Porsche-O-Phile

OK so I get the 951 I just bought all fixed up (alternator belt had snapped for those that missed it). I go out to check on a potential missing hose I noticed (one that goes to the "J" boot), figure it out, hook up the hose and I'm thinking, "hmmm. this would be a good time to shoot the car down to the car wash, give it a halfway decent cleaning, and then take it out on the freeway to see if it 'pulls' better due to the likely fixed vaccum leak I didn't realize I had before". So I go wash it off, get out on the highway and right as I'm getting onto the on-ramp I hear a dramatic change in the engine noise. It goes from the kind of quiet, whispery "whoosh" sound to a loud scream - kind of like a police siren sound. I play with throttle settings for a minute or two and check the gauges to try and figure out what's going on and if it's normal and eventually determine a relationship between boost level and the intensity of the noise. Not engine RPM necessarily, TURBO RPM. It's really scaring me. I brought it home and took a look for any obvious vaccum connections popped off or anything and don't see anything obviously amiss. Any ideas? I really don't want to even think that the turbocharger is somehow shot. . . The weird thing is how suddenly the noise came on and I had all these horrible pictures in my head of poor Eyal's grenaded turbo from a few months back when the hold-down nut went through it. I don't think that's the case; the engine doesn't sound bad or anything, but it doesn't feel "powerful" and still makes this infernal banshee-screaming / police siren noise. Someone please tell me this is something not too bad. . .

Eyal 951

sorry to tell you, but that sounds way to familiar... pull that j boot... didnt think youd be upgrading that turbo so fast did you? you have my help on the job, its a bitch, but not impossible.
~Eyal

Porsche-O-Phile

Uh oh.

So you think it's some sort of FOD?

Eyal 951

maybe, tell me what FOD is and I'll let you know if I think so or not!
~Eyal

Porsche-O-Phile

Sorry - FOD = Foreign Object Damage. Damn. What could have caused this? Isn't that what we have air cleaners for?

hosrom_951

As Eyal said, take off the boot and look inside for damage

Also, take off the IC pipe and inspect them for FOD.

Possible a vacuum leak (the bypass valve may have failed thus causing air to leak, thus wooshing noises).

hosrom_951

Does the turbo still boost to 1.7 bar (on the stock gauge) and pulls?

Any signs of smoke when boosting?

Porsche-O-Phile

It doesn't really go that high - it goes maybe to 1 or a little over; then again, that's about all I've ever seen it go to. No signs of smoke or anything. There wasn't like a "bang" noise that I'd expect from FOD, but I guess anything is possible. Cripes. I've only had this thing two days and I've had the engine apart once, probably soon to be again.

Someone tell me - why do I love these cars again?

Eyal 951

i think it sounds like the same situation as I. did you notice smoke at all? how about worry about it all night, dont get any sleep, then pull the j boot in the daylight and let me know!
~EYal

Porsche-O-Phile

I kind of wondered about the boost level; I posted somewhere before that the car feels "good" and peppy but it doesn't give you that kick-in-the-*** feeling that I've gotten in other 951s (granted they had mods, this one doesn't except for a test pipe).

Porsche-O-Phile

Arrrrgggghhh!!! I hate having to work. I suppose I can drive it to work tomorrow and worry about it tomorrow night. I see absolutely no signs of smoke anywhere - where might it be coming from? Turbo? Exhaust pipe?

Eyal 951

http://cgi.ebay.com/ws/eBayISAPI.dll...sPageName=WDVW

hosrom_951

Exhaust for signs of smoke.

You are saying that the gauge on the car NEVER gets to reach 1.7bar?

Eyal 951

if in fact it is FOD, then you really shouldnt drive it, i can just see those metal shards gashing your cylindar walls.
~Eyal

Porsche-O-Phile

Nope. Never seen it go there. I'm wondering if there aren't some oddball gauge indications though, since my voltmeter constantly shows above the max (i.e. 16v plus). I'm 99% sure this is NOT the case, since no fuses are blowing and the lights aren't insanely bright or anything. It's almost certainly the gauge.

As far as the turbo - man that's nice. I wish I hadn't just spent all my $$$ on this car!