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"Where's the Boost?"

Ok, so I知 tired of driving around in an 8:1 compression N/A 951, it's rather slow without the help of an...um, turbo.

I haven't tached up my motor high at all; shifting before 3K while it is broken (in fear of damaging the turbo.) My gauge builds to 1 bar, no more. The turbo is spinning; you can hear it very clearly. The clutch doesn't seem to be absorbing the turbo effect (no smell, and even if it was slipping the turbo would show boost I would think.) The waste gate lines are all plugged in, I made sure all my major connections are airtight (intake boot, IC pipes, hoses, vacuum lines).

What would happen if they cycling valve died? That痴 all I can think of.

Also, I知 not 100% sure about how the waste gate works. Is there a diaphragm inside that diverts the exhaust gases? If there is, does it wear out, and how easily is it replaced? And most importantly, how would it act if it DID wear out.

Does anyone have a clue?

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Old 10-17-2003, 07:53 PM
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I'm not absolutely sure, but I read in my Upfixin Der Porsche: When the knock sensor senses knock, it retards the timming, if there is just way too much knock, the KLM will go into a "default" mode to where it won't allow more than 1 or 1.1 bar of boost untill the damaged components can be replace, or better gas or whatever was causing the knock in the first place.
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Old 10-17-2003, 08:09 PM
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Are you at home? If so, call my cell, we are finishing up that motor swap - I can look at it too
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Old 10-17-2003, 09:08 PM
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If the cycling valve died, you should still have about .5 bar boost.

drew1
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Old 10-18-2003, 05:38 AM
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Re: "Where's the Boost?"

Quote:
Originally posted by perfecto951
Ok, so I知 tired of driving around in an 8:1 compression N/A 951, it's rather slow without the help of an...um, turbo.

I haven't tached up my motor high at all; shifting before 3K while it is broken (in fear of damaging the turbo.) My gauge builds to 1 bar, no more. The turbo is spinning; you can hear it very clearly. The clutch doesn't seem to be absorbing the turbo effect (no smell, and even if it was slipping the turbo would show boost I would think.) The waste gate lines are all plugged in, I made sure all my major connections are airtight (intake boot, IC pipes, hoses, vacuum lines).

What would happen if they cycling valve died? That痴 all I can think of.

Also, I知 not 100% sure about how the waste gate works. Is there a diaphragm inside that diverts the exhaust gases? If there is, does it wear out, and how easily is it replaced? And most importantly, how would it act if it DID wear out.

Does anyone have a clue?
I don't quite understand your post?

1. Is the turbo broken? Can you confirm this?
2. You don't take it past 3K rpm and have little or no boost? No kidding.
3. Are you having driveability issues? When did it start? Explain what happened?
4. Is the car completely stock?

FYI: The stock guage is a piece of junk.
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Old 10-18-2003, 08:44 AM
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i know the guage is junk, but i'm sure it's reading correctly. the turbo isn't broken. the 3K thing is just a precaution. the car is 100% stock. maybe if my KLR computer is just bugging out, i might pull the battery cable and see if it resets - it's worth a try.

i'm going to look at it tomorrow. i'll call you brad, it's going to be my only day off for a long, long time.
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Old 10-18-2003, 07:38 PM
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Also, how does the KLR sense knock? Is it a microphone like other cars? cause if it is, i think i know what is setting it off.
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1986 951, India Red. (Mine) - Not For Sale Anymore
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Old 10-18-2003, 07:42 PM
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Last time I only had 1 bar of boost, I removed the J-boot and stared at a destroyed compressor wheel. I left a bolt in the air box and foudn its way in and destroyed the blades.

Something to check.
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Old 10-18-2003, 08:20 PM
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The knock sensor is somewhat of vibration sensor between the 2 and 3 cyl. It's bolted to the block.
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my web site Torque values maintainance and repairs lots of my rebuild pics weights and measurements
'84 944 auto/ps/ac/cc
'86 951
Providing ignorance one post at a time.
Old 10-18-2003, 09:08 PM
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Metallic pinging (like for instance, a bad bearing in an AC compressor) can set off a knock sensor. (or any metallic ping within the frequency range of the sensor)

AFJuvat

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Old 10-18-2003, 09:19 PM
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