

If i had over-revved, i would almost certainly have damaged valves.
revs were fine.

As to the proper gear, no way. Much more grunt at 6k in 2nd than 3.5k in 3rd. Not even close!
Remember a tranny is a torque multiplier. QED.

Grant

... The AOS can become overwhelmed and pass an extra squirt of oil.
That's why Porsche came up with the Motorsports AOS used on the GT3s and Cup Cars.
If the next few mornings the car started w/o smoke, all is well.
Happy Boxstering,
Pedro

Pedro Bonilla
1998 Boxster 986 - 311,000+ miles: [www.PedrosGarage.com]
PCA National Club Racing Scrutineer - PCA National HPDE Instructor - PCA Technical Committee (Boxster/Cayman)

---

Racecar spelled backwards is Racecar

"Racing is life. Anything before or after is just waiting" ... Steve McQueen as Michael Delaney in "LeMans"

"If you wait, all that happens is that you get older"... Mario Andretti

"Being second is to be the first of the ones who lose" ... Ayrton Senna

I have had this happen to me on the track. IIRC it has to do with the oil scavenge pump on the right bank of cylinders. It was happening to me fairly consistently at Road Atlanta between exiting turn 2 - slight left hander - and braking in to turn 3 - hard right hander. During braking, the oil surges to the front of the cylinder bank and the scavenge pump can't pump it all out, so some oil makes it through the AOS. I thought I had a problem too, but that is not the case, and I have not had to replace the AOS.

loved road Atlanta ,that turn up under the bridge has to be one of the all time scary turns, it looks like nothing but daylight .We found it triggers that mechanism in the brain that says " I cannot see where I'm going or whats ahead so I had better lift. Corner two at mosport is very much the same. Maybe the boxsters smoke when nervous

Turn 11 used to be much more scary before the changes to turn 10 (added a left - right 10A and 10. James Reeve (a formal SCCA D Production national champion) used to say that the old turn 11 was like driving into your garage at 100 MPH.

Sounds like i'm in no rush, but ought to install a Motorsports AOS thsi winter.

As usual, thanks Doc.

Grant

It does sound like the AOS and would be the likely candidate to be replaced.

Heavy braking before the downshift? that would certainly add to it if so.
BTW, the Motorsports AOS Pedro speaks of is about $700 --Link:
[www.suncoastparts.com]

I do plan on replacing it. But after reading the above, i'm in no particular hurry.

Alas being in 3rd at 3500 also kept me in no particular hurry as you can see for yourself!

(201bronco channel, youtube)

Grant

"Rasputin" until I went full screen! Btw what summit are you atop in that video?

Minus 40 degrees... Is that Fahrenheit or Celsius?

You also see my other ride (off roader), albeit without me on his back.

Jake 16 hands.

Minus 40 degrees... Is that Fahrenheit or Celsius?
Edited 1 time(s). Last edit at 09/15/2011 12:52PM by Laz. (view changes)

by the drastic change of weather as i went from 11,500 to 14,000 (note my cabin's driveway is 9800).

Its not the height so much as what those peaks do to clouds in the vicinity, and what lightning does to them.
Cold, lightly wet, and some electricity that i didn't like one bit.

Going up, for one with a touch of vertigo, was a little challenging. Oddly (well, not really), my knee tendons objected to the decent.
especially sorta helping tow others up and down, and being the pack mule for jackets, water, extra shirts, etc. Mr. Mom with hiking boots.

Got home and ate a huge meal at 4, another dinner at 7. A calorie is a unit of heat after all!

on another note, i dont know what feels faster: Jake at 25 mph or my boxster at 125 mph. The boxster certainly takes longer to get there!

Grant

Minus 40 degrees... Is that Fahrenheit or Celsius?